[64speed]

Valve tip and intact rocker

[HWYSTR455]

Originally Posted by 64speed

Valve tip and intact rocker

HOLY CRAP! Half the tip of the valve is worn away, and the retainer has all kinds of witness marks! I bet the tip of the roller fell off the edge of the valve tip and hung up.

Pull a rocker that didn't let go and take the same pics, as well as the underside of the rocker, bet you will see the same thing.


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[NeighborsComplaint]

Originally Posted by HWYSTR455

HOLY CRAP! Half the tip of the valve is worn away, and the retainer has all kinds of witness marks! I bet the tip of the roller fell off the edge of the valve tip and hung up.

Pull a rocker that didn't let go and take the same pics, as well as the underside of the rocker, bet you will see the same thing.


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That's how I see it too. Seriously side-loaded on contact. Would love to see the roller and underside of the rocker as I suspect the end of the trunnion slot is going to mangled from overtravel binding due to the geometry issue. Also, marks on the pushrods below the normal guide plate scuffing would indicate pushrods contacting the slots cast in the heads. This all could have started the ball rolling with the lifter getting displaced. The fact that both lifter bores broke says the OP "won the lifter lottery" and had both lifter wheels fail simultaneously, wedging both lifter into the cam.

To the OP, since you're convinced the builder is not guilty of any oversight, you should pull that motor out, disassemble and inspect. Hopefully you have a reusable crank, rods and pistons. I would seriously reconsider an HFT cam. Your intent was to build a car that is fast and reliable that can be driven confidently on a regular basis. If you run a high ZDDP content oil and use the additive, I don't see the downside. Were I in your shoes, I wouldn't go back to hydraulic roller and would also put Pontiac style rocker arms with RAIV spec pushrods on it.

There is a guy in the parts section selling a Comp AH10 HFT with Comp Magnum lifters that says it has 7-10 runs on it and it's cheap. That is a very strong cam for a 455. If he kept the lifters in order, you would have the benefit of a cam and lifters that have been broken in without failure and save a bundle toward fixing what you have. It will make all the right noises and be fast as stink for a lot less money.

[PAUL K]

Valve float causes valvetrain separation. The cam has approximately 58 chances a second to knock a wheel of the bottom of a lifter when it's floating... My guess is the the valves floated and knocked the wheels off the bottom of some lifters. It takes a lot of effort to reliably spin a HR set up to 7,000 rpm or more. I can tell from the pictures this valvetrain is not designed to turn anywhere near that number.

Not sure why several folks seem hung up on the use of BBC rocker arms. One of our own members here has been successful using BBC rockers on his build for several years. If you start inquiring you will find most aftermarket rocker arms are based off a Chevy or Ford design and labeled Pontiac. A rocker arm has no idea what brand engine it is designed for.

The builder has already "cowboy'd up" and offered to repair the engine for the cost of parts before he even saw the issue. I'm betting he helps the OP a lot more than he should considering the situation.

Carry on!