excessive crank pressures

[Joe_Van_Duno]

Hey guys,
So at SDAC I was making some fun 30+ psi passes until we noticed some oil dripping from the bottom of the van. Turns out I popped my camshaft seal out from the head. After previous runs I noticed that my dipstick had popped out of the dipstick tube, but I just brushed it off.


Only thing I changed was that I put a catch can on the pcv system. I always used to just vent it "to the atmosphere" otherwise known as let it blow oil all over the top of the transmission. Never blew enough to drip, but there was always a nice rust proofing being done.

Should I be routing that pcv system some other way?

or

At SDAC I was talking with Andy (sorry Andy don''t know your screen name) and on his FBI wagon he has a tube tapped into the oil pan just in front of the oil pump. Unfortunately I didn't get a chance to look at it, so I need some direction as to the theory behind using that setup and the "how to" create it.

Thanks

[OnLooker]

http://www.turbo-mopar.com/forums/photopost/showphoto.php?photo=12878&title=p1000115-1&cat=500

[Joe_Van_Duno]

Then where does that run? Just a catch can? No check
valve or anything like that?

with that installed can I block of the factory Pcv system?

[cordes]

I run basically the factory PCV type system in my car. I run a 5/8" hose to the cold air inlet pipe to the turbo off of the PCV valve where it would have gone to the air box. It works very well for me.

[GLHS60]

You need an un restricted path for crankcase pressure to exit the engine. Nothing can hold back blow by, or crankcase pressure, and if you try and restrict the flow, the result will be blown seals and dipstick popping. Having any connection to the air intake is asking for trouble as oily air ingested into the engine can reduce the fuels octane, promoting detonation. TBI valve covers have two nipples and are often used on high boost and/or high crankcase pressure engines as they have twice the venting area available. Any restriction in what ever vents are used have a venturi effect, and exiting air flow can suck oil along with it, so un restricted flow is the key. I think it's best to make changes in steps to tune your particular engine to it's venting needs. When you added a catch can to your system it obviously became a restriction in the flow and you had crank case pressure that blew out the cam seal and un seated the dipstick, so it was a step in the wrong direction, but an excellent learning experience. The only way for a catch can to be effective in high crank case pressure engines is, it needs to have very large vents so the pressure can exit the can unrestricted, and leave any oil behind in the can. The less the restriction, the less the oil exiting the engine, the less oil in the can. Personally, I never run any PCV system on a Turbo 2.2/2.5, but most other engines need them to prevent moisture from building up inside the engine and causing sludge. Our Turbo engines make enough heat and have a relatively small interior valve cover surface so sludge forming moisture is not the problem it is in most other engines.

Thanks
Randy

[Vigo]

Pretty much everyone who goes REALLY fast with 8v motors enlarges the crankcase venting capacity of the engine in some way. Start looking at the valve covers of all the people who have run 10s (and some in the 11s) and you will notice the pattern.

[OnLooker]

Yes it runs to a catch can. I also keep using the valve cover vent

[Joe_Van_Duno]

Thanks for the info guys. I'll take all the information into account while I work on figuring out my plan of attack.

[turbovanman²]

Do a leakdown test, even with the cobbled factory system, you shouldn't be blowing out dipsticks and crank seals.

[Reaper1]

I agree with Simon. Do a leakdown test. Popping the dipstick happens to a lot of people. It is correct that more venting would prevent that. Unless the seal was really old and it had broken down you should not be blowing out seals.

[Shadow]

You need an un restricted path for crankcase pressure to exit the engine. Nothing can hold back blow by, or crankcase pressure, and if you try and restrict the flow, the result will be blown seals and dipstick popping. Having any connection to the air intake is asking for trouble as oily air ingested into the engine can reduce the fuels octane, promoting detonation. TBI valve covers have two nipples and are often used on high boost and/or high crankcase pressure engines as they have twice the venting area available. Any restriction in what ever vents are used have a venturi effect, and exiting air flow can suck oil along with it, so un restricted flow is the key. I think it's best to make changes in steps to tune your particular engine to it's venting needs. When you added a catch can to your system it obviously became a restriction in the flow and you had crank case pressure that blew out the cam seal and un seated the dipstick, so it was a step in the wrong direction, but an excellent learning experience. The only way for a catch can to be effective in high crank case pressure engines is, it needs to have very large vents so the pressure can exit the can unrestricted, and leave any oil behind in the can. The less the restriction, the less the oil exiting the engine, the less oil in the can. Personally, I never run any PCV system on a Turbo 2.2/2.5, but most other engines need them to prevent moisture from building up inside the engine and causing sludge. Our Turbo engines make enough heat and have a relatively small interior valve cover surface so sludge forming moisture is not the problem it is in most other engines.

Thanks
Randy

Dead nuts On and couldn't have said it better myself! :thumb:

[GLHS60]

I really appreciate your acknowledgement Robert!! This issue seems to be misunderstood and often gets sidetracked. eg. TM advice to a drowning person, take swimming lessons.

You have the best "intercooled" crankcase ventilation system I've ever seen!!!

Thanks
Randy


Dead nuts On and couldn't have said it better myself! :thumb: