Well I am considering the purchase of this JDM type R (b18c) motor swap and I just got the compression test results:

Cylinder1 -228
2 -243
3 -250
4 -248

This R "supposedly" has less than 10k on it and it has a 99 stanp on the head. I am really concerned about the variance of 24 psi between cylinder 1 and 3, spec is a max of 27. Do these #'s look normal to anybody expierienced with these motors?

AL

 

How many times did you do the compression test on each cylinder?
When I do a compression (pressure) test, I check each cylinder three times
and use the average as the result.
You have a 9% difference, from the lowest to highest pressure reading.
Do the compresson test again.
this time make sure to step on the gas pedal all the way, and remove all spark plugs. Do not do the test on a cold engine, the results are unreliable.
crank each cylinder an equal number of revolutions.

 

The engine is cold because it is out of the car. I did the test 3 times and cranked it four and five times. Results were basically identical.

AL

 

Sounds about right.

Mine is a US b18c5 w/ 12 thou off the head and i get 245 across all four, so it sounds right.

 

Just wondering if anybody had some more results on their R.

Also: Since this motor is out of the car I have no way of running it and warming it up, what makes a cold engine unreliable when cold?

much thx

AL