ZR1forMe

As the title asks, is the LS9 affected by the same valve guide issue as the LS7? What is the highest mileage LS9 owned by a member here? Thank you.

timmyZ06

Not again!!!!!!

Search please you'll find plenty of threads, its has been beat to death!

ZR1forMe

Well that's a useful start to a thread with a simple question.

I did find threads, there doesn't seem to be any proof either way and now that those threads are a few years old and mileage has gone up accordingly on the LS9s I was wondering if anybody has heard/experienced anything new. Thank you in advance to those that can provide any useful information.

OnPoint

Some wear has been found on some of them.

The key fact to know is that LS9s are not blowing engines due to dropped valves like the LS7 seems to be.

In fact so far, the LS9 is shaking out to be a very robust engine.

ZR1forMe

mileage being equal?

OnPoint

Well, given LS7s have chunked engines due to valves with 6 - 7k miles on them, yeah.

You'll find mileage in here will vary from about that all the way up to around 80k (which is as high as I think I've seen so far).

And many of them are getting modded and/or tracked hard.

I'll put it this way: I owned a Z. Now a ZR. Knowing what I know now, I'm much more comfortable with my ZR than I would be looking to buy a Z.

ZR1forMe

Thanks. Anybody else? Any of the major vendors care to add based on what they've seen with LS9s taken apart for head/cam work? Thank you.

whatcop?

I had a Z06 that dropped a valve at 13k miles. My ZR1 one of the heaviest modded and hardest driven and I'm at 7k miles now with no issues. I know the mileage is low but she has an easy 40-50 1/4 passes, countless trips to Mexico, it's been north of 200mph, and quite a few days on the roadcourse. Oh and I should add she has had at least 15 bottles of nitrous sprayed through her. She still runs like a raped ape.

QUIKAG

Best info I've heard is there have been some reports of some minor valve kind wear in some engines but it is not causing engine failures. I have 13k HARD track miles and the engine is rock solid. I have no worries and if something does happen not due to my fault (mechanical overrev, etc.), it'll be fixed under warranty.

timmyZ06

You should care about the result, there is many zr with a lot of track time past 25 000 miles and running strong as new. I think gm overbuilt the LS9!

timmyZ06

Thats just awesome!!!

You forgot countless rear tires destroyed!

OnPoint

He had defective tires. Just went up in smoke.

Gary '09 C6

OP,

this is the information that I have been able to compile from the CF thus far...and the same may not be all-inclusive.


http://forums.corvetteforum.com/1583893687-post12.html


FWIW, I do agree with all the comments above by the other posters.


EDIT: I've updated my list for posts #17 and #18 below...

titletaker

I think the engine is very well built and designed, however I feel there are flaws in clutch slave cylinder and hydraulic system. Common complaints from me and other ZR1 owners I know are clutch pedal related. Clutch itself is awesome.

NytmereZ

This, ls7 is a ticking time bomb, I beat the Zr1 like know body's business , and it took it, the forged internals IMO makes the difference.

gkzr1

frc

@3500 miles when I removed the heads off my ZR1 the valve guides had excessive wear. It is a problem.

C5kid

Also just had valve guides replaced in mine 23k on the clock.

My machinist said it was the worst he has ever seen, even compared to LS7.

I don't think you hear about ZR's dropping valves yet because most are super low miles. Yes, you have some guys like whatcop, etc, who are having success. It's the same w/ the Z06 guys, I know a guy w/ a huge cam, spraying the crap outta his car and never had the valve guides done.

^^ has nothing to do w/ the valve guides. You drop a valve in a forged engine it's going to make a hole just like a LS7. GM needs get their sh*t together on these valve guides.

QUIKAG

Who is your machinist and how much experience does he have with LS9 and LS7 motors? Did GM replace the valve guides under warranty at 23k or did you have your machinist do it as a precaution? Why did you open your motor?

There are roughly 4,500 ZR1's on the road and how many known cases of dropped valves are there on the LS9? 3-5, I believe. 3-5 out of 4,500.

While there may be some guide wear, that doesn't automatically mean there is going to be a failure. This had been discussed previously

I agree GM needs to fix this and I bet the new LT series small blocks have this issue addressed, but just like anything man-made the LT series engines will have something else that becomes an 'issue.'

In the meantime, I've spent some time on Rennlist lately and there are unfortunately numerous issues GT3 guys are dealing with over there including seals, smoking, variocam breaking, center lock wheels failing, etc. Also Porsche is really pushing back on warranty repairs for guys who run their GT3 vehicles at track days. If you don't believe me, go check out the 997 GT2/GT3 section on Rennlist.

In short, I think we have it pretty good overall. GM stands behind their product and they have a 5yr/100k powertrain warranty on a 638hp car. How many other manufacturers ON THE PLANET have that? Zero.

Drive the car and enjoy it. I read a while back in an LS9 tech article that the LS9 was the most powerful production engine GM has every produced AND it was also the most durable/reliable. This is straight from GM based on their internal testing. Is it an infallable engine? No, but it's pretty darn close.

jimsalone

I only had 1500 miles on mine when I took it to Katech for the stage 4 upgrade which included the porting of the heads. When they sent my heads out the tech at the place that does their head work said they were so far out of whack they were outside the tolerances. Now that is fixed as part of the upgrade so I feel better when I hammer that beast and wring all 800 horses out of her...usually while embarassing some local idiot who has no idea what they are tangling with