Model Engine Maker
Engines => From Plans => Topic started by: HobbyNut on April 03, 2013, 03:59:30 PM
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Hi, new to your board here, but I do recognize some other posters.
I am starting to build the Lister diesel that is being published in Model Engineer. It is by a fellow Aus. which is what interested me to start, as well as the fact that I had experience with them back 50 years or so.
If anyone is interested, I will post some pics here as I go.
Pat.
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Have at it Pat! Welcome!
Dave
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All I have to do is figure out how to post pics here!!!
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You either need to have the images hosted somewhere, the ones you have on ME will do just go into albums and click so the picture so it is not a thumbnail then right click, properties and copy the url. Then click the insert image icon (next to youtube) on here and paste ithe url between the ] and [
Or you can just add them straight from your computer as attachments, at the bottom of the box you post a reply in you will see " + Attachments and other options" should be self explainitary from there.
J
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Tried the attachments option Jason, and hit preview, and nothing appeared, so I may try the link method. Thanks for your help, both here and over there.
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The images won't show in preview, only at the bottom when the reply is posted. something like this, the large image is using the insert image, in this case from ME and the thumbnail from that image which I saved on my computer.
(http://www.model-engineer.co.uk/sites/7/images/member_albums/48448/423426.jpg)
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Ah, I see that you are clever with this stuff....I am still learning!
See if this turns out.
OK, it works.
This is the end plate for the crankcase. Waterjet cut from 2" MS plate.
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These are some more waterjet cut plates for the crankcase.
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All the pieces tacked together.
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I think you may need to resize the images a bit before adding them as attachments, when the thumb is clicked they come up too big and need scrolling to view. Try about 700 wide.
J
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It looks really good Pat :ThumbsUp:
Looking forward to seeing more of it.
Jo
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Fixed them Jason, thanks.
The pieces are slightly different to the plans around the cover plate. I may redo them.
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Wow! This is going to a fun build to watch. Nice plate work, Hob'. :ThumbsUp:
BC1
Jim
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Wow, indeed! I shall certainly be watching this one.
A full size 6/1 played a big part in my early life. I lost count of the number of times I had the head off for a de-coke . . . it was running way too light a load, and had about 10 feet of 2" water pipe for an exhaust.
Looking good so far :ThumbsUp:
Mike.
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Just so everybody is in the know.
I am building this from plans that are being serialized in ME.
It was originally built by George Punter. He used castings that he made himself. I am not so talented, so I decided to fabricate it entirely from "barstock" and sheet steel, aluminum and brass.
I am also building a Steam locomotive and a traction engine, both also from barstock.
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Hi Pat,
Looks great , one of those eye-openers about what can be done with something, in this case, the water jet cutting. That piece out of 2" plate especially so.
Hugh.
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Very nice. Are you going to run it in diesel mode? I have access to a waterjet cutter at the local Tech Shop that will cut up to 6" steel, but it is fairly expensive.
Chuck
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Very nice. Are you going to run it in diesel mode? I have access to a waterjet cutter at the local Tech Shop that will cut up to 6" steel, but it is fairly expensive.
Chuck
Yes it can be expensive. We cut 3,4,5 and 6" plate almost monthly. 1 job we do takes 16 hrs to cut 1 piece. We charge about $200.00 hr. depending on material, handling etc.
And yes, I do want to run it as a diesel.
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Now, after some re looking yesterday, I noticed I had made a few mistakes. So, I redrew, re-cut and rebuilt the case. I had made the front and back sides identical, whereas they should have been different, I had the relationship of the main brgs. and cam out by 1 mm, and the cover has only 4 bolts, I had many more.
This is what the case looked like after welding
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I then machined the base and top
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I made up the cover and fitted it, after machining the face of the flange.
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Then I tried to make it all look pretty. I still have to add the oil sump/filler thingy. Maybe tonight.
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Sorry about the grainy photos, it is my iPhone's fault!!!
I am cutting all the parts for the fabricated cylinder water jacket today. I may cut them from SS, 1/8" thick.
Here is a .pdf of the parts.
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Looking good, how are you going to tackle the writing on the access cover?
If I build the engihe I think the cylinder could be cut from solid with a circular water chamber, this would help keep the water away from the head stud holes so no chance of leakage.
J
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I'm digging it! I've pondered doing an engine block this way before...so I'm watching intently!
Dave
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Jason, a few years ago I was in Germany on business and wandered into a hobbyshop. I found a sheet of 6mm high letters in a type of plastic for model locomotives it said.
I have them, and tried them on for size last night, and I think they will work.
I'm thinking of putting "LISTA", Then adding Cultus Lake BC under that in 1.5mm letters, which I also have. Just to be different. This will not be a "full 100 point scale" model of a real Lister!
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Sounds like "slater's letters" which I did mention on ME. They should not get too hot on the crankcase so expect you will be OK.
https://slatersplastikard.com/assets/pdfs/AlphabetFlyer.pdf
J
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I'm digging it! I've pondered doing an engine block this way before...so I'm watching intently!
Dave
Dave, I spent 1/2 my life drawing up old castings, usually broken, and replicating them in steel fabrication. Most of it was for sawmill equipment that was designed and built in the 20's and 30's last century!!
I think that just about every cast item can be fabricated. Now that we have precision waterjet, laser and plasma cutting, along with TIG and laser welding.
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Sounds like "slater's letters" which I did mention on ME. They should not get too hot on the crankcase so expect you will be OK.
https://slatersplastikard.com/assets/pdfs/AlphabetFlyer.pdf
J
That's them Jason, the 1106 is the sheet I have. Maybe the others are 2mm. I would not expect the case will get hot enough to do anything. The motor won't be used for Industrial duty!!!
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I have a "white paper" done by Heald Machine on fabricating machine tool bases....from like the late 40's ....interesting reading.
Dave
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I made the cover look fancy.
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I also cut out and welded the waterjacket, cut the Alum shapes I need for the bearing housings etc. and machined up the cam bearing cover.
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Looks great from here Hobbynut!
Dave
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I made a .dxf of the con rod and cut it from 3/4" 6061 T6. Now onto machining.
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Looking good from here also, keep it up Hobbynut.
Don
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:cheers:
Thanks Don. I am also building an 0-4-0 5" gauge steam loco out of MEM. I work on either or both of an evening. I also do some other work on the race car team.
So now that spring/summer is here I will be busy!!
I ground the welds on the waterjacket last night, and also added a few doublers to it for cosmetics!
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:-\
Since my last post, I have had my car rear ended and written off. I have had to find new wheels, and have Dr.s visits etc. I am fine, and so now it is back to hobbies!
:)
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Sorry to hear about the mishap Pat, great to hear you are ok though. The wheels can be replaced. The project is coming along great and happy to hear you will be back in the shop soon.
Bill
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Glad to here you are OK Pat.
Don
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Go easy Pat....The metal and plastic is easy to replace....the flesh ...not so much
Be glad it's just metal and plastic...
Glad your here too!
Dave
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Pleased to hear you are ok.
As Dave said cars are replacable: Model Engineers are not.
Jo
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Thanks guys. I made an effort last night and line bored the case for the crank and cam. Now I can get onto the bearing housings and the crank and cam etc.
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Back at it last night. Cut the blank from some 100,000psi tensile 3/4" plate. Marked the 3 required centers on each end, center drilled and set in 4 jaw. Used the dial indicator to true with lathe in 2 planes.
Machined the crank pin, reset and machined the webs.
Will make a spacer and reset and machine shafts.
Pat.
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Finished off the lathe work last night, just have the keyways to cut now.
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OK, so I have progressed a little further on the bottom end of the Lister.
I machined up the alum bearing housings, made up the 2 bushings and trial fitted them all together, and they worked, even with the crank installed!
Please excuse the the lack of blow by blow pics, as most of what I have done so far is basic machining.
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That is looking great Pat, especially that last picture with the crankshaft installed. Nice ork on it to BTW.
Bill
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Thanks for the interest and feedback. I just work at it as time is available. Making these things is therapy for me!! I would spend all night in the shed if I could, but I get up at 5.00am to go to work...60 miles away! 5 days a week.
Tonight and tomorrow night is Sprint Car racing, so nothing new till Sunday night at earliest.
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I'd missed the news on the mishap. I'm glad to hear you're okay.
Following as best I can...but I'm following.
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Well I have been working on it bit by bit.
I machined up the Big End of the conrod, and machined the arm part, I am going to bush the little end. I assembled the rod to the crank just to see how everything fits.
I machined the water jacket, and faced the ends to length, and machined up the sleeve to fit. I used green loktite and a light press fit to hold them together.
I also started to machine up the governor housing, still have more to do.
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Pat I am just catching up on your latest posts and that is shaping up great. I like........ :ThumbsUp:
Don
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Just gotta love those assembly shots!! Its looking very nice Pat.
