weird crankcase pressure..
Thread Starter
Race Director
Joined: Nov 2000
Posts: 17,103
Likes: 39
From: stop the fun suckers
weird crankcase pressure..
my valve covers are leaking from all the center bolt hole penitrations.. AND FROM THE OIL FILLER CAP!!
I check the PCV valve and its free and looks good.. I've heard this can be caused my some cams.. (i just stroked the motor and added a cam similar tothe hot cam)
thanks for your input
I check the PCV valve and its free and looks good.. I've heard this can be caused my some cams.. (i just stroked the motor and added a cam similar tothe hot cam)
thanks for your input
Burning Brakes
Joined: Apr 2002
Posts: 1,126
Likes: 0
From: Cleveland OH
Re: weird crankcase pressure.. (BluByU)
my valve covers are leaking from all the center bolt hole penitrations.. AND FROM THE OIL FILLER CAP!!
However, I noticed that in one of your other posts that you were running the Comp Cams 218/224 .495/.502 on a 112LSA.
I ran that same cam on my 350 on a 110LSA and never had crankcase pressure problems until I noticed just before my bearings spun that there was a good amount of oil leaking from the crankcase breather valve and the filler cap. I've never seen this happen to my car before that.
What does it mean? I don't really know myself. But I'm interested in hearing others opinions on why some cams might cause that.
Ron
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: weird crankcase pressure.. (RonRed89)
Changing a cam won't cause excessive crankcase pressure that would cause an oil leak. Stroking an engine perhaps could, but only because the rings that were used had not seated properly causing excessive blow by and therefore causing the higher crankcase pressure.
Perform a leak down test and see what amount of cylinder leakage there is. That will give you a good indication of what is getting past the rings and into the crankcase.
Perform a leak down test and see what amount of cylinder leakage there is. That will give you a good indication of what is getting past the rings and into the crankcase.
Thread Starter
Race Director
Joined: Nov 2000
Posts: 17,103
Likes: 39
From: stop the fun suckers
Re: weird crankcase pressure.. (tjwong)
could an intake leak on the lifter valley side possibly cause this also? What would be the proper diagnostic method?
1. inspect plus for oil fouling
2. Perform compression test
3. perform leakdown test
4. pull manifold and inspect for leakage (if compression test ok)
or fix rings in compression test not ok
can someone also explain to be the proper method of doing a leak down test?thanks!
1. inspect plus for oil fouling
2. Perform compression test
3. perform leakdown test
4. pull manifold and inspect for leakage (if compression test ok)
or fix rings in compression test not ok
can someone also explain to be the proper method of doing a leak down test?thanks!
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: weird crankcase pressure.. (BluByU)
could an intake leak on the lifter valley side possibly cause this also? What would be the proper diagnostic method?
1. inspect plus for oil fouling
2. Perform compression test
3. perform leakdown test
4. pull manifold and inspect for leakage (if compression test ok)
or fix rings in compression test not ok
can someone also explain to be the proper method of doing a leak down test?thanks!
1. inspect plus for oil fouling
2. Perform compression test
3. perform leakdown test
4. pull manifold and inspect for leakage (if compression test ok)
or fix rings in compression test not ok
can someone also explain to be the proper method of doing a leak down test?thanks!
Moroso and other sell them. The best ones consist of two guages, side by side.
You remove the spark plug, bring the piston to TDC, screw the hose end of the gauge into that cylinder, fire up the compressor and set the first gauge to the pressure recommended in the instructions that come with the tester.
You then read the second gauge and it tells you how much of the pressure is leaking by the rings, valves, gaskets, etc.
Jake
[Modified by JAKE, 1:08 PM 11/3/2003]
