Oil Consumption ??
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Racer
Joined: Dec 2000
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From: Mesa AZ
Oil Consumption ??
I have discovred that I am pumping oil on #6 cyl fouling the plug after approx. 500miles. I have noticed smoke when decelerating off freeway ramp etc. (engine braking) What is the most likely source? I take it there is a lot of vacuum in the cyls under these circumstances, would it likely be valve seals? I have not performed a compression test yet, will be doing that monday. I don't see smoke when accelerating or at idle, at least not a noticeable amount. I sure hope I don't have to tear the whole engine down 
I have performed a compression test and all cyl. look good, 155-160psi. The suspect cyl is one of the highest.
I have performed a compression test and all cyl. look good, 155-160psi. The suspect cyl is one of the highest.
Last edited by chadman; Jun 10, 2005 at 07:40 PM.
Le Mans Master
Joined: Oct 2004
Posts: 5,269
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From: Orlando Florida
St. Jude Donor '05
Valve seals are likely the problem - how old (how many miles) is that engine/the heads ??
What heads do you have ?? This is a very good excuse to buy aluminum heads with smaller combustion chamber
If you "only" want to replace the seals - take one of the old plugs, drill a hole in it for a NPT fitting, connect a hose to it so that you can use that with a compressor to pressurize the cylinder. that way the valve will not fall down on the piston and you can replace the seal with the heads installed. You probably want to replace the valve springs at this time since you have them out anyway... rent the valve spring compressor from AutoZone - it's free....
What heads do you have ?? This is a very good excuse to buy aluminum heads with smaller combustion chamber
If you "only" want to replace the seals - take one of the old plugs, drill a hole in it for a NPT fitting, connect a hose to it so that you can use that with a compressor to pressurize the cylinder. that way the valve will not fall down on the piston and you can replace the seal with the heads installed. You probably want to replace the valve springs at this time since you have them out anyway... rent the valve spring compressor from AutoZone - it's free....
Race Director
Joined: Feb 2005
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Originally Posted by chadman
I have discovred that I am pumping oil on #6 cyl fouling the plug after approx. 500miles. I have noticed smoke when decelerating off freeway ramp etc. (engine braking) What is the most likely source? I take it there is a lot of vacuum in the cyls under these circumstances, would it likely be valve seals? I have not performed a compression test yet, will be doing that monday. I don't see smoke when accelerating or at idle, at least not a noticeable amount. I sure hope I don't have to tear the whole engine down
Rich
Thread Starter
Racer
Joined: Dec 2000
Posts: 422
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From: Mesa AZ
I bought this motor as an overhauled and built unit 3yrs ago. Just got it running for the first time. My experience has been that valve seal leaks produce a little smoke at startup, I don't have that. Assuming I have good compression is there any way to tell for sure that the problem is valve seals??
Le Mans Master
Joined: Oct 2004
Posts: 5,269
Likes: 54
From: Orlando Florida
St. Jude Donor '05
Originally Posted by chadman
I bought this motor as an overhauled and built unit 3yrs ago. Just got it running for the first time. My experience has been that valve seal leaks produce a little smoke at startup, I don't have that. Assuming I have good compression is there any way to tell for sure that the problem is valve seals??
Honestly, this is easy if you have the equipment to do it yourself (compressor) ... on a re-built engine it can only be due to improper installation of these seals, these normally don't just leak for no reason.... it may be the intake gasket... again, if you can do it yourself it is a lot cheaper to just replace this gasket than paying a shop to find the source for the leak...
Thread Starter
Racer
Joined: Dec 2000
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From: Mesa AZ
Yeah, I installed the intake manifold myself, I can do it again. Here is a little more on the symtoms. If I rev over about 3000rpm and then decelerate in gear I get a lot of smoke from the right exhaust as I'm engine braking. The smoke continues for several seconds after I begin normal driving again as if I sucked quite a bit of oil, then it clears up and no more smoke unless I engine brake again. I certainly want to start with the easiest solution first but I want to get it fixed!! Hate the smoke and the fouled plug.
Thread Starter
Racer
Joined: Dec 2000
Posts: 422
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From: Mesa AZ
What do you all think is the most likely cause. Intake manifold gasket or valve seals?? I'm starting to lean toward the intake manifold since I don't seem to have any leaking down the stems when the motor is off and causing smoke at start up. Am I on the right track??
