New "problem"...blowing oil and the dipstick out its tube when I mat the gas pedal...

[biomedtechguy]

I've had to be aware of oil out of the driver's side valve cover breather ever since I changed from the factory stock PCV and valve covers. I had that factory black breather that has some internal headroom height and "dual wall" design that only allowed vapor to exit via the vacuum hose + PCV valve.
My "new" (4 years old now) fabricated valve covers required a new PCV valve and I bought a nice looking breather. I found way back 4 or 3½ years ago that when I was at the track or on the highway I'd get oil coming out the breather.
At that point I discovered not just any PCV valve functions as it should for a particular motor, and I got a M/E Wagner tunable PCV valve, although I run it in fixed orifice mode, aka "max suck". That seemed to resolve the problem.
Now when I do a "test hit" AKA wide open throttle from launch thru 2nd gear, on 2 occasions, my dipstick pops up out of the tube a bit and the oil sprays out the top. I just recently changed to a new Mopar breather w/foam element to replace a similar (but not identical) one because the foam element in the one I had was oil soaked, dripping oil onto my valve covers, and I knew of no way to clean the oil out.
A friend suggested adding a longer tube height breather to prevent the oil from reaching the top of the breather cap so easily AND adding at least one additional breather. My valve covers ARE baffled under the breather hole, so no direct path up the breather.
He suggested having 4 breathers, 2 per valve cover, but that would eliminate my PCV system and I'm not going to do that.
Suggestions welcome, please help!

 

[Kern Dog]

My experience has been that when the dipstick gets pushed out, that the rings are on the way out. The theory is that combustion pressure is getting past the rings and into the "crankcase" instead of staying in the combustion chambers. Anywhere the oil flows can be subject to crankcase pressure as well. The oil pan is directly below the cylinders so any positive pressure could affect the dipstick passage first.
I don't know if a cranking compression test would reveal a problem since the speeds that you test at are relatively low. The combustion pressures at WOT are far higher than at idle or cruise speeds.
Crusty plugs may be an indicator. A comparison of current cranking compression to previous numbers may show a trend to excessive wear.

 

[biomedtechguy]

the rings are on the way out

Yeah, that's what I was afraid of, but I'm not sure if that is the problem.
The stock bore 71 440 in my car already had been "suped up" when I bought it, with the Purple Stripe cam, 6 pack rods, crank, and so forth. I will say the oil pressure is good, all conditions, and it doesn't blow smoke out of the exhaust.
Anybody else think it's rings?

 

[biomedtechguy]

I may need to work harder on funding the Bill Mitchell aluminum block stroker.
I doubt I'd put much or any money in a rebuild on the 440 I have w/the stroker motor as my planned engine.

 

[F4R/T]

Just remember it could be worse at least it’s always fixable... just time and money, something most of lack enough of.. good luck!

 

[440+6]

Most likely rings, but could be valves, also open to crankcase.

 

[biomedtechguy]

I have a leak down kit.
Looks like I need to use it because...

DAMN! It's such a strong motor otherwise. It's strange that it doesn't smoke out the exhaust, right?

 

[yella71]

My experience has been that when the dipstick gets pushed out, that the rings are on the way out. The theory is that combustion pressure is getting past the rings and into the "crankcase" instead of staying in the combustion chambers. Anywhere the oil flows can be subject to crankcase pressure as well. The oil pan is directly below the cylinders so any positive pressure could affect the dipstick passage first.
I don't know if a cranking compression test would reveal a problem since the speeds that you test at are relatively low. The combustion pressures at WOT are far higher than at idle or cruise speeds.
Crusty plugs may be an indicator. A comparison of current cranking compression to previous numbers may show a trend to excessive wear.

what he said....or just keep your foot out of it

 

[dvw]

Either it doesn't have enough breather or it has excessive blow by past the rings. For now zip tie it down and enjoy beating on it. You can't make it any worse.
Doug

 

[moes]

I would try some Marvel Mystery Oil to see if that would help with the pressure build up in the motor. It's cheap and if it does not work it only cost you a few bucks.

 

[Darter6]

Old trick is a spark plug boot over the dipstick tube then insert the dipstick.
The boot will hold the dipstick in place and won't push out.
The oil cap/breather to the air filter,the crimp on the aftermarket style will drip oil out the crimp.I just clean and apply silicone around the crimp.Or use the factory one as is pictured, never had one drip.Last is where the PCV valve is,is a GM part,Mid 80's that is baffled.Helped with the old Slant's oil woes.

 

[biomedtechguy]

Old trick is a spark plug boot over the dipstick tube then insert the dipstick.
The boot will hold the dipstick in place and won't push out.View attachment 1090092

THANK YOU!!
this trick
I appreciate ALL of the replies! Even if it's something I don't want to hear.
I've only gotten as far as securing the big bore (4.49) BMP aluminum block, so that leaves A LOT of money and parts to finish it, and "it don't come easy"...

 

[HEMI-ITIS]

As you said,a leakdown test will point you in the right direction.I do not use a PVC,I have 2 breathers going to a catch can.

 

[toolmanmike]

What do you have for PCV and breather?

 

[Nevada dan]

Run a compression test

 

[slepr1]

A buddy of mine has a 71 Demon and its 340 did the exact same thing with the dipstick. No smoke coming out the rear either. Was the rings. He ended up rebuilding the engine.

 

[biomedtechguy]

What do you have for PCV and breather?

PCV is the best on planet earth IMO...

I got a M/E Wagner tunable PCV valve, although I run it in fixed orifice mode, aka "max suck".

As far as the breather goes, it's one of these, foam filled. I got it because it looks nice and my old one got soaked with oil, and I don't know any way to clean it out.

As you said,a leakdown test will point you in the right direction.I do not use a PVC,I have 2 breathers going to a catch can.

View attachment 1090094

Thanks brother.
I would consider an electric motor driven vacuum pump if they exist, and if that would help. The Wraptor serpentine belt and accessories system I have would make a belt driven vacuum pump a challenge.
As much as I'd like to wave a wand and drop in the stroker, I may be over a year out from completion.

 

[747mopar]

I'm with everyone else, do a compression test. Even if you don't have previous numbers to compare to just comparing them to one another should tell you something, rings seldomly fail evenly or simultaneously so you should see a discrepancy. I just went through this on my daily driver, 165, 140, 170, 168 were the results, as I said seldomly fail simultaneously.

Good luck

 

[Curiousyellow71]

I don't know what your running for oil pan and windage tray? I have run into engines with a stock oil pan with plenty of oil clearance that the windage would pop out the dipstick... but when it was a quart low it would not do it. Its easy to try to see if it changes your issue. But, I can't say I'd recommend hot rodding much a quart low.
To much blow bye/crankcase pressure is by far the most commom.

 

[PurpleBeeper]

Definitely blowby….but as mentioned, make absolutely sure your PCV valve sucks and your breather allows fresh air into the other side of the crankcase