I seriously doubt that they were matched at the factory. I suspect that it
is a matter of wearing in over the years.
Best regards,
Fred Schroeder
'70 2000
SRL311-13359
TDROC
Home page http://schroeder-family.us
e-mail roadster@schroeder-family.us
----- Original Message -----
From: "datsun parts.com" <datsunpartsdotcom@yahoo.com>
To: <gregs672liter@netzero.net>; <Keith0alan@aol.com>
Cc: <datsun-roadsters@autox.team.net>
Sent: Thursday, July 29, 2004 12:37 PM
Subject: Re: Carb cleaning tip, what not to do
> I heard that they were matched sets, but you know how rumor and inuendo
go. The other interesting point here would be how many times these parts
have been taken off the cars over the past 30 years and cleaned in a solvent
tank and the parts switched by unknowing mechanics and put back incorrectly
no longer preserving the "matched set".
>
> Dean
>
> "gregs672liter@netzero.net" <gregs672liter@netzero.net> wrote:
> Wait wait wait. I am NO expert on SU carbs (or much else for that matter),
but I find it very hard to believe that each piston and dome were percision
honed and matched as a set at the factory. It has been a while since I
looked closely at an SU carb (I have SK sidedrafts) but as I recall they
appear to be cast aluminum parts to me. I can imagine that there were
specific tolerances and some final machining or clean up, but are you
telling me that there was some guy at the factory that specifically matched
each dome with each piston to the degree being suggested? And he would do
this by...? He would check his work by...? To be sure of his work, I think
it would have to be set up on some kind of airflow bench. Sounds VERY labor
intensive to me. Unless you radically sanded the thing, I cannot imagine
that the tolerances changed much. Again, please feel free to enlighten me.
But for now, I suspect that something else is contributing to the
differences you see in the ca!
> rbs.
> Ignorantly yours,
> Greg Burrows
>
> -- Keith0alan@aol.com wrote:
> Hello all,
>
> Puttering with SU carbs today and found an excellent example of what
> not to do. When cleaning the inside of the dome and piston DO NOT USE
> SANDPAPER. They are precision honed and matched as a dome piston pair, so,
also make
> sure that you don't mix them up. Carb cleaner and a rag or paper towel
work fine
> for cleaning. Carquest brand of carb cleaner seems to work the best.
> The result of the sandpapered dome and piston? With the same air flow
> it only raises about half as high as a good one.
>
> keith williams
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