Can I check my compression...

[krue]

with the engine on a stand? If yes then how.
I want to check it before I start throwing money at it. If it checks ok then I'm probably going to throw new timing chain and gears, water pump, harmonic balancer, etc. If not then I am throwing it back together and running it until it quits I want to know before I go to all the trouble of getting that stuck on harmonic balancer off.

Thanks, Krue

[FRENCHBLUE72]

You should just be able to throw a compression guage on the motor and turn it over with a breaker bar...

[crazy longhorn]

i would pull all the plugs, remove the carb(or prop the throttle open), & wire the starter to crank. You wont get a true reading, as the eng wont be warmed up(should give a good idea tho). crazyL

[Jeepster376]

You can do better. You can do an engine leakdown test, with a leakdown guage set and a compressor. It's better and more informative than a compression test. Only thing is no one will be able to relate your 15% leak result to their 150psi compression reading. But like compression the important thing is consistency on all 8 cyls.

[EdB]

Krue, Didn't we do a compression check when you were here. If I rember right,
it was even but low.

EdB

[krue]

Ed I honestly can't remember if we checked all of them or just the two on the back pass. side.

[sdmahr]

I wondered the same thing. I had intended on mounting the starter, take all the plugs out, propping the carb open, and just puttin' the cable to a battery and checking the compression.

I am not at all familiar with "leak-down" testing. Can somebody please elaborate on this a little? I assume you get the cylinder to TDC and then apply compressed air. Do you measure the amount of time to "leak-down"? How many PSI do you do this at? Any methods/suggestions?

Scott

[Jeepster376]

Yes, the leak-down gauge set uses a pair of gauges and a regulator to meter in a regulated amount of air and measures the pressure maintained in the cylinder. The advantage of the leak-down test, is if there is excessive leakage in a cylinder, you can listen to the intake, exhaust and crankcase and determine whether it's rings, or intake, or exhaust valve. And of course the engine doesn't need to be cranked over, so it can be done on a stand.