Originally Posted by jag
For those of you using the engine, how are you shimming for nitro content? The manual says to add (1) .1mm shim for 30%. Others have said to use (2) .1mm shims.
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