colt_impala

iTrader: (3)

I hand ported my 243 heads, had them flowed and a valve job. I also had them milled .010. The machinist unshrouded my valves (wish he'd asked me first).

So here's what I'm trying to find out. I CC'd the heads and they're at roughly 64cc. The reason I wanted them milled was to boost compression by taking the chambers to 62cc, but since the valves are unshrouded I'm back where I started. If my logic here is flawed please tell me.

To get the compression I'm wanting to use a .041 headgasket, which in theory would get me back to my intended 62cc. Can I just clay the pistons, then lay the heads on the block without gaskets, then measure the clay and add in .041 to the equation to account for the gasket to get my ptv clearance?

Full-Force

iTrader: (11)

Decide what amount of clearance you think is safe then get a shim that thickness and put between the rocker tip and valve stem and turn the motor over by hand. Maybe do this without gasket. If it clears without gasket and shim then it should clear with gasket in place for sure.

KCS

iTrader: (20)

Pistons come up out above the deck at TDC, so if you don't put a gasket down you won't be able to turn the engine over.

colt_impala

iTrader: (3)

Gotcha. Where do I get a .041 shim from? I'd say I could use wood, but it may give a little. I could do some trial and error with the table saw.

colt_impala

iTrader: (3)

Could I mic out some business cards and do it that way?

KCS

iTrader: (20)

Why not use a gasket?

colt_impala

iTrader: (3)

I don't want to order gaskets til I know exactly what I need. I'm assuming anything that measures .041 thick would work just as a shim to check ptv.

Jimbo1367

USe the old HG

Whistler

iTrader: (46)

Don't forget to swap valve springs on the cylinder you're checking with some soft "checker springs" otherwise you're going to compress the plunger in your lifter and think you have way more clearance than you really do.

colt_impala

iTrader: (3)

Whistler, would that eliminate the need for using a solid lifter? I was going to use a solid lifter just for checking the clearance.

KCS

iTrader: (20)

Not always. I tried this just recently and with a dual indicator on the retainer I wasn't seeing full lift. The plunger was being compressed some and I suspect it was mostly at max lift, so I don't know really how PTV measurements would have been affected. I had a LS7 lifter converted to a solid and so I decided not to take a chance and used it with an adjustable pushrod and a glob of PlayDoh.