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is the hemi 2 valve or 4 valve
Posted: Wed Jan 02, 2008 6:37 pm
by hemi_426
i have no clue what it is i thought it is a 4 valve if 2v why not 4?
Posted: Thu Jan 03, 2008 10:03 am
by 392heminut
All hemi heads are 2 valve, the hemisperical combustion chamber shape can't be run with 4 valves, the valves would hit each other when they open due to their angle. The 2 intakes would hit each other and the 2 exhaust valves would hit each other. 4 valve heads have each pair of valves parallel to each other so they don't hit when opening. Their chambers are called 'pent roof chambers'.
Posted: Tue Jan 29, 2008 4:10 pm
by Schurkey
392heminut wrote: 4 valve heads have each pair of valves parallel to each other so they don't hit when opening.
There's always an exception: Honda Radial Four-Valve chamber as used on the old XR600R (and others) dirt bikes.