gansei

i want to know proper head shim setting for Novarossi 12 and OS 12TZ

in 25% nitro Fuel.

razzor

Gansei from info i have gathered the guidelines are :
16% - total head clearance of .35/.45mm
25%/30% - total head clearance of .45/.6mm

Also start with teh higher suggested clearance and and come down while checking the piston for detonation regularly.
The higher clearance should give a better top end ,while the lower clearance should improve bottom end torque.
Also check through for posts from AFM ,lots of good info or PM me email address.I have info i have collected saved.

asw7576

Preferably for Novarossi & JP .12 engines : original 0.3mm silver shim + 0.1mm copper shim. That's safe enough to handle 25% nitro.

In my car, you don't have to follow mine : 0.3mm x 2 ( milder compression for break in and longer lasting on glow plug ). When the p/s/r become older, I use only 0.3mm + 0.1mm. I feel using thicker shims make my engine idle better.

I'm using 25% nitro most of the time. Sometimes 30% ( older engine only )