Model Engine Maker
Engines => From Kits/Castings => Topic started by: michelko on December 22, 2020, 03:04:45 PM
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Hi guys,
just started an new project as the title says, it is an Holt 75. It is kind of an chimera. While i am using some castings it is alos based on plans and some is my own design.
The initial plan was building the engine from George Brittnels plan from bar stock. I purchased his set of plans but redid them in metric using a 3d CAD Program.
Some time ago i came in contact with a fellow HMEM forum member called foketry. He was so kind to give his left over casting parts and some cores for the heads and Zylinder jackets.
So i tried to use the castings but keep the design metric.
Now i am nearly ready with the crankcase. I still have to line bore the main bearings of the crank and the middle bearing of the cam.
For this i will use a Straight bar of drill rod and mount a HSS bit in it. I just bored the Bearings at the end plates so i can use them as guide.
Here are some pics an a short video.
Milling out the lower part of the crank case
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boring tje cylinder holes and taping some threads
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milling the end plates/bearing holders
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and here is my setup for boring the bearing holders and the hole for the camshaft
for that i used my beloved wohlhaupter, a realy awesome tool
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and here is the short video from the boring job
https://www.youtube.com/watch?v=x4g12CtOseY
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You're off to a good start there :ThumbsUp: :ThumbsUp: One to follow along with :wine1:
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Hi Michael, I will following along too.
The bar stock plans of George Britnell and parts of the engine are available as a CAD model on my computer already.
So may be some time I will follow your route, because in my eyes also it is a remarkable engine.
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Hi guys,
worked a little on the crankcase/sump. Unfortunately i didīt notice some irregularities on the castings and so i made a hole into the sump wall.
I think i will patch this with a smal piece aluminium jb welded in place.
I have a ac tig machine but i am a little scared because of my low to nothing experience in welding aluminium.
So i think the jb weld woill e the way.
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Hi Guys,
here is some update on the Holt.
I am ready with the sump. Because of the massive casting i decided to make mill out the material also from the underside.
This recomended an cover to close the sump again. I also drilled a hole from the side to connect the chambers. Here i also made a cover plate.
Next step was the main bairing halves. I left aprox 1 mm in the hole for lineboring.
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and some more pics
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Hi Guys,
the lineboring is done. I am realy happy with the result and how the boring bar worked.
I made some brass plugs to fit in the formerly bored holes at the end s of the case. these plugs had an 10H7 boring to guiede the 10mm drillrod. In the drillrod i made a 3mm hole and 90 degree to that a m3 thhread for an set screw to hold the cutter.
The cutter is ground from an broken mill schaft.
The surface of the bored holes came out realy nice , no chatter or something.
Video crankshaft
https://www.youtube.com/watch?v=-cLmn0B9Tj0
Video camshaft
https://www.youtube.com/watch?v=xMugBVjrcZE
The boring bar and the cases where setup into the lathe for boring.
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Very impressive work michelko! :ThumbsUp: :praise2:
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Hello Michel
I have just watched the video - I knew how it's done, but this is the first time I really could see how well and cleanly the cutter removed the material - thank you :ThumbsUp:
I guess that this is a homemade tool, so did you use any tricks to set the depth of the cut ? And how accurate could you set it for the diameter you aimed for ?
Per
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Hi Guys,
the lineboring is done. I am realy happy with the result and how the boring bar worked.
I made some brass plugs to fit in the formerly bored holes at the end s of the case. these plugs had an 10H7 boring to guiede the 10mm drillrod. In the drillrod i made a 3mm hole and 90 degree to that a m3 thhread for an set screw to hold the cutter.
The cutter is ground from an broken mill schaft.
The surface of the bored holes came out realy nice , no chatter or something.
Video crankshaft
https://www.youtube.com/watch?v=-cLmn0B9Tj0
Video camshaft
https://www.youtube.com/watch?v=xMugBVjrcZE
The boring bar and the cases where setup into the lathe for boring.
well done Michael :ThumbsUp:
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Michelko,
I am very impressed with your work on the Holt. I have heard of line boring but have never seen it in action. I have seen George run his at the NAMES show in Michigan. Look forward to seeing yours proceed.
Art
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Hello Michel
I have just watched the video - I knew how it's done, but this is the first time I really could see how well and cleanly the cutter removed the material - thank you :ThumbsUp:
I guess that this is a homemade tool, so did you use any tricks to set the depth of the cut ? And how accurate could you set it for the diameter you aimed for ?
Per
Hi Per,
the bar is an ground drillrod. i just meassured the hight of the cutter bit above the rod. So for example to bore a 14mm hole i set the cutter tip to 2mm above the rod surface.
