gatti-man

Two failed while on their dyno. Reread his post.

Wass

He also stated the failure rate was less than 1%.

2000FRCZ19

you must not have read the same thing I did. they stated only two failures on their dyno, not two total failures. how many failed off the dyno months later? how many are about to fail? how many would have failed if heads were not redone before they failed?

RUBYREDVET

ATTENTION Z06 FORUM!

As posted above in bold, the argument is officially over.
No more posting.
Thank you "vertC6" for ending this argument.
When you gettin your Z?

JwT

Texas Speed both your heads worked, new bronze guides and SS valves for the sodium filled time bombs, ported $1200.00 you pay shipping. That's to great of a price to pass up.....
My 2 cents

JwT

Random84

How many Z06 owners will die before their valves drop? How many more will die while waiting for the heads to be shipped back from a vendor? How many will have some other problem, like spinning a bearing, after getting the heads reworked (I know of at least one)???



So many questions - so few concrete answers. Such is life. But it looks like there are two things we ALL can agree on: there is premature guide wear with stock motors and an increased risk of catastrophic failure in otherwise modified engines. This is, likely totally a game changer!

Oh yeah, and it looks like most all of us agree that the odds of failure are less than 1% even with modified vehicles. But yeah, if it worries you have the valves and guides swapped out for less than the cost of a warranty extension.

Wass

Lou just clarified this: "The ONLY two that have failed, have been on the dyno..."
http://forums.corvetteforum.com/1581566412-post83.html

2000FRCZ19

that was my point exactly. too many unanswered questions and not enough exact proof. I am just glad I didn't stay stock and caught my problem because my car was in the less than one percent category lol.

2000FRCZ19

the only two he knows of anyway. or the only two that have failed while in their possession.

Witt748

You can bet more than two. Heck LG probably doesn't even know about some blown LS7 with their cams in them. It's not just LG though, there are many different cam producers out there who's cams have been in blown engines. I'm sure those companies know of some, but not all of the failures with their product, but of coarse the aren't eager to tell us, probably not too good for business .

It's too hard to keep an accurate count of blown engines.

0Louis @ LG Motorsports

The list of total dropped valves, is less than 5, with OUR customers.

Mike W, dallas Tx- STOCK Z, dropped valve at barber. He bought wheels and slicks.
Preacher- Dallas tx (Cant remember his name) Not our cam, he was the third owner- dropped valve on dyno, he bought a new crate engine, and we put our cam in it.
Tom- Alabama- race car- one piece stainless ex valves, bronze guides, stock intake valves- dropped ex valve, paperweight engine ( may this year)
Tom, houston, our cam, we did all the work, 19k miles. Dropped on dyno last week.

edmundu

Interesting about this one is the 1pc valve that dropped. Obviously it couldn't have been separation, but was this a valvespring or lock failure? Fatigue from the heavier valve over time?

Would you care to commment some more...

2000FRCZ19

thanks for posting on this. as a vendor I am sure it could potentially put you in a sticky situation as things do tend to get a spin put on them on here sometimes. I saw where you noted the higher number of bearing failures and the lack of concern about it compared to the valve debate. is it possible that a lot of the bearing failure could be from oil starvation and people tend to accept that as a cause and understand it better than the valve issue due to there not being an exact known reason? people tend to be most afraid of the unknown.

by the way, until Michelin grows a set and sells you tires they will not have to worry about selling any to me. I hope the courts side with you.

FSTFRC

Louis answered some questions (Lou's son)

0Louis @ LG Motorsports

What would you like to know? It failed in the same fashion that the stock engines fail.

The valve weight isnt a concern, as they are relatively light all things considered.

The valvespring, seats and retainers are all race grade PSI cup based stuff. There was 1500$ in just seats, springs, retainers, and locks. Not the standard comp 921 road going parts. They were all intact, and they were all well within spec pressure wise. The cam is standard issue G7xx, marine based lobes, very gentle on parts.

FSTFRC

Louis,

Did the cars with Stainless exhaust valves have dual springs too?

gatti-man

Thank you for your comments LG! Is there a bulletproof method you have found or is this still just a %1 fact of life owners have to deal with?

JetBlue427

Any idea of how many LS7`s your shopped has worked on over there years? and I read a post on the other thread where your shop has spent tens of thousands with a cylinder head engineer to try and fiqure out this problem? why would you if it is just a few examples and a small percentage?

HyperX

0Louis @ LG Motorsports

I made that post, and yes, we are working to figure out a root cause, because its not normal.

Ive broken every single part, in an LS1, LS2, LS3. Of those, We have never Broken an exhaust valve. We have been racing LS engines since 1999, and we've failed a lot of parts. Broken cranks, broken rods, melted pistons, broken pistons! turned lifters, stuck cams, spun bearings, pushed water, cracked blocks, cracked main caps, broken timing chains, worn cam thrust plates, the list goes on.... We.have.a.lot.of.experience.racing.these .engines. Period.

We will determine a root cause, but it may take a bit.

The good thing is that there are a lot of fixed knowns. We know the valve height of all the LS7s, we know the rocker ratio of all the LS7s, we know the pushrod length, angle, cam lobes, guide material, guide length, seat angles and material....etc...

We will work on a formal write up, and although we have already started testing solutions, but this will document everything in hopes of fortifying the LS7, because it is such a great piece of work.

Louis