OK,

I've been very happy runnin' my stock 74 - I believe she's all she could ever be - but for just one more time before I stroke her .

I'm running Wiseco 9:1 pistons with S&S duo-plugged heads and a Dyna single fire ignition.
The scooter is rubber-mounted and has been the smoothest, least vibrating shovel I've ever assembled.

My question is: how do you make that calculation which gives you piston to valve clearance info. I'd like to plane the heads to as close as possible for max compression or maybe find a head gasket that'll be .030 squished or whatever.
Folks have told me the only way to do it is with clay???? How does that work and where do I find that info on how to do it?

My cam is currently an Andrews B grind with a .485 lift... but I'd like to step up to around a 510 - 530 lift.

Thanks.

 

what you do, is place clay on the top of your pistons, in the area where the valve opens. Then, you assemble to top 1/2 of the engine, to include valvetrain, etc. Crank the engine by hand thru one full rotation. The valves opening will compress the clay. Pull off the heads, then carefully remove the clay from the top of the cylinder heads. Then, using a micrometer, measure how thick the clay is. That will tell you how much valve/pistons clearance you have. To be exact, you have to add the thickness of the cylinder head gasket you will be using.

I did that when I rebuilt a Chevy small block. I assume, that the procedure would be the same for any other internal combustion 4-stroke.

 

10/4 for that answer. What are the clearance values I'm trying to achieve??? What is the safest level of clearance in case of a high rpm mis-shift ???

 

if you are running wiseco pistons,you wont have to worry, they come with vavle pockets on the pistons that will clear most cams and bigger vavles, if you shave the heads remmber to keep the .200 clearince in the head for the top cylinder spickot, if you up grade the cam and stroke it the andrews c grind is hard to beat,nice cam in a stroker, it will have good low end tork with the extra cubes of a stroker and pulls hard on the topend.
freebird