I still have to measure the achived diameter but in the end it is not critical because of the bronce inserts. i will fabricate them to meet the bored hole.
Regards Michael
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Hi Guys,
worked a little on the cams. I made them from Drillrod and they will be hardened also the followers.
I mainly used the profile like in George Brittnells plans but instead of a tangent between base and nose i used a radius.
So the follower will not do abrupt movement.
The bar was setup in my rotary table (not used as this just as holder) and milled with the cnc function of my bf20.
The cams came out nice and just needed a little sanding/polishing.
The cams has a little noth of 2 mm, these is used to index the cams on the shaft. The cams will be fitted with loctite to the shaft, the pins will also be an additional security against loosing /rotating of the cams.
The shaft will be an anharded drillrod of 6mm like i similar used in the bugatti.
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here is a short vido from milling
https://www.youtube.com/watch?v=dfswU4RaAdI
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Here is a drawing with the meassures of the cams
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Hello Michel
I believe we all have a problem with videos no longer showing.
Nice work on the Holt engine
Mike :ThumbsUp:
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Hi Guys,
here is a little update on the cams and the shaft.
With the indexing table i drilled the holes into the shaft . The little pins are indexing the cams and also give a little safety against loosing. The cams are loctited io the shaft after hardening.
The cams are made from drillrod, heated to 800 °C and quenched in oil. Then annealed at 290°c for 1,5 hours.
Also turned the outer bearing and did a testfit with the shaft.
Just have to make the split middle bearing.
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Hi,
here is a little update on the holt.
I made the cylider jakets. They are turned from some free turning steel. For this i used my temporarely to cnc converted lathe.
I also fabricated the big gear for the cam shaft.
Unfortunately i had some problems to make the hole to spec. i aimed for 6 H7 but something went wrong while reaming.
At the end i bored it out on the lathe to fit the camshaft.
Regards Michael
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The engine is coming along great! Thanks for the videos on your progress. That was the main reason I split the crankcase so it would be easier to machine the main bearings.
gbritnell
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Hi guys,
long time no post.
Yesterday i found some time to work on the rockers.
Made them from freeturning steel.
Regards Michael
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I'm glad to see you are getting back to your Holt build.
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Hi George,
yes i am too. But in the meantime i had another toy to play with that took my whole focus.
Greetings
Michael
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Hi guys at least i found some time and inspiration to work on the holt again.
I started on the crankshaft. I decided to build it up from pieces.
The main shaft is from 12mm drill rod an the rod shaft s are from 10mm drillrod.
The webs where milled and drilled/reamed from c45 Steel.
All pieces will be glued together with loctite and additional pinned.
I made some good experiences on my bugatti build with the loctited crank so i am hoping this will also work for the holt.
Michael
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Here is ashort Video from milling the webs with my BF20 CNC
https://www.youtube.com/watch?v=y2UkLhhPcj0
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Distractions - yeah there can be many of those ;) great to see you back here :cheers:
Per
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Here is my setup for gluing the crank.
Later i will additionaly pin it. Just to be sure the connection wonīt come loose.
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Crank is finished.
i additionaly pinned the webs to the shafts with 3mm drilrod bits. they are also glued with loctite and slightly hammered.
Then milled out the parts between the webs.
The crank looks nice. I am happy with the result.
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Nicely done :praise2: Multi cylinder engine crankshafts are not easy :ThumbsUp:
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Great looking Crank :ThumbsUp:
Are you going to put Split Bronze Bearing-Shells in the Block ?
Per
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The engine is coming along great!
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Great looking Crank :ThumbsUp:
Are you going to put Split Bronze Bearing-Shells in the Block ?
Per
Hi Per,
Yes the three inner bearings will BE Split ones.
The outer will BE one piece.
Michael
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Hi All,
I just acquired a Coles Holt engine casting kit. I am in need of the Coles drawings, I would like to purchase any if anyone has something available.
I have no idea if anything is missing in the kit.
Thank you in advance!
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Hi Guys,
worked a little bit on the Holt. The crank bushings are done.
Made them from bronce. the inner ones are split, the middle bushing has also thrust shoulders.
I am realy happy withe the result. the crank turns nice and smooth.
Michael
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Here are some Videos how smooth the crank is turning.
https://www.youtube.com/watch?v=6OWW7GWZxoo
https://www.youtube.com/watch?v=6qWv1yCOnZQ
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Beautiful work, Michael! The crank certainly does turn smoothly! :ThumbsUp: :popcorn: :popcorn:
Kim
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Outstanding work on the crankshaft!
