well after performing compression and leak down tests on my 455, the culprit seemingly turned out to be a leaking intake manifold gasket. Apparently, the modified-for-a-tunnel ram- ski tow was not placing flat torque on the rear intake bolts and so the intake lifted just enough to make the "turkey tray" valley gasket leak like a mofo. I'm putting her back together tonight and we'll be out at Elsinore on Saturday to see if we've exercised the demons. wish me luck!
Cyclone, do not, repeat DO NOT, use the "turkey tray" with an aluminum intake on an Olds. They will not seal properly. All the manifold manufacturers recommend the use of Mr Gasket composition-style gaskets. I believe they are now available in two different material types. Any good speed shop should carry them. Since you are in SoCAl, I know you can find them at Mondello.
Mr.Gaket #404 for standard and #5846 for Ultra Seal.
[This message has been edited by OLDSQUIRT (edited June 06, 2002).]
thanks for the advice oldsquirt. I have replaced the turkey tray with the Mr. Gasket gaskets. You know what's funny is that the guy at the speed shop sold me hipo marine head gaskets and didn't even think to sell me the better intake manifold gasket in the first place. when i came back to him yesterday he said, "oh yeah, you dont want to use those gaskets. Here use these Mr. Gaskets." now he tells me!
Happy to help, Mike. I learned that lesson myself many years ago....the expensive way, I might add. Had poor seal around an intake port. Leaned out the cylinder and burned a piston. http://free.***boat.net/ubb/frown.gif
BTW, great job on the boat. Looks awesome!
thanks oldsquirt! she's got a few issues still, but hopefully I'll find the time to deal with them. Got any pictures of your boat?
hey I think I had the same problem. 1 of my plugs burnt the electrode out. I thought it could be too lean.I am going to change to the other gaskets too. thanks
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