Hi guys, I'm looking at buying a really neat project Z that was TT swap'ed and look very clean. I have done some digging around and I've found in the seller's paperwork the compression test results: (CYL1-6): 131/150/145/145/145/145. I have seen/read that a healthy engine should be ~150 and a pristine one would be 160+. The engine has JWT500's on it already and running upgraded injectors (555's), intercoolers and practically all supporting mods. I don't plan on beating the crap out of the car, but I am a bit worried that this engine might go. From the looks of it; the engine was taken out of a '94 TTz with ~88k miles and swaped fairly recently.

What do you guys say??

 

Those are low numbers. Couple of different ways to test to see if its the rings or leaking valves etc. If it were me I would pass. Rebuilding these engines are a pain. I do a few of them in a year at my shop and they are never easy or fun.

Usually cylinders 5 and 6 are low anyway because they are coolant starved (factory casting material was never removed from inside the block so it prevents coolant going to the back cylinders). I would pull one or two of the plugs out and squirt some oil inside the cylinder. Hook up your compression tester to it. If the compression goes up your rings are worn and in need of either re-honing or a complete rebuild. If the compression does not change it could be your valves not sealing which would require the heads to be rebuilt. There's a few more reasons and tests but the ones I just told you about will give you a good starting point to seeing if its worth it or not.

 

Everywhere I read says that's a pretty standard/good compression for TT.