Originally Posted by afm
The real head clearance of these new based Picco engines can be calculated as follows:
Real head clearance = Thickness of head shims + 0.05mm*
* (that‘s due to the internal construction of the engine and the compression of the head shims, when the cooling head is mounted)
Adjust the shims depending on nitro-content (see table)
Nitro content: 16% 20% 25% 30%
Real head clearance: 0.45mm / 0.45mm / 0.55mm / 0.65mm
Head shims: 0.40mm / 0.40mm / 0.50mm / 0.60mm
Large tracks may require an extra 0.10mm shim to reach higher top speed and improved fuel consumption, but this will decrease acceleration slightly.
AFM
Just to confirm, for 30% I need a "real head clearance" of .65mm which will require .60mm of shims? I don't want to screw this up. I think it comes stock with (2) shims. I will check tonight to see if they equal .40mm.
Does this engine have the same dimensions as the Mega ZX12? I run .55mm worth of shims in my Mega.
Thanks for the info.