I just got a jdm motor. I did a hand cranking compression test and came up with a little above 0 on one of the cyclinders (#2) and came up with 30. I added some oil to the top and it they where about the same. does that mean that #2 has a worn ring?

Question two.

I am trying to crank the motor since I got it attached to the tranny. I am trying to get a compression test. But I cant seem to turn the starter motor. What I did was connected the ground to the ground on the start and the +12 to the screw terminal. It wont turn. Did I forget something? Its not turning the starter. I know the starter is good because It came off my old setup.

Nick

 

?1. thats because you need to have it in the car, and crank the motor with the key, for it to work right.

 

yes, you can do a compression test, without the motor in the car. First make sure the tranny is in nuetral. Then give 12V to the starter and the terminal next to it. make sure you have a ground between the motor and battery you are using. I have done this before, so it does work.

 

i think he got what i was saying. point is, you have to use the started, you cant throw a 19 wrench on the crank bolt and expect a reading.

 

when I did it with a hand crank I couldnt get any compression out of #2. But I got around 30 on the others. Sound like a dead ring?

Nick

 

sounds like you need to use the started like we both said.

 

I used a starter and got 210 straight across. sound good, ok or bad?

 

210 sounds good....
p.s adding oil will raise compression