Sorry, I meant PISTONS! not pizza!
Sheesh! I'm hungry.
Mike H. 67-1600
----- Original Message -----
From: "mike" <twobeaners@earthlink.net>
To: <datsun-roadsters@autox.team.net>
Sent: Thursday, July 29, 2004 7:35 PM
Subject: Re: Carb cleaning tip, what not to do
> Doesn't Z-Therapy advertise on their website that part of they're
> re-manfacturing process is to "match" domes with pizza?
> Mike H. 67-1600
> ----- Original Message -----
> From: "Stan Chernoff" <az589@lafn.org>
> To: <Keith0alan@aol.com>; <datsun-roadsters@autox.team.net>
> Sent: Thursday, July 29, 2004 6:30 PM
> Subject: Re: Carb cleaning tip, what not to do
>
>
> > Keith,
> >
> > Dean should be able to give a definitive answer on matched pistons and
> > domes. He carries Z-Therapy remanufactured complete carburetors for the
> > same price as Z-Therapy with an added free gasket bonus. At least he
> > should be able to supply the acceptable clearances.
> >
> > Z-Therapy is one of the recognized authorities on the Hitachi S-U carbs.
> >
> > Stan
> > ===============
> > At 06:11 PM 7/29/2004 EDT, Keith0alan@aol.com wrote:
> > >Well since I'm a testing kind of guy I decided to experiment a little.
I
> > >pulled 6 dome/piston pairs from carbs I've recently done. The dome to
> piston
> > >clearances were all between 1.5 and 3 thousanths of an inch. Pretty
tight
> > >tolerances. Then I took the springs out and plugged the holes in the
> > pistons. Turning
> > >them upside down and dropping the pistons in they took between 2 and 6
> > seconds
> > >to leak down. Not as consistant as I was expecting. Then I tried
> > something, I
> > >wet the piston edge with silicone spray. One thing you will notice when
> you
> > >pull your domes is that the piston edge is wet with oil or gas. With
the
> > piston
> > >edges wet the pistons did not leak down at all. One thing I noticed was
> the
> > >grooves on the outside of the piston. This is a technique used on some
> small
> > >engines. The grooves hold oil that acts as a piston ring sealing the
> space
> > >between the piston and wall with very little friction. I dragged out
the
> > piston and
> > >dome tht hat been sandpapered. It took about a second to leak down dry
> and
> > >about two seconds wet. The piston to dome clearance was about 6
> thousanths.
> > >
> > > I can't say for sure that pistons and domes were matched at the
> > >factory but the tolerances are awfully tight. I can say for sure that
> this
> > piston
> > >and dome were ruined by being sanded.
> > >
> > >keith williams
> >
> > >
> > > 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
|