How do I check the compression of a motor that is not actually in a car. I want to get a cheap sohc vtec motor to drop in my beater pizza delivery car. Is there anything else i should check for....

 

You should check the oil and, if possible, check plugs and perform a leakdown test. As far as checking the compression goes. If the tranny and engine are still together and the starter is on then you might be in luck. If not I really don't know.

Doing a leakdown test is very important IMHO.

 

How do you do a leakdown test. What results do you recieve. If the tranny is there you just run wires to a battery?? Any info helps

 

A leakdown test requires a fairly expensive tool to do. I don't know the numbers you should expect. If the tranny is still connected to the engine and the starter is still attached then all you have to do is use jumper cables to kick the starter over and do a compression test like normal.

 

What exactly does a leakdown test tell you.

 

Basically the same as a compression but it is more of an accurate gauge of the engines condition than a compression test.

 

You'd supply a constant air flow into the spark plug hole, say 100 psi, and then see how much is staying in the combustion chamber. You'd have two gauges, one would read 100 psi, the other would read say 95 psi, meaning it is loosing 5% of it's compression. What makes it better than a compression tester is you can usually tell where it is leaking too. If it was leaking into the coolant you could take the radiator cap off and see air bubbles in the fluid. Or if it was leaking through the valves you'd feel air coming out of the exhaust or intake. Tool costs about $100.

 

Yeah Brian, $100 is fairly expensive to you.


[Modified by 94IntegraGSR-OVR, 8:25 PM 7/23/2002]