Thanks for encouragement chaps
was full of entusiasm last march, its now dragged on so much that i just need to get on with it and make some progress
progress will be slow but i'll get some stuff posted as and when
it won't necessarily look nice but hopefully will go well enough
martin....porting templates ahhhhh i wish
there is one shop in Oz who set up a CNC machine to do these heads
they know they are the only one......and its all top secret.....never ever seen a picture of their work
most hemi 6 porting is done by a few ex racers who if you pay lots of money will wave the magic wand but once you are in the know you will be shot if you blab. its all a bit silly but i guess sombody's livelyhood is at stake
hemi 6 race engines...who knows what goes into them....its all a closely guarded secret.. group N and Nc touring car racing i.e clasics is still big in OZ and fiercly competitive...nothing like taking your six cylinder to the track and spanking some v8 ass.... only a select few manage it and they aint telling....
hemi 6 developement is in that phase where its only now that people are moveing from standard stock parts + inlet extractors and cam and moving into custom builds.
its an engine that in 145bhp form can be tweaked to 250+ with a carb and cam so the need was never there unless you were drag racing
eg my reserch into rod ratio turned up a set of 2 litre VW rods that are 4 thou too wide but are 6 inches long rather than 5.7??. these paired with either small block chevy or modern hemi pistons would be very nice combo
SCAT in the US do H beam versions of the rods in sets of 4 or 5 for about 400 bucks
but it was quit an expensive option to get appropriate pistons with appropriate pin size to make it all work
and all rods would need a small sliver taken off as well....both ends
blokey in oz has picked that up and run with it....his aim is to build 245 and 265 versions and flog em to OZ and the US there are race series in both places that are 6 cylinder specific and he feels there is money to be made....i've heard nout about my kickback
(modern VWs and audis not common in OZ wrecking yards so you wouldn't just come across the right rod)
he's looking to do 90 thou overbore (4 inch) using the 1971 thick walled case and will probably stick an alluminium head on.
thats all top secret as well so i hope he doesn't come in here
there is one hemi 6 doing near on 500 BHP efi offset ground crank secret rods custom piston ally head etc not sure what its like to drive mind probably an off off switch of an engine designed purely for dyno demos.
so my adventures in porting will be limited
nice smooth clean combustion chamber
all ports matched to manifold
and ideally all the same size
uniformly rough throughout
manifold pinned to head in 3 places to get consistent join between the two.
no templates just a few fuzzy photos of what others have done
will steer clear of doing anything with the bottom of the port. sides and top will be cleaned up and matched can run into fun and water hacking away at that short side.
the port is already large
and the chappy doing the work on the head commented that it was typically american in its design
i.e no thought for velocity just make it as big as you can fit in the head....i.e not complimentary at all
he said whats this head off a bloody parrfin generator?? cheaky bugger
he even suggested inserts to make a venturi effect at the crossover from inlet to head to get some good momentum up behind the closing valve
really raise the pressure behind the closed valve....its an option for later
anyway he seems like a good chap
and he's local
knows his onions, been at it since 1968
has a massive parts washer
has a mate with a flow bench
makes his own guides and seats from special stuff he gets from some race engine supplier
and can make a jag v12 rev to 8000 rpm and not snap anything
other options meant lugging stuff miles and not being able to pop in after work
www.power4peanuts.com
well handy if you are west london based and need a bit of head work done
and i liked the name...
Dave
