Does alum block deck height grow, or just the lash?

[cudabin]

Does the deck height on an Aluminum block grow, or is it just the lash?

For example if you have .038" Piston to head clearance cold, willl it gain .010" when up to 180 degrees like the lash does?

Keith Black Alum block with 9.98" deck hieght...

Cheers,

Arnie

[jsgarage]

I was advised to expect 0.020" deck height growth with a 9.2" deck aluminum Fontana block/aluminum heads, and that a hydraulic roller would be the smartest way to compensate for the growth. If this turns out to be true, I'd say your 10+" deck block will grow a little more.

[Lockwire]

''[quote="cudabin"]Does the deck height on an Aluminum block grow, or is it just the lash?

For example if you have .038" Piston to head clearance cold, willl it gain .010" when up to 180 degrees like the lash does?''
A SBC 9' deck will grow .009. So I guess 10' or so block will be
around .010.

[xenginebuilder]

For example if you have .038" Piston to head clearance cold, willl it gain .010" when up to 180 degrees like the lash does?

Lash change does not equal deck height change, although the extra expansion of aluminum does change the lash.
Roughly speaking a tall deck alum block that might change the lash .018" from cold to hot is only expanding about .006" total, including the cylinder head expansion. If you are close on piston to head clearance, do not count on block expansion to make enough clearance.
In your example of a .010" lash change, the actual deck change would be around .0035".

I was advised to expect 0.020" deck height growth with a 9.2" deck aluminum Fontana block/aluminum heads,

You might see .020" lash change in a worst case, but I think you will find it closer to .014"-.015" from say 75 deg to 200 deg wat temp if you had a solid cam.

[MadBill]

Just to be clear, piston to head clearance changes due to relative temperatures and expansion rates of crank, rods, pistons and block from the mains to the deck. Lash changes due to relative expansion of pushrods, heads, valves and block from the cam journal to the deck. All but the last are multiplied by rocker ratio.

[MadBill]

Make that: "...all but the valve's changes are multiplied..."

[cudabin]

Ok, it sounds like it will grow at least .003 to .004" on the deck so that will give me .041 to .042 Piston to head clearance when warmed up...

Should be good with the Oliver Billet Steel rods right?

cheers,

Arnie

[Lockwire]

If you run an aluminum motor close be careful of the piston rock. As I said it will grow about .010 but take into account how much rock you set with the piston. You just need to account for the movment. Stuart.

[Baprace]

Years ago when I adjusted valves on a aluminum head ( GM ) bbc i would cold lash the valves .007 tighter, a little variance depended on the lobe profile but mostly .007 was a decent number, newer heavier aluminum heads may not grow quite as much and may only want .006 tighter.

[Lockwire]

Years ago when I adjusted valves on a aluminum head ( GM ) bbc i would cold lash the valves .007 tighter, a little variance depended on the lobe profile but mostly .007 was a decent number, newer heavier aluminum heads may not grow quite as much and may only want .006 tighter.

Aluminum grows about 2 to 1 over iron, it dos'nt know the depth. Stuart.

[Caprimaniac]

For a 8.2" deck height alu block/headed SBF and warm lash @ .016 what kind of cold lash is appropriate?

Ask because I don't have time to do alot of checking before leaving for a trip. I set it at 010 cold lash at first (and i seem to remember i took it down to 008?) but the valvetrain is sounding a bit noisy... Clack, clack....

After reading this & other threads on the subject I should be close to 0 at cold.... Could try the thinnest blade?

Thanks
RS

[grant6395]

recently finishes a 342 ci sbf.svo aluminum block,afr aluminum headed centrifugal supercharged stove.solid roller cam.HOT lash .016.cold lash .000.......i didnt have enough balls to set it at 0.i set it at .002.warmed it up before any pulls.sure enough,.018--.020 thow magically appeared.hope this helps...grant

[sjvalleydave]

On our Brodix block/SB2.2 headed SBC..I set them .000/.002 and they will be real close to .018/.020 at 210*...You need to set them at desired lash at operating temp. then let it totally get cold and check them hot...Very simple...We also check the block temp with a gun as setting them in 45* weather is a lot different than 95* weather...LOL

[Caprimaniac]

On our Brodix block/SB2.2 headed SBC..I set them .000/.002 and they will be real close to .018/.020 at 210*...You need to set them at desired lash at operating temp. then let it totally get cold and check them hot...Very simple...We also check the block temp with a gun as setting them in 45* weather is a lot different than 95* weather...LOL

Agree on that, but do not have the time right now. Will get it down to 0- 002 and check later to see if it's correct.

Sure the outside temp will have consequences. How much is maybe harder to calculate. we seldom see 95 air temp here; its in the 70's now "mid summer heat".

Thank you, your answers helped me out.

[billet]

Keep in mind rocker ratio, plays a big role in how much lash difference you will see with the growth of an aluminum head/block. On some of my all aluminum late model engines, it's actually .001 to .002 tight when cold if you wanted it exact when hot. This are 2.0 rocker stuff though.