Model Engine Maker
Engines => Your Own Design => Topic started by: ThomasM on January 29, 2017, 11:45:36 AM
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Hello everyone,
after i introduced myself in the new member section i want to take opportunity to start a new topic.
The newest project i just started is a four cylinder engine that is inspired by a real existing engine.
I have done many searches in the internet to find an engine to scale down and build it as an model engine.
I was looking for :
- A popular and well known engine
- Not to difficult to build
- Four cylinders
- Water cooled
- Not build as an model engine yet
- Side valve design ( not a must but i have never build a side valve engine and i like the design )
- An more or less old engine because newer engines look not very good when all their additional components are removed.
Although i am not a Ford enthusiast i decided that the old Ford Model A engine would be a good project .
It is a very nice engine with a clear and unique shape and it is relatively easy to make the model engine look like the original.
Normally i make the complete drawings of an engine before starting to build it. In this case there is only the complete cad 3d model finished and i have to make the shop drawings on demand while i am already into the building progress. This is because i do not want to spend to much time on the computer making all the drawings at one time.
The engine details are :
- Length : 17,5 cm without gearbox ( about 1/4 scale )
- Displacement : 50 ccm
- Spark ignition , gasoline powered
- Steel cylinder liners made from precision steel tubing
- One pieced crankshaft
- 1/4 " spark plugs
- Gearbox will be added ( without gears in it but a heavy inertia for realistic running and the possibility to reach very low rpm )
The following pictures are the work i have done so far:
I hope you enjoy,
Thomas
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The crankcase is the first casting model of the engine i have made.
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I cannot see any pictures (as yet) but this sounds like a good project that many here will find most interesting. :)
Nick
Edit :- You posted an image while I was typing.
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After a bit of additional grinding and finishing i was able to get a usable mold from the casting model.
The core for the valve stem gallery is already glued in its coreprint.
The second picture is from two of the cores made with core boxes.
The whole casting has 3 cores.
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This picture shows the first pour of this mold.
The surface finish could be better but i decided that this one is usable.
After it is machined it will have to do much grinding but not to much to keep the casting look.
The engine will be painted in a mate finish anyway.
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Looks great to me.
This will be a very interesting build.
Gail in NM
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The following pictures are from the machining i have done so far until today.
1. Clamped the crankcase to the milling table after milling the bottom straight but not to finished size to mill the top to size.
There where no air bubbles or other inclusions in the casting so i must have done something right.
2. The second on shows the crankcase after i machined the cylinder bores to accept the cylinder liners. The liners will be 28 mm outer diameter
and 24 mm inner diameter. The cavities for the coolant, formed by the cores, are visible. I also bored and reamed the holes for the valve
tappets all the way down through the valve stem gallery to the bottom of the crankcase.
In the ford model a engine the distance between the cylinders is not equal. This is the case at my model too. The reason is the need for
additional space between cylinder 2 and 3 to have the room for the middle crankshaft bearing.
The crankshaft has 3 bearings ( front / end / middle )
3 . The third picture shows the crankcase after i marked the holes for the head screws. I marked it with a permanent marker and scratched it
with a tapered piece of aluminium in the chuck to avoid a mistake when finally drilling them. The chance of traveling to the wrong place
two times because of a mistake is smaller.
4 . The finished top with the water passages and the hole for the distributor shaft drilled. The distributor which will be placed above the head will
be driven by an angled gear by the camshaft later.
Hopefully i will have the time to keep working on it soon.
Best regards,
Thomas
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Welcome aboard Thomas. I am a Ford fan and will be following along with pleasure. The foundry and machine work are looking great. Keep us updated.
Cletus
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Hi Thomas, do you take orders for your castings ?
Nice start up with the machining and no blow-holes until now.
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That is a fine start Thomas. A very interesting engine to model as well. One thing to consider when attaching pictures is to reduce their size to 640x480 or 800x600. This helps conserve server space and also allows the pictures to download much faster for those with slower internet connections.
Bill
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Good documentation Thomas. This is going to be a fun build to watch.
Jim
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Thank you all for your interest and your kind replies. This is additional motivation.
@ Bill: I will do the resizing before my next post. Thanks for advice.
@ fumopuc : As a brand new member in this forum its difficult to deal with your question. Could you remind me when this engine runs well after it is finished and all the drawings are correct and ready for being used by another person.
@ Cletus : Thank you. Especially my wife is always very "pleased" when i fire up the foundry in the garden and blow a few liters of diesel through it...
I hope i can finish the machining of the bottom end of the crankcase today.
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An excellent start, I will be following along :wine1:
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I'm always impressed by builders who start with doing their own castings.
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Interesting project Thomas, I will enjoy following along with your project.
Also, welcome to MEM!
Dave
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Actually i wanted to work on the bottom end of the crankcase but i had to resist the wish to clamp it down on the front and the end. There would be two disadvantages when i would have done that.
First there would be much stress on the thin side walls of the part because the clamps would actually try to bend it. The risk of cracking it is to high. Bolting it down trough the cylinder holes would be possible but i have to machine the inner top surface to accept the middle camshaft bearing ( a split one) and every relocation of the clamps would make it necessary to re align the part and find x/y - zero.
So i used my little time i had today to make a fixture that allows me to find the parts x-y zero repeatable and hold it in any position i need to reach all the surfaces not machined yet.
First Picture shows the jig pushed against some stops on the milling table and the spindle is located on the marked x/y zero.
X/y zero is between the cylinder bores 2 and 3. The red corners are the two i machined to an exact 90 degree angle. I will prefer this corners later for indicating.
Picture two : After removing the jig from the table it is bolted to the crankcase through some of the head bolt threads . I use not all of them.
Picture three shows the whole thing clamped down on the milling table ( again pushed against the stops ) .
Now i have access tho all surfaces without relocating clamps or damage the casting.
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Looks very interesting.
You might have mentioned it, but I can't find it...what's the size?
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This will be a interesting thread to follow, starting from home shop castings, nice.
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Thanks for a great build log and photo gallery on your interesting engine project , Thomas. Huge admiration for your ability to make the complex patterns and do your own casting. Dave
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I will enjoy this build, Thomas. You don't have to be a "Ford man" to appreciate the Model A engine.
--Tim
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Thank you for all the comments.
I am on work and will not be at home until Friday. Normally i am at home every late evening so this is an exception.
