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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
After tearing apart my "fixed" heads after less than 20,000 miles, I found out the intake valves can easily be moved from side to side and are completely worn. We also found my intake filled with oil as a result.
35 track days. 2-3 hours of hard core road course work and timed racing per day. This isn't autocross in a parking lot or blasts down a runway. It is 10/10ths driving on prepared racing surface (Watkins Glen, NJMP etc) on either R compounds or slicks. 11 turns, with camber and elevation changes. I can pull 2gs on braking alone. Extreme duty and drive cycle, to the point of complete rebuilds every year. I am WOT 55%+ of the time and hit 150mph+ twice every two minutes for lap after lap after lap. The car only gets to cool down every 30 minutes (for fuel), so heat is always an issue and the components are stressed to the absolute limit. It doesn't see less than 4k RPMs other than during pit-out and pit-in, and the motor lived it's entire life last year between 4k-7k rpms. The brakes get so hot that the rotors glow red and burn the rotor temp paint right off (and I have cooling ducts installed and two piece floating rotors).
I went through 12 sets of front racing brake pads, 2 sets of rears, 3 sets of rotors, 7 full sets of tires, thousands of gallons of gas (including race fuel) and hundreds of quarts of Amsoil (oil is changed every 2 weeks). Brakes are bled every month with Castrol SRF ($70/quart) along with clutch fluid. I had to repaint my entire front end and rebuild almost every part of my car (entire bottom end, new pistons, cam, timing chain, balancer, entire oiling systems, entire cooling system, entire suspension, clutch, transmission, every seal/gasket on the entire car, power steering pump, plugs, wires etc etc all due to failure or almost failure) - except the AHP heads. Valves were perfect. Guides were perfect. Zero movement. Zero play. Zero wiggle. Tested and examined by me and inspected by BTR Performance in Rochester, NY. Last setup chewed through my guides and valves and springs in less than 6 months. I have no dog in this fight and was planning on rebuilding the heads again, but didn't have to.
Engine builder said I added 100k+ miles to the car based on use. Feel free to substitute a different number.
It's like I found a magic set of Hoosier A7s that hold up for 50 heat cycles instead of 5 before giving out. Everything wears, and I for one understand this, as I am replacing/repairing **** all the time. I will continue to monitor these re-worked heads and am happy to report back the minute they begin to fail.
You guys could send them to John Force and they’ll wear again with new guides. The guides don’t fix the geometry issue - they just give you more material to wear away. Carry on.
You guys could send them to John Force and they’ll wear again with new guides. The guides don’t fix the geometry issue - they just give you more material to wear away. Carry on.
Can you say more or link me to a couple threads to point me in the right direction? Stock geometry heads even aftermarket will still have an issue?
You guys could send them to John Force and they’ll wear again with new guides. The guides don’t fix the geometry issue - they just give you more material to wear away. Carry on.
You guys could send them to John Force and they’ll wear again with new guides. The guides don’t fix the geometry issue - they just give you more material to wear away. Carry on.
I have been watching this whole thing and have not done anything yet but I am surprised Katech is still using bronze guides. When I do mine, i think I’m going for the Moldstar guides from AHP, and hopefully that really corrects the issue. If not, something is seriously wrong. But I have been waiting to see wear results from fixed heads start to come in.
I too have worn out a set of WCCH guides. Running a BTR STAGE 3 cam (.652/.632 lift), BTR .660 PLATINUM springs and stock rockers with trunion kit. Put 31,000 miles and every single guide was shot. I wanted the cnc porting was why I sent them there originally.
No grudge against WCCH.
This time around I went with AHP Moldstar 90 guides and Yellow Terra rockers.
So the question is are you running stock rockers and are the spring singles or duels?
I kind of got shot down for saying I will not run stock rockers again with a cam above.620 lift.
Sad to see you go though this. I know how you feel.
Last edited by Gearpuller; 04-02-2018 at 12:36 AM.
I too have worn out a set of WCCH guides. Running a BTR STAGE 3 cam (.652/.632 lift), BTR .660 PLATINUM springs and stock rockers with trunion kit. Put 31,000 miles and every single guide was shot. I wanted the cnc porting was why I sent them there originally.
No grudge against WCCH.
This time around I went with AHP Moldstar 90 guides and Yellow Terra rockers.
So the question is are you running stock rockers and are the spring singles or duels?
I kind of got shot down for saying I will not run stock rockers again with a cam above.620 lift.
Sad to see you go though this. I know how you feel.
This whole valve guide issue is a crapshoot. Katech/WCCH claim thousands of miles with no issues using their cams which run .650-.660 lift on stock rockers using bronze guides, then you see instances like this where a cam with way less lift wears out the guides in 20k miles.
AHP's moldstar 90 guides seem to be having good results, but as Turbo2L stated, is the issue just masked with the MS90 guides?
most times you run a big cam it wear springs and guides by 20-30k just the name of the game. Call Richard he will take care of you
Im happy to get 5k without a spring breaking lol
Literally no one else in the industry recommends stock rockers with bronze guides. Buy any aftermarket head for an ls1/2/3/6/7 etc and they all state roller rockers should be used no matter the cam lift because bronze is soft, the stock rockers on any ls don’t have perfect geometry and will wear them out. Why people with fixed ls7 heads think different is a mystery to me...
04-01-2018, 09:42 PM
WCCH bronze guides are shot
