Boost = dipstick being pushed out

ironhead498

Member
Dec 6, 2008
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I just want to get some feed back on this topic.

The short block in my mustang is stone stock, cast piston, 90,000+ mile, tired little 302.

I've got a breather in the oil fill and had to make up a little catch devise for the oil that would make it through that. Then the other night after getting on it, I could realy smell oil!! When I got home I noticed that the dipstick had been pushed out of the holder about four inches, and there was oil around the ajacent areas.

My guess it that the rings are about shot and I'm getting significant blow by. The turbo puts out around 10-11psi, 12 on a cool night.

My question is if there is anything that can remedy this short of rebuilding the motor. I'm also curious what guys are doing with the factory pcv setup on boosted aplications?

Any input will be appreciated.
 
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You are getting way to much blow by!I can almost bet if you hook a boost gauge also up to the dip stick tube, you will see the same or close to the same amount of boost from it as you do on the turbo boost gauge.Time fr a rebuild!peace






john:p
 
Either put a breather on the other valve cover or get two -10 an fittings welded in and run hoses to a breather tank before you go assuming the worst. There is ways to vent crankcase pressure.
 
Sounds like he does have the tube connected from the oil fill cap to the TB and he's pressurizing the crank case. Its more than likely not blow-by (since your oil fill assembly is how your oil gets to the crank case and now you have pressure coming from your tb to your oil fill cap and into the crankcase) that is unless your exhaust is blue colored, thing your piston rings are shot and some could be blow-by. Oil being blown all over the place I think is more than likely coming from the PCV valve blown out of the back of your intake manifold than the dipstick, I could be wrong, but it never hurts to check. Either way, crank case is being pressurized so you need to change your PCV setup. If you want it to work basically the same as stock (depending on how you have your MAF setup) you could run a tube from your turbo inlet to your oil fill cap and it would work basically the same (the tube hooked to the turbo inlet has to be after MAF to be like stock, some guys on various 'Stang forums have this setup where the tube from the oil fill cap to turbo inlet is before MAF (because they use a blow through MAF, like C&L or PRO-M setups) and say their turbo'd Stangs run fine). That or you can always do the already suggested dual breather setup or a draw tube. Thats my two cents.
 
I don't have the tube from the oil fill to the tb hooked up. The #5 and #3 spark plugs have considerable oil on them so I'm guessing that the rings in those cylinders are shot.
It's got a new pcv valve in it and every time I have checked it it has been in place.

I'v got a blow through MAF set up on the car, and as far as putting a tube from the oil fill to the inlet of the turbo goes I don't unerstand why one would want to put all of that oil vapor through the turbo, intercooler,and MAF. I guess that just doesn't make sence to me.
 
Really you shouldn't run breathers and PCV system at the same time. It's usually one or the other. Like mentioned at this point try putting a breather on the other valve cover. If there isn't a hole for it you can drill your own. If it's still blowing out the dipstick then you know it's time to rebuild.

I can tell you I had the same issue with my stock 302 and Vortech S-Trim pumping out 12psi. When I took the passenger side head off there was present waiting for me, a piece of a piston ring.
 
I had the same issue on my 25k miles SBC. Did a compression check and found low compression in 2 cylinders. Tore it apart and pull the rings off and 3 of the pistons fell apart. I literally thought I got :poo:ty gaskets and chased replacing gaskets due to a ton of different oil leaks popping up. Then I had replaced them all and the dipstick start popping out. So I checked the PCV system and it all checked good which led me to a compression check.

So next time, I would just bypass all the BS and just get a compression tester unless you have something obviously wrong with your PCV system.. Doesn't take too long.
 
So if your running an external breather set-up, you should do away with the pcv system???
When it was tuned I had the egr sytem removed from the programing, and no longer have any of the egr stuf on the motor anymore if that makes any difference.
 
So if your running an external breather set-up, you should do away with the pcv system???

Correct. Otherwise you wind up with a combination of metered an unmetered air. Some believe the introduction of unmetered air is so small that it doesn't matter and can be tuned out of the computer. That may be true, but I believe in either a breather system or a PCV system, not both. It could cause vacuum-leak symptoms if both systems are combined.