VRedZ06

46K total Miles, 21 K of spirited miles and of those 21K about 3500/4000 hard track miles. Also lots of autocross and off/closed road tarmac rally events 3 cross country charity rally events.

MTI Racing GA
MTI Racing CNC Valve Spring Retainers,

Nextech Alloy Valve Springs With Hardened Locks

MTI RACING Super Alloy Hardened Spring Seats

Manley 434Chrome Moly Push rods

Ernie

VRedZ06

Heads are GM heads done up by MTI Racing. Stock valves used. Increased flow and polished.

VRedZ06

Joe just like most of the current slew of failures exhaust valve. Thanks for posting the mods since it was something that I don't do much these days.

Dirty Howie

Sorry you had to join the blown engine crowd (me too). Best of luck on a great and lasting rebuild.

Also glad to hear GM is investigating the problem while the continue to warranty most of the engines GM !!


DH

VRedZ06

Hey good luck on your rebuild also. With the new involvement of GM we are waiting on more info from them before we get too far into it. I am dying waiting.
Ernie

MTIRC6Z

I presume the valve did not drop because of a broken valve spring?

Is it fair to say you regularly saw on track oil temps in the 270 range?

Did you also have a non-stock oil cooler?

Cheers, Paul

VRedZ06

You are correct, but I ran the stock oil cooler for almost all my trsck events. I had just changed the front Z06 cooler with MTI's Swedish Rally cooler that has a thermostatic temperature bypass built in so that you don't use it until the temps get up. I live in the north east so I needed to have that built in for the fall early winter and spring. I was originally going to go with Breathless performance's dual front coolers but they would have never let my oil get to temp in the late fall and early spring. I saw oil the 270 290 range in the hot summer and HOT LAPS. That's why I had to go to a better cooler, (3X volume and 3X cooling capability in the front, 2 X long 2 X wide 2 inches higher, in comparision to the stock coller and it fits perfectly in the space. So I did not run it in the HOTTTTTT yet since the engine let go in August on my way to NJMS Thunderbolt road track. I also have a diff and trans cooler in the back brake vent intakes since they really don't do anything for the brakes and I have a alternate feed for the rear brakes.
But you are right oil temps with the HiTek Hook are in the 270 275 range prior to the hood 290 was the high end constantly when I was on hot laps in the summer. I am getting the header jet coated, (ceramic coated) to help get more heat out of the engine compartment. The car should have a much better air flow design through the engine compartment since there's tremendous heat built up in there. I was astonished when the temps went down 20 degrees by changing the hood.
ErnieO

Pontiaker

EXACTLY! I have been around racing engines all my life and to everyone that says this is normal wear, etc I am sorry but your wrong. There is a problem with the C6 Z engines! That's it, period. There is a weak point in the valve train. I know several guys running other LS series engines some with way more track miles and this just does not happen with normal wear and tear on any engine. I have owned 55 cars and built/raced at least half of them.That's my .02 after being a tech for over 20 years at new car dealerships(started with GM in 88) have built many engines old and new.

With that said I hope GM finds it and we can upgrade to whatever fix they end up with.

I am the second owner of my C6 Z with 35k miles on it now and have way more than 20 track days. My valve train has been modded, aftermarket cam, springs. I still plan on pulling my heads and going with stainless steel valves, port and polish work and new valve guides not sure what material I will go with for the guides yet. I want to do whatever I can to fix what fails before it happens.
Matt

D Howie, sorry to hear about your engine, you and the OP.

Dirty Howie

Ernie

So you didn't get to run your new oil cooler yet. I am interested in this. Do you have a link to check it out??

Do you know or have a quess at how much it will lower oil temps?


DH

Dirty Howie

Hey, Matt

I got to put down some good lap times before she blew. Did 1:51 at ACS on my Nt05's. We will be back there on11/19, try to come !!!


DH

66L72

Just now got on this thread. What a good read.

But your killing us guys that want to know about your valve guide condition

Good luck with the build

VRedZ06

Got the info from Steven at MTI : The oil cooler is a Setrab oil cooler. It is about 15" x 12". (the big one).

I expect to get 20 degrees max if I get anywhere near that number I will be extensively happy.

VRedZ06

Tommy is sending pic's I am just waiting on them.

travisnd

My 2001 Z06 has over 122,000 miles on it. I've been racing it nearly two years now with NASA running TimeTrials and ST2 wheel-to-wheel. I also find it funny that many in this section of the forum think this stuff is normal and defend GM.

I read the same stuff when oil related failures started popping up. Lots of people saying that it wasn't engineered to be run on sticky tires etc. etc. Just ironic that the first car with a factory "Dry Sump" can't be run on Hoosiers. I mean I heard Dave Hill in person say that GM was encouraging customers to take these cars to the track and that they would be warrantied even with trackday use etc.

Just my $0.02... good luck with the repairs

MTIRC6Z

IMHO, if you see a lot of 270+ oil temps you're very likely to eventually have problems with the exhaust guides due to the combination of guide material and heat disapating valve stem. So either change the exhaust guides or change the exhaust valves, you don't need to change both. However changing the guides is probably a better idea than changing the valves since you can't do that without increasing weight at least 20% and messing up valvetrain dynamics.

IF the intake guides are worn badly enough to require changing (to bronze since there really is no other option) you're gunna have to change the intake valves as well, due to the incompatability of the stock intake valve stem surface finish with a bronze guide.

As for choice of guide material, since you can't get replacement stock 'steel' guides, I can't imagine any other option than bronze.

Cheers, Paul.

jswatek

x 1000

Dirty Howie

20* would be great as long as there is a thermostat bypass for daily driving.....


DH

Pontiaker

I have read about some other valve guide material, was it inconel? Cant remember off the top of my head but it was something high tech sounding, lol.

There is a shop in LA where my buddies dad works, they make very high end valve guides for racing, etc. He is also a Vette owner and I am supposed to call him to get the rundown on what they are using for the LS7. I will post what I find out from him.

Even on hot days I never see oil temps over about 235 on the track and I run the **** out of it there.

Mopar Jimmy

On their SUPER high performance applications or purpose built racing LS7 engines I have heard that Katech uses the Inconel (sp?) valves.

On their regular high performance heads/cam LS7 engines, even those making up to 600rwhp, they use the stock (oem) sodium filled Valves, that many folks here have no confidence in, because of the number of reported dropped valves. I have seen that Jason at Katech is running the stock valves on his aggressive looking C6 Z, which has one of their more aggressive heads/cam street attack packages on it (if I'm not mistaken).

Pontiaker

I thought most of the time the Ti valves were holding up ok but the hollow sodium filled exhaust valves were the ones that were breaking. So much has been discussed about this its hard to keep track now, what valves failed the most.