oil in intake
Thread Starter
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
oil in intake
Hi, my brother's '97 'vette is experiencing a problem with excessive amounts of oil being drawn into the intake manifold by the PCV system. It is a '97 with original engine, using post '98 style heads and valve covers. Big cam, big heads, oil catch can is full in less than 100 miles. Does anybody have any idea what might be going on here? Sorry I can't really give any more specific info, this really has us scratching our heads.
Scott
Scott
Race Director
Joined: Jan 2008
Posts: 16,028
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From: oregon
not much more to say.
start with a vacuum test, see if there is any flutter in the gauge. if there is a leakdown test will show you the low cylinder
as stated the other possible is a crankcase that's unable to vent and or your catch can is routed incorrectly. a closed catch can needs to be routed to manifold vacuum. vented catch cans do not. if you're filling a vented catch can there is a good chance you have a good deal of blow by.
does this engine burn a lot of oil? like more than a quart per 1000 miles?
Tech Contributor
Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
You can UP-GDADE to a 2001+ ZO6 PVC system but,, its a lot of work and then ADD a quality PVC catch can.
The catch can elimanited almost all of my oil in the intake issues.
I agree,, make SURE that you dont jave ANY other machancial issues.
Try just adding a catch can to your C5!
BC
The catch can elimanited almost all of my oil in the intake issues.
I agree,, make SURE that you dont jave ANY other machancial issues.
Try just adding a catch can to your C5!
BC
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A catch can does a great job of keeping oil from going into the intake. Installed one on mine last year and am amazed at how much oil it collects. Got mine from Elite Engineering.
Thread Starter
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
I mentioned the catch can in my post: it is full of oil within 100 miles.
NassyBlue, the pcv is set up like your diagram, except that the pcv valve is in the valve cover; would the placement of the pcv valve after the catch can have any effect on the catch can filling up very quickly?
RonSSNova, I am not sure about baffles, will check and get back to you. Valve covers bought from ebay, so may very well not have baffles.
racebum and lucky131969, no compression test or leakdown performed, but I can tell you that when we removed the old heads, we could still see the cross-hatching on the cylinder walls. I told him to perform a compression test, just to eliminate it from the equation, hasn't been done yet, though.
Thank you to everyone for your input, it has given us a few directions to go in; If we ever get it sorted out, I'll let you guys know.
Keep the shiny side up!
scott
NassyBlue, the pcv is set up like your diagram, except that the pcv valve is in the valve cover; would the placement of the pcv valve after the catch can have any effect on the catch can filling up very quickly?
RonSSNova, I am not sure about baffles, will check and get back to you. Valve covers bought from ebay, so may very well not have baffles.
racebum and lucky131969, no compression test or leakdown performed, but I can tell you that when we removed the old heads, we could still see the cross-hatching on the cylinder walls. I told him to perform a compression test, just to eliminate it from the equation, hasn't been done yet, though.
Thank you to everyone for your input, it has given us a few directions to go in; If we ever get it sorted out, I'll let you guys know.
Keep the shiny side up!
scott
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Tech Contributor
Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I mentioned the catch can in my post: it is full of oil within 100 miles.
NassyBlue, the pcv is set up like your diagram, except that the pcv valve is in the valve cover; would the placement of the pcv valve after the catch can have any effect on the catch can filling up very quickly?
RonSSNova, I am not sure about baffles, will check and get back to you. Valve covers bought from ebay, so may very well not have baffles.
racebum and lucky131969, no compression test or leakdown performed, but I can tell you that when we removed the old heads, we could still see the cross-hatching on the cylinder walls. I told him to perform a compression test, just to eliminate it from the equation, hasn't been done yet, though.
Thank you to everyone for your input, it has given us a few directions to go in; If we ever get it sorted out, I'll let you guys know.
Keep the shiny side up!
scott
NassyBlue, the pcv is set up like your diagram, except that the pcv valve is in the valve cover; would the placement of the pcv valve after the catch can have any effect on the catch can filling up very quickly?
RonSSNova, I am not sure about baffles, will check and get back to you. Valve covers bought from ebay, so may very well not have baffles.
racebum and lucky131969, no compression test or leakdown performed, but I can tell you that when we removed the old heads, we could still see the cross-hatching on the cylinder walls. I told him to perform a compression test, just to eliminate it from the equation, hasn't been done yet, though.
