I just sent a cylinder head off to UK to it ported etc. (its a 1500 Spit head).
I specified a CR of 9.2 to 1, which I think is about the highest I can go
and still use regular gas AND have maximum ignition timing, with a hot
cam (290 duration, .301 lift). Has anyone used a higher CR without
detonation problems and without retarding the ignition before maximun
power is acheived (as is done on high CR motors which are built for economy)?
If you have used higher CR, please tell me exactly how it was measured,
ie,did you take into account things like head gasket, ring land volume,
volume between piston top and deck top and curvature of the liquid surface
if a plate was not used. I know I'm being very fussy but this is almost a
cost not important engine and i want to do it right first time.
I'm going to try and make my own adjustable timing BELT set up for the Spit.
Is anyone else interested in obtaining something like this?
I'm gonna order pistons and oil coolers from the UK. If anyone wants to
order these with me please e-mail me directly. I only know prices for the
Spit motor (and TR6 pistons). BTW, Pistons are Hepolites.
Cheers Dennis
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