R53 Engine Health: Compression and Leakdown Test Results
 

Hey Everyone,
I picked up a parts car with a decent engine to swap into my 2004 MCS project. Donor car is a 2002 MCS hardtop with 121K on it. After getting it to run (bad starter and seized alternator) I wanted to test the health of the engine to see if it was good enough to do some preventative maintenance and pop it into the other car.
Compression test:

• Cylinder 1: 150 PSI
• Cylinder 2: 150 PSI
• Cylinder 3: 150 PSI
• Cylinder 4: 160 PSI

So from a compression test perspective it seems like its a healthy enough engine so I did a leakdown test. Full disclosure my leakdown tester is a cheap one from amazon. I am a little reluctant to believe the %'s as it would not stay calibrated. All cylinders had about 40-45% leakage. Which is not great. There were no bubbles in the coolant, so no head gasket issues. I heard very little air from the intake and exhaust so maybe some slight issue there. Mostly I heard air escaping from the dip stick...so there is definitely some air getting around the rings. My question is, with the compression being as decent as it is, and the cylinder leakage being consistent (plus the fact that my leakdown tester is inaccurate), is this engine healthy enough to throw it in another car and get a couple of thousand miles out of it? I'm sure I'll be burning some oil, but this is not my daily and I also have the original engine from my project that I was going to build in the mean time. Thoughts? Thanks!

Edit - roll of the dice, you can buy a lot of oil for cost of a rebuild.

Could be your PCV is blocked up. You can test if it's good by taking off the oil fill cap and then putting the opening of a latex glove over the oil fill opening. Turn the car on and if it eventually starts deflating the glove, you don't have an issue there. If it's constantly inflating the glove, buy a PCV for ~$30 and replace it in 2 minutes, then do your test again.

Cool, thanks for the idea. I'll check that tonight.