Thank you to everyone for your input, it has given us a few directions to go in; If we ever get it sorted out, I'll let you guys know.
Keep the shiny side up!
scott
The lack of a properly baffled valve covers will for sure cause excessive PVC oil consumption. Make SURE you carefully check that out!!
You can also do a quick check for excessive piston blow by just by removing the oil fill cap when the engine is idling. With a properly operating PVC system,, you should NOT have any air out flow thru the opening of the oil fill spout.
Bill
Burning Brakes
Joined: Apr 2009
Posts: 1,163
Likes: 4
From: Concord California
Re-read, got it.. You seem to have massive blow by to get that much oil flow thru the PCV. Problems may be worn rings, hard to say. May need a professional mech. to review and help identify the problem.. Good luck.. You could always intall a second oil catch can.. but that's not a fix.. good luck.
Last edited by Jesse Asis; Sep 6, 2012 at 04:48 PM.
Burning Brakes
Joined: May 2007
Posts: 911
Likes: 27
From: Southern IL
Some of you guys reading comprehension is a bit lacking. 
Original poster stated in post #1 ...he has a catch can already installed... It's at maximum capacity after only 100 miles of driving.
Original poster stated in post #1 ...he has a catch can already installed... It's at maximum capacity after only 100 miles of driving.
Safety Car
Joined: May 2007
Posts: 4,812
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From: Taylorsville North Carolina
There are plenty of threads about this, and issue is pretty common with built motors. Here is a current one going on in AX/RR section:
http://forums.corvetteforum.com/auto...oot-cause.html
I am currently leaning towards routing the valley cover port to catch can and then thru breather. You can even drain your catch can thru dipstick back into motor. This also means expelling gases into atmosphere and plugging the intake port. Why take a chance with oil getting back into combustion chamber. Your inspection rules will have a lot to do with your choice. Good luck with it.
http://forums.corvetteforum.com/auto...oot-cause.html
I am currently leaning towards routing the valley cover port to catch can and then thru breather. You can even drain your catch can thru dipstick back into motor. This also means expelling gases into atmosphere and plugging the intake port. Why take a chance with oil getting back into combustion chamber. Your inspection rules will have a lot to do with your choice. Good luck with it.
Thread Starter
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
NassyBlue, thanks for the diagram, I think it helped us solve the problem. When I went back over to my brother's house, I gave the engine bay a good look-see, and found something that I missed during my initial cursory inspection. In addition to the PCV valve being in the valve cover, as opposed to after the catch can in NassyBlue's diagram, it also had a hose coming form the rear of the passenger's side valve cover which tee'd into the hose coming from the PCV to the catch can. We removed it, and blocked it off, and that seems to have solved our problem. The catch can now has only a few drops of oil in it after a 20 mile or so drive. Rest assured, I have been giving him crap for being a knucklehead ever since! (He's a motorcycle mechanic, so he knows how to spin a wrench, but sometimes he is in a little over his head when it comes to cars. He's smart enough to learn from his mistakes, though.) Thanks a bunch for everybody's input, and I am now going back with the rest of the dinosaurs in the C3 forum where I belong! See ya!
Keep the shiny side up!
scott
) Thanks a bunch for everybody's input, and I am now going back with the rest of the dinosaurs in the C3 forum where I belong! See ya!Keep the shiny side up!
scott
2nd Gear
Joined: Oct 2014
Posts: 2
Likes: 0
Scott
The lack of a properly baffled valve covers will for sure cause excessive PVC oil consumption. Make SURE you carefully check that out!!
You can also do a quick check for excessive piston blow by just by removing the oil fill cap when the engine is idling. With a properly operating PVC system,, you should NOT have any air out flow thru the opening of the oil fill spout.
Bill
The lack of a properly baffled valve covers will for sure cause excessive PVC oil consumption. Make SURE you carefully check that out!!
You can also do a quick check for excessive piston blow by just by removing the oil fill cap when the engine is idling. With a properly operating PVC system,, you should NOT have any air out flow thru the opening of the oil fill spout.
Bill