I have my car almost ready to fire after a lot of headaches and learning never to trust a previous owner. I decided to do a quick compression test while im waiting for a distributer cap. 4 of the 6 cylinders were fine, in the 140-150 range. My problem was with cylinders 1 and 3. Now I did this test on a cold engine, and didnt put any oil in the cylinders. The thing that I found weird was I first tested #1 at 50 pounds. I went and did the rest of the cylinders, then retested #1 at 70 pounds. Did I mess up in how I tested the compression, or should I be looking at rebuilding the bottom end.

Also, on another note, how important is priming these oil pumps. Will they such if they arent primed completely.

Thanks for any insight

Its a '71 240z with an E88 head

Adam

Just to get everyone up to speed you should give a quick breakdown of the work performed to the engine. I remember you were replacing the head. You should run the engine for a couple hundred miles and let everything get seated. Recheck the rocker to cam gap. Then do another compression test. If it is still low do a leak down test to determine if the valves aren't seated properly or you have a bad ring.

Thanks for the reply, I had kinda thought this thread had died.

As far as work goes, I had my head rebuilt - surfaced, new valve seats, old valves reground, mild polish job. Its an early E88 with the small E31 combustion chambers. As for other work, there really hasnt been much. Its running dual webers. I went ahead and tried firing it up, after solving a fuel issue, it fired right up and idles very smoothly. Much too smoothly to have a compression problem. Im assuming I just had some dry rings that werent seating properly. The car had been sitting for a few years. Its all good now, and I just have a few minor issues to deal with, then I can put plates on her and really experience the Z.