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Great result on the Crank Michael :praise2:
Per
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A lovely piece of work and a major milestone crossed passed. Very well done! :ThumbsUp:
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Hi All,
I just acquired a Coles Holt engine casting kit. I am in need of the Coles drawings, I would like to purchase any if anyone has something available.
I have no idea if anything is missing in the kit.
Thank you in advance!
There use to be a dealer on eBay who sold a CD of the drawings on eBay. I bought one, they were only like 10 bucks. By the way, where ever did you find the kit? I would like a set.
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Hi guys,
yesterday i milled the second gear for the valvetrain. The one that goes onto the crankshaft.
It has 25 teeth and is Module 0.9. Made from freeturning steel.
After turning and milling the teeth i broached the keyway with my cnc BF20.
A youtuber named clough42 made some nice content on broaching keyways.
The result is a realy nice keyway and the machine worked just a couple of minutes.
Here is a video from the process:
https://www.youtube.com/watch?v=hF_Jje2GO6g
and here the gears at work:
https://www.youtube.com/watch?v=p40uYJzqq0s
Regards Michael
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Your gear train looks great, Michael! :ThumbsUp: :popcorn:
I assume the clamps on the mill are to keep the spindle from turning during the broaching operation? Interesting use of a mill!
Kim
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Your gear train looks great, Michael! :ThumbsUp: :popcorn:
I assume the clamps on the mill are to keep the spindle from turning during the broaching operation? Interesting use of a mill!
Kim
Yes i was a liitle lazy and did it the Quick and dirty way. Some day i will build a clamp for the spindle, ...maybe ;D
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Always great to see and feel it all go round and round, up and down as it should :praise2: :cheers:
I haven't seen broaching done on a Mill before - but as some here are doing the similar thing with Drill-Presses and Lathes - why not the Mill ;D and the result speaks for itself :ThumbsUp:
Per
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Hi
did the rockers yesterday. The body is milled from an round stock of steel. The round part with the thread is silversoldered to the main part.
I decided to go this way instead of the adjustable pushrod.
The bore will get a brass/bronce bushing.
Still have to clean them.
Regards Michael
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That's a nice set of rockers :praise2: I like the use of the CNC mill for broaching the keyway :ThumbsUp: :ThumbsUp: I haven't seen that before.
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Still following along. Nice work on the rockers!
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Hi
just found some time to make the gearhousing.
Came out nice.
Next will be the cover.
Greets Michael
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Good to see progress and I can see why you are very happy with the latests parts :ThumbsUp:
Per :cheers:
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That gear housing does look very nice indeed! :ThumbsUp:
The Bugatti engine hiding under the towel must be the same one as in your avatar? Did you do a thread on that one also? (edit) Found it.
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Hi guys and thanks for your replies.
Yesterday i made the gearbox cover.
I changed the designe a little bit so i could use lipp-rings as shaft sealing to avoid excessive oil loss.
Used tape and superglue to hold the workpiece on the table.
Worked realy nice.
Just had to sand the mill marks away.
Regards Michael
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Yesterday i made the gearbox cover.
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Used tape and superglue to hold the workpiece on the table.
Worked realy nice.
.......
Regards Michael
Another fine piece of metal sculpture. Nice work. :ThumbsUp: :ThumbsUp: :ThumbsUp:
I am surprised tape and superglue was enough to hold the workpiece. It must depend on having a large glued area.
Mike
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Yes its amazing. Used this method also for the side plates on the Bugatti Build with great success.
Regards Michael
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I've had excellent success using double sticky tape to hold two pieces together that need to be milled/drilled identically, and it holds pieces surprisingly well. But as you say, it is based on the area covered by the tape. If it's a very small piece with little surface area, it doesn't work as well.
Michael, when you say tape and superglue, are you using single-sided tape, so the adhesive of the tape holds one side, and superglue holds the tape to the other side? Or something else?
Thanks,
Kim
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Hi kim i used a kind of masking tape.
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Hi kim i used a kind of masking tape.
Single-sided masking tape? Or double-sided?
And where/how did you use the superglue?
Kim
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Hi kim i used a kind of masking tape.
Single-sided masking tape? Or double-sided?
And where/how did you use the superglue?
Kim
Hi Kim
Have a look here.
https://www.youtube.com/watch?v=e-coDYZCmEw
Dave
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Ah... Thanks, Dave. Got it now. Interesting technique!
Kim
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Hi,
yesterday i made the distributor gear case.
Also used the supergkue method for workholding.
Next will be the cover.
Regards Michael
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Made some parts for the distributor.
Had to make the adjuster a scond time because i made a mistake while turning the piece over to the backside und missed the touch of about 2mm.
