engine experts step inside please
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From: Sitting in his Nowhere land Hanover Pa
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engine experts step inside please
I took apart the 396 that is in my 66 Chevelle that was burning oil real bad. I found out that the engine re-builder lied to me
they said it was only bored out 30 over. turns out its 60 over
but here are some pictures. tell me what you see can be wrong.
they said it was only bored out 30 over. turns out its 60 over but here are some pictures. tell me what you see can be wrong.
Burning Brakes
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Assuming the heads were sealed to the block properly, there are only two ways for oil to find its way into combustion chambers on a 4-stroke;
1) From above via the intake tract (mismatched intake gasket, valve seals/guides, faulty PCV etc.).
2) From below past the rings (wrong/bad rings, undersized piston etc.).
1) From above via the intake tract (mismatched intake gasket, valve seals/guides, faulty PCV etc.).
2) From below past the rings (wrong/bad rings, undersized piston etc.).
Last edited by Viking427; Dec 29, 2010 at 03:27 PM.
Team Owner
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From: Greenville, Indiana
Just a WAG from your pictures:
Intake valves seals aren't there or not sealing.
Rings not sealing in one or more cylinders.
How many miles are on that engine and why does it appear to have a ridge at the top of the cylinder already?
Intake valves seals aren't there or not sealing.
Rings not sealing in one or more cylinders.
How many miles are on that engine and why does it appear to have a ridge at the top of the cylinder already?
Team Owner
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From: Greenville, Indiana
If it's not a ridge, then I'll stick with my first post.
Race Director
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My guess is, incorrect final hone in conjunction with incorrect rings. Doesn't the shine on the cylinder walls look a bit too shiny? I can see one piston stamped as .060. 
Dennis
Dennis
Last edited by Bluestripe67; Dec 29, 2010 at 05:54 PM.
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That was my first observation also.
Racer
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From: Mukilteo Washington
My guess is valve stem seals. Did the same shop do the heads? There should be umbrella style rubber seal that goes under the spring and an o-ring that goes inside the retainer. If either one of those is not sealing, a lot of oil can be sucked into the cylinder.
Jim
Jim
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From: Sitting in his Nowhere land Hanover Pa
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Le Mans Master
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From: columbus oh
Racer
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From: Tucson AZ
Did you do any research on this guy before you brought your engine to him. Good Grief! I'd take the b&^%$ back and tell him to fix it if you did! If you didn't, you're f*&^%$! Tear the hole thing apart and do it right. Get the heads and block down and get them checked by a reputable mechanic, that means fluxed and pressure tested.
Last edited by bdhulderman; Dec 29, 2010 at 10:36 PM.
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Looks like you have some really out of shape bores if all those dark spots I see in them aren't just camera flash issues. I'm looking at about 2 and 8 oclock in all the pics. Those dark spots are where rings aren't making contact. You need to put a TQ plate on it and run a fixed hone through it a few strokes (not a brush/ball type) and see what it looks like.
Compare the 3 on the left with the one on the right. At least that one is sorta burning the oil in instead of just pumping it.
Those are plain cheap rebuilder type pistons that have the wrong dome configuration and lower compression.
JIM
Compare the 3 on the left with the one on the right. At least that one is sorta burning the oil in instead of just pumping it.
Those are plain cheap rebuilder type pistons that have the wrong dome configuration and lower compression.
JIM
Le Mans Master
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From: I'd like to propose a toast... to internal combustion and wind in the face.
Dennis all 8 pistons say .060. and for the valve stem seals inside the spring I can make out a red tube. there are two springs for each cylinder, and I was going to let the new engine rebuild guy tear them apart. I am hoping what you are saying is correct. will let you know in about 2 weeks
A few years ago when I bolted my 454 back togethor it smoked very, very bad. The smoking was either entirely related to bad valve stem seals or leaking intake gaskets. I literaly had oil standing on top of the intake valves. I can't say which item was the culprit as I replaced them both at the same time and the problem was solved.
One other thing, like someone said earlier, those cylinder bores sure are shiney. Possibly there's something there too.