von

Old news but I blew my N/A racing. Its 89GXL and I think the timing was really far advanced plus hot intake charge. Anyways apon inspection I noticed that front rotor has 0 compression wile the rear is ok. Whats up with that? What exactly happend ?

dr0x

Perhaps the front secondary fuel injector is clogged? Maybe something went into that rotor housing and chewed up the seals? Your guess is as good as mine.

HeffBoost

I agree with dr0x, an injector that wasn't keeping up. Or T1 isn't putting out quite enough spark? A combination of the two?

Now I'll have to do some research as to why the rear is usually the one to go 1st.

SaabGuy

Its always the rear part of any engine which goes first, even on piston engines. Its almost always the case on straight 6's.

I think it has something to do with either the cooling system or the fact that the tranny is right there. Probably the cooling sytem.

ZachSpazz

Why then the phenomena of 89-91 RX-7's blowing their front rotor, while the 86-88's pop the rear?

Keith

I dont know about that because I have an 86 with 0 on the front and 90 on the back.

von

No no the rear rotor does go out on all 7s but only because the rear rotor runz slightly leaner than the front rotor BUT this is only noticable wear through the life the engine wich is why the rear goes out after 150k plus miles on the motor.

It has nothing to do with my car detonating in the front rotor. As I took off the lower manfold I saw a few drops of oil in the front rotor port. This was due to the low compression also. But the car doesent blow smoke and still starts and goes ( hardly ) because the rear rotor is completly draging it.

The injector reason sounds like it mighta been the cause. Thnx I will later tell how the housing look