Topic: think I broke something
in Forum: C3 Engines
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Duncanville, TX - USA
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
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#2-1985 Bright Red/Carmine Cp.L-98/auto
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Scott, a stuck open or closed valve could give you a lower comp reading, but it wouldn't explain the oil loss out of the breather/grommets. It would also have some sort of a miss to it, or "popping" from the intake or exhaust.
Did you squirt the oil into the cylinder, or just pour it in with a funnel or something? If you just poured some in, it may not have actually sealed the rings well enough to raise the test reading, if it is a ring issue.
This is starting to get weird..
Did you squirt the oil into the cylinder, or just pour it in with a funnel or something? If you just poured some in, it may not have actually sealed the rings well enough to raise the test reading, if it is a ring issue.
This is starting to get weird..

Joel Adams
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
I have an oil squirt can, gave it three good squirts. Raised the PSI, I just did not know what to expect. If I were to opt to remove the head prior to running the leakdown test would I be able to visually see a valve issue? What effect would a blown head gasket have if it were near the #1. I actually think it is the rings, I am trying to come up with possible miracles. I had oil coming down the back of the engine onto the oil pan and I think it came from the dipstick tube ?? Not positive. If it turns out to be a ring issue, can I replace the piston without removing the engine?? If not, I will have to bring it to a local shop.
15 to 20 psi is a good amount. You have a problem.
I would go ahead with the leak down test to narrow it down a bit more. But I'm betting the head will come off, and the pistion come out. It may have cracked a piston as well.
Ken, If I take the head off now and there is a problem not with the rings will it be visible? Meaning can I see a valve that is damaged or a blown head gasket. My concern is to take off the head and see a normal looking piston. Also, if it is the rings that are damaged or piston as well, can I repair this without removing the engine? I think if it is the later it should just go to a reputable shop.
If you take the head off you'll be able to check the valves,and the head gasket,the only way your gonna see the rings is to pop the piston up above the top of the block,in my honest opinion ,I would'nt just replace one piston and one set of rings,unless the engine is brand new and I knew for sure everything was up to specs.In my younger days I did it with old clunkers,just so me and my buddies could get back on the road that weekend and go partyin,but I wouldn't do it now.If it was me ,I would pop the head off and see whats up,if its the piston or the rings,I would pull the motor out and send it to the shop,or at least pop the piston out and see what the cylinder looks like, it could be gouged.thats my story,and I'm stickin to it 

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Scott...Ken actually pulled the crankshaft in his car with the engine in the car...on his back...in the yard!
So, yes, you can do it like that, but it sure is a pita.
I really don't think you're gonna have a valve problem, or even head gasket. I think you'll find a problem with either the piston, or the rings on that piston.
If you do pull the head(s), and there is a burned, or blown out section of the head gasket, it will be fairly easy to see.
A valve problem, unless it is actually stuck open, will be hard to determine without removing the valve from the head.

So, yes, you can do it like that, but it sure is a pita.
I really don't think you're gonna have a valve problem, or even head gasket. I think you'll find a problem with either the piston, or the rings on that piston.
If you do pull the head(s), and there is a burned, or blown out section of the head gasket, it will be fairly easy to see.
A valve problem, unless it is actually stuck open, will be hard to determine without removing the valve from the head.

Joel Adams
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I will see how far I get tomorrow. Thankfully I work from home alot so at lunch I'll go out to the garage for an hour. I am a little out of touch with what the associated costs are to rebuild an engine. Boil out block, replace all freeze plugs, new bearings ( cam and crank ), new pistons, rings, reassemble, any guess $$. Just had the heads done, new cam, new rocker arms and push rods, new lifters, so naturally it had to be a piston DUH !!
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Dude that sucks, I hope it's not too bad! Your cars picture always motivates me to work on mine.
Aside form piston or ring failure, would not having a crankcase evac or vaccum pump on there with the high compression and blower create/cause problems like this?

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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
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#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Scott has sent me some pics of the engine with the head off. I will post them asap.

Joel Adams
C3VR Lifetime Member #56
My Link
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
in Forum: C3 Engines
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