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-   -   Some smoking under high load, crank case vent? (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/some-smoking-under-high-load-crank-case-vent-948895/)

point-blank 04-05-11 04:26 AM

Some smoking under high load, crank case vent?
 
How's it going guys,

I bought my car about 2 years ago for $500 it had 153K on the clock, it is now at 185K. I was told by the previous owner that it had a lower mileage engine dropped in (who knows haha)

It never smoked or burned more oil than normal (1qt per 1k miles-ish), until more recently.
If I drive hard (pull through a gear or two to redline) it smokes a bit and smells like burning oil.
If I hold it at high rpms 5k+ it will smoke a bit.
It never smokes on start up or normal driving regardless of the temp, and starts and idles fine.
I thought it was oil control rings but wouldn't it smoke all the time?

So I am wondering if I may have a plugged crank case vent, and how I would go about checking for and then repairing that. I searched and didn't find much.

Thanks guys!

-Miles

BomberMan 04-05-11 08:31 AM

The factory PCV system works on a complicated (to me) solenoid valve that you should reference the FSM if you want a checking procedure:

http://foxed.ca/foxed/index.php?page...nual#secondgen

This is not where I would look first however. First off make a note of the color of the smoke, oil smoke should have a blue tinge to it. Since you only have this smoking issue at speed I might be inclined to think you are just running rich for some reason in which case the smoke would be black.

If it is oil a good test to see if it is the OMP or not is to drain some and give it the sniff test. If it smells of gasoline, then you are probably getting blow-by somewhere and may want a rebuild in the future.

point-blank 04-05-11 06:44 PM

It is definitely oil, smells like when you get behind a super old crappy toyota or honda with the blue cloud.

I don't see how it could be running rich, the car is bone stock other than exhaust.

By omp, do you mean my OMP could be malfunctioning, allowing too much oil to be drawn into the engine at full throttle? (this seems like it could actually be an issue as I have had omp problems in the past

K-Tune 04-05-11 07:33 PM

Could be oil control rings...

Black Knight RX7 FC3S 04-05-11 07:44 PM

normally if its a oil venting issue, if you take the dipstick out and it kind pops out of its shaft, you have too much pressure, so you need a way to relieve the pressure.

point-blank 04-05-11 10:57 PM


Originally Posted by Black Knight RX7 FC3S (Post 10555445)
normally if its a oil venting issue, if you take the dipstick out and it kind pops out of its shaft, you have too much pressure, so you need a way to relieve the pressure.

Right, I thought maybe I am building crankcase pressure and getting blow by somewhere, although I am not even sure that is possible

BomberMan 04-06-11 12:33 AM

I don't know too much about the function of OMP's considering that I don't have one. However if you had bad oil rings I would presume there to be enough blow by for you to smell it in the oil sump. Certainly if it was enough to warrant an engine rebuild.

Black Knight RX7 FC3S 04-06-11 01:53 AM


Originally Posted by point-blank (Post 10555813)
Right, I thought maybe I am building crankcase pressure and getting blow by somewhere, although I am not even sure that is possible

rotaries can build pressure to cause oil blow by.
side seals and the oil seals are not 100% sealed proof. There is some combustion pressure leaking into the oil system.
If the oil vents are blocked off, excessive blow by will occur.

Your problem though can be blow by, or the o-rings slowly going kaput.

arghx 04-06-11 07:56 AM

If it's not a turbo engine I highly doubt it is crankcase pressure causing this unless you have blockage in the ventilation system

Alex Thompson 06-19-11 01:14 PM

im having the same problem but with my turbo 2 i just put a new turbo on prob 100 miles ago when i punch it it smokes for a bit but gores away n if i beat it the quickyl shut off it smokes next time i start it


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