Case Colt Ingersoll Tractors banner

Compression test results question

1302 Views 3 Replies 4 Participants Last post by  Hydriv
Hi guys
I did a compression test on a 446 that I am working on and both cylinders are have a reading of 120lbs psi
In what stage of life would you guys say this engine is in? It starts and runs OK, but has a knock which I believe is a bad front bearing. ( I can detect movement in the flywheel, and it keeps eating stators)
I'm trying to determine if I can get away with just replacing bearings. Of course, ripping into it may yield further issues)
Just tryin to get an idea...
1 - 4 of 4 Posts
120 is at the upper end of the specs, so you're good in that regard.

But, please don't run it with a bearing that is so loose you can feel movement at the flywheel. That loose bearing will cause a lot of lost oil flow and probably starve other areas (like rods) that may fail.
Because this is an Onan issue, I am going to move it to the Onan forum so that it catches Boomer's eye.

In my opinion, you could just address the front bearing and seal problem and not touch the rest of the engine to any great degree. However..............since you have to spend the time to tear it down and re-assemble it with new gaskets...................perhaps cross-hatching both bores, installing a new set of rings, checking the end gaps on those rings and polishing the crank journals would be money well spent. To go a bit further, cleaning up the valves and lapping them in would also seem prudent. Even though the 120 PSI readings are excellent, the above would go a long way toward extending the life of your engine for a very low cost. .
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.