Bill
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Construction looks excellent. What does the injection system look like? I saw the video on youtube, but it seemed to knock severly. Did they get it running without ether in the fuel? I'm dreaming up an injection system but seeing other designs is always interesting.
If I wanted plans of the Lister do I just buy the issues or are plans available?
Greg
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That really is looking great Pat!....I'll need to renew my subscription to ME....
Dave
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I have the Digital subscription to ME. It is cheap(!) and you get all the issues online every 2 weeks. DIESEL, the injection appears to be a copy of the real stuff.
:cheers: Thanks guys for the well wishes, I am having a great time building this and my Emma Victoria 5" gauge 0-4-0 loco.
I feel my ability to do A grade exhibition quality machining is lacking, but I am getting better at it, thanks in part from what I am seeing on here.
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Did some more work last night, I drilled and tapped the bearing housings and made sure all of it tightens up and the crank still turns. They do and it does! :cartwheel:
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Sorry about this rather grainy pic of the assembly so far.
I just retook the pic at work here, it is much better.
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Good going Pat :ThumbsUp:
Kind regards, Arnold
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That's outstanding Pat, looks much better than a casting.
Hugh.
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:) Had the time to do some more machining on the weekend.
Made up a piston and gudgeon pin, finished off the governor housing and fitted it. Did some more finishing to the water jacket and put some primer on it.
I have started on making the camshaft in 1 piece, instead of a shaft with the 2 cam assembly slid on. Wish me luck!
Yes, I know I do not have the valve cavities in the piston yet.
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That looks nice Pat. Good going.
Vince
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No I haven't passed away or anything. I have been busy with grandkids and race car repairs and racing. i have done a few things and will post more pics soon.
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I decided to paint a few bits to see what they would look like. The green is too dark so I will redo it.
The cam is a 1 piece affair that I hand ground to shape, using the pattern at the lower right in the pic. It is now finished and appears to be "on spec". The flywheels are being fabricated, as you can see in the parts pic.I made some gears from aluminum to set up the cam drive and idler. it was a bigger pain than I had bargained for, but it seems to work OK now. I will take more pics of the gears in place. The head in the pic is not the one that I will be using. I am redrawing it with the valves and seats in "cages" that will be fitted to the head, which I will make from aluminum. You may note a valve in the pic, and a 1/4" Titanium bolt beside it. I machined a bolt to make the valve, and it appears to work, so the Lister will have Ti. valves!
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Ah....there is the valve...i didn't see it in the first two pics...looks good!!
Bill
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Yes, I forgot to upload the photo at first posting, sorry!
That valve is lightweight!
I finished off the cam gear train installation last night. The idler gear is a task to get happy.
Have not set the cam gear yet onto the camshaft permanently.
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How do you plan on setting it Pat?
Bill
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Locktite green I think....maybe a pin too. The cam timing setting, according to the text in ME, is " set crank at TDC, and cam so that both valves are just opening and closing on overlap" I am not sure if this is possible! 1 opening and 1 closing maybe.... I think I can figure it out from the valve events.
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I think pinning is a good idea as well as the loctite. I did have a bad experience using loctite alone once.
Bill
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Maybe someone is interested in the .dxf drawing that I am creating as I go to check how everything goes together.
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I made the cam followers and guides and installed them.
I have started machining the Aluminum head.
(http://)
And I chucked a piece of 1 1/4dia. cast iron bar and machined up 6 rings. You may notice 2 already on the piston.
(http://)
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I think pinning is a good idea as well as the loctite. I did have a bad experience using loctits alone once.
Bill
>:D loctits alone once :censored: I'll bet there was trouble :mischief:
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Made some more progress on this Project.
I made up a valve guide and seat combo from bronze and fitted them to the head. I also drilled most of the ports and holes in the head.
After fitting the seat/guide sleeve, I machined the head recess to 1.5mm deep in the 4 jaw.
I made a copper gasket also for it.
As you can see I set it up in the lathe for some running in.
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Took a movie of the cam followers too.
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Nice work Pat, I tried to open your video but couldn't get it to start. I have been following along quietly.
Don
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They should open with Quick Time player
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Almost felt like I had won a small lottery last night. After about 15 hrs of work, and very few pics :( I had myself a working oil pump. I completely wrecked one piece that I had silver soldered together. I will now attempt to make a fuel injector pump.
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Well here is last nights work.
I took a piece of brass about 1 1/8" in dia and ste it in the 4 jaw and machined the main barrel ends to 11mm dia.
The milling machine was then used to hack off the extra material to make it approx. how it should look. no special fixtures, just a machine vise and a 3/8"dia endmill.
The result was then placed back in the 4 jaw for some more finesse.
A Dremel and files were used to rough it out more, then a piece was soft soldered on the side for the fuel inlet fitting.
Now comes the fun parts, all the inlet and outlet balls etc.
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Machined up more fuel injection pieces.
I finished off the pump housing and parts except for the piston, then I started in on the injector.
The ME drawing mistakes are too numerous to mention, but if anybody was to ask me, I could give them all the inconsistencies. I have attached a pic of the assembled pump, sitting on a ME page that shows a drawing of the assembly with the fuel inlet at 180d to the adjuster screw. All Georges photos show it at 90d. as does another assembly dwg. in ME, on another date. Anyway, here are a few pics of my weekends work. I did much more, but those pics will have to wait.
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Next issue is supposed to have some additional drawings of the injector and some text to explain it better, well thats what it says anyway!!
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Sure Jason!!!!!
Have a look at the inlet and outlet fittings for the oil pump....see if they make sense.
The injector too, the top has a spigot on the mating face, the bottom does not have a recess for it.
I have just been redesigning, making do as I go, making sure that it fits and works.
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This is a poor pic of what it looks like today
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That's looking really good Pat! :ThumbsUp:
David D
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That's comming along nicely :ThumbsUp:
Dave
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I think it looks amazing Pat. I look back to the first page of this thread where you were just beginning to weld up the crankcase and at where it is now. Its really some impressive progress I think!!
Bill
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Thanks for the kudos, I just keep plugging along a few hours a night here and there. The pipes are not finished yet, as the fuel pump and the injector still need a few parts internally.
I am oiling the main bearings from the outside, which is not how George did it. I am not sure how he did it as there has been no mention in ME.
I am also not putting in the governor that George designed, as he said it didn't really do any governing on his engine, so I am thinking of putting some weights on a flywheel and making a linkage that just lifts the exhaust valve, as there is a valve lifter there. Maybe combined with a fuel shutoff so that it doesn't "flood" during the off revolutions.
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The fuel pump is an interesting piece of work, more like sculpture than machining ;) Thanks for sharing the process, makes it easier to see how other problems can be solved.
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I roughed out a flywheel last night, makes it easier to rotate the crank and check things. It requires more welding and some finessing, but they should be OK.
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Interesting construction. Do you think that's easier than machining from solid?
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Interesting construction. Do you think that's easier than machining from solid?
In my business yes. Waterjet cut the pieces, TIG them together and machine, file the spokes, prime sand and paint...well thats what I am striving for!!!
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Finished off the parts for the injector. I have to devise a way of checking its operation. A little different to a spark plug....I know how to check those!!!
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Spent last night making up a bunch of fittings. I am using some PM Research castings in 3/16 and 1/4 sizes. They come all cast together on a sprue, all you have to do is cut them apart and machine and drill and tap them.
They are well made quality items that machine well. I made up the Tee for the intake and added a piece of 1/4" brass pipe. The extra opening in the Tee I thought may be handy for ease of access to the inlet tract to clear excess fuel or to add starter fluid etc.
I used an elbow on the exhaust, also with a 1 1/4" long piece of 1/4 brass pipe.
I took some 5/16 brass hex bar and machined up the water cooling inlet and outlet hose nipples.
3/8" brass hex was used to make the Oil Sump plug.
All the threads are 1/4-40 except the sump plug which was 5/16-32.
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Started on the fuel tank and mounting brackets. The brackets are from 1/4" Alum. waterjet cut to shape.
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Yesterday at work, I drew up some rocker profiles, then also a section. I figured if I cut them "in section" from 3/8" plate, I could profile them from the side. I did this, then I milled up a "eyeball scale" rocker mounting block, which I drilled, reamed and slit to mount the rockers onto the head. It appears to have worked out.
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Nice work Pat!
Having the water jet at your disposal sure has made parts of this project easier for you.
The parts seem to be dark in color; is this just natural oxide formation of have they been treated in something?
Also just curious do you have any idea what pressure the injection system will run at; or what would be the target pressure for the injector to crack open?
Dave
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Nice work Pat!
Having the water jet at your disposal sure has made parts of this project easier for you.
It sure has!!!!
The parts seem to be dark in color; is this just natural oxide formation of have they been treated in something?
Just happens to be the way it looks.
Also just curious do you have any idea what pressure the injection system will run at; or what would be the target pressure for the injector to crack open?
