Nissan NS30 Compression

[Shubobo72315]

I just had my 1999 Nissan 30 2-stroke's compression tested and both cylinders were right at 100psi in each. Isn't this a little low? I have replaced my head gasket, but don't really know about taking on the task of replacing the rings. What do you guys think about a 100psi ??

 

[TOHATSU GURU]

Re: Nissan NS30 Compression

I think since the compression is even you are fine. Your gauge is different than my gauge which is different from the next guy's gauge.

 

[Shubobo72315]

Re: Nissan NS30 Compression

Your gauge is a lot better than my gauge Im sure, so what is the lowest you would let your outboards compression get to? Also, does anyone know how many rings are on each piston and if they are the same?

 

[TOHATSU GURU]

Re: Nissan NS30 Compression

Anything from 90 to 110 would be normal depending on your gauge. Your looking for the reading to be even on both cylinders rather than a magic number that indicates a problem. If you engine was 95 on one and 105 on the other you would have a problem. If the engine is over 5 in difference you have abnormal wear. If I had a 1999 and my gauge read 80 on BOTH I would get a different gauge, but I wouldn't be worried about the engine. Unless, you have over 3000 hours on it that is. It's a two ring piston and both rings are the same.

 

[Shubobo72315]

Re: Nissan NS30 Compression

thanks for all your help