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[Z06] Longevity of aftermarket cam in daily driver
C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
I pulled the heads over July 4th weekend and found the cam lobe with most wear (I believe it's #3 intake) had a failed lifter. I was using Johnson stock type lifters along with new GM plastic trays. The needle bearings are gone (missing) now from this one lifter and the roller has a flat spot along with wear.
I think it's safe to say the lifter caused the cam lobe failure, but what caused the lifter bearings to fail?
Valve train instability (loft)
Lubrication
Failure from a high load
I shared my experience and parts pictures with Cam Motion. They didn't offer ideas on the failure mechanism, but they did offer me assistance with replacement parts. I like working with Cam Motion due to their small(er) company feel and quick communication.
I still owe this forum some spring measurement data from my 75k miles using the same springs at .650" lift.
I guess that the moral of this story is that you will have to accept more valvetrain wear & maintenance from aftermarket cams
Well, I would put this another way. When one is using a vendor with limited experience with the parts and no long-term durability testing, you will occasionally become victim of that vendor's lack of experience. This is what caused my camshaft lobes and one lifter to fail. Another vendor supplied the redesign, which incorporated single helical springs with Ti retainers. A lighter load on the camshaft, and the vendor also supplied a camshaft that was less aggressive, as well. This vendor's design did not solve all of the issues, as the valves and valve guides were "toast" after only 19000 miles. So I am still trying to solve the LS7 design and manufacturing problems even now, 14 years later. My latest heads should help, and my head expert says that they should be good for 50K miles between rebuilds. Hoping for success.
I guess that the moral of this story is that you will have to accept more valvetrain wear & maintenance from aftermarket cams
Originally Posted by Apocolipse
Which springs were you running and which valves are in the head?
I should first state that the camshaft I am running is pretty mild. It is a 220/244 degree grind on a 116 degree LSA, Theoretical overlap is 0 degrees. am running new Del West intake valves and new Ferrea 2042 exhaust valves. Valve springs are suitably shimmed PSI 1516ML and lifters are Johnson 2110. Cam is AHP116, as manufactured by Iskendrian. My current plan is to have the valve springs and retainers replaced every 20k miles. My cylinder head expert recommends checking the heads for valve guide clearance every 50k miles and rebuilding as necessary..
I've setup hundreds of daily drivers using aftermarket grinds for over 25 years reaching power 500-1500bhp ranges on many different types of engines.
The secret is simple. Use the lightest spring possible, the lowest lift, and the slowest ramp rate lobe.
This lends durability & stability to the valvetrain at high rpm, maintaining valve control. It minimizes wear of valvetrain components such as guides and seats.
It increases economy and reduces the possibility of valvetrain related catastrophic failure.
I should first state that the camshaft I am running is pretty mild. It is a 220/244 degree grind on a 116 degree LSA, Theoretical overlap is 0 degrees. am running new Del West intake valves and new Ferrea 2042 exhaust valves. Valve springs are suitably shimmed PSI 1516ML and lifters are Johnson 2110. Cam is AHP116, as manufactured by Iskendrian. My current plan is to have the valve springs and retainers replaced every 20k miles. My cylinder head expert recommends checking the heads for valve guide clearance every 50k miles and rebuilding as necessary..
Apologies for another question - is this the newly configured setup or the one that failed? The setup above is very similar to what I am currently running, however Cammotion grind.
This may skew your statistics but my experience for cam life was over 5 years, but less than 16000 miles. This was a Comp Cams grind with 114 deg LSA and inlet/exhaust duration of 228/248 deg with lifts of 0.623" and 0.652" at the valves. Six cam loads had failed and one lifter, all within 16000 miles. As best I know, the shop I used, which was well known and reviewed on CF selected excessively stiff valve springs for the application, which eventually resulted in cam lobes being destroyed and the eventual failure of the camshaft.
Should this data be used to define the camshaft life for aftermarket camshafts. Well that depends on your viewpoint. I think my situation was common for owners using known shops to install aftermarket cams in their cars, and it seems like the best selection was not done by the vendor. Will you fare better than I did???
Realizing that I would have to replace the camshaft and the lifters, I opted for a more docile camshaft, a CA116 grind. While I knew I was giving up some peak HP, it was worth it to me to get rid of the cowl shake at traffic lights. This also improved WAF (wife acceptance factor). First chance to look at the CA116 camshaft came after another 20,000 miles. This time cam looked great, but valve guides and valves were all toast, so heads were rebuilt again. So, second time around, the camshaft was absolutely fine and was reinstalled in the engine for more duty.
Steve
That altered piece of PVC is exactly how I got my damaged lifter out. Cheap and effective. BTW, if anyone reading this ever has a problem like this, and you dont know what to do next, you must NEVER drive or pry up on a lifter that wont come up towards the top of the block, ESPECIALLY an aluminum block. Much like valves that wont come out of the head, NEVER fix anything with a BFH. You'll cause serious damage to the block, or valve guides.......
Have any forum members used this treatment. It appears to really improve longevity and decrease service intervals. I may ask Tony to use this when he does my head and cam in a few months after I get
the required supporting mods. I'd love to hear from anyone that has real world experience.
Have any forum members used this treatment. It appears to really improve longevity and decrease service intervals. I may ask Tony to use this when he does my head and cam in a few months after I get
the required supporting mods. I'd love to hear from anyone that has real world experience.
Wont help spring life though…which is what causes the damage typically
07-13-2022, 06:01 PM
