I added the FOT folks into this as some might be interested in this stuff. I
made a cam unit for the back of the distributor. I milled it out of a block
of aluminum and made a cam that was 2" in diameter from a big .250" thick
mild steel washer. After I shaped the cam I just heated it up red and
dropped it into a can of oil. The thing I had found was the small lucas cam
was fine for a Can -Am car but I needed a lot of middle range tractability
and their cam was too small to get the amount of variation. It was kind of
neat too. I made a top loading shim pack for the enrichment device from
the ends of a set of feeler gauges. So I had this pack of shims in a little
box and a special one to act as the cold start device and you could add or
subtract shims with the engine running so it was great for race track tuning
as it was very very accurate.. Never made a drawing, just a sketch with
dimensions .Just cut and fit while the engine was in the dyno. Obviously the
part was based on the Lucas cam casting but this was infinitely better and
of course larger to accommodate the larger cam . I used a generator
bearing in the cam pivot center instead of the stupid Lucas oilite bronze
which wore both on the inside and the outside and changed the mixture all
over the place. Also the top and bottom bushings were not always friends so
this bearing fixed the lot.
I did a long test on velocity stacks on the TR-6 with injector placing. I
mounted rubber hose onto the manifold inlets and the hose was slit in
several place so that I could quickly move the injector. I just jammed the
injector through the slit and they wobbled around a little but, so what,
this was a dyno test. Worked too. I found the further out I got the
injector the better the power all through the range. So when I finally got
the injector out as far it could go in the coachwork I made a little steel
bullet that I mounted laterally into the center of the velocity stack and
inserted the guts from the Lucas injector and feed the fuel in from the
side. The little bar that held the bullet also was the fuel feed to the
injector. It was amazingly easy to do. This put the injector shooting the
fuel straight down the center of the inlet tract instead of onto the walls
the inlet parts. Can't really say it made a big power difference but it
allowed a leaner mixture and looked very very cool and mysterious to my
competitors. I showed this to the Lucas racing people and they immediately
sent out a bulletin with a drawing. Lovely that was, like hell. I made
this all legal to the rules as we were allowed any injector, and velocity
stack and any fuel line. The SCCA didn't like it, but it met the rule. The
fun part was still on the dyno I pointed injector straight OUT of the stacks
and it still made more power than when mounted in the manifold as stock. I
was in the throws of making a set of stacks that would turn and go over the
top of the valve cover so that I could get the length that was indicated by
the dyno tests with the hoses. Never finished them though, got too
interested in something else I guess.
Before I did all this stuff I had long rubber hoses holding the velocity
stack and then I mounted Weber venturis in the hose. This made the power
range better by picking up the air speed which compensated for the
impossible original injection distributor unit. (this was when I still had
the original vacuum unit but operating manually.) In the dyno these hoses
were so long I had to suspend them from the top of the cell with wire,
that's when I started working on the "over the engine top" units..I keep
myself busy on these long airplane rides dreaming up stuff.
----- Original Message -----
From: "T.R. Scratchings" <wob@dandrade.freeserve.co.uk>
To: "kas kastner" <kaskas@cox.net>
Sent: Thursday, October 16, 2003 4:32 PM
Subject: Re: velocity stacks and stand-off
> Interesting-
> We bored out a set of Lucas manifolds a few years back to 48mm, then
fitted
> Dell'orto butterflies with the TWM full radius stacks Siamesed together on
> 1-2 /3-4 /5-6 and found 15 bhp straight away. Well, it wasn't quite that
> easy - blending the overbore into the manifold took an age, then we had to
> shim the thin butterflies into the spindles & add an overhead linkage
> adapted from a 2.5 PI setup, but it was amusing and all done for
charity...
> I still hope to bring a 6-pot to VIR with this kit on -what did you
do
> with Lucas PI in its time? - all we ever see is blurred thumbnails of
mighty
> long inlet tracts and upstream injectors, but never a view of the metering
> unit! I've been looking for ages for the cam actuated rear end for a 6-cyl
> unit, but still no luck!
> Hope you are well, and look forward to reading the book when it reaches
> these shores...
> All the best
> Jon Wood
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