Oil Leak....Gone?????
Discussion
A while back we posted about an oil leak that could not be found on the right front of our 383 SB.
Just checked the garage floor after a short drive yesterday, and for the first time in almost a year, I don't have the shape of the rear frame members on the floor outlined in oil.
Let me pass on what appears to have been the problem, as this might help some other "leakers". (sorry, this does not apply to prostrates).
We actually finally found where the oil was coming from by driving the car on the lift, jacking up the rear of the car about a foot, starting the engine, raise the lift and observe the engine from underneath as it was running. The oil was appearing between the head and the block, at the front of the block. Of course we all know there is no oil there under pressure, just return oil from the rockers in the valley. After long discussions with Fel-Pro (the gasket makers), and the machine shop that prepared my block, it was determined that the oil was leaking around the front of the intake manifold, and migrating down the head gasket (maybe on the inside). But the final concensus was that "it shouldn't happen". One theory was that there was pressure building up in the block, which was possible because I had suspected the breather system I built was not always working properly as there appeared to be an excessive amount of condensation in the valve covers at times.(observed when the oil filler cap was removed).
http://home.comcast.net/~rosenracing4/wsb/html/view.cgi-photo.html--SiteID-675983.html
It was decided to remove the intake manifold and reseal the front edge, temporarily remove the breather system, and use an ordinary breather cap and use the vaccuum from the intake manifold (Edelbrock said not to use the vaccuum on the breather with their EFI system.
When replacing the valve covers which had to be turned around because of the new hose configuation, they would not seat because of the mods I had done to the rocker girdles.
http://home.comcast.net/~rosenracing/wsb/html/view.cgi-photo.html--SiteID-571419.html
Then the problem became clear. There wasn't enough clearance for the breather ports in the covers to breathe. They fit into the grooves I had cut in the girdle bars.
I only installed the girdles at the suggestion of the speed shop where I bought all the engine parts. He was supposed to be the Chevvy expert, so I did as he suggested, as this was the first Chevrolet engine I had built.
Removed the girdles, put the old breather system back on, and drove the car 21 miles back home. It appears all is well.
In summary, it appears that the pressure problem was there from day one, but the engine was tight enough to contain the oil. Finally, a small leak did start after about 5000 miles, and it took me about 3500 miles to find it!!
I hope this might be of some help.
Jack
Just checked the garage floor after a short drive yesterday, and for the first time in almost a year, I don't have the shape of the rear frame members on the floor outlined in oil.
Let me pass on what appears to have been the problem, as this might help some other "leakers". (sorry, this does not apply to prostrates).
We actually finally found where the oil was coming from by driving the car on the lift, jacking up the rear of the car about a foot, starting the engine, raise the lift and observe the engine from underneath as it was running. The oil was appearing between the head and the block, at the front of the block. Of course we all know there is no oil there under pressure, just return oil from the rockers in the valley. After long discussions with Fel-Pro (the gasket makers), and the machine shop that prepared my block, it was determined that the oil was leaking around the front of the intake manifold, and migrating down the head gasket (maybe on the inside). But the final concensus was that "it shouldn't happen". One theory was that there was pressure building up in the block, which was possible because I had suspected the breather system I built was not always working properly as there appeared to be an excessive amount of condensation in the valve covers at times.(observed when the oil filler cap was removed).
http://home.comcast.net/~rosenracing4/wsb/html/view.cgi-photo.html--SiteID-675983.html
It was decided to remove the intake manifold and reseal the front edge, temporarily remove the breather system, and use an ordinary breather cap and use the vaccuum from the intake manifold (Edelbrock said not to use the vaccuum on the breather with their EFI system.
When replacing the valve covers which had to be turned around because of the new hose configuation, they would not seat because of the mods I had done to the rocker girdles.
http://home.comcast.net/~rosenracing/wsb/html/view.cgi-photo.html--SiteID-571419.html
Then the problem became clear. There wasn't enough clearance for the breather ports in the covers to breathe. They fit into the grooves I had cut in the girdle bars.
I only installed the girdles at the suggestion of the speed shop where I bought all the engine parts. He was supposed to be the Chevvy expert, so I did as he suggested, as this was the first Chevrolet engine I had built.
Removed the girdles, put the old breather system back on, and drove the car 21 miles back home. It appears all is well.
In summary, it appears that the pressure problem was there from day one, but the engine was tight enough to contain the oil. Finally, a small leak did start after about 5000 miles, and it took me about 3500 miles to find it!!
