Mark2009

At some point of instability (bounce or float), yes. But I haven't been talking about checking/measuring valve instability on dynos, so I am unsure why you latched onto my post.

hoefi theorized that a Spintron is run like an inertia dyno, as best I understood his post. A quick zoom up the RPM scale and all measurements are quickly recorded. That does not seem to be correct.

JetBlue427

I am gona go out on a limb and say the combustion engineers at GM and Chrysler (SRT Viper) know more then anyone on this forum regarding using sodium valves in a production car

ramairws6

Very good thread/discussion by the way. Keep it coming. Were all stubborn to what we think the problem is but either way the issue needs to be found....

ramairws6

Originally Posted by Mark200X
What do you think his answer was?

Here's what I think his answer was: A sodium valve is not necessary in the LS7. I think you could go so far as say that his position is that the sodium valve is a mistake.

Clearly the LS7 engineers disagreed with him on the first part, and probably on the mistake part too (since they continue to use sodium valves in high performance engines). You simply have to decide who knows more about the LS7 engine and the LS/LT platforms in general, with respect to the combustion and valvetrain details and goals... the people that designed it, or hoefi.

You have to keep the bean counters in mind on these valves also. It's a cheap light valve that "supposedly" is the ticket for valve weight stability and heat disapation, but does it really work well in this combo for longevity!?

propain

Since WWII....


and I would say GM over hoefi...

ramairws6

Hahaha, yup..... sure looks like they've been working out great

propain

You're right... maybe 100 out of 31,000 in production is just dismal. Funny how people think this forum is the center of the universe.

FrankTank

100% really on this point.. but would add the same about Katech and a spintron.

propain

I agree with that as well, but its all we got. I'll take data over lack of data however small the audience.

The lack of data before the spintron could also be directed at how many cars Katech has modded with OEM valves or lighter than OEM without issue. That is however the principal argument for SS valves currently as well.

Mark2009

I'm not sure I'd hang my hat on cost as a debate point... the OEM valve costs twice as much as the Rev valve (which is probably the cheapest LS7 exhaust valve on the market).

Otherwise, I see your point -- in order to save money, the bean counters insisted on a valve that costs more than a simple hollow valve which in turn costs more than a simple solid valve. Well done

.

FrankTank

Well put, it's really this at the crossroads. Me for example, I look at the reputation and success of WCCH and how many sets of LS7 heads he's built , and how many for example also RPM (Charlie) has built , stock and street cars over the last few years with the now so controversial SS valves and we see little to no failures...short term they seem to be holding up great.

It's an interesting conundrum as well...katech certainly being an authority and expert on the LS7 , trusts the work and expertise of WCCH, although they don't recommend the same when it comes to the valves..but just the mere fact a company like Katech would entrust their head work with WCCH in turns makes me comfortable enough following WCCH recommend of the SS valves...even though katech says stick with OEM

and honestly , even though I put them in my heads (SS valves), I would agree I really don;t think the OEM valves are the problem, I think its a machining issue with the guides. ..and the different rocker ratio the LS7 has vs the other LSx motors that have more similar set ups to each other. This amplifies the problem with bad guides.

ramairws6

100!? Really?? That is some good **** your smokin'. Gotta get me some of that

'06 Quicksilver Z06

I wonder if anyone ever offered up any clarification as to what happened to this one. Looks like broken valves to me.

http://speedtalk.com/forum/viewtopic...29538&start=45

Any vendor in here can, and very likely has had a failure, or will have one.

Dirty Howie

Mark

Your point is valid. But so is the fact that no body including GM is perfect. Mistakes can be made, have been and will be. It is beyond disputing that these motors fail prematurely and too often. It stands to reason that there are likely measures that can be taken to combat this fact. We can argue if one approach or another makes sense or not. But the argument that GM is GOD will not fly in my book.


DH

Dirty Howie

Thanks for the link Ricky

I never heard about this site.

Seems like some fellas with a lot of experience.

Why is it every where you turn people are putting SS valves in?

Did I read that right? Katech has had motors fail too?? I thought they had an unblemished record?? Maybe this guy is making it up


DH

hoefi

I wish I was that smart.

I was merely repeating what was passed on by two wise gentlemen who died well over a century ago.

Werks

I can just feel the sarcasm popping off of the screen lol. It's so ironic that people seem to take such a perverse pleasure in trying to continually prove Katech wrong instead of just leaving it at they have their belief on what the correct thing to do is and you have a different opinion. IMHO until there is a lot more testing done by a bunch of companies there is no definitive right or wrong in this situation, there is only what you deem to be appropriate in your situation and what you do not. Katech has never stated that you must only do this or must do that, they have always said that they "recommend" this. Key word being "recommend", if you do not agree then go with what you feel is correct or what one of the many other shops may "recommend".

It's no secret that I went the Katech route with my heads and it's also no secret that you went the WCCH route. All that I know is that if I ever read a post about a head done by WCCH with SS valves failing I'm not going to be the one coming on here putting up a sarcastic post saying "Oh wow, look a WCCH head with SS valves failed did I read that right???" etc. etc. Why? Because I like to think of my self as a mature adult that is above that and mainly because I'd feel like a giant douche bag finding personal satisfaction in someone else suffering. Personally I hope that all of the "so called" fixes to the valve issue that have been put out work so that all of us only have to go through this once in our life time! (something that I think we can all agree on we should not have to be dealing with in the first place!)

In any case though to avoid any confusion I took the liberty of correcting an error in your post above in red. I would not gloat too much though as the guy that posted the picture on that thread stated it was an Air Attack head which means that it was used in a boosted application in which heat often plays a major factor in a valve failures. So first of all we have no idea of how much boost the guy was running when the engine failed. Secondly we also have no idea what configuration the engine was being run in. If it was super charged Katech recommends their Ti/Mo intake and stock exhaust valves , if turbo charged they recommend their Ti/Mo intake and Iconel exhaust valves.

So....there can potentially be more factors to the story than just the type of valve used. In any case let's all please stop making these posts and/or threads into some veiled attempt to prove someone wrong or bash a company and turn it into a place to exchange information and discuss things in a pleasant manner as this thread was supposedly started (by you) to do.

hoefi

Reread my post on thermo dynamics (more than once if required). I was VERY CLEAR on what I wrote.

Bottom line is, if you feel what I wrote is wrong, then I am sorry, you have lots of studying to catch up. Stay off the keyboard for a few weeks and borrow some books from the library. I am serious.

hoefi

No need to guess. Here are the answers:

1) IMHO, a sodium valve is not necessary in the LS7. Lots of LS7 running with non-sodium valves. Including Katech's turbo LS7 with the solid Inconel valve. Any report on burnt valves yet??? Not even one?

2) I wouldn't say the sodium valve is a mistake. I think it's a poor choice. I also think it's poorly executed in terms of final design and quality control.

The only real mistake is GM's refusal to move into the new era and start building multi-valve OHC engines. In terms of lighter is better, what better way to lower the weight than actually throwing some drivetrain parts away. Yes, hollow is lighter than solid, and titanium is lighter than hollow, but "nothing" is the lightest.

Rock36

Shhh... that failure happened over here in Germany so it doesn't count