Boost = dipstick being pushed out

yea id run 2 breathers for sure before i tore it down

90lxcoupe said:

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.

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Good Advice

If you want to know the shape of the motor do a leakdown test.

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.

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.

When I took the passenger side head off there was present waiting for me, a piece of a piston ring.

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Not the kind of present you wanted was it

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 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.

Rick 91GT said:

Not the kind of present you wanted was it

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No, that present cost me about $7,200 after it was all said and done.

ironhead498 said:

So if your running an external breather set-up, you should do away with the pcv system???

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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.