[Tim280zx]

What psi might you expect out of the cylinders of a "stock" 280zx with Triple Mikunis. It has some kind od performance cam from Motorsport. It has the Hi-6 from Crane accel 8.8 Crane Coil. The psi is reading only 100 to 115. That's low right? I am told I should exoect it to be about 175-195 regardless of whether everything is installed correctly. I don't know alot about the car because I got it from a salvage last year. My motor man now says the 100 psi is way too low and wanted the lash specs for the specific cam that was installed but I don;t know exactly which was installed. How do I ID the cam? stamps on the ends? He thinks the thing is timed off the back of the cam instead of the proper way of reading the timing. The snow will be flying soon so the car is sleeping until about March. But when it gets warm again I will want to get it looked at again and fixed.

Advice any and all woudl be appreciated.

Tim

 

[Roadman]

Hi Tim------------Yeah, 100 psi is a little low. On a N/A L-28 engine 150 - 165 would be better. Did the mechanic also do a leak-down test on the engine? This is a good idea, and gives you a little more info. Also, if the compression changes upward when a little motor oil is squirted into the cylinders, the rings are suspect. Air injected into the cylinder under pressure can indicate worn valves, seats or guides according to where it escapes (intake or exhaust system). These simple tests can indicate whether the problem is rings or condition of the head.

I would suggest you contact Motorsport for cam info. They may be able to tell you what to look for when you id the cam. I've never seen an L series engine that was timed from the rear of the engine, nor have I heard of one set up this way.

Roadman
Gulfport, MS