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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
What I can tell you is that we had a meeting with 5 high-ranking GM engineers and they are taking the issue very seriously. They are so passionate about Corvettes and small block engines in general that they take forum posts to an almost personal level. I can also tell you that we told them they can have 100% access to all of our recorded data and we provided our opinions on the topic based upon our racing background. We will help them in any way necessary.
The same pattern I saw on mine (although I was in spec) and other years ago (3 friends cars were the same but out of spec on intake side), and on since then. Yet one "cylinder head expert" on here reported that he has never seen this while demonizing lightweight exhaust valves. Makes you wonder.
Also question do you guys have and data on the heads that you have done in past, saying katech heads will outlast the motor. Any data on mileage and oil what car was used for to see where guides are at after so many miles. It would help a lot to see if problem is still there or not.
Also question do you guys have and data on the heads that you have done in past, saying katech heads will outlast the motor. Any data on mileage and oil what car was used for to see where guides are at after so many miles. It would help a lot to see if problem is still there or not.
Sure. C5-R engines torn down after the 24 Hours of Le Mans with virtually no valve guide wear.
There isn't much that has enough miles on LS7 heads yet, but we have had one or two and they look good.
Well that's about 3000 plus miles not really a lot but interesting I would love to see some data, I say that's the most about 3600 miles in 24hours. And after some testing and seeing on other heads valve guide wear starts almost immediately, I think the least amount of mileage if can remember on an ls7 had 2k miles on it with valve guide wear.
Well that's about 3000 plus miles not really a lot but interesting I would love to see some data, I say that's the most about 3600 miles in 24hours. And after some testing and seeing on other heads valve guide wear starts almost immediately, I think the least amount of mileage if can remember on an ls7 had 2k miles on it with valve guide wear.
24 Hours of Le mans is equivalent to over 250,000 street miles.
The C5 R engine and the LS7 have that much in common? Not really knowing what's causing the wear and breakage for sure on these engine makes it hard to pin down much of anything. I have been waiting to see a number of fixes with some real mileage come back clean to help make a dicision about which way to go to fix something that I am not definitely sure is broken.
The C5 R engine and the LS7 have that much in common? Not really knowing what's causing the wear and breakage for sure on these engine makes it hard to pin down much of anything. I have been waiting to see a number of fixes with some real mileage come back clean to help make a dicision about which way to go to fix something that I am not definitely sure is broken.
The LS7 is an evolution of the C5-R head although there are many differences. The LS7 was developed by GM with a lot of technology transfer from the C5-R engine and Katech. The bronze guide/titanium valve/molybdenum-coated stem combination from the C5-R head is the same thing we are doing to fix the LS7 head. We know what is causing the wear. It is caused by valve seats not machined concentric to the valve guide and combined with loose stem-to-guide tolerance and roughly-finished chrome nitrided intake valves. Putting in a bronze guide, doing a valve job so it's concentric, and a molybdenum-coated valve stem fixes the problem and makes it like the C5-R race engine.
The LS7 is an evolution of the C5-R head although there are many differences. The LS7 was developed by GM with a lot of technology transfer from the C5-R engine and Katech. The bronze guide/titanium valve/molybdenum-coated stem combination from the C5-R head is the same thing we are doing to fix the LS7 head. We know what is causing the wear. It is caused by valve seats not machined concentric to the valve guide and combined with loose stem-to-guide tolerance and roughly-finished chrome nitrided intake valves. Putting in a bronze guide, doing a valve job so it's concentric, and a molybdenum-coated valve stem fixes the problem and makes it like the C5-R race engine.
Thanks for the reassurance. Do you recommend the Katech Ti/Mo exhaust valves (as mentioned in your first post) over new stock exhaust valves (your last post mentioned only the intake valves) for an otherwise stock engine (cam, springs, etc.)?
Thanks for the reassurance. Do you recommend the Katech Ti/Mo exhaust valves (as mentioned in your first post) over new stock exhaust valves (your last post mentioned only the intake valves) for an otherwise stock engine (cam, springs, etc.)?
OEM exhaust valves are fine, but Ti/Mo exhaust valves are the best choice because of the coating. We use Ti/Mo in the track packages and a lot of street guys also want them just so they can have the best. Some don't have confidence in the OEM exhaust valve, which is misguided, but that's why we offer options.
07-21-2015, 10:51 AM
Katech Stage 2 Z06 SN#82