Dave
Dave, I have no idea at all. The original designer has not made any indication of what he had for pressure. The pump is .188 bore x about .250 stroke. The jet is a #80 drill. So I have a volume of .007 cu.in. trying to get thru a .0135" dia hole. Now if I multiply the volume x 30 =.42 cu.ins/min flow. P=f/a and the Lister manual says 1350 psi, I think I saw somewhere. I do not know what pressure my pump is capable of . George Punter, the original builder, was having trouble with too much fuel I think. Time will tell. I am only using a ball point pen spring in the injector. I am going to try and test that function this weekend.
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Still following you quietly Pat and admiring your work.
Vince
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Had a late night last night. I had decided that the time had come to make another Ti. valve, and fit both of them. I did get that done, then I put it all together, and checked it out.
The spring retainers are made from drill rod. I am having an issue with 1 valve not seating, but more lapping should fix the problem.
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Still following you quietly Pat and admiring your work.
Vince
Thanks Vince, I check on your build too. I wish I had more time to spend in the shed!!! I have many projects on the go,(just ask my wife!) I had too much fun with my kids in my younger years to think about retirement days, so its hi ho, hi ho, off to work I go.
The pic below, shows just 3 of my hobbies, the motored bike is 1 of 7 motor cycles that I play with, the dark mass in the background is a 1930 Ford Cabriolet with a 400 Chevy, and the Lister. What you can't see is the 5" G Emma Loco, the freestyle steam traction engine, my RC Helicopters from the 90's and my "honey do" list. :shrug:
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Hi Pat,
Not had much to say but this is a wonderful model of the engine. :ThumbsUp:
Our SA Steam Tug Yelta has a similar Lister engine as its' generator. I rebuilt it about 8 years ago. That particular engine has a pre WWII head and valves with sufficient stem length were unobtainable. One of my volunteers was into vintage cars and he took me to this beat up old shed on the outskirts of Adelaide in which was the most amazing collection of antique engine valves. For the princely sum of $10 I came away with 2, 1938 Chevrolet valves which had the correct stem length. A bit of work on their heads and voila. The factory supplied valves with the wrong stem were $250 and a refund obtained.
Best Regards
Bob
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Ah yes Bob, those old stovebolts had a lot of parts that you could use on something else!! I had a 1930 Chev. touring back in '65. I used drive it to work as an apprentice at the Copper Refinery in Townsville QLD.
I am liking the Lister build, except for the fuel injection, it will be the ultimate test of my patience and machining skills.
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I have been messing with the valve timing, and cranking it with a drill, and I have had it firing with a wiff of starter fluid. The fuel pump has been problematical, but with some investigation I found that the piston needed to be .040 longer. I made a new one, lapped it in, and the pump now works.
I will be building a new injector though, as I think my first attempt is not precise enough. I have been given a good suggestion/idea from a guy in ME that I am going to try.
I have another flywheel to fab and machine, finish both the flywheels, the injector, some plumbing, the muffler and the air "filter " to make and its done.
Then comes the running.....
A latest pic, last night after paint, for you all.
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That paint job is great. Really looking like the real thing.
Vince
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It's actually a real one, NOS. Hugh.
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Love the paint job too...anxious now to see it run. Its been fun following along!!
Bill
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That is certainly looking Awesome!.....Can't wait for the next step!
Dave
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Looking good Pat!
And it is encouraging that it is showing signs of life :ThumbsUp:
Keep us posted on your progress.
Dave
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Well, I have spent lots of time on this engine in the last few days. I got the pump working, modified the injector, made up a fuel line from the tank and tried it out. The injector does work, but fuel comes out of the overflow drain as well. The engine still will fire sporadically, but not twice in a row. I spent about 4 hours trying many things, rechecked valve timing, pump timing, valve sealing, head gasket, etc,etc.
I am going to completely strip it and check things over again.
I am using diesel with 30% ether as the fuel.
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Might want to try upping the ether content....small engines like this will conduct heat away very quickly....when the piston comes up on compression...the compression heat will come out of the chamber very fast....If it were me....I'd up it.
Additionally, considering this is fairly unchartered territory model wise ( injected compression ignition)....I know there is a guy in I think New Zealand who makes really nice injected diesel models....might want to talk to him....
I'll find his web site....
Dave
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Nope....Denmark.
http://www.findsminimodelhotbulbengines.dk/
The man's name is Find Hansen.
He has 3 true diesels besides a bunch of hot bulb.
Dave
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Reading his web site....he only mixes a small percentage of mineral oil in with the kerosene. so NO ether.
:shrug:
Dave
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The "biggest" thing I get out of his site is the CR......20:1 minimum according to him. I think that is my problem. I may get it to run if I preheated it quite a bit.
I will make a thinner head gasket, and new rings.
Back to the garage!!
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That is high...and the injection pump needs to be higher than that to pump appropriate amounts of fuel in....
Dave
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Find Hansen isn't telling anybody how he solved the problems, so you better look elsewhere :
Strictly IC had a series on the DUX 9.5 cc diesel engine in issue 78 (introduction), 79-82 contruction, 80 cylinderhead, 81 injector + Glowplug, 82 Swirl camber in cylinderhead + injector pump + speed control. There are other parts made in those issues, but those are the important for making it run.
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I do not have all the SIC mags unfortunately. I have sent an email to George asking him a few questions.
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I have been watching this with interest. It is a good looking engine. I wonder if your drill motor will be able to run it up to speed at 20:1 CR. Does the engine have compression release for starting?
Jerry
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Yes it has a valve lifter, I have not had any trouble with the drill yet. It is a 1/2" 2 speed Bosch hammerdrill/drill.
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Does anyone have the above mentioned strictly IC mags for sale or loan? I have all of them to Issue 65. ::)
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I may be able to help you out hobby, either send me a Email or add me in Skype :ThumbsUp:
pete
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I have been watching this with interest. It is a good looking engine. I wonder if your drill motor will be able to run it up to speed at 20:1 CR. Does the engine have compression release for starting?
Jerry
Jerry here is the lifter
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Here it is in in its latest condition.
The fuel pump was modified, the piping was all cleaned up and connected. (Many small compression fittings later!!) The breather was machined and silver soldered, the air inlet was completed, and I machined up a solid hunk of alum. for the valve cover.
Unfortunately the injector does not work for me yet, I am having a lot of trouble sealing it.
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What kind of pressure does your pump put out Pat?
Dave
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Dave, I have no idea. I know that it is sufficient to pump fuel everywhere! I have not tied to measure the pressure.
I have to fit a seal to the u/s of the piston, as fuel will make its way past the piston and into the crankcase.
With the new pump arrangement and bleeder, I can control the volume of fuel to the injector. The injector is 2 piece, with some very small ports that align, and I cannot get these 2 faces to seal. I have lapped them a few times, but once installed, they leak.
A thought that I had late last night as I was milling/hogging the valve cover, was that my making the head from Alum. may be causing a big headache! When cranking it by drill, the head and exhaust do get warm, but I wonder if the alum drains away too much heat.... anyone with thoughts on that?
Here are some more pics of my progress in the past few days.
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What I do know....is that Detroit Diesel Fuel injector pumps are held to 33 millionths clearance.....if you a plunger in your hand for a few seconds...it won't go in the barrel.
Just make sure you have the volume and the fit....and I'd fix it up with a gage at some point to gauge the pressue created while running through the injector.
Dave
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I have been following this build as one of my future plans is to build 20cc two stroke diesel loosely based on the Petter Atomic range.
I will list my design thoughts as some may help in getting your engine to run.
Reading literature on full sized engines it appears that a direct injection engine will a bore of more than 100mm will cold start with a compression ratio of around 14-1. If the cylinder is smaller or a separate combustion chamber is used, both of which increase heat loss, a ratio of 20-1 or more and/or starting aids (glow plugs etc.) will be required. From this I was going to aim for a compression ratio of 25-1 and as compact as possible combustion chamber.
A bore of 25mm and a stroke of 40mm looked possible with my current lathe giving around 20 cc. for 25-1 compression the chamber would be cylindrical 10 mm diameter and 10 mm long (actually a bit smaller to allow for some piston clearance). The fuel injector would have to fit with this. I chose two stroke as I felt that getting this compression ratio with a compact combustion chamber and clearance spaces for the valves would be beyond my current skills.
The density of air is around 1.2kg/m3 so 20 cc of air is around 0.024g. Taking a fuel air ration of 14-1 this would require 0.0017g of diesel fuel. The density of diesel fuel is around 0.8kg /dm3 so at full output around 2mm3 of fuel would be required. This could be achieved with a plunger of 2mm diameter and a stroke of 1.5mm (plus a bit to allow for leakage).
