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Suddenly more blowby from valve cover vent???


Guest Tim78zt

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Guest Tim78zt

What does it mean when I suddenly see a ton of blowby coming from the little open K&N vent on my valve cover? Of course this started happening after it was run real hard and also I'm off about 15 psi oil pressure. Car cruises on the freeway showing about 45 lb (half-way mark) when it used to show about 60 lb. This engine has about 18,000 miles on a megabuck teardown/rebuild. Rev-limiter on the Crane HI-6 is set at 6200rpm.

Thanks in advance for any ideas!!

 

Tim78zt

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My turbo motor was doing the same thing...turned out to be 2 broken ringlands on one piston and one cracked ringland on another. Do a leakdown test to see how much pressure you are leaking down and what cylinder(s) is (are) the culprit.

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Guest Anonymous
Originally posted by Tim78zt:

What does it mean when I suddenly see a ton of blowby coming from the little open K&N vent on my valve cover? Of course this started happening after it was run real hard and also I'm off about 15 psi oil pressure. Car cruises on the freeway showing about 45 lb (half-way mark) when it used to show about 60 lb. This engine has about 18,000 miles on a megabuck teardown/rebuild. Rev-limiter on the Crane HI-6 is set at 6200rpm.

Thanks in advance for any ideas!!

 

Tim78zt

Blowby= blown motor.
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Guest Tim78zt

Z-Gad and everyone,

I was running 12# boost through my DFI/ intercooled/ceramic-coated lump. Is it still safe to drive before/after the leakdown test? Is the damage already done? It seems to run fine, no extraneous noises. What is the proper procedure for a leakdown test? Cold/hot engine? How do I set up each cylinder for the test. I have a MityVac which should help.

 

Tim

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well Tim, I took mine down to a buddy of mine's shop. He had the proper equipment to do the test. It only took the time to remove the plug, blow compressed air into the chamber and read the gauge in his hand. There were two gauges, one showing the amt of air entering the chamber and one showing the pressure of air which remained in the chamber. He also had me remove the crankcase breather tube to see whether the air was escaping through the crankcase. You may want to call around to a couple of local shops and see whether or not they can do it. A compression test would be the next best thing, but isn't as diffinitive.

I drove mine to the shop. It ran fine for me too, but the oil pressure was a little down and just had smoke coming out from under the hood (very noticable at stop lights).

 

Mike

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Guest Tim78zt

Yeah, Mike, the smoke at stop lights is really the embarrasing part. People look over and you can tell by the look on their face they think my engine is on fire there is so much vapor coming out of the hood vents.

I asked the local Z garage about the tester and he thinks he can find the one he's used before. So I'll just take it easy (and not drive it )until I can get it over there.

 

Tim

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