Generation IV Internal Engine 2005-2014 LS2 | LS3 | LS7 | L92 | LS9

why L92 s drop valves?

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Old 09-26-2009, 10:09 AM
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Hi all. I might have the chance to get a 08' Caddy 6.2. I've heard these are prone to droping valves.

What would be a easy fix? I'd prefer not to have to remove the valves for wightweight pieces.

Would switching to a quality aftermarket valve spring be a solution or must the heavy valves be replaced ???

thanks,
Jim
Old 09-26-2009, 10:32 AM
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ok. so I've read the locks are supposedly the cause of failure. Maybe the valve itself according to one post. Any suggestions would be great. Thanks
Old 10-01-2009, 03:12 AM
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I've been told the "BeeHive" Springs **** themselves if you give em to much therapy..
Old 10-01-2009, 08:20 AM
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the one engine failure Ive seen broke the valve at the bottom of the keeper.
I have not seen another one, Im kind of surprised that this motor has such a bad rep.
I work at a obama motors dealership and rarely work on these.
Old 10-01-2009, 08:46 AM
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Is this an issue with the GMPP L92 heads too? There's a lot of guys here running them, but I don't recall hearing of them having problems.
Old 10-01-2009, 10:47 AM
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The main cause of valve train failure is loss of control. Properly setup I don't think the L92 heads are any more prone to failure than any other stock component head. I run stock L92 valves and have for about 15k miles. I also run PAC 1521 springs, Manton 11/32 pushrods and YT Ultralight rockers - all setup properly. My cam has .660 lift so it's not like the system is unstressed.
Old 10-01-2009, 12:15 PM
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Originally Posted by WKMCD
The main cause of valve train failure is loss of control. Properly setup I don't think the L92 heads are any more prone to failure than any other stock component head. I run stock L92 valves and have for about 15k miles. I also run PAC 1521 springs, Manton 11/32 pushrods and YT Ultralight rockers - all setup properly. My cam has .660 lift so it's not like the system is unstressed.
Is this your "little" cam? Doesn't sound that little anymore.

I run the stock valves on my L92 heads to 7k all the time. I use the stock rockers with Patriot xtreme dual springs. About 7-8k miles so far at .600 lift.
Old 10-01-2009, 01:12 PM
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I ran the stock LS3 valves on Comp 921's/stock rockers w/ a 231/243 .617/.623 115LSA cam for 10k miles with no issues. Matter of fact, I even had a TC failure and almost all the valves hit the pistons and the 2 piece welded hollow stem intake valves just bent and did not break. I think these valves are much tougher than people think and would wager that most valve failures come from valve float or a production flaw.
Old 10-01-2009, 09:27 PM
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Dropped alot of jaws at the dragstrip, but never any valves. I know I am pushing this motor hard. 12.50's in a 6000+ LB SUV on 24's.
Old 10-01-2009, 09:44 PM
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good info!



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