dtrrx7

Is there any way to compession test the motor with the motor out of the car?

797

sure just hook everything up, straddle it and crank er over! I dont see why you couldnt just turn it over by hand as if you were turning the key.

TurboSE

i dont think you can get it to turn fast enough with ur hands to make decent comprssion like a starter motor w/ a fully charged battery Just IMO

797

possibly, and im not saying im right at all, b/c i doubt i am, but wont the motor still make compression as long as you turn it over?

Power Aids

someone told me you should test at wot that sounds fucked up to me.
shouldn't the compression allways be the same? other than the difference between hot/cold?

IanS

iTrader: (4)

I would think that you would be able to tell if all sides were even or not by turning it over by hand. Obviously wont be accurate though. If anything, get someone to test their compression the same way using a running engine to get a decent reference point.

trochoid

iTrader: (6)

Starting rpms are somewhere around 250, you need at least that. The test is done at wot to allow the maximum amount of air to enter the engine.

When turning over by hand, there is too much time for the compressed air to bleed past the seals, thereby not geting an even close to accurate reading.

You can do the test with the engine out of the car by hooking up the tranny and starter.