what is good compression for a 87 sport model 7 and if the compression is low how do u fix it rebuild motor?

 

100-115 is like new 100-90 decent 90-80 geting weak prob less than 1 year under 80 could blow at any time

 

I consider anything under 90 PSI (on any face) low and the engine is ready for rebuilding, but I believe the Mazda spec is 85 PSI.

 

Good compression is about 110, excellent compression would be like 120-130, thats pretty much factory new.

Searching would have told you that.

 

so will just rebuilding the motor with new seals fix the compression prob as long as nothing as worn on the rotors?

 

the odds are that a rebuild with new apex seals wsould inprove the compression as long as the side seals and corner seals are in spec, and the housings are in good shape

 

But that is a lot of "if"s.......

 

well you cant tell for sure on anything till u can see the internals of the engine!!!

 

Depending on the mileage most of the housings are reusable as long it wasn't a violent death. Overheating for long periods of time will also cause irreversible damage. I would start planning for a rebuild, and get it done before it goes. Since yours is a turbo severe detonation really isn't that much of an issue with you.