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FE Power Forums => FE Technical Forum => Topic started by: Mbowling on March 11, 2021, 12:39:01 PM

Title: Valve lash with aluminum heads
Post by: Mbowling on March 11, 2021, 12:39:01 PM

I’m working on my 487 and it’ll have TFS heads.  It’ll have a solid flat tappet and I’m wondering if the called for valve lash should be set the same with aluminum heads vs iron?

Title: Re: Valve lash with aluminum heads
Post by: blykins on March 11, 2021, 12:52:22 PM

On iron block, aluminum heads, lash will grow .006" when hot.

Title: Re: Valve lash with aluminum heads
Post by: gt350hr on March 11, 2021, 12:54:15 PM

  it has to be tighter with aluminum heads . I go .005-.006 tighter "cold" than an iron head. Others will have their opinions. Use of an aluminum block would be tighter yet.

Title: Re: Valve lash with aluminum heads
Post by: blykins on March 11, 2021, 01:16:49 PM

Quote from: gt350hr on March 11, 2021, 12:54:15 PM

  it has to be tighter with aluminum heads . I go .005-.006 tighter "cold" than an iron head. Others will have their opinions. Use of an aluminum block would be tighter yet.

Yep, about .014" on all-aluminum combo.

Title: Re: Valve lash with aluminum heads
Post by: Mbowling on March 11, 2021, 01:42:59 PM

This is going back 20 years but On my 410” all aluminum sprint car motors I’d usually tighten them up by .010-.012.  Which meant with some cams there was zero lash when cold.

Title: Re: Valve lash with aluminum heads
Post by: Barry_R on March 11, 2021, 06:34:33 PM

I usually see about .008 growth on aluminum head/iron block FE stuff.
On aluminum block/aluminum head I start off at .003 to get .016-.018 hot

Title: Re: Valve lash with aluminum heads
Post by: Stangman on March 11, 2021, 07:59:48 PM

I have been doing 8 on my cold setup with aluminum head/iron block.

Title: Re: Valve lash with aluminum heads
Post by: 66FAIRLANE on March 12, 2021, 01:09:50 AM

Pretty consistent results. With iron block, aluminium Ebock heads and aluminium Erson rockers I find .007.

Title: Re: Valve lash with aluminum heads
Post by: blykins on March 12, 2021, 05:30:16 AM

Small fluctuations like that could be the temperature that it's ran at, or even the method that's used to run them.

Title: Re: Valve lash with aluminum heads
Post by: My427stang on March 12, 2021, 07:58:42 AM

Aside from holding a valve open at extremes, or if you are right on the edge of clearance, better too tight than too loose.  -.006 is what I use on iron/alum for initial start, but almost always run lash a little tighter in the end.

Title: Re: Valve lash with aluminum heads
Post by: plovett on March 13, 2021, 07:47:56 PM

My "number" is 0.007" cold to hot.  That is with a factory iron block, Edelbrock heads, and Dove rocker stands.   No doubt the number is going to vary.  I don't know what my ambient temperature or "hot" temperature really was when I came up with that number anyway.   So for my 0.018" hot lash setting I used to set it to .010" cold.   Theoretically that'd be 0.017" hot.   A little tight is better than a little loose.

pl

Title: Re: Valve lash with aluminum heads
Post by: Nightmist66 on March 13, 2021, 07:56:28 PM

Quote from: 66FAIRLANE on March 12, 2021, 01:09:50 AM

With iron block, aluminium Ebock heads and aluminium Erson rockers I find .007.

I have the same basic parts. Factory iron block, Ed heads, Erson rockers. I also noticed .007" on mine. Looks like Paulie has the same on his, too.