I will progress on this Saturday.
@ zeeprogrammer : I have the drawing not with me so i have to wait to post detailed numbers on the engine. As an indication : The crankcase is 175 mm long and the engine will have 24 mm bore and 28 mm stroke. The displacement will be about 50 ccm.
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Hi Thomas
I currently don't get a lot of time but will be following along as I can.
Love The thin Wall casting!
Pete
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Hello,
I just want to keep you updated what i did yesterday.
The machining of the lower side of the crankcase is finished. I also machined the front and end of the case to the right angle to be able to use this surfaces as a reference when clamping to do the camshaft boring. The front and end is not machined to size because this surfaces had to be machined together with the oil pan to give a suitable sealing surface.
Also the crankshaft main journals are finished. The crankshaft will run at roller bearings at the front and end and a split bronze bearing in the middle.
The next thing i will do is the crankshaft. I need it to locate the exactly position where the crankshaft leaves the crankcase to bore the the journals for the camshaft. The camshaft will be driven by gears so the distance between them has to be precise.
@ zeeprogrammer : The stroke of the engine will be 30 mm not 28 mm as i have posted a few days ago.
I also posted a picture of the basic outer measurements of the engine without the gearbox.
I will keep you informed about the progress. Actually i see a few other topics in this forum with absolutely unbelievable engine projects. The V10 engine is in fact the best i have ever seen in model engine building and the 8 cylinder inline engine in the other just started topic will also become a masterpiece when finished.
Best regards,
Thomas
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Hello,
As i already told the next thing to do is the crankshaft and here it is.
On this crankshaft i had to use normal steel. I Europe this material is called St-37 ( S235 ) and it it is good for welding and general purpose.
Unfortunately it is not very good for turning. On my previous four cylinder engine i used leaded steel 9SMn28 ( SAE 1213 ? ) and this was a pleasure to machine but the crankshaft was based on a rod material not a flat material like this crankshaft.
Unfortunately i was not able to buy flat material optimized for turning or milling like 9SMn28 ( 1213 ) so i had to use what was available.
- Picture one shows the material cut to size and clamped to the tool support ( ? ) of my lathe. I had to use the lathe to machine the index bores
because the z - axis of my mill is not high enough to do this on the mill.
- Picture 2 : After that i machined the holes for fixing the material to the milling table to mill the shape of the crankshaft as best as possible. My
plan is always do do as much work as possible on the mill and use the lathe only for turning ( or grinding ) the bearing pins.
- Picture 3 and 4 show the crankshaft after the finishing pass and after i sandblasted it.
- Picture 5 : I used my support grinder for machining all the bearings and crank pins while holding the crankshaft between centers whit the index
holes. With this material the tool pressure while turning it would be to high and the surface finish would also not be usable.
- Picture 6 : Finished crank pin.
- Picture 7 : After rouging out the ends i also grind these.
- Picture 8 : After i parted of the ends with the index holes on my band saw i had to use my steady support to face and chamfer the ends of the
crankshaft.
- Picture 8 : Finished crankshaft. I love it.
Now i am looking forward to do a bit of foundry work and pattern making . I need connecting rods and want to cast them because cnc machined rods would not look good in this engine.
Best regards,
Thomas
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Only 8 pictures where possible i one post. So here is the last picture...
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Hi Thomas, thanks for showing your way to make the crank shaft.
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The end result looks like it was drop forged.
Gerrit
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Excellent work on the crankshaft :praise2: :praise2:
I used C45k for the last two crankshafts I have made. What grinding wheel are you using and at what speed?
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Thomas,
I wanted to let you know that I'm following along. I have to make an effort in the evening after I get home from work to reply. When I start work at 6:00 am your build is still active on the side but not when I leave. Are you going to use a water pump? or thermo siphon? Great work on the castings by the way.
Art
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Hello,
Sorry for being a little late to answer but actually i am very busy from Monday to Friday on my job. Luckily this is only a temporary situation and will only last for the next about twenty to years when i hopefully retire.....
@ Gerrit : Sandblasting was the easiest way to get rid of the different surface looks at the machined and unmachined surfaces of the part.
@ Roger : Now when you have told me i remember that i have used C45 steel in the past for a part i cant remember. I remember also that this
was relatively easy to machine. For my next crankshaft i will look for this material because it should be available as flat material everywhere.
The question about the grinding wheel is something i was a little afraid of ....
Please dont laugh but i used a 1,5 mm parting disc ( diameter 125 mm ) for a hand grinder. The rpm setting on the support grinder is about
8.000 rpm which is the limit for this disc. The disc is specified for use on stainless steel, i think this type is a little finer.
The rpm setting on the lathe was about 50 rpm the lowest i can reach with my retro fitted frequency converter .
I dont tell this is the way to go but for me there are a few advantages to use this disc in the support grinder. At first i dont have to mess with
the condition of the grinding surface like flatness and the exact angle in relation to the part. The second point is that i was able to remove
much metal from the milled crankpins without the necessary to use a turning tool without the risk of ruin the part because of the heavy tool
loads. I had to avoid side loads on the parting disc when i was removing the excess material by cutting into the steel the same way you do
when using a hand grinder. Only the last ginding passes to the finished size where done by traveling in the x axis direction whith only little
removement of material. The surface i got after i was on finished size ( 12.00 mm on all bearings ) was nearly perfect and i only had to use
a stripe of sanding paper for a few seconds to bring it to visually perfect condition.
Again, i dont say this is the way to go but i was able to make the crankshaft by doing so and it gives me a very good result.
Of course you have to make sure to protect your late from the grinding dust and clean it after the procedure.
@ Art : I will try it without a water pump like ford did on the original engine. I hope for stationary running without or with little loads it should be
ok. Whe the engine will run at idle for a unlimited time without overheating i am happy. If not i will ad a water pump like many Model A
owners also did.
Now i proceed with making the connecting rods.I decided not to cast them like i told because milling them with the cnc would take less time.
I hope i can finish them today and make another post.
Thomas
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Hello,
It needed a little more time than i expected but now i have the conrods.
This conrods are standard ones. There will be bronze bushings pressed in on the small end and two pieced bronze bearing cups on the big end.
I add a few pictures again. I hope i dont post to much pictures. Please let me know if i waste to much webspace.
- 1. Drawing with measurements
- 2. After milling the blanks to size i drilled and threaded the big ends.
