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Author Topic: Fixed Low Compression  (Read 1121 times)

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Offline OkieFarmJeep

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Fixed Low Compression
« on: October 03, 2015, 10:34:41 AM »
A quick update on the Okie Farm Jeep.  Some history- my engine was ran quiet and started right up but lacked power. It also had an intermittent miss on #4.  Compression checks showed 50# in 1,2,3 and only 20# in 4 when dry and only slightly better when wet.  I was pretty convinced that it was broken rings.  I tore the head off and confirmed this.  A look at the valves also found #4 was pitted on the valve and not sealing well.  Lastly I bent #1 Exhaust valve ever so slightly getting the head of the engine.  The head had become one with the block and that was a story in itself.  The trash (carbon) you see here is from cutting the ridge off the cylinder.  The photo I took of the number 4 exhaust valve was not very clear but you can see the problem.  Luckily, everything else was good- no problems with bearings or the rest of the ratating assembly.  I was also glad to find the bore was standard and that makes me feel better in case I ever need to have it bored I have room to work.   The valve seats were in good shape as well and after a quick lap all the valves sealed right up.  All the work was done with the engine in the vehicle.  Plasti-gauge showed everything was tight so after honing the cylinders and a good cleaning it went right back the way it was.  Fired right up and took it for a short run to seat the rings.  Quick re torque and check of everything one last time and my wife and I took it to town to get feed us and the chickens.  It just feels right backing up to the feed and milling company and getting feed- like it was an ad from the 1950's.  ;D  Runs like a sewing machine and now as so much more power.  I can accelerate up hills I used to have to down shift on.  Today I took a new compression test and I have 105 # across the board.   I think that may improve a tick as the rings continue to marry with the cylinders.   All in all I am a happy camper and this is one of the cases where a total rebuild was not needed.  If your engine runs / sounds good- has good oil pressure and just lacks compression- this may also be a possibility for you. 

Offline athawk11

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Re: Fixed Low Compression
« Reply #1 on: October 03, 2015, 10:38:40 AM »

And I agree.  I've recently had the same experience.

2-1949 CJ3As
1-1946 CJ2A