Box Stock

Valve lash on hemming head

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Bigld

Member
I'm running hemi head predator and I replace stock thick head gasket with thin head gasket and I'm having trouble setting lash. I first set lash at 0 so there was no pressure on push rods I could roll rod with my fingers freely. The kart would only hit 5700 rpm so I loosened valves and got it to Rev higher about 6300 rpm but would not hit 6300 every time I Rev ed it up would be between 5900 and 6300. Any idea what lash should be.
 
I set lash on all my motors to 0 whether it's a out of the box motor or a modified motor. I know that if you get the lash to loose it hurts hp, makes it hard to crank, and it won't run like it should on the race track. Just from my experience.
 
Try setting the lash at .001 or .002 both sides and see how that does. One thing you have to think about is that hen you change the gasket from a .040-.045" thick gasket to a .009" thin one, your moving the head almost .030 closer to the block, so the valvetrain geometry isn't going to be exactly the same as it was, but I never had problems with the lash after doing it myself. .002-.003 is generally where you want lash to be once the engine is up to temp
 
Where do you set your lash when cam maker recommends a COLD setting ? I've seen as much as .006 COLD recommended by cam maker.
 
I set them at zero reguardless of what the cam maker suggests. Id be afraid the lash would grow enough that the pushrod could slip out of its spot on the rocker if the lash was set at .006 cold on a hemi predator since there is no guide plate for the pushrods on these engines and the rockers sit at an angle
 
I do not feel good about .10 lash but that the only thing that works is there something else I can try to bring that down to the .003 .002 area.
 
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