646-75lbh restore

Troubleshooting, rebuilding, repairing Onan engines.
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Spike188 Canada
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Re: 646-75lbh restore

Post by Spike188 »

Another setback this morning. This motor had an "what did they do that for" point box on it. :pullhair: The stator was also missing but the engine was running it you had a charged battery.
CCKA cam.jpg
With what is know about this engines history and the overall condition of the 646B it came from, cam condition should have been expected.
CCKA Cam points lobe failure.jpg
The points lobe had galling on the lead in of the cam on both sides. My first though was remove the points and change over to electronic ignition. Further inspection of the other lobes reveled a slight imperfection on the back side of on lobe. Well there goes the dream of finishing it this week. Can you say Debbie Downer?

A month ago when the 4118AH was purchased there were some Onan's in the weeds.
CCKA cam doner.jpg
This one not only has a good cam, but also a few other parts that will be useful.

Never look a gift horse in the mouth.

Spike.
Spike Colt - 9 & 10, Case - 108, 118, 444, 446, 448, 646, 646bh, Ingersoll 4016, 4118AH
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Spike188 Canada
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Re: 646-75lbh restore

Post by Spike188 »

The donner camshaft is from a JD 318, and a newer series of engines. The lobe lifts are a lot higher than the CCKA cams. :47: The options now are finding a good camshaft or using the old one with electronic ignition.

Any suggestion?

Spike
Spike Colt - 9 & 10, Case - 108, 118, 444, 446, 448, 646, 646bh, Ingersoll 4016, 4118AH
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Eugen Canada
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Re: 646-75lbh restore

Post by Eugen »

If the profile of the lobe is mostly the shape it should have and only local parts are pitted or gauged, would it not be possible to fill in with some welding and file it back into a smooth finish of the right shape? I would not do that to the valve cam lobes, but the points shaft doesn't put a lot of pressure on the lobe.
Case 224, 444, 644, 680E
Kubota B26 :blush:
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Spike188 Canada
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Re: 646-75lbh restore

Post by Spike188 »

Boomer to the rescue! He shipped me a NOS cam, intake valve and guide today. Now the pistons and crank will come back out to have the valve and seat ground.

:creeper:

Spike
Spike Colt - 9 & 10, Case - 108, 118, 444, 446, 448, 646, 646bh, Ingersoll 4016, 4118AH
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Re: 646-75lbh restore

Post by Eugen »

Spike188 wrote: Tue May 04, 2021 5:40 pm Boomer to the rescue! He shipped me a NOS cam, intake valve and guide today. Now the pistons and crank will come back out to have the valve and seat ground.

:creeper:

Spike
That is good news Spike! What are you cutting the valve seats with? I ordered a tool from India 3 months ago and it never came :oops:

I had mine done by Mike.
Case 224, 444, 644, 680E
Kubota B26 :blush:
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