- 3. Cover for the big end.
- 4. Drilling and reaming of the holes with the cover already bolted on.
- 5. A simple holder for clamping the conrod for cnc machining.
- 6. Milling
- 7. Finished conrods.
Best regards,
Thomas
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Great documentation of the machining of the conrods. :ThumbsUp:
Jim
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Thank you Jim. By the way : Is the Rans in your avatar yours ? 912 powered ? Flying and model engine building seems to be a common combination...
Thomas
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Thank you Jim. By the way : Is the Rans in your avatar yours ? 912 powered ? Flying and model engine building seems to be a common combination...
Thomas
Your correct on all 3, Thomas. :) Here's a link to a thread I did with some info and pictures (go to post #12): http://www.modelenginemaker.com/index.php/topic,5886.0.html
Jim
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Hello,
I want to make a little update.
Things are going a little slow because i have to make the castings, moulds and patterns on demand when i need the part.
The next part i did was the oil pan.
Here is the description of the attached pictures :
1. The mould of the oil pan. In the background you can see the red pattern. It forms the outer shape and also the core so i donīt have to
make an extra core box.
2. The casted part turns out to be usable. The surface finish could be as always better but i use sodium silicate as a sand binder for the
complete mould. I like the advantages over the disadvantages. I believe oil bonded sand would give much better surface results but i dont
know where to buy at a reasonable price. I experimented with greensand ( bentonite clay binder ) also but i dont like the effort of mulling the
sand after use and not being able to store the moulds for a few days before pouring them.
Other people know much more about casting than i do. I am always very lucky when a casting is a success but i am getting better.
3. After roughing the sealing surface on the belt grinder i clamped the oil pan to the mill table and drilled the holes for fixing the pan to the
crankcase ( 3 mm ). I also i milled four flat 16 mm spots to the bottom to have a reference when i turn it around for milling the sealing surface
to size.
4/5. I used four 8 mm nuts between the milling table and the reference spots for machining the other side.
6 . After bolting the pan to the crankcase it was possible to machine the surfaces of the complete crankcase together with the oil pan to finished
size.
7. Drilling of the water inlet into the crankcase.
Now i want to complete the crankcase with the cylinder liners, valve guides and so fourth. I also have to make the bearings for the connecting rods and the middle crankshaft bearing.
Best regards,
Thomas
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Very nice :ThumbsUp: :ThumbsUp: Home casting is something I have never tried but your results look good :praise2:
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Just stumbled in Thomas...impressive build. I'll have to keep the sodium silicate trick for one-off parts for later use. The crank fabrication was fascinating. Will be checking in on future visits to the site. Paul
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Hello everybody,
I want to keep you informed on my Model A engine project. It has been a while since the last update but i have much work to do at my house and also at work.
The engine block of this engine is the part that needs most of the time to machine compared with all my previous builds but now it is finished and ready to be painted. I think i will use the same dark green color with mate finish on it that i have used on my hit & miss engines.
Here are the pictures :
1. Machining of the conrod big end bearings. The bearing where split after machined to size.
2. Assembled big end bearing.
3. The cylinder liners are made prom precision steel tubing. All i have to do is tuning it to length and chamfer the inner corners. The outher
diameter is already close to the engine block bores and has only to be grind with emery paper to become a nice press fit. When i pressed the
liners in i also used loctide to ensure they are not leaking between the water passages and head gasket.
4. The crankshaft with all the bearings mounted for testing. Everything moves without to much friction.
5. I do not know the correct word in English for the pieces with are valve stem guides and valve seats in one piece. This did not stop me from
machining eight of them and pressing it into the block.
6. The setup for machining the inlet and exhaust ports and also the sealing surface with the holding threads for the valve gallery cover. The red
marked ports are exhaust ports and the black marked ones are for inlet ports. The inlet ports are machined at a 40 degree angle because two
cylinders use one common inlet where exhaust ports are separate for each cylinder. This is the same in the original engine.
7. Finished ports. The ports are 6 mm diameter.
8. The finished engine block with the STM-2 hit & miss engine painted in the dark green color i eventually use on this engine too.
The cylinder liners are also already honed with a shop made honing tool to remove any possible deformation while pressing them in.
Thank you for your interest. I ll keep you informed.
Best regards,
Thomas
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Wow. I don't know how I missed this thread until today. Great stuff Thomas. I have great respect for those with home foundries. Being a Ford guy, I will be following along with great interest.
-Bob
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Hello everyone,
I just finished the camshaft and want to show it to you. The camshaft is build from pieces like in most of my other engines too. Normally i use setscrews to fix the lobes on the shaft but in this engine there is not enough space to extend the lobes in axial direction to have enough space for the setscrews. So i had to fix the lobes in a different way witch you can see in the attached pictures. I use 3 mm steel balls from a disassembled ball bearing as a key. This is no new method but it is the first time for me i use this this technique.
I also had a little headache how to make the angular gears for the distributor drive witch had to be assembled together with the lobes to the camshaft. I am not equipped properly to manufacture angled gears. The gears for the distributor need to have a drive ratio of 1:1 and a bore of 8 mm for the camshaft has to be possible. At he same time the outside diameter has to be 12 mm or smaller. I searched a lot and was not able to find the right gears for this purpose. Every time i found something that might be usable at least one requirement was not fulfilled.
So after a few tries and errors i ended up with the easiest method i can imagine. I just milled the the teeth in the corner of a round blank without turning an angle to it before. the depth is the same as it would be when milling a normal gear but measured from the corner. the rotary table is set at a 45 degree angle on the milling table. This gears dont have to transmit notable power and run good when the backlash is set a little larger.
Here is the description of the attached pictures :
1. milling the teeth of the angled gears. The gear on the camshaft is made from steel while the one one the distributor shaft is made from brass
2. Position of the lobes on the camshaft. " A " means " Auslass = exhaust " , " E " means " Einlass = inlet.
3. Making the lobes. The outside shape is cnc machined. The lobes have a relatively hard opening curve but valve clearance would be large
( 0,5 mm ? ) so the opening acceleration would however be smooth.
4. Drilling the bores for the 3 mm steel balls in the needed positions. The square aluminium piece on the left is for setting the 90 degree angles in
the different directions. On a four cylinder engine you only have to deal with 90 degree angles in different directions so no setup with the
rotary table is necessary.