The theoretical compression pressure would be 25 Bar. To get a good fuel air mix I guess that the fuel pressure should be at least twice this, say 50 Bar. If the injector needle has a diameter of 1.5 mm this would require a spring load of 900g or 9N. Looking at commercial springs this seems to suggest a wire diameter of ~0.6mm for an outside diameter of 5mm .
Please double check my calculations before using the data. I will certainly redo them before I cut any metal.
Keep up the good work and I wish you every success. :ThumbsUp: :ThumbsUp:
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That would all seem logical Roger. I would think an adjustable injector volume might be advantageous to compensate for Stoichiometric variation, injector leakage, cylinder blow down....ect.
This is a tough problem!....little plunger pumps that run at these pressures are not easy to build. I have got to think an O ring on the plunger would be a must.....but am willing to be proven wrong... 8)
Keep at it Pat....We're pulling for ya!
Dave
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Thanks guys, I do intend to stay at it. I am making another head, from steel. I have a "bad vibe" about the alum one. I also intend to do away with the contra piston style pre combustion chamber and just put a 1/2 sphere combustion chamber in the head face. I also intend to put a glow plug into this chamber from the side of the head. There is lots of room for it.
Thanks to some good people on here, I have been sent some info on the DUX injector, and I am planning on using that basic design, maybe utilizing a tapered pin with a "score" down 1 side, and some form of clamping screw to keep it in, and a banjo fitting to supply fuel.
I will make a drawing and post a pdf for comments.
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This is what I intend.
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These are the thoughts I had for injectors. The left hand one had a groove down the side of the needle, on the right hand one the end of the needle was turned down to 0.5mm.
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The Dutch guy in SIC (can't remember his name) calculated that the injector orifice in a 10 cc diesel engine should be 0.07 mm in diameter :o
He solved that by making a scratch with a needle at the pointed end of the rod inside the injector.
ps what happened to the spellcheck funktion :'(
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Tell me more about the fuel. I think you said diesel fuel and 30% ether. Can they be mixed? I have only seen ether used as a starting aid by being sprayed into the air intake and only if the factory engineer was not watching. Does the ether stay in solution or does it boil off or gas out in the fuel lines between pump and injector? If it is gassing out, I wonder if you can get enough pressure to the injector.
Do you have a procedure to bleed all of the air out of the system between pump and injector?
If you do not have a governor that will manage the pressure/volume of fuel supplied to the injector, how will you control the engine speed. There are a lot of things that I have never seen but I have never seen a diesel run as a hit or miss engine. I would not think that your flywheel is big enough carry through a missed cycle.
I'm just noodling some thoughts here. I would really like to see this run.
Jerry
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Jerry, the video of the Dutch DUX running, he has a lever that basically decompresses the exhaust valve and the engine just runs slower, until he depresses it too much and it stops. He also can control speed by varying volume, and by advancing and retarding the pump timing. He has all of those built into his system. Pretty impressive.
There is another flywheel to be fitted also. I just have not got around to putting it together, as I wished to put a swing weight governor on it.
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"the injector orifice in a 10 cc diesel engine should be 0.07 mm in diameter" That sounds sensible. A full size engine (500 cc per cylinder+) will have a few holes in the 0.2-0.5 mm range.
What you are trying to achieve is very good atomisation of the fuel so that the droplets will be small enough to quickly reach ignition temperature. I was going to attempt this by limiting the lift of the needle to produce a very fine annulus. The fuel should be emitted as a mist rather than a jet. What does your spray look like with the injector out of the head?
Dave, I was intending to vary the pump stroke but this requires a little more thought on my behalf so I can vary the delivered volume without affecting the timing of the start of injection. It works differently depending on wether you have an open inlet port as in full size practise or an inlet valve.
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I work in imperial, and .07mm = .0028" = hair dia!!
I am thinking now that I will just scratch the side of the plunger with the sharp end of a Tungsten from my TIG. welder.
I cannot see how a spring loaded injector would make any sense in an engine this small. It looked like George got his to "work", but now I am having doubts.
My spray looked more like droplets. But I have a #80 drilled hole.= .0135 or .343mm about 6x what is needed. And I have had trouble sealing the 2 halves of the injector, so there has been leakage of pressure, and volume.
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My understanding is that by having a spring loaded needle you are restricting the size of the orifice at the end of the injector. When the fuel pressure is below the spring pressure nothing comes out (assuming a good seating). When the fuel pressure rises to the level of the spring pressure the needle will open just enough to let the pressure drop to below the opening pressure. As the pump keeps feeding fuel the needle lifts just enough to balance the flow. The needle lift may be a few 100th of a mm giving the small gap needed to atomise the fuel.
I fully appreciate the problems in doing this at the design stage, let alone actually making a system leak free enough to work. From my experience with full size engines, mostly old narrow gauge railway locomotives, after compression pressure the action/condition of the injectors was critical to starting.
You are much further down the build than me and as ever I wish you every success :)
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This is the "injector" that I have settled on(for now!).. It is of the DUX design, using the scratch as the orifice.
I hope to rebuild the pump with a new piston, a seal and maybe a stroke change. The DUX uses a very "abrupt" cam for operation.
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Now that the injector is mostly done, I am starting on a new pump. This time it is from silver steel, with a tool steel plunger. Once again I am using the "DUX" as a sample.
I wish myself luck!! :wallbang:
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Give it hell Pat!
Dave
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The rest of us are certainly hoping for success too :ThumbsUp:
And I'm well aware of the fact that you're set yourself quite a challenge => big satisfaction when you get it to run :)
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Thanks for the support!!!
May not get much done this week, as we have to rebuild our race car for the year end race this Sat. night. just picking up the frame from repairs today.
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Hi Pat
Good look with the new pump; I'm pulling for you.
I wanted to send a couple pictures of the pump and injector for my long term Diesel project; it is a 1933 Deutz MAH about 5 or 6 hp.
Years ago I rebuilt the pump which had suffered internal water damage. New inlet and outlet check valves were made hardened and lapped; also a new plunger and bushing were made. I ground the plunger with my tool post grinder and lapped the bushing.
Pictured is the quick and dirty test stand I made to check things out; a gage was added between the pump and injector. I'm wondering if a setup similar to this would be beneficial to you during your debugging phase?
I was very happy with my work; with the injector removed and the discharge line plugged the pump will easily put out 5K psi. With the injector in place it cracks open at around 2K and sprays a nice fog. I showed this to a Deutz mechanic who works on the modern ones and he told me that set up will run the engine no problem.
The engine still needs a lot of work before I will be able to try out the rebuilt fuel system.
I have been enjoying your build and I'm sure you will get the bugs worked out and we will get to see a video of it running.
Dave
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:noidea:
I have been :wallbang: because the volume I am trying to put into the injector is way beyond the capacity. I have a 3/16" dia piston x 2mm stroke. By my calcs. this is about 36cu.mm per stroke. Now, if all I need is 2cu.mm per stroke, I have big problems. George Punter has 4mm dia. piston x 2mm stroke which is 3.1416 x (2x2) x 2 = 25 cu.mm.
So, if all this is "true", I have to cut the stroke to almost nothing, or the bore to almost nothing.
Back to the lathe I guess. or :DrinkPint:
I think I need a smaller lathe and/or stronger glasses!!!!
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:noidea:
I have been :wallbang: because the volume I am trying to put into the injector is way beyond the capacity. I have a 3/16" dia piston x 2mm stroke. By my calcs. this is about 36cu.mm per stroke. Now, if all I need is 2cu.mm per stroke, I have big problems. George Punter has 4mm dia. piston x 2mm stroke which is 3.1416 x (2x2) x 2 = 25 cu.mm.
So, if all this is "true", I have to cut the stroke to almost nothing, or the bore to almost nothing.
Back to the lathe I guess. or :DrinkPint:
I think I need a smaller lathe and/or stronger glasses!!!!
What's the possibility of engineering a by pass circuit for the surplus fuel ?.
Stew
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You are very unlikely to get 100% efficiency from the pump so won't be delivering anything like the swept volume.
J
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You are very unlikely to get 100% efficiency from the pump so won't be delivering anything like the swept volume.
J
Well thats what I figured too Jason, I think I will end up with a 3mm dia (1/8") piston, the stroke will be what it is, 2mm.
The pump that George Punter built, and is detailed(?!) in ME, has a bypass with a needle valve, but the only way I could get anything to the injector was to turn it off completely. It is in the pressure section of the pump, so it gets = pressure as the injector. So, if the opening in the valve is greater than the injector all the fuel returns to the tank, IMO, and by observation.
The "DUX" design does not have such a thing, he just lifts the piston off the cam to vary the stroke.
Jason, have you seen the "DUX" pump dwg.? and /or read his description of operation?
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Not for a long time, do you know what issue of SIC it is in and I'll take a look again.
J
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Not for a long time, do you know what issue of SIC it is in and I'll take a look again.
