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Old 03-27-2006, 10:42 AM   #36
Les, slight limp
Board Member
Join Date: Sep 2005
Location: clayhanger, uk

Janspeed, my thinking was that the squishjet as you call it, would be a sort of progressive collection starting at the piston wall and collecting more or less the complete length of the groove,if the groove was 1 depth for it's whole length, wouldn't you get a faster but less sustainable jet, i can't see the point in going to the edge with the groove, the piston wall is a massive quench area, on the burn pattern photo's there is no burn at all next to the wall (i'd be worried if there was ) and after doing it i began to wonder if i should have made them shorter.

Anyone got any theories about how the combustion pattern is altered by the groove, maybe the jet hitting the plug area divides after hitting the wall so you get 2 burns, 1 each side of the jet, there are so many plausible sounding theories about combustion it's impossible to pick a clear winner.

If the thickness of the deck proves to be ok, i shall mod my other head and change them, so if anyone wants to try this, who's not too far from the midlands uk it'll only cost you a tenner for the head gasket, pointless fitting an expensive 1 for how long it'll be on, my advice to anyone is don't try this on your expensive ported etc head, you might not approve of the effects, try it on a throwaway head first, you can always pass it on afterwards and share the cost, it's great that theres so much genuine interest in this, there's not really a proper way to do a volvo head yet, we haven't got as much squish area as other heads so we are not going to see as "much" effect, trouble is our heads are a pretty efficient design to begin with, so i was very surprised and pleased to get such a noticeable transformation.
regards les.
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