Need help from you engine builders please
Thread Starter
Instructor
Joined: Dec 2000
Posts: 108
Likes: 0
From: Derbyshire,England
Need help from you engine builders please
I have my 350 out of the car and part dismantled. I have taken out one of the pistons to measure it for wear before i install my new cam and heads. Everything is fine and well within tolerance.
Can i put the old piston and rings straight back in or do i have to fit new rings and or glaze bust the cylinder wall. I really dont want to replace the rings as everything seems fine.
thanks in advance.
David
Can i put the old piston and rings straight back in or do i have to fit new rings and or glaze bust the cylinder wall. I really dont want to replace the rings as everything seems fine.
thanks in advance.
David
Le Mans Master
Joined: Jul 2001
Posts: 9,622
Likes: 16
From: absecon nj
Re: Need help from you engine builders please (ukvette72)
how many miles do you have on it now and does it use any oil ?If i had it out id rering it and hone the cylinders while its apart now.also what did the rod bearings look like any wear to it copper showing through?
[Modified by pats406nitrovette, 1:04 PM 4/20/2002]
[Modified by pats406nitrovette, 1:04 PM 4/20/2002]
Thread Starter
Instructor
Joined: Dec 2000
Posts: 108
Likes: 0
From: Derbyshire,England
Re: Need help from you engine builders please (ukvette72)
Thanks for your reply Pat,
I don't know how many miles the engine has on it as it is not original, (it has however at some time in the past had a 30 thou rebore and a crank regrind) which was one reason to pull one of the pistons,the bearings seem pretty good with only some just starting to show brass in places. I am however replacing all of them just to be safe. The bores look really good i can still see the cross hatch hone pattern on the cylinder walls and the wear ridge at the top is almost none existent, the rings pistons and bores are all within the tolerances given in David Vizards book "how to rebuild your small block chevy".
I really don't want to do any work to the bores or pistons if i can help it!even if this meens going back into it next year!
My main concern is now that i have disturbed one piston, when i put it back it may not seal as it did before am i worrying unduly?
thanks again.
David
I don't know how many miles the engine has on it as it is not original, (it has however at some time in the past had a 30 thou rebore and a crank regrind) which was one reason to pull one of the pistons,the bearings seem pretty good with only some just starting to show brass in places. I am however replacing all of them just to be safe. The bores look really good i can still see the cross hatch hone pattern on the cylinder walls and the wear ridge at the top is almost none existent, the rings pistons and bores are all within the tolerances given in David Vizards book "how to rebuild your small block chevy".
I really don't want to do any work to the bores or pistons if i can help it!even if this meens going back into it next year!
My main concern is now that i have disturbed one piston, when i put it back it may not seal as it did before am i worrying unduly?
thanks again.
David
Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
Re: Need help from you engine builders please (ukvette72)
Unless a ring breaks it will be as good as it was before. Without a compression test, i'm not sure how good it was.
On my 72 the previous owner put half the pistons in backwards. To correct this i put them in right, switching pistons only, keeping the rings in the same bore. This saved having to hone it, and the 3,000 miles it took to break in, which was 6 years. :cheers:
On my 72 the previous owner put half the pistons in backwards. To correct this i put them in right, switching pistons only, keeping the rings in the same bore. This saved having to hone it, and the 3,000 miles it took to break in, which was 6 years. :cheers:
Melting Slicks
Joined: Mar 2000
Posts: 3,206
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From: WANTED: '68 rear valance with b/u light assemblies IM, e-mail, or PM me here. Thanks!
Re: Need help from you engine builders please (ukvette72)
You need to be measuring the taper in the cylinder. If out of spec then hone it, otherwise break the glaze and install pistons with new Moly rings. Chances are that if you have cylinder wear it will also be time to grind the crank.
Moral of the engine-building story is to do it right the first time. This is not an area to cut corners.
Moral of the engine-building story is to do it right the first time. This is not an area to cut corners.
