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Discussion Starter #1
I have recently built a stroker motor from a 351W with a Scat rotating assembly for a 408(actually a 414 because it is .060 over). The kit came with Keith Black forged IC750 pistons.
I assembled the engine using ProComp CNC Aluminum heads with 2.02 intake and 1.60 exhaust valves.
The valves are hitting the pistons at the top of the valve reliefs. I would have thought that the pistons would have had big enough valve reliefs - since they are designed for a stroker engine.
I contacted the piston company, and they said it had enough material to cut the required opening - but not to get to close to the sides of the pistons(because it could get into the top ring).
I will clay it again - because I am concerned about the side clearence also.
Has anyone had a similar experience?
Thanks
Joe
 

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Agreed that cam timing is the primary factor for if and where the P-V interference occurs, but there are other factors as mentioned and more. Do a clay print and post the results with a few different good photo angles for us. Measured minimum actual clearances, and where, would also be helpful.

David
 

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Wow what are your cam specs?..I am running a pretty healthy solid roller cam and slightly larger valves and I have tons of clearance using the same pistons..I am also running edelbrock vic jr heads which I understand the pro comps were designed after..
 

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Discussion Starter #5
Ok guys thanks for the replies. I reclayed the pistons, and it is ok - not sure what I saw the other day - maybe a senior moment or my arthritis meds kicking in -haha
I had purchased to long of push rods - they were on the valves tips ok =but making the valves hit the pistons. Remeasured push rods, and installed new ones - everything is good.
Valves opening and closing with .150 to .180 clearence.
With the long push rods it was locking the motor up.
Again thanks for the help.
Joe
 
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