J
Jason, Issues 78 to 82. (2000-2001)
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There is more than one way to atomize the fuel. If you have enough distance, the fuel jet can impinge on the air in the cylinder. In a bore this small that probably won't be efficient but it may still result in a running engine. It's said that a diesel injection system needs 150-200 bar to function well. The pressure and the orifice size together determine the velocity of the fuel as it's injected into the cylinder. Too large an orifice, low pressure and the fuel dribbles. The Dux does vary injection volume rather simply with a wedge between the pump cam and pump plunger.
I too have been working on a model diesel injection design mostly in my head. At this point I hadn't found a solution that is much better than what Martin Alewijn designed for the injector. I understand some early diesel engines did use a simple orifice injector. You can buy drills down to .002", but I'm not sure if my spindle would be good enough to use it without breaking the drill.
DUX pump is Ø3mm and 4mm stroke, but who knows how much stroke is really used in operation. The pump is in #82.
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Yes, he has an explanation of how "vacuum" in the pump pulls fuel from the delivery pipe, even when it is covered by the piston.... Not sure how that works, and nor is he, but he says it does work.
That is why I intend to try his design, adapted to the Lister.
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Yes, he has an explanation of how "vacuum" in the pump pulls fuel from the delivery pipe.
That implies there is no delivery valve so what keeps the system charged for the next injection? Very interesting bringing this down to model sizes I'm following along quietly and so far I'm gobsmacked at what's been achieved.
Best Regards
Bob
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I would guess the fork in the plunger actually bends to let fuel in, but it seems this would fail sooner or later.
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That implies there is no delivery valve so what keeps the system charged for the next injection? Very interesting bringing this down to model sizes I'm following along quietly and so far I'm gobsmacked at what's been achieved.
Best Regards
Bob
Bob, there is a delivery valve, a spring loaded ball, but there is no inlet ball valve. The cutoff to the inlet is by the piston blocking it. in other words, the inlet is at the very bottom of the stroke, so that when the piston moves up the dia of the inlet, it cuts off fuel flow.
What is "weird science" is that he varies the piston stroke, and the inlet never gets fully or even partly opened.
Dieselp.., the piston is actually "suspended" on a spring steel rod. It is connected to the base of the piston rod, and the pump mount, with a L of about 25mm I think. I don't have the dwg here at the moment.
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The plunger in the Dux has a slot cut in the top. The same feature he describes as sealing the inlet port on the upstroke likely causes it to leak on the downstroke.
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The plunger in the Dux has a slot cut in the top. The same feature he describes as sealing the inlet port on the upstroke likely causes it to leak on the downstroke.
Maybe, but his text states that the split is to help seal the inlet, and the plunger has to be held so that the slit does not line up with the inlet. He has a locating device to hold it. He states that the slit in the top, and spreading the plunger open, helps to seal the plunger. I cant see how myself, as the plunger/piston would then be oval at the top, and be a SOB to get in the barrel. I am not attempting that, especially in a 4mm dia piece of drill rod.
BTW, I worked on my pump last night, left it at 4.8mm dia. but shortened the stroke to 1.6mm, added a spring loaded ball valve to the outlet, deleted the bleed off valve, and will be making a new ball valve for the inlet.
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When you see the print's you'll understand, but this is what it looks like.
Greg
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That is exactly how I see it Greg. The split tho' always remains as it is there, 90d to the inlet hole.
SIC Issue 82 page 30/47 top right is a drawing and a explanation.
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When the pressure rises on the upstroke, the "blades" in the plunger are pushed outward, well at least the one with the low pressure hole behind it. And when the spring returns it, I'm guessing the blade bends inward just enough to allow fuel to flow from the fuel feed port. I don't see anything mystical. This might not work if the slit in the top of the plunger wasn't present. Could the pressure be low enough to cause the fuel to boil? I suppose.
Greg
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A bit too mystic for me.. :help:
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I'm really not sure what he was getting at in his explanation. If I remember right Gogu Constantinescu may have had a similar explanation for his "sonic" diesel injection system. I remember reading about it years ago but couldn't find reference to it now. If you lower the pressure of a liquid to it's vapor pressure it will boil, technically it's not a vacuum bubble, but if that's how he understands it. The vapor pressure of kerosene at room temperature is 2mmHg, a very low pressure. Whether or not this is possible would need to be calculated based on plunger area and spring force.
This has reignited my interest in model diesel injection so I'll have to see how good I am at lapping 3mm bores.
Greg
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After reviewing some inline injection pumps, I found no injection pump has a feed port with a check valve on it above the plunger. So, on the down stroke there is a low pressure condition. the plunger return spring must be strong enough to overcome the "suction". It's a normal thing. Because liquid fuel doesn't expand (much), the only possibility is the fuel vapor due to very low pressure, which collapses as soon as the feed port opens and pressure rises.
Greg
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Last night I spent about 3 1/2 hours rebuilding my pump, with a feed 1 way ball valve. It appears to work OK, and the pressure generated by the pump appears to be OK. I have obtained a gauge today that I will attempt to read the pressure that is generated by the pump. I removed the spring from the outlet valve ball, but I intend to test it with and without.
Then I have to attach it to an injector. :noidea:
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Keep at it Pat!.....Pictures please!
Dave
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Pictures!!! I don't have time to take 'em!!
Well, not a lot of them anyway....Here is 2 pics of my progress tonight, the head has 1 guide and seat fitted c/w valve, the injector is assembled, I have to make and fit the feed line fitting yet. The second valve is semi finished, and the seat /guide assembly is roughed out on the outside dia.
I made up a line from the new pump to a gauge and cranked it over with the drill. The best reading was 50psi(300Kpa) I think that is enough to do the job. My seal at the bottom of the pump still needs work, as it was leaking past. A long way off the theoretical 50 bar. that was suggested as may be required. I flattened a piece of 1/8 copper pipe as hard as I could in the vise, and it sprayed out a small opening in a very fine spray.
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A page or two back I mentioned the spring loaded injector that George Punter used on his and my reservations about it working. Well :ThumbsUp:, The latest edition of ME he says he removed the spring from the injector "as it didn't seem to make any difference".
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Thanks for the pics Pat!....lots to think about heh?
Dave
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The best reading was 50psi(300Kpa) I think that is enough to do the job.
At 20:1 compression ratio cylinder pressure will be ~300PSI. The pump must exceed cylinder pressure in order to get fuel to flow out of the injector. The parts look great. Did George Punter mention his pump pressures?
Greg
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Greg, he does not mention any pressures at all. I am not sure how to increase the pressure with what I have. I do have to seal the pump better, maybe use a steel housing, smaller bore, ???.
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When you did the test, are you certain there was no air trapped? Any air in the system would limit maximum pressure. If it's leaking around the plunger a tighter fit may be required.
Greg
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What Greg said!....
Dave
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When you did the test, are you certain there was no air trapped? Any air in the system would limit maximum pressure. If it's leaking around the plunger a tighter fit may be required.
Greg
Greg, I may have had some air entrapped, I will do a better test when I have an extra pair of hands to assist. (maybe get 1 of the grand kids to operate the drill).
Dave, I appreciate your support, keep it up!!and Greg, I do need a tighter fit also!!!!
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Pat
I've had mixed luck making tight pumps....It ain't easy!
I feel for ya!.....keep at it bud...
Dave
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Pressure test last night yielded 200psi. Then it blew out the bottom past the O ring.
New pump coming up. methinks. The "DUX" pump has a gland nut to hold the seal in the bottom. That may be a good option, as you can tighten it to increase seal pressure.
Maybe I am too much of an amateur at making high pressure pumps, but how does an O ring that is 3mm ID x 6mm OD seal 300+psi when it just slides over the piston, and into the barrel, with a washer and spring to hold it there. :headscratch:
That is the method used by George the builder/designer of this Lister.
My wife says" it looks good, why not just look at it!!" I come in the house at 10.30pm smelling like a kero rag!
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:lolb:
Hang in there Pat.....there aren't a lot of model injected diesels out there for a reason....it's a "hard to do"....Persistance!
Dave
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What size have you bored the pump you don't want a 6mm hole for a 6mm O ring, more like 5.5mm. to get a piston seal
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Jason, I am being "general" in my description, as the bore is .188" actually and the sleeve is .312" dia where the O ring is. yes it is a bit "non snug" but I reckoned that the washer with spring pressure would make it up.
I have looked at a lot of diesel pump sections and doing what is required, in the space available is being a bit tiring!!
But I will "steam" on...
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Take no prisoners Pat!
Dave
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For a piston you want the ring to be compressed down in dia onto the piston not compressed by the spring, in otherwords when compressed the resulting oval shape of the ring will be wrong if you relly on the spring to compress it.
What section ring are you using on the .188" shaft in the .312" bore?
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What section ring are you using on the .188" shaft in the .312" bore?
.063" Jason. I know it isn't correct, but like I said, I thought that the spring pushing on a washer above the O ring may squish it enough. I now know it will not!!
