Ended up getting a s4 motor from the junkyard yesterday. I thought it would be a good candidate after turning the motor, and noticing that there was an engine fire I figured the FPD failed, not the engine. I finally got it into a garage, hooked up a compression tester.

I'm not sure what you guys use, but I'm not sure how to get that thing spinning at any decent RPM to measure the compression. We turned it by hand and got about 50+psi on all rotor faces. For turning it by hand how good is that? I've never done a compression test out of the car.

 

Bolt a bell housing and starter to the block.
Spin motor, check compression.

 

yeah you wont be able to get accurate reading until you spin it with a stater. you can put your hand over the exhaust ports and feel for even pulses of air. 3 per rotor.

 

yeah starter + bell housing for good results, what i ussueally do if buying a motor i cant test ( like in a junk yard) ill spin it by hadn listen for compession, then ill remove exhuast manifold, shine flash light in look at housings and apex seals, then press them with a finger to see if there springing or stuck, also looking for signs of lots of oil or coolent in the housings..

 

Well I tore it apart to be safe. Everything was good until we got to the front housing. the lip for the coolant seal was broken. Good thing I didnt just try my luck