5. The steel ball in its position just before forcing the shaft in. The shaft with the steel ball is 0.1 mm larger than the keyway in the lobe.
6. Finished camshaft.
7. Camshaft located in the engine. It is tricky to place the additional split brass bearing in the middle but it is possible.
Best regards,
Thomas
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Thomas,
I just noticed this thread today and I had to go back to the first to see everything. Wonderful build and very creative. I gave me some ideas to use on my projects.
I will be following along. Keep us posted
Mike
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A creative way to locate the cam lobes, simpler than pinning which is what I would have tried.
Gerrit
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Nice work Thomas! :ThumbsUp: :ThumbsUp: :ThumbsUp:
I like how you assembled the camshaft. Are the lobes just pressed on, or did you also use Loctite?
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Gerrit, i also thought about pins to fix the lobes but the wall thickness is only one millimeter at the " valve closed circle " so i dont trust the pin hole in the lobe not to wear out and become loose.
Yogi, i also applied Loctide but i think it would work without it because it is a form-fitting connection.
Best regards,
Thomas
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Hello everyone,
There is nothing spectacular today but i want to keep this building thread complete and want to show the distributor drive and a picture of the engine with the unfinished cast model of the cylinder head. The temporary bolted on ugly aluminium plates at the front and the end are to keep the camshaft in its axial position to test the distributor drive. The distributor shaft runs in two roller bearings 10x6x5 mm and there will be an shaft seal ring on the top also. It rotates free and smooth when the camshaft is rotated. One thing less to worry about...
I have to redo the cast model of the cylinder head you see in the picture because this one dont turn out usable out of the 3d printer. I also want to leave away the extensions for the screws so it would be easier to grind the surface to a usable and smooth finish. After that i will glue the extensions for the screws on. But now i can see the appearance of the whole engine ( without the gearbox ).
I will work on this casting simultaneously beside of making the other parts to complete the valve train.
Best regards,
Thomas
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Hello everyone,
It has been a while since my last update but i had to do a few things at the house. I now have a paved yard and driveway and we are able to walk from the car to the house without the need of rubber boots which is very useful.... Also the nice weather is often calling for other open air activities.
So here is the next update and i hope you are still interested.
Pic. 1:
I have made the next set of castings which are the cylinder head and the housing for the camshaft gear drive.
This parts are not machined yet but maybe i will work on them today.
Pic. 2:
I tried to make some pistons the way i usually do which means i turn the outside diameter and the inside from the rod material and parting the pistons of after that. This time something went wrong because after i milled the slots for the conrods the pistons where not round anymore and not usable. Maybe there was internal stress in the rod material ? So i decided to make the tool you see in the picture ( #2 ). With this tool i am able to machine the whole piston oversize with all the holes, slots and so on and turn the outside and top to finished size without having to clamp the piston on the chuck. The tool simply pulls the piston trough the piston pin hole against the tool when the screw on the backside is tightened.
Pic. 3:
Milling the slots for the conrods. The piston is still oversize so i had no worry damage it when clamping it tight.
Pic.4:
Turning the outside diameter and the length of the piston with the described holder. The pistons are 23,95 mm diameter.
Also the slots for the rings where machined now. I machined them very carefully because the surfaces on the side of the slots are sealing surfaces an they will not brake in because there is no movement there when the engine is running. In the past i had many times problems with my rings not sealing properly because i did not consider this fact. There is a chance that a piston ring which is not perfectly round on the outside and therefore is leaking between the cylinder wall and its outside diameter will break in during operation. But there is no chance it will break in when the leaking is between the surfaces of the slots in the piston and the ring itself.
Pic.5:
Turning the grooves for the piston pin retainers with the help of a mandrel (?) which holds the piston through the opposite piston pin hole.
Pic.6:
Lapping the surfaces of the piston rings top and bottom for sealing against the grooves. The ring compressed in the holder. There is only a very small ring gap because the rings are split by breaking them.
Pic.7:
Finished pistons whith pins and rings. One piston already jumped into the engine.
There are holes in the reduced diameter below the second piston ring. I hope this will help the second piston ring to scratch off the oil from the cylinder wall and bringing it down to the sump when the piston moves down. The disadvantage of this holes is that compression will only take place when the rings are working from the beginning. A good fit of the piston in the cylinder will not compensate leaking piston rings with this holes.
Pic.8:
I pinched of the piston ring retainers from a spring and bent it a bit for better installation.
That is all for now. I hope you stay tuned.
Best regards,
Thomas
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still watching like it a lot
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Hi Thomas, I am following each part of your build log. Good to see any progress.
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Hello everyone,
To keep my thread up to date here a few pictures about my recent work.
1.1 - 1.4 : A few of the steps of how i machined the casting of the camshaft gear housing. I placed the sprue of the casting on the backside so it was usable to clamp it in the vise to machine the inside of the housing and also to clamp it in the bandsaw to part the front section off wich becomes the cover.
2. : Milling the cylinder head casting flat but not to finished size to have a surface to clamp on the milling table
3. : The sprue and the riser of the casting are very useful for clamping it to the milling table. On the upper side of the casting i only had to drill the holes for the head screws at this point.
4. : Machining of the combustion chambers and drilling of the spark plug holes (1/4 x 32).
5. : Finished combustion chambers with the sealing surface milled to size.
6. : Engine with pistons
7. : Mounted cylinder head without gasket to check if all holes are on the right place.
The engine more and more looks like it should. I think i am half way gone but there are many difficult details ahead.....
Best regards,
Thomas
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Following your build with great interest.
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I have been checking in from time to time also Thomas. You are making some fine progress..it's really coming together nicely!!
Bill
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Excellent progress :praise2: I'm still following along in the background :wine1:
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Fantastic work, Thomas
I'm glad to see the idea of casting parts from 3d printed molds works. I attend a makerspace that has 3d printers and I had ultimately wanted to try it out.
Do you need to finish the surface at all or are the molds usable straight away?
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Hello Brendon,
Im sorry for the late answer. I have seen one video on youtube ( myfordboy ) and he has used a pattern of a flywheel right of the printer successfully. I dont know exactly why but my patterns are not usable without filling, priming and grinding. Maybe there is to less draft angle on then or the texture my printer creates on the patterns is to rough.
