Engine Rebuild - Am I in Trouble?

Randy McC

Member
Just finished my Farmall C engine rebuild with a Reliance rebuild kit. Kit instructions said to 'not' remove pistons from sleeves to avoid damage to rings. Pushed pistons far enough down to connect to crankshaft without exposing rings. Seemed to assemble with no problem. Head recently redone, valves closing and opening as they should. New head gasket torqued at 65 lbs.

Engine has not been started and run. I did a dry/cold compression check and all 4 cylinders are 30 psi. Do I have a problem? If yes, would I get 30 psi if there were no rings on the pistons?
 
You say you have not started and ran the engine, correct?

Assuming there are rings on the pistons ( I think you would have noticed if there weren't), let's hope they are facing the correct direction, and they need to have their gaps spaced equally around the circumference of the piston. Hopefully the sleeves were pre-honed and had a light amount of oil on them.

If all the above is verified and the valve timing correct, I would run the motor and she how it does after a break in period to set the rings. I have never ran a compression check on a rebuilt motor that hadn't been started yet, so I don't what to think about the 30 psi. Yes that number would be low for a broken in motor, but as for a fresh overhaul never ran...I'm not sure. I hope others will chime in.

Also, check your compression tester on something else to make sure that it isn't the problem!

Good luck
 
I agree never heard of IH sleeves and pistons come assembled, but Cat 3406,C-15, and such, comes with the rings on the pistons, inside the liners, wrapped in plastic.
 
Thank you, all. I will contact Reliance to confirm the rings were installed on the pistons (pretty sure they were from the feel of the piston movement in the sleeve). I adjusted the valves prior to the compression test. Regarding the comment on full throttle, the carburetor was not installed at the time I ran the test but I wouldn't think this would affect the compression when the valves are closed. I will re-torque the head gasket to 80 lbs.

I am away on business travel until this weekend. I will try to start the engine on my return and report the result back to the forum.
 
Compression tests of a rebuilt engine before it is started, run, brought up to temperature, and WORKED and broken in mean NOTHING.

It's the NORM for the rings to be installed on the pistons before they are assembled into the sleeves.

If the pistons didn't simply fall out of the sleeves during handling and attaching them to the rods it's quite likely the rings are present and accounted for.
 
Did you hae the front cover off to replace the front seal and by any cha nce did you get the cam gear and crank dots lined up correct. If you had the crank out it could be possible they arent lined up correct. Single dot on cam gear with single dot on cam gear.
 
Did you look at the ring positions on the pistons prior to installation? The ring gaps have to be positioned at different locations so they don't all line up together. Like if you have two rings the gaps are at 180 degrees to one another. That includes the oil rings also. Who knows how they were assembled. You should buy your own ring compressor, they are cheap.

OTJ
 
(quoted from post at 12:30:58 03/22/17) How would you put the connecting rods on the pistons without removing them from the sleeves?

You push them out the bottom just enough to get the retainer and piston pin, connect the rod and reinstall pin and retainer, push it back into the sleeve. But before you do this you install the sleeve without o-rings to check fit and sleeve protrusion.

Done all the time on Deere and Cat engines.
 
Just take it apart and look at the pistons. Pulling the pistons out of the sleeves isn't a big deal. And putting them back in isn't a big deal either.
Head torque should be 90 ft-lbs.
 
Till it is run to oil the bearings why would it need to be checked and on an un used engine I wouldn't think it would be very accurate anyway.
I would wait to run it a day or so first.
 
I agree to run it. On a fresh assembly, there should be no way to hurt it. If it needs to come apart again, running it won't make it any more work.

One thing I thought about, if the sleeve/piston assemblies were sitting around for a while, there probably isn't much oil left around the pistons. I'd squirt a tablespoon or so of oil into each spark plug hole before starting it. That will probably give the compression a temporary boost to help the starting as well as giving the rings some needed lubrication.

You can check compression after running it an hour or so. If it runs OK, I probably wouldn't bother with it.
 
Maybe you wern't cranking it fast enough to get the true compression.Some 6 volt batteries won't turn it fast enough.
 
Just wanted to thank everyone for the comments and to let you know my engine rebuild was a big success. I re-torqued the head from 60 to 80 lbs. and pull started the engine. It runs with good oil pressure and no smoke and seems to have a lot more power. I'll run it a few more hours and recheck the compression. I am sure it way up from the original 30 lbs.
 

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