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09-06-2005, 06:38 PM
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#1 |
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Chance
 
Join Date: Sep 2001
Location: Belcourt ,ND, USA
Posts: 750
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pistons play??
How much play should a piston have after it has been broken in? I am able to move my pistons in my 396 big block (casting #3855961). The reason being I pulled the engine to swap heads from open chamber to closed chamber and I noticed the pistons were black so I tried moving a few and I there is some play in between the piston and cylinder. Please let me know.
Chance
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1968 Chevrolet Stepside BB 396 w/TH400 1972 Chevrolet 3/4 Ton 4x4 BB 496 w/TH400 |
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09-06-2005, 06:54 PM
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#2 |
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Registered User
Join Date: Jun 2002
Location: Knoxville Tenn.
Posts: 3,058
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Normal-as much .004 if forged pistons- less with cast.
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56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer |
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09-06-2005, 06:59 PM
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#3 |
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Chance
Join Date: Sep 2001
Location: Belcourt ,ND, USA
Posts: 750
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movement
I know it moves more than that so I guess my block needs to be bored. To the best of my knowledge the block has never been bored so it is standard. When I bring it to the machine shop how much should I get it bored? I would like to to be as minimal as possible.
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1968 Chevrolet Stepside BB 396 w/TH400 1972 Chevrolet 3/4 Ton 4x4 BB 496 w/TH400 |
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09-06-2005, 07:04 PM
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#4 |
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Registered User
Join Date: Apr 2005
Location: Bridgeport, AL
Posts: 363
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if it runs good and doesn't have blow by I would run it.
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67 chevy stepside, 6 cylinder, three on the tree, small window. Currently in resto. |
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09-06-2005, 07:20 PM
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#5 |
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Chance
Join Date: Sep 2001
Location: Belcourt ,ND, USA
Posts: 750
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blow by
The motor runs good but there is a slight noise and the tops of the pistons are black. The inside of the tail pipes are also black.
Chance
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1968 Chevrolet Stepside BB 396 w/TH400 1972 Chevrolet 3/4 Ton 4x4 BB 496 w/TH400 |
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09-06-2005, 07:55 PM
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#6 |
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Registered User
Join Date: Jul 2004
Location: Shakopee Minnesota
Posts: 174
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Is the black wet? If it's not wet it's probably just carbon from the motor running to rich. Did you do a compression check acro all of the pistons before you tore it down?
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09-06-2005, 08:21 PM
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#7 |
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Registered User
Join Date: Feb 2002
Location: Vacaville, CA
Posts: 2,745
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As far as how much to bore it, leave that up to the machine shop. They will mic it and see exactly how much it will take to get the bores back to round again. In other words it depends on how much they are worn. .020 would be ideal .040 would hopefully be max, that way you have some left to rebuild again.
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 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI |
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