Regards Michael
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Hello Michel
I love the offset milling spindle of the side or your Holt engine. :ROFL: :ROFL: :lolb: :lolb: :Jester: :Jester:
Mike
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Yeah that willl become my universal workshoptool powered with fuel
;D
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Beautiful work, Michelko! :popcorn:
Kim
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Hi guys,
just drilled and tapped the holes for mounting the sideplates.
Also milled the legs.
At least the engine now stands solid on the table.
Just ordered some Material for the cylinder liners.
this will be next step.
Regards Michael
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forgott the pics of the side plates
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Hello Michael,
The engine is looking very nice. :ThumbsUp: :ThumbsUp: Did you do the side plate castings?
Cheers :cheers:
Mike
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This is coming along very nicely! Thanks for the update.
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The side plates look great! :popcorn: :popcorn:
Kim
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I like that very much! :ThumbsUp: :ThumbsUp:
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Excellent :)
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Very fine looking engine. :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :cheers:
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Hi guys,
thanks for all the positive comments.
Today i worked on the big flywheel.
There is a vendor in Germany that sells cast steel flywheels in the right size.
I turned the outer ring, drilled an reamed it and the broached the keyway.
Al went nice, i love the look.
Regards Michael
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Here is a short video from the broaching
https://www.youtube.com/watch?v=AYoMAmJj7hA
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Hello Michael,
The engine is looking very nice. :ThumbsUp: :ThumbsUp: Did you do the side plate castings?
Cheers :cheers:
Mike
Hi Mike,
maybee you know foketry? Hi is actual building a 18 cylinder Isotta Frashini and showing it on HMEM.
Hi did the castings that i have. Hi has given me the castings of the crankhousing and the sideplates and also the Models for the Cylinder and som other parts.
Regards Michael
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Hello Michael,
Who is the supplier of your flywheel? I'm enjoying the engine build :)
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Hi guys,
thanks for all the positive comments.
Today i worked on the big flywheel.
There is a vendor in Germany that sells cast steel flywheels in the right size.
I turned the outer ring, drilled an reamed it and the broached the keyway.
Al went nice, i love the look.
Regards Michael
Cast steel...not iron? Impressive! :cheers:
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It is from Bengs Modellbau.
Yes Cast Steel.
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Hi Mike,
maybee you know foketry? Hi is actual building a 18 cylinder Isotta Frashini and showing it on HMEM.
Hi did the castings that i have. Hi has given me the castings of the crankhousing and the sideplates and also the Models for the Cylinder and som other parts.
Regards Michael
I know of foketry and have followed the build of some of his engines. He is a very energetic and fast builder. And somehow finds time to help other builders.
Regards
Mike
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Hi Guys,
today i disasembeld the block to repair the hole in the lower part.
I used some aluminium and filed it to size and jb welded it in place.
While in there i took a short vido of how smooth the crank and flywheel ist running in the bushings. Realy happy with that.
https://www.youtube.com/watch?v=hEC7KU5VdfQ
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While in there i took a short vido of how smooth the crank and flywheel ist running in the bushings.
Very impressive how easily and smoothly that assembly turns. Well done! :praise2:
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The original design of the crankcase was one piece. According to the instructions you had to file the bearing surfaces flat by going through the window in the end of the block. There were holes drilled through the upper surface where the cylinders bolt on. You would go through these holes to drill and tap for the bearing inserts. The bearing were then mounted and the block was line bored. A really over complicated affair with the bearings possibly being out of alignment after machining. This is why I split the crankcase into 2 pieces so the the bearings could me mounted flat and securely then bored.
Your crank turns real nice.
gbritnell
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The original Design ist realy unbeleavable complicated.
Thanks to goerge for the upgrade in the Design.
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Hi Guys,
today i made the crankcase breather. It is made from brass. I cut the Tubes and ground them at an angle. Then i silver soldered the tubes together.
The flange and the cap are soft soldered to the pipes.
At the end i did some cleaning with an brass brush on the proxxon grinderto remove the coloration from soldering.
Regards Michael
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Beautiful art work, Michael! :ThumbsUp: :popcorn:
Kim
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Looks fabulous! :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :cheers:
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I believe that this is another one you will end up being very proud to have made :praise2:
Love all the details :ThumbsUp:
Per :cheers:
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Hi Guys,
at least i found a little time to work on the Holt.
I made the cylinder liners from cast iron and glued them into the jackets.
I turned the liner with a slight slipfit and used loctite 648 to glue them in.
Used this method also on the seal an the bugatti with very good results.
After that i had to lapp the liners because of the relativ rough survace from turning.
