Just like the title says. Does anyone know how to do this??

 

would you just crank it over at the crank pulley with a wrench? Im wondering the same thing...

 

just hook up the starter to a battery and jump the starter wire.

 

You better hold the F*^%$ on. it will want to walk away from you. HTH

 

I am curious about this as well. Is there some kind of hoist that shops use to test the compression of the motors? I am looking to buy a GSR motor as soon as I find one with low miles. Will the only way to get compression #'s if the shop has the motor / car (do the test then) and then pull the motor?

 

Most Compression Tests are done when the Motor is still in the car.

 

yes but that dosent help when you just spend 3000$ on an engine swap and want to make sure there isnt a valve missing before you put it in.

 

The wrench will never spin it fast enough.

A battery and jumper cables to the starter should do it. Never done it, but I would be willing to try. The starter isn't going to turn it fast enough to have it walk away or anything. Besides, you'll have all the plugs out so there won't be any compression. You should be fine.

Take the plugs out and try to bump it a little. If it isn't too scary, bump a little longer until you can bum long enough to do the test.

Let us know what happens.

 

If you want I can give you exact psi numbers of my JDM GSR cranked by hand, cranked by hand after headgasket and cams were replaced, craked cold by starter and the compression that it is getting now that it is in car and running strong. When I first did a compression test i got really low numbers but that was cuz the motor was totaly cold dry and cranked by hand. As long as all cillinders are thesame and none are way off you are fine. I wouldn't hook it up to a battery it will make the motor move to much and might dent the oil pan and that can lead to oil starvation.

 

I see what you are saying as far as the #'s just reading straight across at a lower range with the motor out of the car. I'd be interested to hear what the compression is hand cranked (battery / jumper cables) vs. the motor being installed Thanks!

 

ok, i have done this before grab a battery or a jump starter or a charger connect the positive terminal with some heavy duty wire 4 gauge or bigger and connect to starter the nut on there, then negative terminal to a ground on the motor preferribly on the tranny, then take a small piece of wire and connect to starter signal on starter, and touch it too the positive side of your charger or battery etc and it cranks and you can check compression....

 

The first time i did i compression check after I got it it posted 130/120/120/120. After taking the head off cleaning it replacing cams springs head gasket and all other gaskets I could find it posted 150/145/145/145. Thats all cranked by hand. After i put it in the car warmed it up and checked by turning the motor with the started like you are supposed to, 220/210/215/215. Thats on a JDM GSR from HMO with stock block.