It's certainly true that there isn't a lot of oil flow up to the rockers, and
that the kit increases the flow to them. What I cannot convince myself
of is the necessity of this. If I saw Spitfire engines destroying rocker
arms, I'd install the kit (heck, I have on sitting on the shelf). But this
isn't an area I see being damaged. The existing oil flow seems to
be perfectly adequate for the rockers.
The area I do see being destroyed on these engines is the bottom
end. Particularly the #2 or #3 piston rod bottom ends. These are the
two rods that receive only half the oil flow as the #1 and #4 rods. The
oil galley has one orifice for each of the three main bearings, and simply
splits the center one to feed both rods.
Far more important, I suspect, then increasing oil flow to the rockers
is to increase oil flow to the center main bearing. Hence the
drilling out recommendation for that passage.
In fact, I suspect the rocker feed kit could make the oil
problem to the rod ends worse by removing available oil.
I emphasise the word suspect, because I do not know
this as a statement of fact.
>>> Glenn Trunnell <trunnell@earthlink.net> 08/02 11:36 PM >>>
I have to disagree with the others, I have this item (I got mine from
spitbits) and it connects to one of the galley plugs unlike the VB one which
connects to the pressure switch. If you have ever looked at the rockers
with the engine running, there is very little oil sent to the rockers, this
kit greatly increases the flow and I have never had any problem with oil
smoke. Also every tuning publication that I have ever read recommends it
for the Spitfire.
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