Paulc19

Just did a compression test on my Turbo 13b that I recently swapped into my rx7 FC, and recently fine tuned my ECU for daily driving on the weekdays, and screaming down the freeway on weekends with my friends. Drove it for about a week now with 0 issues, but was curious about the health of the motor anyways and was wondering what the compression was like. Here are the results, and to me, they seem a bit odd:
(Note: these tests were taken cold. I would burn myself If I were to try to take it after turning off the engine)
Rotor 1: 70.70.100 (psi)
Rotor 2: 100,100,100 (psi)
There is a bad seal on rotor 1, I get that, But its the large difference in wear between that one and the others that concern me. What could cause such a difference in wear rates? How long do you think this motor can last?

j9fd3s

iTrader: (3)

more likely to be damage and not wear

Paulc19

What do you mean by damage? As in the seal is cracked or bent? I also heard that seals now don't crack, they bend so that shards don't fly around the engine and cause catastrophic engine failure which means going back to my second question ,how long will this run.

j9fd3s

iTrader: (3)

your guess is as good as anybodies. if it is a stock seal its likely that its cracked in half or there is a chip missing from the corner. if it is not a stock seal it might be bent (and then might come back)

dguy

iTrader: (8)

Damaged apex seal bridging two combustion chambers. Sucks but since your compression is pretty damned good everywhere else (if its accurate) youre far better off pulling and rebuilding now rather than later after more potential damage. Even if it runs well.

Paulc19

Probably the best idea. My friend has a camera he can stick into one of the spark plug holes so we might be able to see what the condition of the seals are like on the front rotor. Depending on how fast I can get him to help me do it, ill post my findings here.

Paulc19

Im going to say that its probably been rebuilt in its life. This was a S5 turbo motor that was put in an S4 rx7 after the previous owner blew the motor, then I came along and pulled the motor from his rx7 to put into mine. But as I said, ill get my friend to take a camera and stick it "where the sun don't shine" to see what the condition of the seal is like. Something I also forgot to mention: I should probably re-do the compression test, as it wassn't done with wide open throttle :P
Edit: Something else I just thought of. I've been driving this car for a week now, so if the seal were shattered, wouldn't it have already affected the compression of the other two?

WondrousBread

I also have a scope I used for that, and unfortunately it doesn't seem to tell you that much unless you have catastrophic damage.

I looked in my spark plug hole a long time ago with it, and after my engine blew, the scope still shows me the exact same thing despite zero compression on the rear rotor. All seals still look normal. You would probably be able to see if there was gouging or chrome flaking though. You'll get a much better view through an exhaust port, but it's more work to get into there than into a spark plug hole.

Good luck, definitely post those pictures

Paulc19

Thanks for the support. Initially I wanted to look at the seals, then directly spray them with sea foam through the plug hole, then let it soak and burn it off, to see if it was just jammed because it had been sitting on a pallet for a couple months before going into the car, though now that you say it, i might as well remove the turbo and do it that way