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Author Topic: Valve adjustment with aluminum heads?  (Read 3657 times)

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dubsan

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Valve adjustment with aluminum heads?
« on: June 08, 2013, 10:04:46 PM »
In a new 427 engine stock bore and stroke I have a comp roller cam  under a new set of Edelbrock aluminum heads. Tech sheet from Comp says twenty thou on the valve lash.   Do I need to change this lash to compensate for the different expansion of the alum heads? To my way of thinking the expansion of the head moves the rocker shaft away from the cam. Is this correct? 
Pls advise
thanks
Larry 
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jayb

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Re: Valve adjustment with aluminum heads?
« Reply #1 on: June 08, 2013, 11:25:49 PM »
That is correct.  Your lash cold will be .006" to .008" tighter than it is when the engine is fully warmed up.  Lash the valves tight to start, warm the engine fully up, and re-set the lash to .020", and you should be good to go.
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Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC
- 1969 Shelby Clone, Drag Week 2015 Winner Modified NA (Average 8.98 @ 149), 585" SOHC

   

rockhouse66

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Re: Valve adjustment with aluminum heads?
« Reply #2 on: June 09, 2013, 06:45:06 PM »
I just did this on a 428 with Ed heads and used .014 cold and it came out very close to .020 hot.
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Jim

dubsan

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Re: Valve adjustment with aluminum heads?
« Reply #3 on: June 10, 2013, 01:45:35 PM »
Thank you Jay and Rock
.014 it is  with hot check to follow
Larry
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