jay_lt4

iTrader: (4)

info from the gm technicians dealer forum- seems some of the 6.2 L92 engines are having problems with the valves breaking off,, some have posted the valve broke right where the keepers go and another stated that is broke off behind the head of the valve,, taking out pistons, cylinders, engines locked right up.

and these are just stock trucks, several have already posted that they have trucks at there dealers waiting for an engine.


i guess those of us with stock valve L92's are screwed, if the valves are having issues on stock truck engines, what will they do at 7000 rpm with high spring pressure



.

blu00rdstr

I heard from Richard @ WCCH the stock intake valves should not be used for modded motors, especially the hollow stem LS3 intake valve. I have stock exhaust valves but I bought stainless steel Manley intake valves from PowrMax.com.

HTMtrSprt

Did it say if they were inatke or exhaust valves that were breaking, or both?

jay_lt4

iTrader: (4)

intake valves

SUTTERERMAN85

iTrader: (42)

hmm.....

supersub

iTrader: (25)

Some one that used to be on here(Quick) had one of the stock valves snap off and took out the piston,block, and head.

See5

iTrader: (53)

It takes a pretty tough spring to handle that heavy heavy low tech intake valve. I might think a lighter valve (LS3) and a single spring might not be so self destructive. (hope not)
Having said that, I beat the hell out of my previous stock L92 valves with dual Patriots at numerous track days. No problems.

bluethunder364

iTrader: (5)

****, I have an order in for a full set of stockers from GMPD that are on the way. Would return them however the web site states that this is a special order item and non-returnable. Now what?? Nothing like buying two sets of valves for your heads.
Will be running #26918 springs

See5

iTrader: (53)

Could be that the truck guys were lugging them and knocking, which is as tough as it gets for a valve. I heard there were also some lubrication issues with the earlier DOD motors.

OnyxSilveradoSS

iTrader: (4)

would you have to do anything to new/replacement valves or could you just put them in?

WizeAss

iTrader: (5)

I have Rev stock replacement stainless valves in my car.... they didnt have a hollow stem on the market at the time. If I upgrade in the future I will just change the intake to a lighter hollow stem from Rev Valves.

WKMCD

iTrader: (2)

Well, that makes me feel a little better.

WKMCD

iTrader: (2)

This from Richard at WCCH:

Hi Kevin,
I've seen a couple of stock valve failures, but honestly I can't say for sure if it was just a defective part or bad installation. In one guys case I suspect it was a valve/piston clearance issue. You valves seem to be holding up well. I don't think I would get too excited about this at this point.

I'm not going to get too excited at this point.

Websy21

iTrader: (34)

What the ****! I'll be pushing my setup hard with FI and close to 1k hp, am I doomed?

See5

iTrader: (53)

FWIW I weighed up some valves a while back:

Stock L92 intake-108.6 grams -- Some non magnetic alloy
Manley 11620 -119 grams- Intake- The Manleys are solid SS
Manley 11621-92 grams- Exh
LS3 intake -89 grams -- hollow alloy and my current favorite (NA) with single springs
LS3 exh same part# as L92 Exh- some non magnetic alloy

WKMCD

iTrader: (2)

I'm running N/A with a small cam. I don't think I'd run the stock valves for boost or spray. Give Richard at WCCH a call and see what he recommends.

My $.02

See5

iTrader: (53)

I have another new set of the Manley SSs intakes if those can make you feel better?
blu00rdstr above is going to try and blow his up as well

WKMCD

iTrader: (2)

I definitley don't think I'd count on the 918's to control these big intake valves. Comp 921's or nothing for me.

LambSkin71

iTrader: (2)

thats great i just bought a l92 long block, planning on running a good size cam, not sure what yet, suggestions are wellcome, and a gmpp single plane intake and 750 or better carb. do I need to be worried about this issue? Does anyone have a set of coils they want to sell?

blu00rdstr

Blow up the solid stainless intake valves I bought from you? Not likely.

It's pistons that I don't get along with. But I think the forged LS3 shortblock you're sending me is indestructable, therefore I'm going to crank up the boost way up high and not tune it.

Just kidding. I did buy an ECS meth kit for extra insurance.