| Update: Last night we pulled the upper timing belt covers to check the timing belt placement on the 4 camshafts. It appears that all 4 lines are right on the dots located on the cam gears. We double checked this a few times to be sure. So it seems that the problem I was suspecting is so far not the cause of my low compression. How possible is it that if the crank sprocket is not lined up properly with the belt yet all 4 cams are, that it would cause low compression in one cylinder bank but not the other? We dont really want to tear the whole front of the engine apart if we dont have to but will if it could possibly cause this problem. I have ponderd all possible reasons for low compression in one bank and came up with: -Bad Head Gasket
-Burned, ground, or improperly seating valves
-Cracked or warped head
-Bad piston rings
-scored cylinder walls
-Cam timing off causing valves to open or close at the wrong time letting compression out After looking at each of these one by one, the cam timing seems to be the most suspect as the engine is not burning/leaking any antifreeze or oil, seems to have plenty of power and reaches full boost. I find it hard to believe that all valves in one head could be bad equally the same, likewise, if it were everyday wear on the engine, all 6 cylinders should be about the same compression. When doing the compression test I had all 6 spark plugs out, balance tube off, and the throttle completely depressed on all cylinder tests. I tested them all once again to make sure I didnt make a mistake. Last summer we resealed all 4 valve covers and made sure to inspect the cams for wear and all wear patterns on the cam were normal with no shavings or indications of bad internals. I personally have owned 3 different Z32s so I am aware how NAs and TT's SHOULD run. His seems to run great except for a shaky idle. By this I mean the idle is stable and the tach does not bounce at all, however you can hear a slight miss in the idle through the exhaust almost. When sitting in the car you can feel the idle in your seat. Out of all of the tests performed on the car to see what the problem could be, the compression test was the only thing that was out of the ordinary. Any other ideas? I have built a few engines and worked on many so I feel pretty knowledgeable as to how they work and how to track down problems with the symptoms, but I just cant figure this one out.
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