fixed heads?

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Jun 16, 2018 | 10:12 AM

63 silverpearl

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fixed heads?

I noticed while searching for a C6, there were questions about "have the heads been fixed"? Did GM have a problem with heads? If so, what years were involved? Thanks

Jun 16, 2018 | 10:15 AM

Turbo6TA

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From: SW Florida

2021 C6 of the Year Finalist - Modified

Z06 / LS7 engine heads only.

If you have an LS2 or LS3 C6, don't worry about it

Jun 16, 2018 | 12:57 PM

Sox-Fan

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Quote:

Originally Posted by RobJoy

The latest figure I've seen is that APPROXIMATELY 10% of the LS-7 engines were affected. Have not been able to find an exact number.

Every ls7 head was finished at the same foundry using only two CNC machines. Every one of them has the same issue with concentricity of the valve guides. Every.Single.one.

Jun 16, 2018 | 01:12 PM

Dano523

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Quote:

Originally Posted by Sox-Fan

Every ls7 head was finished at the same foundry using only two CNC machines. Every one of them has the same issue with concentricity of the valve guides. Every.Single.one.

Yep, problem is the the Ls-7 rev's out out to 7K, and this slop of the guide to stems ends up with the valve face not hitting squarely on closing, and can cause problems with the sodium valves heads snapping off the stems isntead.

The lighter sodium filled valve is superior to the heaver solid SS valves for a higher rev'g motor, but the problem is even with the guide to stem corrected, it's just a mater of time before the two wear again, and your back in the same boat again.

So granted that the fit of the two needs to be corrected in the first place, it's the use of the solid SS valves at replacements the solves the problem of the valve heads snapping off long term instead.

Last edited by Dano523; Jun 16, 2018 at 01:13 PM.

Jun 16, 2018 | 01:21 PM

Turbo6TA

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2021 C6 of the Year Finalist - Modified

Quote:

Originally Posted by dano523

.... It's the use of the solid ss valves as replacements solves the problem of the valve heads snapping off long term instead.

bingo !

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