I hope this might be of some help.
Jack
Great news. Stud girdles are a great idea for high lift, high RPM motors. Moroso sells valve covers that have a pipe welded to the top of the cover for use with stud girdles. The idea is that nothing protrudes below the inner surface of the valve cover and hits the valve gear. This would also allow greater flow out of the breathers.
Fantastic News Jack! And you didn't have to even pull the motor out! Wonderful. I will check for this on my motor as well. I had a similar issue with the rear corners of the manifold leaking, and was able to fix it. I'll check up front though. Congratulations!
Cheers!
-Mack
p.s.The stud girdles are good for running over 7-7.5k rpm for extended periods of time, but not exactly necessary for the type of driving most of us are doing with these cars. Cheap insurance I suppose. I have a set hanging in the garage and haven't even bolted them on.
p.p.s Jack, did you see the special on SpeedVision about the making of the C6 vette? It was pretty cool with a guy running down some highway at 180+mph during testing. May have been at the autobahn or somewhere.
Cheers!
-Mack
p.s.The stud girdles are good for running over 7-7.5k rpm for extended periods of time, but not exactly necessary for the type of driving most of us are doing with these cars. Cheap insurance I suppose. I have a set hanging in the garage and haven't even bolted them on.
p.p.s Jack, did you see the special on SpeedVision about the making of the C6 vette? It was pretty cool with a guy running down some highway at 180+mph during testing. May have been at the autobahn or somewhere.
[quote=
p.s.The stud girdles are good for running over 7-7.5k rpm for extended periods of time, but not exactly necessary for the type of driving most of us are doing with these cars. Cheap insurance I suppose. I have a set hanging in the garage and haven't even bolted them on.
p.p.s Jack, did you see the special on SpeedVision about the making of the C6 vette? It was pretty cool with a guy running down some highway at 180+mph during testing. May have been at the autobahn or somewhere.[/quote]
Mack
You're absolutely right about the rpm thing.
Initially, I thought I might have the engine run about 8000 rpm on the track, so the girdle sounded like a good thing. In the real world, being a stroker, the peak h.p. and torque comes in around 5800 rpm. I know the cam can be adjusted for that, but right now, most of my driving is between 2000 and 2500. We can get into the bragging rights /horsepower thing, but we'll save that for a later date. Right now the girdle will stay off.
Didn't see the C6 thing. Not sure if I'll trade my C5 in for one. Can't really see how, and why you'd want anything better.
Heading to the airport right now, heading down your way. Going to the "Big Easy" for 3 days of baseball.
Catch you when I return
Regards
Jack
p.s.The stud girdles are good for running over 7-7.5k rpm for extended periods of time, but not exactly necessary for the type of driving most of us are doing with these cars. Cheap insurance I suppose. I have a set hanging in the garage and haven't even bolted them on.
p.p.s Jack, did you see the special on SpeedVision about the making of the C6 vette? It was pretty cool with a guy running down some highway at 180+mph during testing. May have been at the autobahn or somewhere.[/quote]
Mack
You're absolutely right about the rpm thing.
Initially, I thought I might have the engine run about 8000 rpm on the track, so the girdle sounded like a good thing. In the real world, being a stroker, the peak h.p. and torque comes in around 5800 rpm. I know the cam can be adjusted for that, but right now, most of my driving is between 2000 and 2500. We can get into the bragging rights /horsepower thing, but we'll save that for a later date. Right now the girdle will stay off.
Didn't see the C6 thing. Not sure if I'll trade my C5 in for one. Can't really see how, and why you'd want anything better.
Heading to the airport right now, heading down your way. Going to the "Big Easy" for 3 days of baseball.
Catch you when I return
Regards
Jack
I feel the same way. Seriously, unless your hitting 7 grand or more for like several minutes at a time then the girdle is pointless. Don't even think it is all that necessary on the strip to be quite honest. We don't see the high rpms long enough. Like you say Jack, peak hp and peak torque come in somewhere between 5000 to 6500 rpm, and I'm more worried about the bottom end holding the 500+hp and 500+ ft.lbs of torque than I am the valvetrain stability under 7 grand with mechanical rollers. With a hydraulic roller you might consider a rev kit for anything over 6500rpm which is another story, but then we're comparing apples and oranges. Just my opinion of course. The girdle will stay on the wall until a track day on a 3+ mile long course.
Cheers!
-Mack
Cheers!
-Mack
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