So i had to build a lapp. I made the shank with an MT2 taper.
The sleave is made from aluminium.
Building the lapp took me several hours, lapping the cylinder just a couple of minutes.
Next step will be the pistons and the rods.
Regards Michael
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Hi,
Finished the Pistons today.
Very Happy with the result.
https://www.youtube.com/watch?v=16CHCPHKlFc
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Looks like a perfect fit :ThumbsUp:
Per :cheers: :popcorn:
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Excellent!
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Rods are ready. Made from 7075 with split bronce bushings.
https://www.youtube.com/watch?v=GAQHI7ed0hA
Regards Michael
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A question to other Holt owners:
how much oil do you fill in? How high should the level be?
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Just enough so the connecting rod scrapes the surface of the oil when it rotates.
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Glad to see you back on this :ThumbsUp: I like your homemade lap, I have always bought mine from Acrolaps. http://acrolaps.com/index.htm
Excellent progress :praise2:
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Hi Roger,
not sure where to source the laps in germany. so itīs a hobby and i like to make my tools self.
Regards Michael
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Was a litle dilligent on the Holt and made a bunch of studs to fasten al the single parts like cylinders and case parts.
Also made the midle bushing for the cam. It is also a split bushing from bronce.
Regards Michael
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All the small but important parts as well and they look good :ThumbsUp:
Per :cheers:
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Hi Guys, heads are done.
The cast Iron machined quite nicely, but man what mess.
that black dust is all over the shop, and most in my nose :Lol:
Think i was working in a cole mine.
The last cast iron parts wll be the rings.
Regards
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Nice looking set of heads, Michael! :ThumbsUp: :popcorn: :popcorn:
That can be dirty stuff to work with, can't it :Lol:
Kim
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:ThumbsUp:
Nice looking set of heads, Michael! :ThumbsUp: :popcorn: :popcorn:
That can be dirty stuff to work with, can't it :Lol:
Kim
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Nicely done :praise2: :wine1:
My next step on the Junkers is also a lot of cast iron machining ::) Maybe we need an emoticon for black bogies :thinking:
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That's growing up to be a very fine looking engine. Lots of mighty nice machine work! :ThumbsUp: :ThumbsUp:
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Thanks to all for the kind words.
After some lazy time i am realy motivated to finish the project as soon as possible.
Any sugestions about the valve timing? maybe george can give some information?
I am not sure how to set it. The engine should run at low rpm
Regards
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My engine runs best at about 15 degrees BTDC. I can adjust it while the engine is running but it doesn't change the performance much. Unless you advance it too much. If you get it down about 8-10 degrees the engine will run slower but then it won't throttle up very well. The biggest issue with the engine is when you run it real slow for an extended period of time the fuel will collect in the updraft manifold and when you Rev it up it will smoke for a couple of seconds while it pulls the unburned fuel out of the manifold. I have been able to idle my engine down to 4-5 hundred rpm.
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Hi george thanks for your reply.
You wrote about the ignition timing. Thats adjustable without disassemble the engine. So its easy trial and error.
I wouldlike to know the valve timing. Thats not to easy to adjust so it should match as good as possible.
When did your engine starts opening the intake cycle?
Thanks in advance.
Regards
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The camshaft is what is known as a symmetrical cam. The intake cycle and exhaust cycle are identical. There is even overlap at TDC. The way I set the cam to crank relationship is to rotate the engine until the #1 cylinder is at TDC. Adjust the cam position until the intake and exhaust are moving as close to the same as possible. (Intake opening, exhaust closing.) I usually make a mark on the flywheel with a felt tip marker at TDC, with a register point. When the intake opens make another mark. When the exhaust closes make a second mark. They should be evenly split from the TDC mark. The firing will be 360 degrees from this point. (1 revolution)
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Perfekt. Thanks.
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Hi all. Another step is done. Sunnday was piston ring day.
Made them from GGG60 after the Trimble method.
Used my little oven for heat treatment.
I made a little jig to hold the rings for the annealing process.
The rings came out nice.
Happy with the result.
Regards Michael
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Hi,
today i made the valves.
I used 3mm drillrod for the stem and 9mm for the disk.
The two parts are silversoldered together.
I made a dummy guide from brass to check the funktion. Still waiting for the bronce to make the guides.
I hope it will arrive next week.
The seats will be cut with my selfmade seatcutter.
Michael
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Very nice work on the valves, Michael! I made a seat cutter just like that one for my last engine, and will use it again on the current one.
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Excellent :praise2: Having a small furnace to heat treat the rings is much better than a gas torch :ThumbsUp: