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Bad blow by after valve springs

Old 03-07-2010, 07:38 PM
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Bad blow by after valve springs

Originally when I purchased my truck I did not loose any oil or have any blow by issues, went on a few long trips, 600 miles or so, and no issues. Recently I installed 60lbs exhaust valve springs with the exhaust brake and I have noticed some serious blow by, loosing about 4q on a 600 mile trip and coating the underside of the truck and tailgate.

I am wondering if I messed up something when I did the valve springs, I have double checked my lash, but was thinking maybe the valve seals have gone or something. Any ideas?
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Old 03-07-2010, 08:58 PM
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Might be a coincidence.
By any chance has your oil pressure gauge been erratic? I lost that many quarts when my sending unit failed.
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Old 03-08-2010, 01:33 PM
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When you reinstalled the valve covers did you by chance not get one seal all the way to the head? Changing valve springs have no affect on blowby.
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Old 03-08-2010, 11:26 PM
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There was some leakage from the valve cover seals, but I have since replaced them all and the o-rings. I'm wondering if one of the valve seals popped up or something, are they easy to replace or does it involve pulling the head. I do not think it is a popped head gasket or worn rings as there has been no loss of power or any oil or water mixing in the sump or radiator.
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Old 03-09-2010, 10:09 AM
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Valve seal would have nothing to do with blowby. However the brake could. Try running a tank with the brake off. Could you have a vacuum leak?
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Old 03-09-2010, 12:31 PM
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I just got through fixing a problem with oil blowing out the blowby and painting the backend of the truck. Here's a short vid of the turbo return dropped down into a pan. Just idling, you can see a few bubbles while the end of hose is submerged, but when the flapper is closed it becomes a whole different story. At 2500 rpm it would prolly blow the oil out of the pan.

ps,...Can't make fun of my Boomhauer voice.

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Old 03-09-2010, 01:09 PM
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Originally Posted by Fueling around View Post
By any chance has your oil pressure gauge been erratic? I lost that many quarts when my sending unit failed.
How would the oil pressure gauge sending unit cause oil loss?
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Old 03-09-2010, 01:33 PM
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Originally Posted by lgp9999 View Post
How would the oil pressure gauge sending unit cause oil loss?
When mine failed it pumped oil through the diaphram and out the side of the block.
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Old 03-09-2010, 01:44 PM
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Originally Posted by GAmes
Originally Posted by lgp9999
How would the oil pressure gauge sending unit cause oil loss?
When mine failed it pumped oil through the diaphram and out the side of the block.
Ditto.
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Old 03-09-2010, 04:26 PM
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Is there an electronic oil pressure valve?
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Old 03-09-2010, 04:27 PM
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Originally Posted by dguru View Post
Valve seal would have nothing to do with blowby. However the brake could. Try running a tank with the brake off. Could you have a vacuum leak?
It sure would. Boost leaking past the seal will pressurize the crank case just like combustion gasses passing the rings.
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Old 03-10-2010, 12:28 AM
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Originally Posted by OneBigDoofus View Post
I just got through fixing a problem with oil blowing out the blowby and painting the backend of the truck. Here's a short vid of the turbo return dropped down into a pan. Just idling, you can see a few bubbles while the end of hose is submerged, but when the flapper is closed it becomes a whole different story. At 2500 rpm it would prolly blow the oil out of the pan.

ps,...Can't make fun of my Boomhauer voice.
So you had to replace your turbo seals? I am going to hopefully check the valve seals this weekend, is it just a visual inspection? or do I need to remove them and replace them?
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Old 03-10-2010, 10:42 AM
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You really can't eyeball the condition of valve seals without removing the spring and seal. At that point you might as well replace the seals while you're in there. It cost me less than $50 using genuine Cummins parts. It gets a little more expensive when you decide that you're going to upgrade the valve springs and install a 4kGSK while you're at it.
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Old 03-11-2010, 11:36 AM
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Originally Posted by Kiff View Post
So you had to replace your turbo seals?
Replaced turbo cus it had plenty of miles on it. I have it on the shelf and will prolly attempt a seal/bearing kit in it, if there's no damage.

Dropping a tube in a pan is a 30 min job at the most. Make sure you have a air tight seal at the connection when sliding hose on.

To be honest, just stop using it as mentioned above and see if it slows down the burping of oil.

Maybe I missed it but did you install the brake and springs at the same time?
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Old 03-14-2010, 12:39 PM
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Yes I did the springs and brake at the same time. I will try capping the vac line completely and see if that helps the issue. I would not suspect bad rings or head gasket as there was no loss of power and no white smoke or sputtering and I haven't lost any coolant. I also added a boost elbow around that time and set the wastegate around 30psi so the turbo seals sound more to be the culprit
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