Compressions Test.

[DJPhrost]

Hi, I know this is probably the wrong forum for this, but I couldn't find a diffrent one.
(This is on a Turbo motor)
Is it possible to do a compressions test on a motor that is completly out of a car?
I need to know if a motor is good before bought, is there any other way to check check if a motor is good short of a dyno? If the compressions test shows the motor compresses fine, what other could be wrong with the motor that would not be worth fixing or is unfixable?

Thanks in advance.

[KeWLKaT]

yes, doable, just turn the crank by hand.

also, basically check EVERYTHING

[DJPhrost]

Well everything is seperated, motor is here, trasmission is over there, etc.

If you could be sort of detailed.

[04 elantra cvvt]

See if the owner will let you take the oil pan off and check the main and rod bearings. Turn the engine by hand no less than three times to check each cylinder. That should gove you enough to check compression. Just make sure that all are pretty even. Do a visual inspection of the engine. Good Luck.

[Gregster]

I dont know if this true or even possible. I've heard that you can briefly crank over the engine by directly hooking the starter + and - to a standard car battery. Anyone else here this?

Greg

[DJPhrost]

04, he will. I just need to know everything that will let me know that the engine is worth buying. It's an RB25 with a 240sx, everything is included. (I know, totally wrong messageboard but this is the only board I post on.)
I don't want to waste x amount of thousands of dollars on a dud motor.

[tharptroy]

do a leakdown test. im pretty sure you dont need to crank the engine for that, and from what I understand, they give you a better idea of the shape the engine is in. you'll have to cite some alternate sources on how to do one though =/

quick google search pulled up this:

http://www.wcengineering.com/articles/leakdown.html

its a bit more work, but I'd do it if I was in your position.

[ricerrx7]

A leakdown test is good, but a compression test is better. A compression test will let you know if the valves are opening correctly.

[DJPhrost]

Well here's another question. I hear (is this true?) there is a compression tester that holds compression so you don't need the starter connected?