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-   -   oil control rings look mint, turbo verified fine, yet burns oil.. (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/oil-control-rings-look-mint-turbo-verified-fine-yet-burns-oil-847776/)

KillerRx4 10-16-09 12:54 AM


Originally Posted by BLUE TII (Post 9564615)
I didn't see it stated here but what you measure on the cast iron oil control rings for wear to be within spec is the shiny flat wear surface that develops at the point of contact with the side housings.

If this band of wear around the control ring is too wide the ring is out of spec. Don't know the width off hand :(

Yeah, its 0.5mm max.

R_PROWESS 10-20-09 12:06 AM

what are these rotor blowholes they speak of... i dont understand

KillerRx4 10-20-09 02:48 AM

Sounds to me like a hole or crack in rotor face.

R_PROWESS 10-21-09 10:12 PM

I completely misinterpreted it as integrated into the design "blowholes" that were either cast into the material or machined which if plugged would cause malfunctioning. lmao im so backwards sometimes...

12AllWays 10-22-09 12:18 AM

Keith I have to say that would be an odd but nice discovery if it was the rotors having "blowholes" in them... Wierd....

R_PROWESS 06-19-10 11:00 PM

Since I like COMPLETED threads with resolutions I'll update this for future reference.

The culprit ended up being the oil ring carriers, NOT the O-rings or the rotors or turbo or anything else. What I don't know for sure is how they wore so quickly. I guess I had no end play for whatever reason. No, I did not check for end play after assembly.

Lessons learned:

1. Buy a digital or dial indicator and check that end play.
2. Buy some calipers and check the “chrome” on the oil ring carriers via FSM procedure. To the trained eye, yes, it's easy to see worn out carriers. The untrained eye isn't going to know the difference without utilities. Beware to anyone who says “make sure the sealing edge of the ring is sharp.” That statement is pretty irrelevant taking into consideration worn out carriers are just as sharp as fresh ones if not sharper, I cant think of any circumstances where the rings would be rounded off due to wear.

Bottom line, if I would have had these 2 basic instruments from the get go, then I wouldn’t have spent so much time figuring out something which is now so obvious and entirely avoidable.


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