Engine Block Cylinder Wall Thickness - Team Camaro Tech
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post #1 of 7 (permalink) Old Dec 28th, 08, 05:46 PM Thread Starter
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Joe
 
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Engine Block Cylinder Wall Thickness

I have a 1965 327 engine block that has been bored .030 over. The cylinder walls were sonic tested, and measure about .080-.090 in many areas, with some areas measuring as thin as .058!
Has anyone ever seen this before, on a block that has only been bored .030 over?
What can have been the cause of this?
Is the block usable with such thin walls, and if not, why not?
If I fill the block water jacket with "block fill", would that solve any wall stiffness issues? If so, then what other issues can NOT be addressed by filling the water jacket.
Thanks in advance.
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post #2 of 7 (permalink) Old Dec 28th, 08, 06:51 PM
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Mike
 
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Re: Engine Block Cylinder Wall Thickness

What kinda of sonic checker were they using? Seems weird it is that thin. I have sonic checked many a block and even 400,s are around .200. I personaly dont like to use any thing with a finished wall thickness under .215 on the thrust side and thats pushing it IMO. I have found some blocks up to .285 and thicker etc.
Sure they had the sonic checker calibrated? or was it measuring in Metric mode? Some Sonic checkers also use a dielectric? type lubricant on the probe also, and if it is not used it messes up the readings.

2002 Jerry Bickle Cavalier, 446" Small Block, Brodix Canted Valve, lenco 5 speed, 7.54 @ 180. mph,1.06 60', 2235 lbs for 2014. GM Canada Docs, Highly Optioned 69 RSZ28 , Hugger Orange, White Stripes, 42,000 mile survivor, owned since 1973.

Last edited by rszmjt; Dec 28th, 08 at 07:05 PM.
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post #3 of 7 (permalink) Old Dec 28th, 08, 07:36 PM
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Ed
 
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Re: Engine Block Cylinder Wall Thickness

Core shift could certainly cause variations in wall thickness. Anything under .200 depending on HP level would be iffy. Race motors want to see 300-400 at least.

Maybe measure a known good thickness on the block (one that you can measure with a caliper)?

Ed

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post #4 of 7 (permalink) Old Dec 28th, 08, 07:55 PM
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Mike
 
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Re: Engine Block Cylinder Wall Thickness

[QUOTE=BigBlock1969RS;1127875]Core shift could certainly cause variations in wall thickness. Anything under .200 depending on HP level would be iffy. Race motors want to see 300-400 at least.

Good Advice. This is why they have aftermarket blocks. Good luck finding a production passenger car block this thick, it just doesn,t happen.

2002 Jerry Bickle Cavalier, 446" Small Block, Brodix Canted Valve, lenco 5 speed, 7.54 @ 180. mph,1.06 60', 2235 lbs for 2014. GM Canada Docs, Highly Optioned 69 RSZ28 , Hugger Orange, White Stripes, 42,000 mile survivor, owned since 1973.
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post #5 of 7 (permalink) Old Dec 28th, 08, 09:07 PM
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Joe
 
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Re: Engine Block Cylinder Wall Thickness

Quote:
Originally Posted by 1965tripleblack View Post
I have a 1965 327 engine block that has been bored .030 over. The cylinder walls were sonic tested, and measure about .080-.090 in many areas, with some areas measuring as thin as .058!
Has anyone ever seen this before, on a block that has only been bored .030 over?
What can have been the cause of this?
Is the block usable with such thin walls, and if not, why not?
If I fill the block water jacket with "block fill", would that solve any wall stiffness issues? If so, then what other issues can NOT be addressed by filling the water jacket.
Thanks in advance.
If they check the cylinders in 3 equally spaced spots, and its coming up around .058, then the core has not shifted. I would be surprised if the checker is not working properly.
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post #6 of 7 (permalink) Old Dec 29th, 08, 06:05 AM
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Gary
 
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Re: Engine Block Cylinder Wall Thickness

I'd have it checked again by another shop. I don't think it could be bored and have the bores come out round with .058 cylinder thickness. Think about it - that's just over 1/2 of a tenth of an inch. Most shops recommend no less than .150 or so on the thrust surfaces and even that's iffy for a performance engine.

Gary Adrian
FCS Harmony Racing

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post #7 of 7 (permalink) Old Dec 29th, 08, 04:59 PM
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Mike
 
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Re: Engine Block Cylinder Wall Thickness

Quote:
Originally Posted by Busted Knuckles View Post
I'd have it checked again by another shop. I don't think it could be bored and have the bores come out round with .058 cylinder thickness. Think about it - that's just over 1/2 of a tenth of an inch. Most shops recommend no less than .150 or so on the thrust surfaces and even that's iffy for a performance engine.
Gary, You make a Good point, I have honed lots of production blocks with a hand held Sunnen Cylinder Hone as well as in the Sunnen CK10, and it,s allways a struggle to keep the cylinder walls straight and round.
They must have made a mistake IMO, as even if the block was std bore that would only put the cylinder wall thickness at .073, if you add 1/2 (.015) the overbore amount (030) per side to the .058. I doubt it could have survived all those years at .073 with std bore without a cylinder wall failure.

2002 Jerry Bickle Cavalier, 446" Small Block, Brodix Canted Valve, lenco 5 speed, 7.54 @ 180. mph,1.06 60', 2235 lbs for 2014. GM Canada Docs, Highly Optioned 69 RSZ28 , Hugger Orange, White Stripes, 42,000 mile survivor, owned since 1973.
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