i have a problem here with oil blow by. i know there are a lot of posts on it wich i read but i have everything in place. i have the pcv valve in place vented to the intake and all was good for about a week. we were tuning the top end running very rich. i smelled oil and stopped and there was oil blowing out of the valve cover vent. it never did this before and it happened all the sudden. now my air fuel ratio is way out of wack going from 10 to to 13 to one when before is was right on. what could cause this problem, a broken ring? would an intake gasket cause this? any help would be greatly appreciated.

 

I had the same problem. Mine was working fairly good then all of a sudden I was smoking bad. That was with a Ford PCV from an 88 TBird turbo coupe (MotorCraft #127A). I had gotten a bad PCV valve, even though I have heard none Ford PCV valves have problems, my Ford one also died. I now have added a brake booster check valve from a 94 Honda Civic before the new PCV valve as back up to prevent boost from going into the crankcase. I haven't tested it yet, but I think (hope) that will solve my problem.

Craig

 

what psi of boost were u running when this happened?

 

I had the same problem too. Turned out to be 3 broken rings with two broken ring lands on the pistons.

Good luck.

 

what kind of boost were you making when you broke the rings, we r at 7lbs and we were running at 10 to1 air fuel ratio with no detenation at all. i am just curious to know why it would break a ring running low boost with a very rich a/f ratio. what were you running your a/f ratio at? and how much boost were you running?

 

I am running 8-9 PSI boost when this happens. I took a trip and it would smoke bad when I would get into the boost. The next day it didn't smoke. I took out my PCV valve and found out that it would leak sometimes when I blew in it.

I have been blowing oil out the dip stick when I am under boost. I think this is caused by the leaky PCV valve.

With the new Ford PCV valve and the Honda one-way check valve, I think my problems will be fixed.

I will know this weekend once I get it back on the road, it has been down the past week.

Craig

 

I second the call on broken ring lands...If it were just the PCV valve, under idle you shouldn't see excessive crankcase pressure coming out of the breather. Would also be why your AF is wacky, bet that one or two cylinders aren't making the compression that they should be.

Check cyl #6 and 7...

MJB

 

mine is fine unde rnormal driving, but under boost, it likes to puke oil vapor. This vapor will fill my puke tank and then spit oil everywhere. My pcv and valve covers are vented to the atmosphere (breather tank), so I know it is not an intake issue.

I suspect either rings gapped wrong, or broken ring/ring land thing

 

turbo mike, do you roadrace motorcycles. what ring gap is everyone running in there engines for 20 pounds of boost. i have a dart block with steel crand, oliver rods and je dished pistons. the motor is now tore down and there is not a broken ring and the rings seated perfectly. we did find a hose that was torn. i wonder if this was the reason the block was being pressurized. i doubted the broken ring bit because we had no detonation at all. we started our tune very conservative and went from there. anyways, what do you gap your rings at? thanks, pat

 

Are you running the stock type PCV valve? You should buy the Ford turbocoupe PCV and then run a brake booster valve to prevent boost from pressurizing the crank case.

Another thing I did was run a tube from the valve cover nipple, under the oil fill, to the inlet side of the turbo (the vacuum side). I also run a brake booster inline on it too while using the stock oil fill cap.

Do you run a breather on the valve cover?

 

Did you take a REAL good look at the ring lands? They'll stay in place until you pick and pry at them a bit.

It just sounds too odd that you had no blow-by and then while on the dyno it's blowing out the breather.

MJB

 

I've been told by my engine builder that excessive blow by on a boosted motor can occur due to detonation. The detonation rattles the piston around, causing the rings to loose their seal. Anyone else ever heard this?

Rob

 

we pulled the rings out today, they have lost all their radial tension. i think we were gapped to close. we have a new set of rings coming from childs+alberts and they told us what they said was the best set. they also said to run a gap of at least 32. we were running 22 per the je tech paper that they sent for mild boost. we were running 6psi. we are running a hone through the bores and starting over. hopefully this time it will work out. we are going to be running a steel compression ring and a garless oil ring as they said this is the best combo they have found. i will let you know how it all turns out. you never said if you roadraced motorcycles or not, i do some track time at nelson ledges in ohio.

 

Sorry, bro. Forgot to throw in the motorcycle info.

I don't race, I just do trackdays - Done all the Pocono tracks, VIR, Summit, BeaveRun, and MoSport.

Here I am at MoSport...Sick track...

 

funny you mention this. I had been noticing a huge lack of performance and some bad blow by. I guess 52% leak down on one cylinder and 20+% on several others could cause it hence the dart block and new short block.
130mph on a 4cylinder is not bad I thought?

 

My car seems to have some blowby issues. I have a breather on one valve cover, my PCV is vented to atmosphere and I still get oil vapor coming out of the breather and dripping onto my header. I did a leakdown test and every cylinder was between 3%-6%. I hook up a vacuum pump to the other valve cover to provide crank case evacuation, and it fills the catchcan within a 30 minute drive and starts overflowing oil from the can. I've disconnected the evacuation pump until I can figure what to do next. Any ideas on this one? Both compression and leakdown tests look pretty darn good, so why all the vaporizing of the oil and apparent blowby?

Mike

 

I have this issue.... I have dual valve cover vents, and the PCV atmosphere vented, and still get vapor puke!

 

this guy had prolly the same issue

https://www.theturboforums.com/forums/attachment.php?s=&postid=241793

 

Are yall guys running the turbocoupe PCV ?

 

I had real bad blow-by, enough to push oil out of my breather caps. Excessive blowby is only caused by 1 thing... that's bad rings. Sounds like you might have to pull off the heads and check out your rings.