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Rocker arm failure on track

Old 10-09-2018, 08:54 PM
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On a dedicated race car, non-VTEC rockers are lighter and their rollers allow a more aggressive cam profile. However, for street use, VTEC allows a very aggressive cam while maintaining street manners and flexibility. 4Piston reported a while ago that the added VTEC back to their 330hp 2L K-series used in an SCCA P1 CN chassis to give the driver added flexibility when they had to deal with traffic situations.
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Old 10-10-2018, 09:16 AM
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Originally Posted by DavidNJ View Post
On a dedicated race car, non-VTEC rockers are lighter and their rollers allow a more aggressive cam profile. However, for street use, VTEC allows a very aggressive cam while maintaining street manners and flexibility. 4Piston reported a while ago that the added VTEC back to their 330hp 2L K-series used in an SCCA P1 CN chassis to give the driver added flexibility when they had to deal with traffic situations.
My S is a dedicated track ho, so I might need to look into that more. Thanks!
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Old 10-10-2018, 11:50 PM
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Note that these rockers range from $800 (original blue) to $1000 (newer gold). Ferrea makes a purple set for 4Piston, also $1000.

They are really designed for high revs and very aggressive or high-lift cams. For most applications, they are probably overkill.
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Old 10-12-2018, 08:52 AM
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Could this be from over tight valve lash ?
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Old 10-12-2018, 09:27 AM
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I guess I have a hard time believing that the rocker failure was the cause, you'd think that if it failed on its own it would not prevent a valve from closing to allow PTV contact as you have the spring pulling the valve back up once there is nothing to press it down.
He has shown that the spark plug has seen something so I guess I am curious if something made its way into the combustion chamber then lead to a valve not being able to open or being stuck open and tagged by a piston. The rocker would break when pressure was applied to the valve that didn't want to move.

It just seems weird to me since the picture he posted shows the retainer / keepers / springs / valve stems seemingly normal.
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Old 10-13-2018, 10:53 AM
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To me that spark plug looks like something flat hit it square on the end. The only thing I can think of that would do that is a piston and the only way a piston would make contact with the spark plug is if a wrist pin busted. my theory is that the busted rocker is the result of something worse. I really hope I am wrong, otherwise you will have more to fix than the head.
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Old 11-07-2018, 09:38 AM
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Actually didnt break just one...this came off the intake side of #2 after I got the assembly lifted:

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Old 11-07-2018, 09:52 AM
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Could it have been simple valve float? Piston contacts the valve forcing up on the rocker, but doesn't seem likely given the rpm stated. Makes me steer more towards the piston contact via broken rod/wristpin. Valvetrain was just a casualty rather then the cause in that case.
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Old 11-07-2018, 10:11 AM
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Originally Posted by s2000Junky View Post
Could it have been simple valve float? Piston contacts the valve forcing up on the rocker, but doesn't seem likely given the rpm stated. Makes me steer more towards the piston contact via broken rod/wristpin. Valvetrain was just a casualty rather then the cause in that case.
Quite possible, but I wasn't at redline at the time, just shy of 8,000rpm actually.
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Old 11-07-2018, 10:43 AM
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Originally Posted by RedCelica View Post
Quite possible, but I wasn't at redline at the time, just shy of 8,000rpm actually.
Right, which makes me think your bottom end let go first. You got a motor that cant turn more then 90 degrees. You have a piston that became separated and wedged up against the head crushing the plug and valves on that cylinder. All your valves are in place, none dropped. But if you have a piston sperate from the wrist pin, now its out of time with the valavtrain and wham! Hits the valve when its in the down/open position forcing the valve back up against the rocker wile its trying to go down, not up.That's my theory. Not sure what else it could more likely be.

Last edited by s2000Junky; 11-07-2018 at 10:46 AM.
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