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Terry Bride · 08-01-2012, 09:26 AM

Hey Phillip,

This catastrophic hemi story has given me a little deja vu!
We installed a 517 that the customer supplied into a 70 Challenger that suffered the same fate. This one last about a year with limited driving.
The autopsy revealed that the #3 int. valve had dropped and killed the head and piston and had scattered valve seat bits through out the other bores.
The lash cap and keepers were still in place in the retainer and the tip was in the lash cap but there was another piece shaped like a "C" on the below the tang in the keepers. The bottom of the tip that was left in the lash cap was convex so it had run in a broken state for some cycles. The order of failure was the hardened tip had broken off of the valve and had run with .100" remaining to hold the valve in the retainer and this had peeled off the end of the valve to the point where it let go.
If the valves in your heads were the Mopar Performance valves, take a measurement of the tip that was left in the lash cap and make sure the tip is the same as the tip length of an undamaged valve. This one here was the same length if you stacked the 'C' shaped piece on it, so it was only the hardened tip that initially broke.
Hope you can salvage some of this!

Terry

08-01-2012, 09:26 AM	#17
Terry Bride Junior Member Join Date: Jun 2011 Posts: 23 Likes: 8 Liked 0 Times in 0 Posts	Re: The saga of my Hemi has ended Hey Phillip, This catastrophic hemi story has given me a little deja vu! We installed a 517 that the customer supplied into a 70 Challenger that suffered the same fate. This one last about a year with limited driving. The autopsy revealed that the #3 int. valve had dropped and killed the head and piston and had scattered valve seat bits through out the other bores. The lash cap and keepers were still in place in the retainer and the tip was in the lash cap but there was another piece shaped like a "C" on the below the tang in the keepers. The bottom of the tip that was left in the lash cap was convex so it had run in a broken state for some cycles. The order of failure was the hardened tip had broken off of the valve and had run with .100" remaining to hold the valve in the retainer and this had peeled off the end of the valve to the point where it let go. If the valves in your heads were the Mopar Performance valves, take a measurement of the tip that was left in the lash cap and make sure the tip is the same as the tip length of an undamaged valve. This one here was the same length if you stacked the 'C' shaped piece on it, so it was only the hardened tip that initially broke. Hope you can salvage some of this! Terry