Greetings FoT
Ibm now working on my 2nd generation TR-4 race motor and I am in the process
of further refining my port work. On the first build I did little more than
match the ports
from the head to the manifold, clean up some casting and knife edge the bridge
where the intake splits. Upon closer examination of my previous work I noticed
that by just matching up the ports I have opened up the intake ports at the
head/manifold
to 1-5/8b . Theoretically this would cause a bit of a stall in the flow as
the intake runners
are less than 1.5b and the port up to the valve is less than 1.5b , i.e. a
fat spot midway to the valve. I am currently using a 1.5b valve to help me
size the port in the head.
Theoretically the largest part of the intake tract should be at the
carb/intake
joint and tapering down to the valve size of 1.5b to get max velocity of the
fuel air mix.
In order to do that I would need to open up the intake runners quite a bit and
there isnbt
a whole lot of material in the walls of the intake runners.
At this point I can fit a 1.5b valve in the head port from the intake side
almost down to the valve guide which I have taken down near flush with the
port wall. Ibm running Mikuni HSR 45bs so flow from the carbs is the least
of my troubles. Ibm curious as to how much can you or should you open up the
intake runners. The exhaust side is a bit of a mystery as well with
rectangular ports.
Any advice in maximizing the flow/velocity on both sides would be appreciated.
Thanks,
Jim Gray
RMVR
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