I connected up the new injector last night, made up a teflon seal for the pump, and tried my luck again. With the injector out in free space, it definitely sprays a fine mist. A little too much mist maybe, but it does spray. The teflon seal held mostly, but there is still some leakage. I modified the operating cam also to a more abrupt ramp to speed up the piston travel. The "DUX" cam is more of a spike on a shaft, doesn't look like a cam as we expect a cam to look.
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Pic taken last night just before retiring..
This is the steel head and new injector fitted. It has way more compression, but I still have a leaky exhaust valve. Also the timing is off I think, I get too much blow back through the inlet and suction in the exhaust. They also do what they are supposed to, but the overlap is too severe/lengthy.
I had a minor (so far as I know) catastrophe last night. While spinning it over testing the pump and injector, it came to a sudden mechanical halt. I pulled the front cover and can see that the stub shaft for the idler gear has come loose, moved out and has been hit by the crank web. I will dismantle this weekend and check damage. :'(
Didn't use loctite did I
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Dismantled engine, and yes the idler shaft was U/S, so I made a new one, a little longer in the thread this time and I loctited it in.
I put the slot on the outside so that it is easier to assemble and tighten. The slot in the head is almost impossible to get to.
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I like it Pat!....Keep at it friend!
Dave
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Have not done too much for a few days. checked the cam lobe separation, was supposed to be 110d, was actually 140d. How did that happen :shrug:
Cut the cam in half between the lobes, drilled and reamed each side .188"dia x .188 deep, pressed in a shaft about 3/8" + cut width long, adjusted lobes to 110d, exhaust leading, and silver soldered the piece into 1 again. Works like it should now.
Assembled it, and checked compression, I have about 245psi. (16:1 compression ?).
Now I have to build that new pump.
Got sidetracked on my 1930 Model A Ford Cabriolet street rod chassis build with my eldest grandson for a few days. :)
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I drew up the new pump, and have been working on machining it up out of steel.
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Looks good Pat!
Dave
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:whoohoo:
Made all the parts except the lever and assembled the new experimental pump. The ball valve on top has given me some drama, I cannot seem to get it to seal as well as it should. It is spring loaded, and appears to work on the bench, but when I fit it to the pump, it seems to leak on the down stroke. I will persevere.
Some pics of the parts and assembly.
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With a ball valve, the inner diameter of the port needs to be very round, and the flat face needs to be very flat. If they are just drilled, you will run into trouble
The gospel according to Ray Hasbrouck........
Ray recommended a boring bar and an end mill ....but not to drill to size.
Dave
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If they are just drilled, you will run into trouble
Ray recommended a boring bar and an end mill ....but not to drill to size.
Dave
I am in trouble!!
I do have an 1/8" end mill that I will flatten the bottom of the valve with. That is this evenings project. I also cut the lever out, so maybe I can get that operating too. I had to change the outlet valve design last night, to a brass insert with a 1/8 id x 3/16 OD x about 3/8 Long with one end closed except for a 1.25MM dia. hole that the 3/32" ball sits on. The .110" dia. spring sits on the ball and the outlet tube adapter screws on and clamps it all in.
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Looks good!
Greg
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Dave, good advice. I redid the ball valve and it works 9 times better. I am going to set the ball 1 more time, but it does work. I finished the pump off last night, pic below, there is 1 nice thing about the volume/stroke adjusting arm, it can be used as a primer. :ThumbsUp:
I hooked it all up to a pressure gauge last night late, and I could hand pump it up to 60psi fairly quickly. The faster I pumped the quicker and higher the pressure went. It slowly bleeds back, so I obviously have to get a better seal at the ball. Next is drilling the flange mounting holes, making up a correct length pushrod, and an engine test.
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Coming along nicely :ThumbsUp: :ThumbsUp:
I hope you are successful with the new head and fuel system :cheers:
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Coming along nicely :ThumbsUp: :ThumbsUp:
I hope you are successful with the new head and fuel system :cheers:
Me too!!
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Still having trouble keeping fuel pressure up. The pump worked very good on Wed. night with 10-40 oil, but did not fare well with paraffin/ether. It appears that I will need a feed line 1 way valve. I will attempt to fit the one from the old pump.
I fitted the pump to the engine last night and cranked it with the electric drill. It filled the lines slowly, but would not generate any pressure at all. I tried pressure feeding the inlet and it helped, so I am presuming that I have back flow probs.
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Have you considered using diesef fuel rather than paraffin? It is a little more viscous and also has better lubrication properties. In days gone by it was recomended to add lubricating oil to paraffin when used as fuel for a diesel engine.
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Yes, I think George was running his on RC model diesel which would be Paraffin, ether and upto 20% castor oil or synthetic
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Yes I seem to remember that suggestion some time ago...might be good to get it functional with that ....solve one problem at a time so to speak,,,then figure out how to get back to pure diesel.
Dave
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I have tried pure diesel, diesel and 30% starter fluid, and paraffin with 30% starter fluid. The starter fluid is ether. The caster oil should not be needed for combustion, it is only for lubrication in a 2 stroke to my knowledge. I have to concentrate on getting the pump to operate efficiently and without any backflow.
I have a project to catch up on with 1 of my grandsons so I have not done much toward fixing the valve in the pump.
The head gets quite warm when I crank it over with the drill for a few minutes. It has actually fired a couple of times but not enough to get overly excited about...
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have you tried the methods used by the steamers for there feed pumps and clack these need to pump at 200 psi and hold it as a clack
we use a Dbit to square off the seat then ream the hole not the other way round
or make up a drift to hold the ball on the seat formed as above and tap with say a 1 ounce hammer discard that ball and uses a new one for the pump
you could make up a drift as before but glue the ball into a centre drilled hole in the end and burnish the seat with slow rpm again discard the ball
an other point we have to use stainless balls but these are not the best for roundness in your situation using oil as the liquid I would use steel ball bearings these are sold by the bearing houses in small quantities units of ten are common these will be round and hard
Sorry for the multitude number of points
hope it helps I am not trying to teach you to suck eggs
Stuart
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How are you determining where the leak is? Leakage was my main concern in building an injection pump this small. How did you finish the pump bore and plunger OD? I expect a lapped finish is required. A production injection pump of maybe 8-10mm diameter has only 3-4 microns of clearance. How to achieve this over a 5x deep bore in the home shop I'm not sure, but I was going to try lapping the bore with Acro barrel laps I purchased for the job.
Don't give up!
Greg
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Dave, Stuart and Greg, I appreciate all your comments and suggestions. I had not made any ball valves until this project!!!
The piston and barrel were lapped with a "fine" lapping compound and lots of oil, but I must admit ,it is a tad loose now, so I will make a new piston.
The stainless balls are definitely soft. I have flattened a couple. I know it is leaking back as when the piston retracts, the fuel also retracts slightly. It will not maintain pressure in the line, even when the pressure gauge is attached. And I can see leakage thru the gland. If I tighten the gland any more, I will need a spring of gigantuan proportions to return the piston. :cussing:
The new ball valve will have a 1/8" dia. ball, as I have some of those in steel.
Also, in my design, I made the inlet centered on the lowest point in the stroke. The inlet port is 1.3mm dia. That would mean that for .65mm of stroke, it is possible to push the fuel back out thru' the inlet. That is why I think I need to put a ball valve on the inlet also. George Punter had one on his.
I am trying to think of a way of getting a polished .125" dia. bore, that is true for about .75" length, and a piston that is the same.
I do have about 24 sheets of Crocus cloth.
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when I make our lube pumps which can get up to 400psi or so i get round the fit problem with using 3/32 rams by using a cartridge made up of two o rings and a spacer between them this is to adjust the flow.
the ball valve is sprung up to the lower o ring and that gives the seal the ram just lifts clear of the top o ring to let in the oil when the ram descends it will seal in the top ring and when it is at its lowest point it lifts the ball from its seat on the o ring.
with this arrangement a close fitting bore is not required
I did have a sketch of the arangment but my youtube acct. was hacked and I have lost all the docs/photos that were on there
Stuart
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The trouble here is the need to meter miniscule volumes. Any compression in the packing or seals will lead to increased stroke. I don't think you can rely on packings or orings for this pump.
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The trouble here is the need to meter miniscule volumes. Any compression in the packing or seals will lead to increased stroke. I don't think you can rely on packings or orings for this pump.
Exactly....the miniscule volume and skyhigh pressure!!!It would be great if I could increase the stroke a pile, as well as make the action more severe.
The "DUX" uses a very severe cam to get the fuel pressure spike at the right time. That is the other thing I am working on, a new cam, keeping in mind that the same cam operates the oil pump, so I have to ensure that the stroke etc. works for it too.
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The trouble here is the need to meter miniscule volumes. Any compression in the packing or seals will lead to increased stroke. I don't think you can rely on packings or orings for this pump.
