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JOHNFAK

Excessive Crank Pressure or tappet cover

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Not sure yet there's so much oil and hard to track down exact source even after cleaning 3x. Im starting to lean to the the oil leak is comming out of one of the two rear breathers due to excessive crankpressure (higher HP truck with ppump) . However I'm not sure what to do about it. Already have the 2 breathers. http://blogs.dieselpowermag.com/6817455/whats-new/cummins-vs-crank-case-pressure/ I've heard that a vacuum leak or turbo seal leak can cause that. Doubt its turbo as its new ...... Any ideas of input into this one. How to test vacuum leak/drawdown ...... and what do do about reducing oil leak. There is 0 blowby from the front oil collector at front, 0 blowby from the oil fill cap and I cant see any blowby at the source of the leak (tappet cover vents) whilst idle. Dont know if thats a clue or not ...... but engine seems real strong and healthy.

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Even though this only happens under high boost (greater than 50 psi) and I have no blowby ?

Why else would the crank case pressure build?

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Why else would the crank case pressure build?

Lost me. What Im trying to say is under normal driving I see now blowby. So doesn't indicated an engine wear problem as then I would have it under normal driving conditions - I will try and get a video. When it does happen is under large acceleration under boost. This is a 600HP truck. So Im *guessing* there is enough crank pressure at that power to push past the rings and create this scenario - thats my assumption. Other would be a turbo oil seal leak or a vacuum seal leak - just from what I have read. Kinda makes sense but not fully aware of how that would create extra pressure in the crank apart from its no longer sealed correctly as those both have oil feeds for cooling/lubrication.

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This kind of problem does occur with failure of the engine mounted vacuum pump... for some reason it puts pressure into the crank case. I believe Genos sells a rebuild kit. I found these threads: http://forum.mopar1973man.com/threads/8065-Vacuum-pump-Rebuild-time! http://forum.mopar1973man.com/threads/7614-Vacuum-and-power-steering-pump-recommendations

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When it does happen is under large acceleration under boost. This is a 600HP truck. So Im *guessing* there is enough crank pressure at that power to push past the rings and create this scenario - thats my assumption.

Ultimately piston and rings issues are the biggest reason for blow by issues. Compression test removes that factor by doing the test and knowing your pressures. Yes. A good tight engine will have 400-450 PSI of compression. Now any cylinder damage be it rings, piston, head or valves will show up as lower pressure on the test. Then a leak down test will tell you where the leak is going like in to the oil system, coolant, exhaust or maybe intake.

This kind of problem does occur with failure of the engine mounted vacuum pump...

Yes these thing can and do happen but still it would be a good thing to test the compression to rule out the possibility of any cylinder damage issues.

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Yes these thing can and do happen but still it would be a good thing to test the compression to rule out the possibility of any cylinder damage issues.

I get that ...... but it seems to ignore a few different/key things :tongue: 1) Its a 100k mile engine 2) It has no blowby under normal operation <== where did it go if it was a bad seal/engine ? 3) Its highly modified pushing 50-70psi boost Not your typical hauler. Now having said that - at some point I will. But right now looking to see if anyone knows about the vacuum issue I was talkign about or about adding extra breathers. Heres a link http://www.dieseltruckresource.com/dev/pressures-been-building-and-ive-got-vent-t199914.html?t=199914

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Then think about this........ At 50+ psi boost, how else does the engine build more crank case pressure? Does the vacuum pump know or care what the boost is?

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No what I mean on compression check is if the cylinders were bad - wouldn't I have blowby when engines warm at idle ? Vacuum pump was a separate deal based on some threads of vacuum leak causing raised crank pressure Sent from my SM-N900V using Tapatalk

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No what I mean on compression check is if the cylinders were bad - wouldn't I have blowby when engines warm at idle ? Vacuum pump was a separate deal based on some threads of vacuum leak causing raised crank pressure Sent from my SM-N900V using Tapatalk

Not always. Some cases where a single piston is damaged will not show any signs at all till high boost may two pistons? But yes you correct if you had all 6 with wore out rings you'd see more of it.But one or two cylinders might not be enough to create a blow at idle where at full boost now its excessive. A vacuum pump can only throw so much air into the system it can only flow so much. If you just cap it off completely and test run and still getting blowby your still looking at a compression test to see where you sit. Compression test and a leak down test let you test cylinder by cylinder the heath of all them without tearing down the engine. Yes it will require you pull all 6 injectors out but that's all. But then you can see the pressures of each cylinder and see whats up. If there is a low cylinder now you can do a leak down and see where the compression gases are going. So if you hooked up compressed air to a low cylinder to can look for the hissing air at the oil fill cap (bad rings / possibly a bad head gasket), radiator cap (blown head gasket), fuel tank (cracked head into the return rail), intake (bad intake valve) or exhaust (exhaust valve). So now you diagnosed everything and you would KNOW exactly what going on cylinder by cylinder. Now you can make a educated plan of what to do next. Rather than stumbling around in the dark guessing...

