Put together my Screamin' Eagle forged rocker supports with S&S forged non-roller tip rockers and matching arms. Did a test fit to measure side clearance. Measurements were taken at the bottom of the arm, before using assembly lube or installing rocker lockers.

At 76F, had 009 on two, 011 and 012 on the others. Threw them in the freezer overnight, infrared temp gauge said 27F, all of them went down 001. Threw them in the oven next day, IR said 250F, all of them went up 002.

Went through this process to decide if I wanted to use shims to reduce some of the ticking over and above the rocker lockers. Decided not to shim, I can't imagine sound would be that much different with a 002 increase when it's hot.

 

Was the measurement taken with the rockers mounted on the head? It will change..

 

And once mounted, you would need to warm up all of the parts to see where they end up.

The end clearance spec is based on room temperature.

 

Supports were not bolted to the heads because I'm doing the upgrade with a fully assembled engine in the bike. My goal was to see if the clearance shrank or grew when hot versus cold to help me decide if I wanted to risk using shims. Now that I see how much it grows when hot, I'm not doing the shims. Once I have them bolted on, I'll measure again at room temp to see if the unbolted clearance changes. Thanks!

 

One more note, I bought 007 shims for a twin cam from Zippers and 010 shims on Ebay for a shovelhead. The ID / OD of the shovel shims fit perfectly in a twin cam.

 

If they are not used/measured on the heads when heated and cooled, you will not be able to take into account the expansion and contraction of the head/support bulkheads. YOu are only taking the steel into account, not looking at the aluminum, which will change these numbers quite a bit.