Never Be beaten by Equipment
Kas Kastner
Sent: Saturday, May 05, 2007 1:24 PM
Subject: Re: [Fot] Intake Manifold Crossover
When I was doing radical MGTD engines in the early 50's I closed the balance
pipe with material and welded in a fill and smoothed, it did provide better
power and amazing it also smoothed out the idle on a big camshaft. But those
engines had a single port for two combustion chambers. It so amusing that when
I sold my MG special that had that manifold on it the guy thought I trying to
pull something off on him cause the idle was pretty smooth for a big cam. I
drilled a 1/2" hole in the balance pipe covers and the idle came right back
rough as a cob and he was happier.
I was talking to Jimmy Coan just yesterday about this, and he remembers I
did it on the TR-4 in the engine dyno and the mid range and idle
characteristics were so bad we had a hard time stopping the engine from
shaking out of the cradle. From this even though the flow bench said other, I
passed on the mod. With the S.U.s or Stromberg it is important but of course
on Webers each inlet port has it's own carb so no contest there. Can't explain
it.
The cross over balance pipe contributes to the flow of the mixture when you
have only two carbs for four cylinders.
Lets start with the mixture flow going to number one, then the flow must
reverse itself to get to number three, this makes number three slightly
leaner, but now the inertia of flow is going to three and the next open valve
is number four so it gets a higher inertia of flow, then to number two and the
reverse takes place and the flow is leaner as the inertia of flow was going in
the opposite direction, but number one now benefits from the flow to number
two and so it is slightly richer than number two. make sense? It really works
that way and is the reason I always check the number two and three plugs on a
full throttle clean shut off. Those cylinders are most prone to detonation
because of this.
This being true ( and it is) you would think that plugging the balance pipe
would better all around, but it's not. Weird!! Your power may differ :-)
Never Be beaten by Equipment
Kas Kastner
----- Original Message -----
From: SHANE Ingate
To: jaboruch@netzero.net
Cc: fot@autox.team.net
Sent: Saturday, May 05, 2007 11:48 AM
Subject: Re: [Fot] Intake Manifold Crossover
I don't know anything about this, but intuitvely, if it
was important, I would think that we would have seen
x-overs on ALL intake manifolds through the demise of
carbs.
Shane Ingate, what the $%#@ do I know, in Md
>I have been debating the merits of blocking off the cross over tube in my
>TR4
>intake manifold. I have read that the tubes create turbulance and should
>be
>blocked off. Reading it and practical application, however, are 2
>different
>things. I have also heard of some MG racers blocking them off, but
that
>still does not make it right. Have any of you Listers tried this? Any
>dyno
>testing to determine if it is worth while?
>Joe(B)
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