But filling and grinding them is no big deal since i have learned not to print the whole pattern as one part. It is better to print multiple smaller parts that are more easy to finish. The surfaces are more accessible and after finishing all of the surfaces i glue them together. I print with PLA fillament.
I am currently working on the shape and the pattern for the exhaust manifold. Maybe i will give the lost PLA method a try but i am not sure if it would be possible to burn all the plastics out of the pattern before casting....
Best regards,
Thomas
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Ah, I suspected that some finishing work would be required (*depending on the printer of course). Thank you for taking the time to explain :)
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Hello everybody,
It is about time for the next update. I split this update into two posts.
Post #1 will contain thing i did right which is not much this time.
Post #2 will contain my countless, frustrating and demoralizing fails while trying to cast the exhaust manifold.
Picture 1 : machining of the backplate which will be bolted to the crankcase to hold the gearbox. At the original engine this is a part of the crankcase.
Picture 2 - 4 : The casting and machining of the gearbox. It looks large, especially in comparison to the rest of the engine but it is the right size.
Picture 5 : Drilling of the coolant passage in the cylinder head. My milling machine has not enogh clearance on the z - axis to do this and i dont want to rotate the milling head because it is time consuming to set it back to zero degrees exactly. So i used the late for this. The drill bit in the picture is a masonry drill which i grinded to cut aluminium. I dont have and was not able to get such a long drill in 7 mm diameter.
Picture 6 : The machined blanks for the camshaft drive. They are 50 /25 teeth M1. I machined them longer to be able to make a few more gears out of them.
Picture 7 + 8 : The engine with the still not painted gearbox hosing and the assembled camshaft drive. The camshaft drive will also act as an oil pump wich will bring oil up to the valve gallery to lubricate the valve tappets. The oil line for this will be bolted on the hollow screw beside the crankshaft.
Post # 2 will follow....
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Here is Post #2 wich is the proof that the most difficult and time consuming part of an engine is the exhaust manifold. :Mad:
Here is the story: Of course the manifold has to look as close as possible to the original. So the way to go is to cast this part. The outher shape is not a big deal but it is not possible to make a two pieced model of because there is no possible parting line on it. So i wanted ( and still wanting ) to use the lost wax method on this part and burn out the PLA - printing material out of the mould before casting.
While trying this i ran into a few problems which i was not able to solve until now :
1. The core ( which forms the gas passage ) can not be machined after the part has cast so the mould has to inklude a core.
This core is very thin ( 8mm ) and long because it goes trough the whole manifold .
2. The right material to make this core would be sodium silicate bonded sand but it is not possible to to use it on this shape.
The reason is i was not able to fill the sand in the plastic model and compress it because there are to much corners and the sand is not
liquid enough to squirt it in. So the only way is to make the core out of plaster of paris and use a injection sqirt to fill the model.
3. The plaster of paris made core is to fragile.
I tried to support the core with short pieces of steel wire to prevent it from falling to the bottom of the mould but i failed because of a
different reason.
4. The heat treatment of the mould to burn out the lost model is also a problem. While trying to cast the part as a one piced part the whole
mould would be a large block of plaster of paris. It lasts a very long time to bring the heat to the inside of the block to vaporize the
embedded plastics. This time is so long that the whole block will become cracks and beginns to become unusable.
The heat resistance of the plaster of paris investment material is not high enough. Maybe one mould out of ten would be usable.
Conclusion : As you can see in the pictures i tryed many times to make a one pieced casting of the manifold and every time i tried the reason for the failure was different. Yesterday was my last attempt and the problem was that there was still plastics left in the mould when i filled it with molten aluminium.
New plan : :ThumbsUp:
I give up and will try something different. I will cast smaller sections of the manifold wich will include only one corner in the gas passage so i will we able to use sodium silicate sand for the core and maybe also for the outer investment material. Many of my problems are caused by the plaster of paris material so i have to ged rid of this material at least for the core section.
I will use brass to cast the sections to be able to hard solder them together when i have all of them. My first try will take place today.
Here a few pictures of my failed attempts. No comment.
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I admire and respect your dedication and effort to create a "true" scale replica for this engine.
Thank you for sharing,
Thomas
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I don't know if it is of any use, and I don't have all the details, but I have heard of a method for making such items. A model is made of the interior of the manifold in engineering wax, and this is coated with graphite, this is electroplated with copper to the thickness required. Once finished the wax is melted out, and flanges etc., silver soldered on.
Ian S C
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Hello Thomas,
I have been quietly following this build from the beginning. I have enjoyed reading every post, until I read about your problems with the lost wax (lost PLA) casting for the exhaust system. That part was not so good.
In the past I had similar problems with ordinary Plaster of Paris. I was advised to buy the correct investment powder that the jewelry trade use for casting precious metal. Their investment is a mix of different refractory materials and plaster and much more resistant to cracking during burn out. Unfortunately the shipping costs can be more than the cost of the investment powder unless you have a jewelry maker near you. You can also find "investment powder" in e-bay.
What are you using for the burn out? That can also be a problem due to the amount of time (12 hours) required. An electric burn out furnace is preferred over fuel fired.
Good luck with your project, keep trying
Mike
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Check out Shapeways. 3D Laser sintered parts for fairly cheap in stainless steel/bronze should work just fine. Check out George's thread on his Holt 3 cylinder
Dave
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Hello Thomas
As Ian SC suggests, electroforming in copper is one alternative.
Steamer has also suggested 3D printed metal parts in stainless steel/bronze from Shapeways.
I have been investigating 3D printed metal for my exhaust system. Have a look at my recent topic http://www.modelenginemaker.com/index.php/topic,7391.0.html
The big problem with 3D printed metal parts is the unpredictable warping and shrinkage during the hot metal fusing stage which follows the printing stage. You must anticipate errors of 2% to 4% in the finished dimensions, unfortunately they are not predictable.
Mike
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Hello everyone,
Thank you all for the good sugestions i really appreciate that.
The sintered parts method sounds very interesting. I will keep that in mind for the future.
The only problem at his situation is that i cant do this at my homeshop. I want to make that part myself.
Electroforming sounds also very interesting and many years ago i experimented with an education kit to create a thin coper layer around a plastik part to chrome it after that. So it seems that electroforming could be possible in a homeshop but all the chemicals are rather expensive or not available for private use.