Exactly....the miniscule volume and skyhigh pressure!!!It would be great if I could increase the stroke a pile, as well as make the action more severe.
The "DUX" uses a very severe cam to get the fuel pressure spike at the right time. That is the other thing I am working on, a new cam, keeping in mind that the same cam operates the oil pump, so I have to ensure that the stroke etc. works for it too.
Pat. My hat is off to you sir. Your doing something difficult. You know it is....but you're not backing down.
That's courage. If I can assist in any way ....I'd be proud to. :praise2:
I agree with the Oring comment from diesel. I am wondering now how to best go about making a true plunger pump for this. The fit must be very good. You got the juices goin......not going to sleep much tonight..
:facepalm:
Hang in Pat...
Dave
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Just a thought but would it be possible to use the smallest commercial pump and an itty bitty cam, (pimple on a pumpkin style), to give minimum lift.
Trying to think outside the box, maybe I need to be put back in it.
Best Regards
Bob
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Dave, :stickpoke: you are helping by checking up on me often. I have all these thoughts about this, and I have watched the video, and I have emailed George, and he has replied, but I just have not had success .....yet!
I have not installed the glow plug yet, because of the injection problems, but I think it will be required.
Bob, I am not sure about the "smallest commercial pump" that you are referring to. Not many diesels use a piston pump these days, and I cannot think of any pumps of small volume high pressure design. A grease gun is about the smallest I know of.
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Pat....I'm thinking ballizing...or bringing the bore close and then pressing a precision ball through to work harden the surface and bring it to a reasonable size and finish
I've never personally done that...but I've done a little bit of reading on the subject.
Once that is determined....make a plunger to match.....it's got me thinking....what's the bore of the pump?
Dave
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http://www.metrologyworld.com/doc/ballizing-0001
Something to think about.....
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and here
http://www.itiball.com/tungsten_carbide_balls.php
Dave
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If you look at this patent drawing on page 2, and blow it up....you will see that there is a poppet valve on the intake of the pump which basically gives it near zero volume on TDC. good for metering. With a simpler version shown on page 5.
Dave
http://www.freepatentsonline.com/6330876.pdf
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Keep in mind...dead volume will kill your performance!.
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The original, as designed and detailed in Model Engineer bore, is 3mm. I made the original at .188(3/16)..too large.
The pump I have now is .125" bore. I am using a piece of 1/8" drill rod as the piston/plunger.
I will check out the attachments you have kindly provided, and see if there is anything that will help me.
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I think it's going to be all about the fit tolerance, and the dead volume.
If we can do that, we got it licked...as an engine has been built to this before? I assume?
Dave
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http://www.youtube.com/watch?v=zXzqGHn0CDY (http://www.youtube.com/watch?v=zXzqGHn0CDY)
Dave, have a look at the link there. That is the engine running. You may notice that you do not see him starting it.
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Thanks for that Pat!
funny he states in the video that the injector pump has a 4 mm bore.?
Dave
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My mistake, it is 4mm....that is why I picked 3/16", come to think of it.
I emailed him re my problems, and he said that he was having similar problems. He pulled the spring out of the injector. The only way he could get it to run "slow" was to restrict the inlet to 1/8" dia. I asked him if he heated it to start it, but there was no reply to that yet. He has a needle valve on the return line to adjust the fuel volume going to the injector. he said that it is too coarse and a small movement makes a too big change. said he was going to fiddle with the taper on the needle. I couldn't get that working at all, it was either too closed, or too open.
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Hi HN,
Thanks for the link.
The main thing I found interesting was the fuel used was model aircraft diesel fuel. The exhaust is a bit of a give away with the white smoke which leads me to believe castor oil is present. In turn this suggests that the fuel is more viscous than ADF and allows for a less precise fuel pump in terms of fit. His by pass system puts high pressure fuel back to the suction side of the fuel pump, also reducing the need for micro sized fits within the pump. Probably why a bigger bore fuel pump is required.
Just my thoughts and observations from afar.
Best Regards
Bob
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I'm considering a 3mm plunger for my project. The scale of these parts is a problem and probably the reason we don't see much in the way of model diesel injection. The only other functional model injection I know of is Find Hansen's (http://www.findsminimodelhotbulbengines.dk/) work and unfortunately he doesn't talk about the pump. I wish I could work on my project, but at the moment all my diesel injection drawings are on a crashed HDD.
If the viscosity of the fuel was enough to get the pump working it only proves that the fit is that critical. Castor oil is approximately equal to SAE50 in viscosity. White smoke is generally indicative of poor atomization of fuel in a diesel.
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His by pass system puts high pressure fuel back to the suction side of the fuel pump, also reducing the need for micro sized fits within the pump. Probably why a bigger bore fuel pump is required.
Just my thoughts and observations from afar.
Best Regards
Bob
Bob, the bypass does go back to the inlet, but what I found was that it is at greater pressure than the incoming, so it tends to go to the tank as well. you may be right, in that the backflow takes care of the overvolume.
Like my wife says to me at times," it can't be that hard to do"!!!! It bugs me that this is so difficult.
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My Dad was a Master Mechanic for the local Fire Department. Every once in a while they would order a new truck and he would go visit the company that built the trucks..well, while in the bid process for one, he was invited to got to the Detroit Diesel factory, and while there, he toured some of the manufacturing area's
He was a big fan of Detroits and called them" Detroit drippah's "
He said this technician showed him some injector assemblies, and showed how they went together. He then held the plunger in his closed hand for a few seconds, and then tried to assemble them and they wouldn't go. The Tech stated that the tolerance was .000033" (33 millionths) He was stunned.
Now we're not making hundreds of thousands of injectors....just one......so
Now 3x that tolerance is .0001" or 1 "tenth"....WE MIGHT be able to do that in a home shop....but I think it won't be easy, and we'll need to think about that for a bit :thinking:
Dave
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Bob, the bypass does go back to the inlet, but what I found was that it is at greater pressure than the incoming, so it tends to go to the tank as well. you may be right, in that the backflow takes care of the overvolume.
Like my wife says to me at times," it can't be that hard to do"!!!! It bugs me that this is so difficult.
Hi Again,
Is there any reason not to fit a non return valve on the pump suction or as part of the filter to prevent fuel returning to the tank?
Maybe another email to George to clarify what's his setup in this area.
Best Regards
Bob
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My mistake, it is 4mm....that is why I picked 3/16", come to think of it.
I emailed him re my problems, and he said that he was having similar problems. He pulled the spring out of the injector. The only way he could get it to run "slow" was to restrict the inlet to 1/8" dia. I asked him if he heated it to start it, but there was no reply to that yet. He has a needle valve on the return line to adjust the fuel volume going to the injector. he said that it is too coarse and a small movement makes a too big change. said he was going to fiddle with the taper on the needle. I couldn't get that working at all, it was either too closed, or too open.
Pat,
What size orifice is specified for the injector?
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he was invited to got to the Detroit Diesel factory, and while there, he toured some of the manufacturing area's
He was a big fan of Detroits and called them" Detroit drippah's "
I was working at the detroit Diesel factory doing some electrical upgrades. While there i made a friend named Guy. I talked with Guy about an idea I had to build a 1/4 scale Bugatti engine that really ran. Instead of laughing Guy brought in a cardboard box full of stuff and told me i was going to need this. It had 1-2-3 blocks, V-blocks, 6 inch caliper, ect. About a week after that I bought my lathe and mill. I think you guys know where this is going but Detroit Diesel is where modeling began for me.
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I know EXACTLY where that's going........."Bubba"!
Those who know us ....know where that came from!... :lolb:
Sounds like Guy was a heck of a guy!
Dave
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And you know....I had a similar conversation with a man about my dream of building a steamboat....His offering was lots of kind words and encouragement...when EVERYONE ELSE was laughing.
His name was Ray. Thanks Ray!
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OK Pat, I'm going to get a 4mm ball bearing ball...and see if I can run an experiment this weekend
Dave
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OK.....purchase made.
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Now 3x that tolerance is .0001" or 1 "tenth"....WE MIGHT be able to do that in a home shop....but I think it won't be easy, and we'll need to think about that for a bit :thinking:
Dave
.0001" or 2.54 microns is possible with a lap. But it's the 3-5x bore that is tough and I certainly don't have any way of checking it, and not even a pin gauge set. My approach was going to be plunger from hardened and ground drill blank, tool steel pump body lapped to fit. I have no idea how many attempts it would take to get it right. I think in the real world a hone would be involved prior to lapping.
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Hey Diesel,
:noidea:
I hear you there!....I'm concerned that at this size, a bell mouthed hole will result with a lap....but as we're both speculating at this point, and I don't know how I'm going to measure it either.....so it would seem we need a method to measure this with
My approach was to perhaps ream .001 undersized, and try to use the Ti ball as a final sizing device...make the pump rod the same size as the ball...and count on honing the couple of tenths difference once the tube contracts after the ball goes through.... :shrug:
Let's both give it a shot and compare notes perhaps....nothing like some data hey? :cheers:
This one's got my attention though!...this is tough problem Pat...and my story about my Dad is what snapped my interest to it!
