02redhawk

On various forums I have seen a couple member (vendor?) comments about the OEM LS6 lightweight valves not being "recommended" for forced-induction applications, mainly in high-boost situations and/or coupled with H/C setups. I've also internet-read (dangerous, I know) that when using LS6 valves a multi-angle valvejob cannot be as extreme as when using standard-factory or aftermarket-solid valves. Similarly, the valve-margins on the LS6s are supposedly too thin to begin with. I wish I could find those comments again, as I'd link them to this thread to illustrate my point. Nevertheless, I'd like to make this a discussion topic:

- Does an LS6 valve really not withstand the more extreme EGTs of a FI / cammed setup? (as compared to a solid aftermarket, in terms of durability/longevity.) I can understand how an aftermarket valve with higher nickel content would be more heat-resistant, however GM chose the sodium-filled valves to improve the heat-transfer of the valve-face up to the valve-stem & cylinder head....and similarly, (the valves) have been successfully durability validated even with their thinner valve-margin (granted, though, with a factory cam / non-FI).

- Whom here is running an LS6 valve with a cammed/FI application? Whom has encountered heat-induced issues (ie, tulip'ing of the valve-face and/or catastrophic failure) on the LS6 lightweight valves?

- For you head porters, can you cut an LS6 valve just as effectively as an aftermarket solid?

- Certainly the OEM LS6 valves offer a significant weight savings over most other economical options, and can complement a lightweight, matched valvetrain for great rpm-stability.


Of course, for what its worth I'm considering their usage on my LS2 with ported -243 heads, a mild cam (218/230 .59x" 117) and a MP112HH pushing ~8psi; street-driven daily-driver (-0- track usage)........ (Cost isn't of concern; I already have the LS6 valves in my possession and I haven't gotten my spare set of -243 heads ported yet)

Thanks to all for their comments and input....

jobberone

At eight lbs you are probably ok with those valves as long as your fuel pump, fuel and tune are good and you're not into it all the time. They are not the best thing for a FI engine though. I would go with Manley superduty valves. It's easy to scorch and tulip lesser valves when things aren't perfect.

Basically you're buying insurance. It's cheaper to put the right parts in beforehand than to have to tear down your engine and then put them in. JMO.

Z06supercharged

Im using stock LS6 valved 243 heads with a blower cam (only changed springs to Patriot Golds) at 15 psi. No problems at all for last 10K.

corvettebob1

Unless someone has come up with a magic way of manufacturing valves, only the stem is sodium filled.
So why would the valve tend to tulip more in F/I usage?
We do not run leaner A/F in fact it's quite the opposite.
I realize the head of the valve is thinner to reduce weight but it still passed GM's durability testing while seeing much leaner A/F ratios!

bullitt4110

8 psi is still pretty low boost so I dont think it would even be a concern. I personally have ran them with 12 psi and zero issues.

jobberone

Yes, the stem is Na filled. Didn't insinuate anything else.

Valves not built for the high heat/cylinder pressures will tulip over time. Just my experience. It won't happen with the proper alloys and the right tunes unless you get insane boost numbers. JMO.

You must not be addressing just me but I'll weigh in. Yes, the more rich the less likely to detonate or scorch what lives in the cylinder. Up to a point. FI 101.

Those valves aren't built for boost. They'll live for awhile but aren't the right dimensions or alloys for big boost. Heat is the killer.

02redhawk

Thank you kindly for the responses thus far... My enticement to using them is the ~30g mass savings per valve, as I am a huge proponent of having a lightweight valvetrain for stability and longevity. Aside from Ti valves (and their hefty pricetag), are there other aftermarket lightweight valve options better suited to the higher heat of H/C + FI ? Either factory 2.00"/1.55" or 2.02"/1.57"...

jobberone

You can't beat the Manley superduty valves. You can get hollow stem intakes in 2.05 and sodium filled exh in 1.57. They have the alloys you're looking for and will last as long as possible. You still need a good tune, gas, and fuel management system along with injectors. You don't need Ti valves unless you plan on revving over 7500 IMO. The stock rockers are good to 7K. Remember you are not going to be turning high revs for long periods of time nor frequently. Unless you're going to road race the car???