Excessive Blowby/Crankcase pressure.

[jwsfarrier]

Hi all. Looking for some input on my current problem. I have a rebuilt motor with about 32,000 miles on it(truck in my signature). The problem I'm experiencing is, in my opinion, excessive oil in my intake coming through my breather tube. My Crankcase is vented via passenger side valve cover to a mishimoto high flow oil catch can, then into my intake just ahead of the turbo. Even though I have the catch can I am still getting quite a bit of oil in my intake and my intercooler Plumbing. At idle I am also noticing crankcase gases coming through my dipstick tube. Also because of the excessive oil in my intake and intercooler, I'm getting quite a bit of oil weeping out of the boots. I know some oil is normal but this seems like an excessive amount even with the catch can. I will work on getting some pictures posted of my setup. Thanks for the help

 

[jwsfarrier]

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[jwsfarrier]

Got some pics for you guys. Let me know what you think. I have tried a few different set ups to vent the crankcase and catch the oil vapors. I used a Racor CCV 4500 and the thing filtered great but the filter element was toast in a week. Totally saturated. Currently, there seems to be so much blowby its just bypassing the catch can and flowing through the intake.

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[quickster]

I wonder if the piston cooling jets atomize the oil too much, creating the mist. I have great compression in my '87 w/6.9. But after it warms up I get a good amount of blowby in the intake. I have a video of the motor running without the valve cover on- looks like it's on fire.

 

[quickster]

Like that setup btw!

 

[jwsfarrier]

Thanks quickster! Yeah, I tried going to just an RDT to keep stuff out the intake and intercooler plumbing. Serious smoke show! The amount of oil present seems to have increased in the last 5000 miles or so. Could any of this be attributed to worn valve guides? I know the motor has only 30 grand on the rebuild but.......

 

[gnathv]

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You should have a drain on the bottom to return oil to crankcase.

 

[Dane Rickford]

I had a blowby issue a while back. It was creating enough pressure to blow my dipstick out about a half inch. I ran a quart and a half of Marvel’s mystery oil in my next oil change and ran the truck HARD for a couple hundred miles, and no more blowby since then. What can happen is oil Carmelized on to the cylinder wall and can cause excessive blowby. Marvels cleans that carmelization off

 

[quickster]

Glazing on the cylinder walls would keep the rings from seating and sealing correctly. My motor was rebuilt 90k ago and was sitting for the last 6 years before I resurrected it. I was running it hard but still have a smoke issue under hard accel. So I'm trying to figure the blowby out too.

 

[jwsfarrier]

Thanks for the info guys. Ill give the MMO a try. I have run a quart or so in previous oil changes . I'll give it a little more and then a good work out. Gnathv- I chose not to return oil to the crankcase because i had read the trapped oil vapors could contain impurities that might contaminate the oil. Instead i replaced the drain with a Fumoto valve that made it easy to drain any oil sitting in the bottom. The Racor worked great but the filter element would be saturated in week or two. The filter elements are around 30 bux a pop. So it sounds like rings just have not sealed/seated ? That would make sense. Any thoughts on worn valve guides. Would that create more blow-by ?

 

[gnathv]

I have a powerstroke, but also had an idi. I ran the hot shots stiction eliminator in both. I reasoned that if it would remove the stiction (varnish like build up on the injectors) that it would clean anywhere the oil flowed. I just did oil cooler o rings and the oil cooler looked new inside at 273,000 miles. After running in my idi it ran smoother and cooler. And as experienced with mmo less blowby. Here’s a picture when I did glow plugs 2 weeks ago. Also in my idi, the oil didn’t turn black immediately after a change.

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[Thewespaul]

Valve guides can be a tremendous source for blow by especially with the 7.3 guides. I would pop a valve cover off and see where you notice gasses coming from. Valve guides wear tends to put heavy carbon deposits on the valve springs if run that way awhile.

 

[gnathv]

Worn Valve guides would cause more oil consumption and oil leaking down valve stem into combustion chamber. If guide is worn enough that valve isn’t seating you would increase blowby.

 

[jwsfarrier]

I will definitely check under the valve covers. I have always noticed the passenger side sounded a bit different. Can you change valve guides with the head on or does it need to come off? Thanks again for the info, I feel like im closing in on it.

 

[gnathv]

Normally if your valve guides are worn enough to replace, there is other wearing in the rest of valve train and needs to be checked.