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Not always. Some cases where a single piston is damaged will not show any signs at all till high boost may two pistons? But yes you correct if you had all 6 with wore out rings you'd see more of it.But one or two cylinders might not be enough to create a blow at idle where at full boost now its excessive. A vacuum pump can only throw so much air into the system it can only flow so much. If you just cap it off completely and test run and still getting blowby your still looking at a compression test to see where you sit. Compression test and a leak down test let you test cylinder by cylinder the heath of all them without tearing down the engine. Yes it will require you pull all 6 injectors out but that's all. But then you can see the pressures of each cylinder and see whats up. If there is a low cylinder now you can do a leak down and see where the compression gases are going. So if you hooked up compressed air to a low cylinder to can look for the hissing air at the oil fill cap (bad rings / possibly a bad head gasket), radiator cap (blown head gasket), fuel tank (cracked head into the return rail), intake (bad intake valve) or exhaust (exhaust valve). So now you diagnosed everything and you would KNOW exactly what going on cylinder by cylinder. Now you can make a educated plan of what to do next. Rather than stumbling around in the dark guessing...

ok - kinda makes more sense. Still dont think its the issue based on history of truck - but I guess I wont know until I do compression test. Been talking with a couple higher HP ppump truck guys and the consensus is its pretty common. Baffled breathers or a catch can seem to be the route of choice .......... think I'll go that route to keep it under control until I get time to chase teh vacuum and validate/rebuild ...... and get my hands on a compression tester and validate.

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Might be true that with higher HP number its possible the blow gets worse but still where do you draw the line in the sand saying this is too much and band-aiding the problem might or might not be the answer. I tend to say the racing crowd is a bit different being the truck goes from idle to WOT and stays there the entire time.

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The more I think about this the more I am thinking it is something simple. I am thinking more like John is, there is simply more air stuffed into the cylinders and therefore more is going to be getting by the rings. You may be on the right track with baffles. It may be that there is enough oil floating around that it just gets blown out the breather under high boost. Is there a way to fabricate a catch bottle and tie both breathers into it?

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The more I think about this the more I am thinking it is something simple. I am thinking more like John is, there is simply more air stuffed into the cylinders and therefore more is going to be getting by the rings. You may be on the right track with baffles. It may be that there is enough oil floating around that it just gets blown out the breather under high boost. Is there a way to fabricate a catch bottle and tie both breathers into it?

Well I think I have two options on the breather side. 1) - add a breather to oil cap on valve cover - and put a splash plate underneath to allow gases in but no oil. 2) Route both breathers via a 3way tee to something like this placed higher than the breathers (to allow oil drain back) http://www.amazon.com/gp/product/B003C0173E/ref=s9_simh_gw_p263_d0_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-3&pf_rd_r=13TNXZCQY6DKNM14A7GX&pf_rd_t=101&pf_rd_p=1630083502&pf_rd_i=507846 Then For anything that goes into the catch can - route it back into the side of the block - probably in the oil drain return line for twins on passenger side of block. Im not convinced I don't also have a vaccum pump issue ........ how do you block it off and is it safe to do so (to test) ? I might rebuild it anyway with the goulds or similar cummins rebuild to feel better about it.

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Some sort of catch container with a drain would be the way I would go. The baffles would help, but I would think they still would create a mess (just not as quick as before). With out going outside to look at mine how is the vacuum pump plumbed into the block? Is it possible to block it off or block the vacuum side of the pump for test purposes?

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Yeah the problem with the billet tappet cover is there is no gravity to fight against like mikes vp44 vent So the vented catcher will let me have some lines routed against gravity which I think will reduce spill as well as an extra vent Sent from my SM-N900V using Tapatalk

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Another thread IM reading .....

 

http://www.competitiondiesel.com/forums/showthread.php?t=85410

 

check out post #9

 

Right now Ive mocked a catch can out of PVC endcaps to see how it works ...... then I'll go with something like ......

 

http://www.dhgate.com/product/greddy-oil-catch-tank-oil-catch-can-top-quality/142364626.html

 

And just allow it to drain back when not under pressure.

 

 

Still thinking of doing a compression test sometime. But there is literally no crank vapor coming out at idle.

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Man, shipping on that oil tank is unreal. $32 for 5 to 13 day shipping. 2 to 8 days $48. Whoa!!!!!!!!!

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Dunno - If you read the threads theres a number of people dealing with it. Some from higher HP, some from the billet tappet cover.

Right now I need to get the oil under control so will do some sort of catch can.

Funny thing is if I just route a hose down (no gravity to fight) the amount of oil is actually only a couple drops. Similar to my 01 that had your vented PVC mod over the negine. This 12v billet cover has no baffling and no gravity to fight - so Im starting to think poor design in the tappet cover more than anything else - but will see and keep you posted.

Edited by JOHNFAK

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