Hi folks,
This spring-loaded pin sounded familiar. I just checked the H2's in my
52TD
and found that both pistons have the bras spring-loaded pins. I also checked
the
pistons of another (basket case) 52TD that I have. Both sets have the pins. I
took a photo of the piston ends from my set and did a quick and dirty webpage to
show them
<http://home.earthlink.net/~budkrueger/H2Piston.html>
I also looked at the Haynes SU Carburetor book. Their image #7.5 shows the end
of an H2 piston and you can see the pin in line with the needle and the
alignment
slot. I included a copy of the image on the webpage.
The pins are apparently not uncommon and protrude by about 0.010".
Bud Krueger
Lawrie Alexander wrote:
> Scott,
>
> As I re-read your original post and the various replies and suggestions, I
> believe most everyone mis-read what you actually wrote. You described a
> piston with a spring loaded pin in it, not a carb body with a spring loaded
> pin. As such, this pin is not there to raise the piston for mixture checking
> purposes. It is, in fact, as you surmised, a sort of shock absorber to stop
> the piston coming down with a resounding thunk.
>
> It is true that you have mis-matched pistons, as only one piston has this
> pin, but that fact presents a problem only if the weights of the two pistons
> are different. By itself, the difference in design should not affect
> anything as far as your being able to synchronize the idle speed or mixture.
> When the engine is running, the piston will be lifted by the incoming air
> flow at least as far (and probably a little further) than that pin will
> raise the piston.
>
> I'd suggest that you determine whether your two pistons weigh the same. If
> they don't, check with someone who has a stock of H2 pistons and try to
> match one or the other of the two that you have, to get a pair. Then, with
> matching needles correctly installed, unworn jets, correctly-set float
> heights and properly synched airflow and mixture, you should have no further
> carb problems.
>
> Lawrie
> British Sportscar Center
>
> -----Original Message-----
> From: Scott Allen <scottinarl@hotmail.com>
> To: mg-t@autox.team.net <mg-t@autox.team.net>
> Date: Saturday, January 05, 2002 7:50 PM
> Subject: Re: TD Carb Question
>
> >Hi Terry,
> >
> >Problem is the pin does not go through the carb body. It is inaccessible
> >when the carb is fully assembled, nor is there a slot or hole for it to go
> >in so it can fit flush.
> >
> >Perhaps the piston is mis-matched with the carb body and I have one that is
> >supposed to be used with a carb that has an external pin to check the
> >mixture?
> >
> >My thought/worry is that since it does not fit flush I'll have use the
> >mixture to compensate for it as it'll want to run lean?
> >
> >Thanks,
> >
> >Scott
> >
> >>From: TATERRY@aol.com
> >>To: scottinarl@hotmail.com
> >>Subject: Re: TD Carb Question
> >>Date: Sat, 5 Jan 2002 22:36:58 EST
> >>
> >>In a message dated 1/5/02 16:20:56 Pacific Standard Time,
> >>scottinarl@hotmail.com writes:
> >>
> >><< Should I worry about this? Should I have him shave the pin down so
> that
> >> it's flush against the bottom of the piston? What is the pin's purpose?
> >> >>
> >>
> >>Scott, the pin is just for testing the setting, you push up on it to raise
> >>the piston instead of using a screwdriver to raise it.......the fact that
> >>one
> >>carb doesn't have it, means you don't have a matched pair of
> >>carbs.......but
> >>thats nothing to worry about. Some carbs had the pins, some didn't but
> >>that
> >>would not have been the case one car in the production line.......so
> >>someone
> >>has replaced one carb for some reason.......no big deal.
> >>Terry
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