Posted By: sixpackgut
Aluminum motor growth - 01/01/18 05:59 AM
If an iron block aluminum head growth is roughly .006 what might one expect out of an all aluminum engine?
Aluminum motor growth
Posted By: madscientist
Re: Aluminum motor growth - 01/01/18 06:20 AM
I've seen .014-.018
Posted By: sr440
Re: Aluminum motor growth - 01/01/18 10:51 AM
They don't grow Ray. They expand........ If they were to grow they would get old............
Posted By: bonefish
Re: Aluminum motor growth - 01/01/18 03:13 PM
Originally Posted By sr440
They don't grow Ray. They expand........ If they were to grow they would get old............
Posted By: challenger451ci
Re: Aluminum motor growth - 01/01/18 03:31 PM
My Indy Maxx with SR heads grows about 0.0.020" at temp. Indy told me the deck height would change about 0.010" at 170F. With a 1.7 rocker, that's ~0.017" lash change.
Posted By: Dragula
Re: Aluminum motor growth - 01/01/18 04:20 PM
Originally Posted By challenger451ci
My Indy Maxx with SR heads grows about 0.0.020" at temp. Indy told me the deck height would change about 0.010" at 170F. With a 1.7 rocker, that's ~0.017" lash change.
That's about what we see...
Posted By: an8sec70cuda
Re: Aluminum motor growth - 01/02/18 03:53 PM
My KB block/MP head hemi grows about .013" cold to hot. I lash the valves at .010" cold for .023" hot.
Posted By: sr4440
Re: Aluminum motor growth - 01/02/18 04:58 PM
when I read " Indy told me the deck height would change about 0.010" at 170F. With a 1.7 rocker, that's ~0.017" lash change." My 1st thought is "doesn't your pushrods and valves expand also?" I know that the valves and the pushrods don't expand as much as the block (steel vs Al) but they do expand. Which is why if you run a iron block and iron head the clearance tightens up a few thousands. (iron vs steel)
Joe
Joe
Posted By: Al_Alguire
Re: Aluminum motor growth - 01/02/18 06:54 PM
All of my aluminum block/head deals have grown between .014-.018"
Posted By: Efidart
Re: Aluminum motor growth - 01/02/18 07:08 PM
Originally Posted By an8sec70cuda
My KB block/MP head hemi grows about .013" cold to hot. I lash the valves at .010" cold for .023" hot.
Ditto.
Posted By: sixpackgut
Re: Aluminum motor growth - 01/02/18 07:15 PM
Thinking out loud here. So compression could actually be a 1/2 point lower when warmed up
Posted By: rowin4
Re: Aluminum motor growth - 01/02/18 07:41 PM
Originally Posted By sr440
They don't grow Ray. They expand........ If they were to grow they would get old............
I have expanded as I got older LOL
Posted By: rowin4
Re: Aluminum motor growth - 01/02/18 07:46 PM
On a new build , aluminum block/ aluminum heads, what would be the best gap setting for initial startup ?
Posted By: Cab_Burge
Re: Aluminum motor growth - 01/02/18 07:52 PM
I would and have set them .012 tighter on a aluminum motor at room temps around 70F and then recheck the lash with the motor warmed up 
Adjust as needed
Adjust as needed
Posted By: challenger451ci
Re: Aluminum motor growth - 01/03/18 04:01 AM
Originally Posted By sr4440
when I read " Indy told me the deck height would change about 0.010" at 170F. With a 1.7 rocker, that's ~0.017" lash change." My 1st thought is "doesn't your pushrods and valves expand also?" I know that the valves and the pushrods don't expand as much as the block (steel vs Al) but they do expand. Which is why if you run a iron block and iron head the clearance tightens up a few thousands. (iron vs steel)
Joe
Joe
Yes, everything expands. Steel is about 1/2 the rate of aluminum. I was only referring to the change in lash due to deck growth being about 0.017" with 1.7 rockers. There are other factors, some add lash, some reduce it. Ya gotta check it hot to know for sure where it'll end up.
Posted By: Anonymous
Re: Aluminum motor growth - 01/03/18 04:03 AM
Where and what are you measuring when checking for growth?