Which exhaust valve to get...
 

I just picked up a 08 z06 2 weeks ago and im thinking of just replacing the valves and guides soon. so my question is what kind of valves are u guys using? valve guides? is there a sponsor i can get them from? I Dont want to replace the heads right now with aftermarket, i just want to fix the main problem with these heads. Any info is really appreciated. Thanks fellas!:cheers:

• Ok here is the deal in a nut shell.
1. Some say it is a geometry problem.
2. Some say it is just a valve guide problem.
3. Some say it is both the valve guide and hollow stem valves.

• You are going to have to make your own decision on this as it is all over the place. You still will use your heads so if it is geometry problem you did not solve anything. These steps seem to be the most popular.
1. Send your heads out and have them done with new guides and Stainless Steel.
2. Send your heads out and have them done with new guides and OEM valves.
3. Send your heads out and have them done with new guides and Ti exhaust valve.
Or you can go with aftermarket heads like Brodix or PRC, and do any of the valve guide and choices available.
Like I said the solution seems to be all over the map on this. There doesn’t seem to be any right or wrong combo, I personally think this thing is a bit overblown and many have done nothing at all and are having no problems.

I would send the heads out to check the guides and replace exhaust valves with stainless ones. Might as well cut the deck down a little while you have them off.

I would find the most competent vette shop in your area that is familiar with the LS7 valve train issues, and pay them to do an inspection of the valve guides using the now very popular "wiggle" test. If your guides are in spec, most would say you're OK with what you have. If you're looking to track the car frequently, I'd say build the heads regardless of the results of your "wiggle" test.

First order of business is to check your heads and see if you have any excessive wear (wiggle test). If none, you are unlikely to have a problem.

Here is the procedure for the 'wiggle test':

http://forums.corvetteforum.com/1582871091-post151.html

You might want to read that entire thread.

And as MTPZ06 said, if you're going to track the car or modify it for significantly more horsepower than there are several upgrades to the OEM parts that you may want to undertake.

2 questions:

1) Do the PRC or WCCH heads solve the geometry issue?

2) Has there been any report of failures with these aftermarket heads?

Thanks!

People in here who are addressing the problem, are largely using bronze valve guides and solid stainless steel exhaust valves.

http://forums.corvetteforum.com/c6-z...st-valves.html

Ask the dealer or zone rep if any revisions have been made to the ignition/torque-control system programming and make sure your car gets them if available.

I would suggest going with the latest version of the OEM valve and having the guides replaced with OEM guides. I think Lingenfelter is able to do this or you could ask. Have the rocker arms carefully checked. I would replace the OEM valvesprings with new OEM ones as a matter of good practice at the same time: at the very least have the OEM valvesprings carefully checked. [Just ship them the COMPLETE assembled head complete with plugs. DO NOT clean the head [enclose in heavy duty mil plastic bag] -- use an appropriate amount of insurance, pack the box well to avoid any damage (double box) and document this. A professional shop can glean a large amount of forensic information from the schmutz, witness marks etc. that are left on used parts. Of course they will want to subsequently charge you a cleaning fee -- pay it.]

I prefer guide liners over replacement guides in aluminum heads. Undersized ID and use a diamond hone to final clearance.

Don't take advice from anyone telling you to replace the exh valve with a stainless steel valve. The oem exhaust valve IS stainless steel. If they can't get even that little detail right, then what else have they f'd up?

oem is 2-piece... people are generally suggesting a 1-piece ss replacement.

And oem is hollow sodium filled, when people refer to SS valves around here they mean 1 pc solid stainless

Stainless Steel, solid stemmed exhaust valve. (Can be one, two or three piece)

Stainless Steel, hollow stemmed exhaust valve.

LS7 - OEM - Stainless Steel, hollow stemmed, sodium filled, inner cooled exhaust valve.

Exactly.

If someone wants to write out a full description of the OEM valves, then they are welcome to.

But at their failure rate it's likely not even worth the time. Certainly not worth mine.

You know the great thing about this forum is the fact that anyone can have an option. We all know what opinions are like huh? Op feel free to search the forum on the great OEM exhaust valves in the LS7. You can find it by typing in (Another Dropped Valve) in the search engine. Perhaps you should look there first. :thumbs:

:iagree: You are so right.

The other thing is, that link I gave the original poster, http://forums.corvetteforum.com/c6-z...st-valves.html

The last paragraph in the first post made in it, has a dozen names on it, to go along with the other dozens of names of those who have already dropped stock exhaust valves in here.

The "beauty" is, that there is always room for one more.

I don't think I've ever seen anyone turned down for "membership consideration" into the dropped stock exhaust valve club, who showed up with stock exhaust valves.

Anyone with them, is eligible. Anyone with them, can apparently be considered for membership.

So don't get caught up in splitting hairs about descriptions of valves without looking at the big picture.

That picture showing in graphic detail the carnage of more than 7 years of dropped OEM hollow stemmed sodium filled stainless steel exhaust valves, otherwise known as the "stock exhaust valves".

want to drive it like you stole it without getting caught?oem hollow exhaust valves gotta go!OR ELSE END UP LIKE ME AND MANY OTHERS,(kaboom)

Really?? You don't think details are important???

Don't bother telling your machinist any details. Just tell him / her that you want "Stainless Steel" valves. You'll get hooked up.

While your giving your machinist instructions, might as well tell them to do whatever the hell they want, because details don't matter. Bearing clearance??? What the hell are those, they don't matter. Pesky details....

Getting your oil changed, don't worry about details. Any oil will do.

How about a paint job?? Don't bother with the details. Any color will do.

Buying your better half something swanky???? Don't worry about details, just get anything on the rack. Size?? Who cares, details aren't important.

Wow is it me or do I feel some tension here. Bottom line it's up to Op to do what he thinks is right and what he can afford. He started this thread to get information and hopefully he has it.:D

What is their failure rate?

Are they failing because they are two piece?

Are they failing because they are hollow?

This would be excellent information for those contemplating a valve change to know :)
.

If your machine shop has experience in handling this matter, and has had tremendous success in handling it, then they should know what you mean.

That's part of why many if us chose the shop that we chose for our head work.