Author Topic: Four cylinder scale engine  (Read 22197 times)

Offline ThomasM

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Four cylinder scale engine
« on: January 29, 2017, 11:45:36 AM »
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
 

Offline ThomasM

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Re: Four cylinder scale engine
« Reply #1 on: January 29, 2017, 11:49:26 AM »
The crankcase is the  first casting model of the engine i have made.

Offline Nick_G

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Re: Four cylinder scale engine
« Reply #2 on: January 29, 2017, 11:50:14 AM »
.
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.

Offline ThomasM

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Re: Four cylinder scale engine
« Reply #3 on: January 29, 2017, 12:01:46 PM »
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.

Offline ThomasM

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Re: Four cylinder scale engine
« Reply #4 on: January 29, 2017, 12:14:07 PM »
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.

Offline GailinNM

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Re: Four cylinder scale engine
« Reply #5 on: January 29, 2017, 12:46:36 PM »
Looks great to me.
This will be a very interesting build.
Gail in NM
I would like to be the kind of person my dog thinks I am.

Offline ThomasM

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Re: Four cylinder scale engine
« Reply #6 on: January 29, 2017, 01:08:57 PM »
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

Offline Tennessee Whiskey

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Re: Four cylinder scale engine
« Reply #7 on: January 29, 2017, 01:36:34 PM »
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

Offline fumopuc

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Re: Four cylinder scale engine
« Reply #8 on: January 29, 2017, 01:49:03 PM »
Hi Thomas, do you take orders for your castings ?
Nice start up with the machining and no blow-holes until now.
Kind Regards
Achim

Online b.lindsey

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Re: Four cylinder scale engine
« Reply #9 on: January 29, 2017, 02:04:31 PM »
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

Offline Flyboy Jim

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Re: Four cylinder scale engine
« Reply #10 on: January 29, 2017, 03:13:24 PM »
Good documentation Thomas. This is going to be a fun build to watch.

Jim
Sherline 4400 Lathe
Sherline 5400 Mill
"You can do small things on big machines, but you can do small things on small machines".

Offline ThomasM

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Re: Four cylinder scale engine
« Reply #11 on: January 29, 2017, 03:23:21 PM »
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.


Offline Roger B

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Re: Four cylinder scale engine
« Reply #12 on: January 29, 2017, 03:57:19 PM »
An excellent start, I will be following along  :wine1:
Best regards

Roger

Offline kvom

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Re: Four cylinder scale engine
« Reply #13 on: January 29, 2017, 03:58:23 PM »
I'm always impressed by builders who start with doing their own castings.

Online Dave Otto

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Re: Four cylinder scale engine
« Reply #14 on: January 29, 2017, 06:59:57 PM »
Interesting project Thomas, I will enjoy following along with your project.

Also, welcome to MEM!
Dave