[Healeys] HS4 gasket issue

[Michael Salter]

My guess would be that the mating faces of the carbs are not flat or the
spacer is compressed at the stud holes.
I encountered the same issue with my MGBGT.
Carefully filing the carb faces flat and sanding the faces of the spacers
on a surface plate seemed to eliminate the issue.
Also use no sealant on the gasket surfaces ... it can make them slip under
high vacuum.

M

On Sun., Sep. 4, 2022, 7:26 p.m. Bob Haskell, <rchaskell at earthlink.net>
wrote:

> Listers,
>
> The tri-carb intake parts are:
>
>    - intake manifold
>    - gasket
>    - heat shield
>    - gasket
>    - 1/4" insulator
>    - gasket
>    - HS4 carb
>
> The gaskets are all the same, shaped like the carb base with two holes for
> the carb mounting studs.  I have a reoccurring issue of the gaskets tearing
> and blocking the air stream.  A couple weeks ago we found the two gaskets
> on either side of the heat shield were bad on the front carb.
>
> Today it looks like the gasket between the intake manifold and the heat
> shield is bad on the center carb.  The first time was a couple of years ago.
>
> The only non-standard parts I have fitted are the 1/4" insulating spacer
> and the nuts that hold everything together.  I got sticker shock for the
> spacers - $40+/each.  So I made my own using  a 1/4" thick linen phenolic
> laminate sheet, a router and a MGB HS4 spacer for the pattern. Instead of
> nuts and lock washers, used AN half height lock nuts.  Had also fitted a
> PCV valve to the first intake manifold, but have recently removed it.
>
> Any thoughts as to why the gaskets are being destroyed?
>
>
> Cheers,
>
> Bob Haskell
> Austin Healey 3000 BN7/BT7 registrar
>
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