Professional ceramic invesment slurry as you suggested was also on my own " problem solving list ". I searched the web for this and the only available source for this could indeed be suppliers for dental laboratorys.
But dont ask about the price. Also this expensive investment materials are ceramic based and i think i would run into big problems when the time comes to remove the material out of the part. I think ultrasonic would not work on such a small diameter. Plaster of paris could be dissolved whith a fairly cheap solvent and the help of ultrasonic while sodium silicate bonded sand can be removed by cooking the part long enough in boiling water.
As advertised i started to cast the manifold out of individual parts to be able to use sodium silicate sand for the outher shape and the core. I just burned out the first mould with my propane torch. The whole mould was red glowing and because it is so small the heat surely made it all trough and all the plastic is vapourized.
I am not sure if i can cast this mould today because its sunday but maybe i will test the patience of my neighbours.....
Best regards,
Thomas
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That engine was originally used in 1928 to 1931 Fords. Back in the early 1960's I had three or four different Model A Fords. It was a great little engine, the only chronic fault being that it leaked oil thru the rear main bearing seals. This oil would then migrate to the clutch plate, so that every time you let the clutch out became a new and exciting experience. Sometimes the car took off very smoothly. Sometimes the clutch engaged with a lot of chattering and shaking, which shook the entire car. Sometimes, just when you thought the clutch wasn't going to engage at all, it would "catch" at the very last moment and you either stalled the engine or took off so damned fast it would almost give you a whiplash. Great job on the build.---Brian
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Hello Thomas.
A complete copper Elecroforming kit is available in the UK from Gateros http://www.ebay.co.uk/itm/Bright-Copper-Electroforming-kit-for-plating-non-metals-/253099158892?hash=item3aede2ad6c:m:m5nSuHUPb3iLj1BOp8Osz8A
A 22.5 Kg sack of jewelry investment powder is available in the UK from H S Walsh (jewelry makers supplies) http://www.ebay.co.uk/itm/Pioneer-Smoothcast-Extra-Fine-Investment-Powder-22-5-KG-Casting-Metals-TC0451-/253007797911?epid=24003895796&hash=item3ae8709e97:g:1doAAOSwN2VZTSJR
Maybe a propane torch for burnout produced too many hot spots
Hope this helps
Mike
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Mike , that was the hint i probably needed. Everytime i looked for professional investment powder i found the ones at dental laboratory suppliers for a unbelivable high price. I also recognized the jewelery makers use this kind of stuff but i didnt look at the pricing because i was thinking dental laboratory = expensive , jewelery = more expensive ....
I will order a sack of it and try it out. Meanwhile i can do other things such as experimenting with brass pours or machining something else when i have the time.
Did you already use this investment ?
Thanks again to all of you for all the advice ! I will keep you informed.
Best regards,
Thomas
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Hello Thomas
H D Walsh are an old long established firm of jeweler suppliers, Their products are second to none.
You still have the problem of providing support for the long central core. You could try pushing thin pins of the same material as the casting through the walls of the PLA before you pour in the investment. The casting should fuse with the pins, if not you can drill and tap some small plugs and afterwards file then smooth.
You should also think of building a burn out oven from loose fire bricks, that should keep the direct flame off the investment and also spread the heat evenly. It takes a long time.
Plenty to experiment with
Cheers
Mike
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Hello everyone,
I followed your advice and purchased a bag of professional investment powder. This was the right decission because it makes the burnout progress a lot easier but not bullet proof. It is of course still possible to break the mould while burning out the PLA printed model.
The last weeks i tried differend methods of breaking a mould before pouring and i was sucessful in every single of them.
I also bought a used electric burnout killn to make the burnout progess more controlable.
My last four attempts in casting the exhaust manifold where all with moulds which where gravity feed like the ones showed in my previous posts. On my last failed attempt i decided to switch to another technique.
This part asks for vacuum casting because of its thin walls and the overall shape.
So i have build a simple vacuum chamber to swich over to vacuum casting for my future attempts ( hopefully not to much ).
My first attempt was today and it was a " successful fail ".
It was a fail because the manifold is not usable but also a success because the vacuum chamber worked very well and the casing was the best of all of my previous ones.
I think this is the way to go and it will lead to a sucessfull casting sooner or later.
I have used an empty oil spray bottle for the flask at my first attempt. Unfortunately i didnt do any pictures of this because i was to excited trying this new way to fail.
Pic. 1 : The vacuum chamber. I took care to use only combustible materials such as plastic tubing and chipboard. Only the two pieced sealing on the top which is closed after the flask is inserted is made from aluminium.
The vacuum is produced from a strong industry vacuum cleaner i usually use to clean my machines and shop.
Pic.2 : The casting after the investment had been removed. It is at least 90% complete so i call it a 90% success. The buble at left side of the picture is the top of the mould while pouring the investment. It is most likely only an air bubble in the investment. This casting defect is no big deal and i dont worry about that.
Pic.3 : Every single printing layer is visible in the casing. I believe this is a good sign and proves that the vacuum casing progress has worked.
Pic. 4 : The biggest problem is seen in this picture. It seems that the casing was only feed trough itself and the flow through the feeder stopped for some reason. I am not able to evaluate this exactly. The first thing i will do is to increase the diameter of the feeder in my next attempt.
Pic. 6 : I broke the casting while investigating the crack. Hopefully the enlargement of the feeder is also the solution for this defect.
Pic. 7 : The area wich didnt fill is a little mysterious for me. The core is covered with metal but why is it not copletely filled ? Maybe i have to increase the leght of my flask to bring this area more to the inside of the mould. Actually there was only a few millimeters of feeder leght over this section because the spay bottle i used to do the flask was a little short.
I will do more pictures on my next ( hopefully sucessful ) attempt to show more of the process.
Maybe some of you have other thougts about the casing defects ?
I feel i am about to be sucessful.
Best regards,
Thomas
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Hello !
I finally did it !
After i have done any possible mistake when designing a model for investment casting i sorted out the problems and was sucessful on the todays pour of the exhaust manifold. ;D :cheers:
After switching from gravity feeded casting to vacuum casting the last remaining problem which you can see in my last post was a shrinkage problen due to the small feeder.
The solution was to increase the feeder to prevent it from solidification as long as possible. I also heated the top aera of the mould after pouring with a propane torch while maintaining vacuum for five minutes.
