1978 Allis Chalmers 670T info

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   I have a 1978 Thyokol/LMC snowcat that has a 670T engine in it. I've owned it for maybe 10 years and hopefully have made it more reliable during the winter.I've gone through multiple electrical issues and finally found a bad master switch that seems(so far) to have been the culprit all along.
I've removed and replace the starter many times thinking this could be the problem because the gears that mesh with the flywheel had oil/water all inside. I figured when this mixture froze, it wouldn't allow the bendix to operate correctly.
The yellow cover that goes around the flywheel has a plug on the bottom of it but I can't find any info on what if anything is supposed to be in there.
I only see one plug on the top(at bout 11 o'clock looking forward to the cat) but it doesn't look like a fill hole because there's a plate or piece of metal 1/8 from the bottom of the hole.
There is a skid plate right under this cover which i had to cut away to find the plug. This tells me it's never been serviced or drained in decades.
Any information about this engine or knowledge you'd like to share would be appreciated. Thank you very much

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noel petersom Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Dec 2023 Location: Bear Valley, CA Points: 2	Post Options Post Reply Quote noel petersom Report Post Thanks(0) Quote Reply Topic: 1978 Allis Chalmers 670T info Posted: 06 Dec 2023 at 6:35pm
	I have a 1978 Thyokol/LMC snowcat that has a 670T engine in it. I've owned it for maybe 10 years and hopefully have made it more reliable during the winter. I've gone through multiple electrical issues and finally found a bad master switch that seems(so far) to have been the culprit all along. I've removed and replace the starter many times thinking this could be the problem because the gears that mesh with the flywheel had oil/water all inside. I figured when this mixture froze, it wouldn't allow the bendix to operate correctly. The yellow cover that goes around the flywheel has a plug on the bottom of it but I can't find any info on what if anything is supposed to be in there. I only see one plug on the top(at bout 11 o'clock looking forward to the cat) but it doesn't look like a fill hole because there's a plate or piece of metal 1/8 from the bottom of the hole. There is a skid plate right under this cover which i had to cut away to find the plug. This tells me it's never been serviced or drained in decades. Any information about this engine or knowledge you'd like to share would be appreciated. Thank you very much

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DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 20535	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 06 Dec 2023 at 7:12pm
	I'd say it was rated at 158HP @ 2,400 RPM. An engine used in the Allis-Chalmers 7045 farm tractor and L2-series Gleaner combine. Oil changes every 100 hrs with 15W-40 motor oil for older flat tappet camshaft engines. Tappets adjusted to .017" cold. Injection pump timing is 16 degrees BTDC.