Dave
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OK.....purchase made.
Are they Ti or Carbide?
I have been using a hardened drill steel as a piston, the cylinder has been just CR or C1018... I tried making the cyl from Drill rod also but I had trouble(dull tools and more drive than experience!!)
The "ream to .001 undersize" is the problem with me, how? do I need to make a .001 undersize reamer? way beyond my expertise I'm afraid. I have a .125 reamer, so I'm going to use it, then take a 5/32 dia drill rod and grind it to suit. Well that is the plan, and then lap it into the cylinder.
I am in process of making a toolpost holder for my dremel.
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Pat,
What size orifice is specified for the injector?
Dave, it is a #5 gas jet. I could not find one locally, but I had an old Coleman stove in parts and scavenged 1 out of it(well I think it was a #5) I wouldn't know, but it was very small. smaller than #80 drill. I wrecked the jet while fitting it one time, so I ended up with a #80 jet. The #80 is about 4x the size I think.
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Pat
you said you wanted small holes look here its at the start of his blog it references small injectors and date from 1955 interesting picture of a wire threaded through holes in a human hair
http://oxtool.blogspot.co.uk
Stuart
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Pat,
I'm taking it upon my self to try to figure out a process for a tight fitting plunger pump...I have my own ideas on that, and would like to give it a shot...so before you invest in any of my muses...let me try it out....just in case it's a complete and utter failure......at least you can get a chance to laugh!
As far as making a reamer...it's not that hard, I can show you that.....but I just got home from work and I have honeydo's....so probably this weekend....
Dave
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Drills down to .002" (http://www.harveytool.com/prod/Browse-Specialty-Carbide-Cutting-Tools---End-Mills/Drills---Countersinks/Miniature-Drills_140/Miniature-Drills_126.aspx) are available, but I don't know that I would bother with anything that small on my equipment. Spindle alignment and TIR must be very good.
A #5 gas jet is 0.2mm(.008") I think this is far too large for an injection engine of this displacement. It may explain why the engine in the video runs the way it does. But what do I know, I haven't built one yet. #*$&#*&% me! My hard drive is dead and recovery would cost 1450USD, and I don't even know how much data they might be able to recover. I had a lot going on recently and my backups got 3 months old. Back up your data! I don't even know what I lost.
The finish from a Dremel mounted on the lathe will be less than satisfactory, in my opinion at least. It doesn't cost much to try. You can buy undersize reamers. I have an over/under reamer set that includes a -.001, nominal, and +.001" in fractional sizes, I think. .001" over or under are available individually from most suppliers.
Greg
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Greg, I will try the undersize reamer route. I feel your pain in the hard drive crash, I have one at home too with about 10 years of drawings on it that I cannot get to.
The "DUX" injector style is the one I have now, and it appears to work when I put about 120psi of air through it, but only just a slight bit comes thru, so I imagine with 4-500psi against compression, it should be OK.
I had my doubts about the Dremel tool post grinder setup, as the Dremel is a plastic case and it will distort!! There is a poster on 1 of these boards who swears by the 1 he made, says it gives excellent results.
My experience with grinding is with a full size crankshaft grinder my father had in his workshop. lots of coolant, and a grinding wheel about 36" dia.!!
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Pat
The Tungsten Carbide precision balls aren't going to be here until next week sometime....so I'll have to forgo any testing along that lines until then
But they're coming.
Dave
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:praise2: :praise2: :praise2: :praise2: :praise2: :praise2: :praise2: :praise2:
Oh boy what level of work is that it is a spectacular thing is that I donot believe I can bring to this forum because apparently seen god mother, encouragement and congratulations friend grabbing a spectacular job these
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Well I am still at it, a new injector pump is on its way in the garage.
I have been waylaid a tad by another project with 1 of my grandsons. I must finish it before his graduation in the spring of '14!! (It is the 1930 Ford Cabriolet Street Rod Project.)
For the pump I am using a piece of 85000 psi Stainless steel tubing for the cylinder. It is DOM tubing, meaning "drawn over mandrel" and the ID appears to be about .010" smaller than 1/8". I will see how that polishes up with lapping.
I think I have another development on the Lister Build Log coming up too. I will post pictures when it becomes reality.
Thank you for all your input(s) into my ongoing saga.
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Pat
I got the "balls" this week....but it will have to wait till the weekend....work's nuts right now!
Dave
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Pat
I got the "balls" this week....but it will have to wait till the weekend....work's nuts right now!
Dave
I hear you, nuts, balls....it's nuts here too where I work.
No problem Dave.
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Pat
I got the "balls" this week....but it will have to wait till the weekend....work's nuts right now!
Dave
I hear you, nuts, balls....it's nuts here too where I work.
No problem Dave.
:lolb: :lolb: :lolb:
I hate it when work does this to me!......
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As they say now; "back in the day", I had a real problem trying to work and honky tonk, so, I quit work :lolb: :lolb: :'(
Whiskey
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As they say now; "back in the day", I had a real problem trying to work and honky tonk, so, I quit work :lolb: :lolb: :'(
Whiskey
You don't happen to have worked in a paper mill?
I have been to Springfield a few times for work, I was with Voith.
I didn't know that I would live this long, so I spent all my money on my kids, so now it is work, work, work!!!!
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I know my engine is not running...yet....but look what I have now.. :ThumbsUp:
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That doesn't look fabricated at all.
Cheers, Hugh.
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That doesn't look fabricated at all.
Cheers, Hugh.
Fabricated from molten cast iron and aluminium!!! way beyond my expertise I can assure you.
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Looks like you got a parcel from Eric, now you can make a pair. Its a pity he did not make the flywheels from a split pattern but they are should be soft enough to fettle away.
J
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Looks like you got a parcel from Eric, now you can make a pair. Its a pity he did not make the flywheels from a split pattern but they are should be soft enough to fettle away.
J
Should send them to Jo.....she is the "fettle fanatic"
Yes Jason, Eric did send them to me. I have not tested the "workability" of the cast iron yet. I broke the spindle, slide collar on my mill, so I have to repair that before I start any milling/flycutting.
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Maybe you should send them to me and I will give them the attention they deserve. :embarassed:
Jason doesn't trust me with his, I think he thinks I might get too fond of them so he won't risk it :ShakeHead:
Jo
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Maybe you should send them to me and I will give them the attention they deserve. :embarassed:
Jason doesn't trust me with his, I think he thinks I might get too fond of them so he won't risk it :ShakeHead:
Jo
I have noticed a trend that you are attracted to castings, (or vice versa)!!!!!
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Ah the magnetism of it all :LittleDevil:
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I have noticed a trend that you are attracted to castings, (or vice versa)!!!!!
I am attracted to other things as well :LittleDevil: but I have more success with castings :-[
Jo
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You may have noticed :thinking: that I haven't posted much lately. I have been helping a friend move back to Aus. He has been here for 40 + yrs, and is now retiring back to his homeland. He and his wife went on a trip to England and Ireland in Sept., where she had a fall and compacted a vertebrae in her lower back. L1 if I recall, they are in their 70's, so my wife and I have helped them pack all their stuff.
He was building a 2 place helicopter, which I have now inherited, it is a 1983 Rotorway Exec. A full kit with all upgrade packages. It has never been built completely, so is now in storage along with my 30 Model a hot rod chassis. I intend to sell or donate it to a worthy, (read educational) cause, or museum.
I do have a Pilots License, and I have flown R/C helicopters, but real helis have not been my favorites to fly. Something about a million precision parts flying in very loose formation :lolb:
Will be back at the Lister very soon.
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When your ready, i will be here watching!
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Well the '30 Model A street rod is finished except for carpets and top. We are still in process of selling house and moving, so no machining taking place :(
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Moved to "new" house, now getting all the equipment into place and working. New mill and lathe still to be picked up and moved in. Next 2 weeks should see some action.
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Sounds like things are starting to settle down a bit Pat. Will look forward to seeing the Lister project resume. Meanwhile pictures of the new lathe, mill, and shed space are always welcome too :)
Bill
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New Mill is in. Lathe is on Back order.
I tested it out by machining 1 of Eric's Cylinder water jacket castings, partly!
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Still watching with interest :ThumbsUp: A small 'real' diesel is high up my projects list.
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Spent a few hours sorting out "stuff" from our recent move. Setting up shop in basement and placing all like dia cutters in drawers etc.
Took wife and grandson for a beach cruise and fish &chips in the newly finished ModelA Cabriolet.
I also calculated the milling settings for some new Lister cams with help from Brian Rupnow and JasonB.
Received some more castings from Ennech in GB for the Lister. Can't wait to get back at some machining, as soon as my lathe arrives in Vancouver!