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Old 01-14-2009   #53 (permalink)
RallyBob
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Real Name: Bob Legere
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Originally Posted by lamchop77 View Post
Do you know what the combustion chamber volume is for the 2.2 head? Could you tell me the size of the cut outs for the valves you used (depths, diameters, etc). What is the max valve lift that the pistons will accomodate?
Even though this is directed at Hiro, I can tell you from experience that all these factors vary greatly. The chamber volume of the 2.2 head in standard form is about 54-55 cc's, however if the valves have sunk in the head, or the chamber has been ground away, or the head planed, or the valve sizes changed....then it could be anywhere from 52-65 cc's!

As well, with different valve sizes, different cam profiles, and different engine stroke dimensions, the valve relief size and location can be different. In general, the shorter the stroke and the more aggressive the cam....the further 'outboard' the valve relief must run as well as the depth must be increased. A big stroke engine such as Hiro's 2.7 needs very minimal valve reliefs cut to be honest.

Valve lift alone is generally the least of the issues to consider for piston clearance, a small lift cam with lots of duration and tight lobe separation will have greater interference issues due to the overlap (the valves dwell in the open position for a longer period of time). Peak valve lift is never achieved with the piston near TDC, so it is seldom a problem.

HTH,
Bob
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