compression test on motor set

[goldollar]

Can you do a compression test on a motor by manually turning the crank, or do you HAVE to do it use the ignition. Ive asked this question befor but i didnt really get any clear answers. Any info would be greatly appreciated.

[RobDET]

i had a crx swap and when i turned the motor with the crank i got like 12 psi. When i used the starter after driving the car for about 10 minutes i got 200 ish...

[goldollar]

oh ok. i guess that answers that answer that question. **** i really need a good way to test this motor, anyone got any suggestions.

[Movingviolation240]

use compressed air and you can test it without the starter, but the problem remains that the motor has to be warmed up to get an accurate reading. Now if you wanted to be really crazy (saw a redneck do this once) you take a torch and heat up the inside of the motor through the open plug hole and you get halfway accurate numbers.

Basically though you have to heat the thing up to get the right readings, when it's cold it just has too much leakdown.

PaulOrlando, FL

[goldollar]

aight cool thanks for the replys. ill just do a leakdown test and take my chances.

[Movingviolation240]

even your leakdown numbers are gonna be way off with a cold motor.

Paul

[goldollar]

damn. so is there any thing i can do.

[SpeedRacer1]

Well whats the background on the engine? There is'nt much to do on an engine outside of a chassis other than take the fokker apart.

[MojoMan]

Are there still plugs in it? What does the exhaust manni look like? What does the turbo look like? Was there an intercooler with it and what did it look like inside the pipes? etc, etc, etc. If you cant get any ideas off of these things then pull the head, it doesnt take long if the intake and exhaust are off. It takes like 20 minutes. Maybe more if youv'e never done it and even longer if the intake and s*** are still on. Just use deductive reasoning. Does it still have the original oil from when it came from over seas? Drain the oil in an shallow pan and look through it for gunk and metallic particles. There are many ways to find out the condition. One of the fastest is to take the valve cover off and maybe even rotate the crank pully with the motor braced and watch everything go. I hope these give you some ideas. Good luck.

[goldollar]

thanks, everyone fo rthe advice, i thinl ill defenitly do what you suggested MOJO. The motor is a red top that my freind has and i can get it for like 1300 with ecu and harness, he got it on a deal, but im just a little caucious. But Ill figure somehing out.