Mopar Jimmy

Random84

Actually, that's the very same argument used by some of the solid valve proponents all of the time (see 2000FRCZ19's post above). That's kind of the funny part. I agree though, selective use of data can be often times deceiving.

I do think that time will show guides/solid valves to be very reliable in the LS7 heads, but it is awfully presumptive to make definitive, I-have-the-fix type statements that many throw around here while nit-picking the logic of others.

Around and `round we go!

AzDave47

GM made a part number change in 2008 for the exhaust valve, but no-one outside GM knows whether the valve itself was modified or if it just meant there was a different supplier for the same valve or for whatever reason.

Forum members have their own opinions on their favorite exhaust valves. Since this is Katech's thread, kudos to them for giving us another choice.

2000FRCZ19

yep the price of a new engine if you stay stock if you were in my shoes. I would have joined the hole in the block club. think what you want but the stock valve is a piece in the puzzle. I have seen heavy ss exhaust valves run well over 150000 miles. they even saw redlines of 8500 rpms at times. I am not worried about an issue with my current set up. based on info outside of this forum the stock valve and guide set up is not optimal. if you do enough research on potential problems of the sodium valves you will see it has its own problems. not saying they are the root cause but they can contribute to the problem. hope your heads don't look like mine with the same mileage once you open them up or worse yet they open your block up. i am betting you can't run your car to redline everytime you get in it with the same confidence I have.

2000FRCZ19

I agree with you. the fix for me isn't the fix for everyone. if I was racing often I would use the ti valves. for my application the cost isn't justified.

has anyone sent a set of valves to these guys for analysis?
http://met-tech.com/motorsports.html

'06 Quicksilver Z06

100%

forg0tmypen

I don't have any anxiety driving my car on stock valves. I am confident that if the guides are machined correctly, and the valves seating properly, and all geometry correct, then the sodium valves will be more than fine. I've heard the valves went through more than just a part number change. I was told GM made changes to make them stronger. I just can't get over the fact that these SS valves are close to 100g.

AzDave47

Unfortunately late MY 2008's and newer engines let go with the valves, too, so whatever the problem is, some of the valves have still failed even after the PN was changed.

I am more concerned that it is a guide problem that causes the other issues, but none of us can be certain, we just each have to deal with it in our own way after evaluating the information available.

forg0tmypen

Correct. We all have to take the information we learn and apply it the best we can. I feel there is more evidence suggesting the exhaust valves aren't the cause than evidence suggesting they are. I've waited almost two years to start modding my car/addressing the issue. The key provision, like I said: don't be wrong. I strongly feel there is a right and wrong answer as to how to address this guide wear issue. My 2 cents. If I had the money right now, and who knows maybe I do, Id throw a set of these valves in there because they pass the weight test and won't force a compromise on another part of the engine which might force you to have to change out another part to compensate and when do you stop and when is everything verifiably stable for 100,000 miles? Who has 100,000 miles on a set of SS exhaust valves in an LS7? That's great some have 15,000. What happens if the setup fails at 40,000? What did you accomplish then? Again this is just my 2 cents. I don't lose sleep if another forum member runs SS vales in their heads. Maybe Im wrong, maybe there are multiple solutions. I hope I am.

RFE-57

Jason,

Are these new valves solid? And what intake valves would you pair with them?
THX
B

LanceFitzgiben

I plan to keep this car so I will plan on trying to accomplish head work in the spring that will get me a good long ways down the road. My car has about 40k on it, and gets about 10k per year.

2000FRCZ19

not worried about corrosion and scale build up from moisture trapped inside during manufacturing? or inconsistent thicknesses?

zman62

There will always be spectators and players. The players did not want to be a victim so they went with the ss set up. They work well. Are they heavier? yes. However with a heavier spring there is no floating and the motor revs just as before. Some of us have torn them down after the install to double check and gather data. All is good.

I am sure the Katech valve is great as well. Due to the weight savings no need to go with a heavier spring. As time goes on there will continue to be a new fix. The one thing you dont want to do is sit and wait. If you do there is a good chance you will end up being a spectator/victim.

ClarksZ06

I agree 100%.
I went all out with Manley's duel coil .700 lift spring with my .660 lift cam to have extra assurance with the SI SS valves WCCH installed in my new heads. I would rather spend a little extra to be safe than sorry.

2000FRCZ19

so who has an ls7 with ti exhaust valves that has 100,000 miles on it? do you think a ti exhaust valve will live in a street engine for 100,000 miles? think that coating will last that long? anyone got proof that its ever been done on another street engine? ss has a proven record. what makes the ls7 so special or weak that it cant run an ss valve as so many other engines have for years? the aftermarket ls7 heads run them. are all the aftermarket head companies all wrong too? its your money spend it how you want. just make sure you dont spend it only to find out you guessed wrong for your intended use.

just some random info found outside of the forum.

General Recommendations
For most street engines, a quality stainless-steel valve is recommended. Titanium is generally preferred for most race applications, but some engine builders that specialize in turbocharged applications prefer a high-nickel Inconel valve. Hollow-stem valves tend to work great on the intake side, but are much more difficult to manufacture and to inspect for defects on the I.D. surface. Many upper-echelon engine builders shy away from hollow valves for that reason in endurance (NASCAR or 24-hour style) racing.

Stainless-steel valves are most common in street and mild-performance racing. Titanium is used when valve weight is important and cost is not a consideration. Inconel is used when exhaust gas temperatures get really high. Stainless steel (for street performance) has much better durability characteristics than titanium, and the street guys won’t usually see the real benefits of titanium. In racing, use titanium when you want to lose weight…and spend a lot of money.

If durability is your customer’s concern and he’s already making as much power as he wants and is already turning the engine as high as he wants, then use a stainless-steel material. If he’s running nitromethane, then an Inconel exhaust valve material will be his best bet if he wants to finish a race.

WhiteDiamond

Nothing like another session of complaining to get Jason out of here.......I was looking forward to a couple of the answers asked for.

'06 Quicksilver Z06

I'd be interested in knowing the answer to this too out of curiosity.

In the past, they recommended their Titanium/Molybdenum intake valves when going with the bronze guides.

A set of those runs about $1200.00. So another $1200.00 for these exhaust valves, puts you at $2400.00 just for valves.

You get done with springs, retainers, guides, hot tanking, valve job, and any other work to your current heads, you'll end up with about a $3600.00 into reinforcing your stock set of heads, if you go with the titanium intake and exhaust valves.

It will be interesting to see who goes this route first and what kinds of results they get.

tim414

I owned a '69 Pontiac 428 HO 4 speed....was my first car in the 70's....almost non-existent nowadays....many did not survive the gas crunch...

LS9Drew

For that kind of coin your better off doing Trick Flows or AFR Heads and selling your stock heads.

But its another option for people to choose from to fix the problem and thats good never like hearing about people having motor issues

FSTFRC