Here are the pictures :
1. The casing model whith investment already injected into the gas channel. There are also five little steel pins on the backside going trough the walls to support the investment core. The large feeder is a candle. I connected the pla model with hot wax to the candle.
2. There is not much clearence with the flask i have made ( 60 mm diameter ).
3. The holes in the flask are temporarily closed with tape.
4. After pouring and solidification of the investment and removing the tape the flask is ready for bourning out the wax and pla model. This takes four hours after increasing the temperature of the electric burnout killn up to 700 degrees within the first two hours.
5 - 6. Total happyness after the pour. The manifold is complete with no defects and ready for finnishing. :cartwheel:
Now i am back in business. I wil keep you informed.
Best regards ,
Thomas
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Nice work Thomas....that was quit an accomplishment to get a good useable manifold casting. Can't wait to see it fitted up to the block. Paul
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Thomas,
That looks great, but I must admit that it isn't something I would attempt. Great work!
Art
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Excellent, way beyond me but excellent :praise2: :praise2:
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Hello everybody,
Thanks for your kind comments.
With the experiences i have collected with the exhaust manifold i was able to cast the intake manifold being successful at the first try.
The inner diameter of the intake manifold is only 5,5 mm and even smaller as it is on the exhaust manifold.
As you can see i painted the manifold to make a little contrast to the sandblasted exhaust.
I think i am gettig closer......
The pictures :
1. The red hot glowing flask after burning the pla model out shortly bevore inserting it into the vacuum box for pouring.
2. The manifold after removing the investment. The investment in the inner section has to be removed by driving a rotating steel cable which can follow the corners trough the manifold.
3. It is useful not to remove the sprues or risers to early. They are useful for clamping the part to be able to machine it.
4 + 5. The two manifolds bolted provissionally to the engine for my personal amusement .... ;D
Now i will continue with finishing the cylinder head and the distributor....
Best regards,
Thomas
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Impressive work Thomas.
Dave
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:pinkelephant:I want one
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Thomas,
The whole works as a family photo is great.
Art
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Fantastic work Thomas.
-Bob
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Hello,
Last weekend i was able to make the flyweel and distributor.
I also worked on the the carburettor this weekend. Everytime i build a carburettor i believe that i will be the best carburettor ever. This did not happen until today. All the carbs i have build until now worked but everyone of them has its own weak point. This time i will try a two needle type carb. The problem with the air bleed type is at my understanding that the vaccuum becomes low at idle and therefore the vaporisation of fuel becomes difficult. I hope with a two needle type i can reach a more controlable and better vaporisation at low idle rpmīs.
I also had the idea to make the travel of the second needle adjustable more or less regardless from the opening of the throttle.
In the picture with the carburettor parts you can see a black square plate with only one hole in the upper right corner. Thias part is bolted to the carburettor square or at an angle. When the part is fixed to the carb square there wil be no travel of the second needle when the throttle is opened. Whe the part is bolted on the housing at an certain angle the travel of the throttle and therefore the needle valve in the throttle will be influenced.
Here are the pictures :
1. The distributor is made of a 3d-printed part with grooves for the copper wires. After i inserted the bended copper wires i filled the grooves with polyester resin. The lower section of the distributor is of a different type of plasic with a higher melting point and glued on. The linkage to the cylinder head is made of a piece of fuel tubing to get the best possible thermal insulation.
2. The carburettor body. The part is build from three pieces of brass and a turned piece of aluminium.
3. All the carburettor pieces. I didnt grind the needles for the needle valves myself because my wife has enough carburettor needle valves in stock....
4 + 5. The assembled carb. The spring on the outside will not be visible on the engine because it is on the backside. I dont know if i will make a throtle lever to operate the carb directly or if i will make some kind of linkage to operate it with a mini gas pedal mounted on the engine stand .
6 - 8. The carb mounted on the engine. The silicone sealings for the intake and exhaust manifold are also already in place. 4 brand new 1/4 x 32 spark plugs are in place.
The to do list becomes shorter....
Best regards,
Thomas
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very impressive!
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This really is some great work Thomas.
-Bob
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real nice would like to have one
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Excellent :praise2: Carburetors are always fun ::) I hope that your new variant is successful :wine1:
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Hello everyone,
It has been a while since the last progress on the Model A engine. The last few weeks i started the engine a few times but the carburettor described in my last post performed not the way i hoped. Also i had to sort out a few problems with the distributor which caused heavy misfiring of the engine. This misfiring caused a damage of the crankshaft which i was able to fix.
It is to early to show the engine running because i only can do very short runs of it. There is no radiator and coolant in it and after 20 seconds the engine becomes unbelievable hot. Without a working cooling system it is simple not possible to make tests with different carburettor settings and setups.
I wonder if it is normal for side valve engines to become very hot in a very short time ? Maybe it is because of the flat shaped combustion chamber whith a large surface area which catches most of the heat of the combustion gasses ?
Anyway, a radiator is needed and this was my work today. It is my first day of my 2 weeks christmas vacation and i was very productive.
The radiator is build from copper and brass tubing soft soldered together. It is 135 mm wide and 150 mm high. The cooling fins are made from aluminium.
The pictures :
1 / 2. Drilling of the 32 cooling fins. The measurements are 135 mm x 19 mm x 2 mm. After drilling undersize i reamed the holes with a 6 mm reamer to get a tight fit on the vertical tubes for a god heat transition. The vertical cooling tubes are 6 mm outher and 5 mm inner diameter.
3. Two fins are attached to the vertical tubing before soldering the lower copper tube, the wather hose attachement and the two covers of the vertical coper tube together. After this the vertical brass tubes are perfect aligned and the cooling fins can be slided on.
4. More copper tubing for making the top of the radiator. The upper horizontal tubing is larger ( 20 mm diameter ) to create some kind of water reservoir.
5 / 6 . The finished radiator. I plan to 3d print a cover for it in the future which makes it look the same as the original model a radiator grill .
Merry Christmas !
Frohe weihnachten !
Thomas.
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Thomas, it looks good. Are the fins just a friction fit onto the tubes?
Bill
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Hello Bill,
I used a little bit of loctide on them. I forgot to say.
Thomas
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Hello everyone !
After i had to sort out a few issues with the transistor ignition which killed tons of hall effect switches ( bad lead to engine block ) the engine is running. :cartwheel: You will see a video of it in my next post. The video is made with my smartfone so unfortunately the sound quality is not the best.
