Very low compression ... 60 psi

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MoparFan

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HI,

today I have check the compression on my 318...warm engine, around 60 psi on all cylinders (except #1 and #5, did not check)...a couple of days ago I have checked but with a cold engine and got around 90 psi on those I checked (#1,2,4,6,8 had to stop)...
SO what do you think?
the engine needs a serious rebuilt?
or my compression gage is wrong?
Can an motor run decently with 60 psi?

...that thing made a tire scream (a little...open diff, 2.45 gears, 235/60r15, single shitty exhaust) ...I just don't understand! :drinkers:

Thanks
 
My rule of thumb was if it was under 100psi it probably wouldn't run right. If you had all the cylinders at 120 and one wass at 80, it wouldn't be running on that cylinder.
I would check/relace the gauge.
Also remember to disconnect the ignition, and hold the throttle wide open while cranking it.
 
You need to do the comp. check with the go pedel to the floor. As for the 60 psi I would think that engine would be very low on power and would run like a@@. Should be at least around a 100 psi. Is there a problem with the eng? Why did you do a comp. test?
 
Do it hot, remove all the plugs at once, prop the carb open at full throttle, then do it again. 60psi will run (actually had a friend with a Jeep 258 that ran with 50...lol) but you should be much higher for any performance. I'm thinking if it can spin the one tire at all, you did the test wrong.
 
Thanks everybody for your input on that one.
I will redo the test as you told me, hot engine, pedal to the floor.

As for why I did the test, it is mostly out of curiosity. And also, my project of building another engine in parallel is really uncertain :sad2: , so I wanted to do some test to know if the engine is healty or not... :cwm10:
From the odometer the car as 63000 miles or 163000 miles...so I want to know what is going on inside.
 
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