To make this build log complete i also post a few pictures of the machining of the parts to make the engine complete.
I have to admit that i was not able to stop the massive oil pumping as a consequence of not properly working oil control rings so i have to use 1:50 mix to run the engine. Maybe i will build a little two cylinder test engine in the future which is easy to dissasemble to have the possiblity to do a little reserch on oil control rings but i am happy with the " 1:50 solutuion " also.
The carburettor which is used is a simple one needle type without air bleed and was initially for temporary use but it works so well i think i will keep it. Of course it still needs a litte fine tuning. The idle could be a bit lower but i am close.
The cooling without wather pump is working very good. To my surprise no water pump is needed.
The pictures :
1 : The water hose attachment. I usually planned to cast this little pats like most of the other parts too. But it was easier to solder them together from seperate parts.
2 + 3 : The mounting for the radiator fan shaft is also a soldered part.
4 : The cover for the valve stem gallery. The oil line goes to the camshaft gears. I hope the oil wich is collected from the gears is pumped to the valves.
5 : The ignition wires are 0.5 mm copper wire. I have seen many pictures of the original model a engine with unisolated wires so i copied this.
6 : The cooling fan is made with the 3d printer. It is driven 1:1 by a rubber belt made from tire inner tube.
7 : The fuel tank is recessed in the wooden engine stand so i have made an opening to check the fuel level from the outside. There is a led light in the box behind the glass tank to make it easier to see.
Best regards,
Thomas
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Beautiful work.
I love the sound of it.
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Excellent :praise2: :praise2: What are you using for fuel? The tin seems to suggest some form of cleaning fluid :headscratch:
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Roger, actualy coleman fuel is chemically nothing more than catalytic gasoline. Here in germany coleman fuel is not available but we have
" Reinigungsbenzin / cleaning petrol " for degreasing issues . This is the same stuff.
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Just beautiful, and the exhaust note is awesome. So, are castings and plans going to be available :stir:?
Cletus
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Thomas,
That sounds great and responds to tapping the throttle well. I would say you nailed the carburetor.
Art
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Hi Thomas,
great sound.
Very well done.
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Fantastic engine Thomas!!! :ThumbsUp: :ThumbsUp: :ThumbsUp:
Congratulation! :cheers:
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Very nice Thomas!
Beautiful work and sounds great!
Dave
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Thomas,
Very well done. Your engine runs as good as it looks.
Chuck
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Thomas,
Nice work congrats for reaching the goal of a running engine.
Can you tell what diameter the carb is, and whats the displacement of the engine?
Michael
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Roger, actualy coleman fuel is chemically nothing more than catalytic gasoline. Here in germany coleman fuel is not available but we have
" Reinigungsbenzin / cleaning petrol " for degreasing issues . This is the same stuff.
I started out using normal unleaded petrol but have recently changed to Alkylate fuel that I can get in the local agricultural store, 'Landi' here in Switzerland. This reduces the smell problem.
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Hello,
Thanks for all the kind commends.
Art, you are probably right, maybe i nailed the carburettor. I did one little thing with it that changed the behavior of the carb totally. It improves gasoline suction and turbulence ( and therefore atomization ) at low rpm very well i think.
This is probably of public interrest but i have to proof this bevore and make a drawing bevore i post it.
Roger, with the kind of petrol we use ( alkalythe / cathalytic ) i can even run my hit & miss engine in my living room. But with this engine and the needed 1:50 mix this would probably not the best idea.
Cletus, I will make the plans ready for the engine but it will take a little time. This was the plan from the beginning. Also there is no reason not to cast a few more parts from my casting models if someone wants to build one.
Michael, the engine displacement is 54,23 ccm with a bore of 24 mm and a stroke of 30 mm. The venturi diameter is 4 mm but there is a special slot / groove in the venturi wich makes all the difference i think.
Best regards,
Thomas
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Fantastic degrees of experiments, thanks for the amount of informations shared ! wow, dedicated work through this successful built, congratulations, this is a very beautiful engine...
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Fantastic work, Thomas :ThumbsUp: :ThumbsUp: :ThumbsUp:
Congratulations on this really nicely made and great running engine!
Plani
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Thomas,
What firing order did you choose for your Ford engine?
Thanks.
Chuck
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Thomas,
What firing order did you choose for your Ford engine?
Thanks.
Chuck
Chuck, it fires 1 - 3 - 4 - 2
Thomas
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Thank you, Thomas.
Chuck
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Thomas, you may wish to put the video and a few finished pictures in the "Showcase" section as well with a link back to the build thread. Thanks for taking us along on the build of this little beauty.
Bill
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Fantastic work!
Is it correct that you made this engine in just under a year (judging by the start of this thread)? If so, you make great progress :)
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Thomas, you may wish to put the video and a few finished pictures in the "Showcase" section as well with a link back to the build thread. Thanks for taking us along on the build of this little beauty.
Bill
Bill, i will do this but i want to make a nice new video first. I have made a few improvements on the radiator fan and other things.
Best regards,
Thomas
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Fantastic work!
Is it correct that you made this engine in just under a year (judging by the start of this thread)? If so, you make great progress :)
Brendon, i started planning the engine with the first sketches approximately two months before my first post.
Best regards,
Thomas
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Hello everyone,
As i already said the trial carburettor i have made to test the engine works so nicely that i will keep it. The slot i have milled in the venturi barrel improves the suction of fuel so well that it was possible to mount the fuel tank 18 cm below the carb without problems.
I also think there is a huge improvement in atomization ( maybe because of heavy turbulence ) especially at low rpm / idle .
I tried another venturi without the described slot and it was not possible to adjust the needle to a position suitable for high speed and low speed.
This moved me to draw the carburettor as a drawing for sharing it. Maybe some of you guys has some time to build one and test it on a petrol engine of the size 35 - 60 ccm if you can deal with the metric measurements ?
The picture is only low resolution, i will try to post a high resolution drawing in a Zip - file also.
Best regards,
Thomas
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Hi Thomas,
Thanks for posting the carburettor drawing.
I will try it on my Austin engine when it comes time to run it.
It looks similar size to your engine.
I may change the out side shape so it looks more original, but keep the barrel and Jets the same.
Regards
Tony.
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Excellent. An absolute showpiece. :ThumbsUp: