Subject: [Healeys] HS4 gasket issue

From: Bob Haskell <[email-masked]>
Date: Sun, 4 Sep 2022 19:21:31 -0400

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    <font size="2"><font face="Courier 10 Pitch">Listers,<br>
        <br>
        The tri-carb intake parts are:<br>
      </font></font>
    <ul>
      <li><font size="2"><font face="Courier 10 Pitch">intake manifold</font></font></li>
      <li><font size="2"><font face="Courier 10 Pitch">gasket</font></font></li>
      <li><font size="2"><font face="Courier 10 Pitch">heat shield</font></font></li>
      <li><font size="2"><font face="Courier 10 Pitch">gasket</font></font></li>
      <li><font size="2"><font face="Courier 10 Pitch">1/4" insulator</font></font></li>
      <li><font size="2"><font face="Courier 10 Pitch">gasket</font></font></li>
      <li><font size="2"><font face="Courier 10 Pitch">HS4 carb</font></font></li>
    </ul>
    <p>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.  <br>
    </p>
    <img src="cid:[email-masked]"
      moz-do-not-send="false">
    <p>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.</p>
    <p>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.</p>
    <p>Any thoughts as to why the gaskets are being destroyed?  <br>
    </p>
    <pre class="moz-signature" cols="72">
Cheers,

Bob Haskell
Austin Healey 3000 BN7/BT7 registrar</pre>
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From: Michael Salter <[email-masked]>
Date: Sun, 4 Sep 2022 22:34:56 -0400

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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, <[email-masked]>
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
>
> Support Team.Net http://www.team.net/donate.html
> Suggested annual donation  $12.75
>
> Unsubscribe/Manage:
> http://autox.team.net/mailman/options/healeys/[email-masked]
>
>

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<div dir=3D"auto">My guess would be that the mating faces of the carbs are =
not flat or the spacer is compressed at the stud holes.=C2=A0<div dir=3D"au=
to">I encountered the same issue with my MGBGT.</div><div dir=3D"auto">Care=
fully filing the carb faces flat and sanding the faces of the spacers on a =
surface plate seemed to eliminate the issue.</div><div dir=3D"auto">Also us=
e no sealant on the gasket surfaces ... it can make them slip under high va=
cuum.</div><div dir=3D"auto"><br></div><div dir=3D"auto">M</div></div><br><=
div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">On Sun., Se=
p. 4, 2022, 7:26 p.m. Bob Haskell, &lt;<a href=3D"mailto:rchaskell@earthlin=
k.net" target=3D"_blank" rel=3D"noreferrer">[email-masked]</a>&gt;=
 wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8=
ex;border-left:1px #ccc solid;padding-left:1ex">
 =20

   =20
 =20
  <div>
    <font size=3D"2"><font face=3D"Courier 10 Pitch">Listers,<br>
        <br>
        The tri-carb intake parts are:<br>
      </font></font>
    <ul>
      <li><font size=3D"2"><font face=3D"Courier 10 Pitch">intake manifold<=
/font></font></li>
      <li><font size=3D"2"><font face=3D"Courier 10 Pitch">gasket</font></f=
ont></li>
      <li><font size=3D"2"><font face=3D"Courier 10 Pitch">heat shield</fon=
t></font></li>
      <li><font size=3D"2"><font face=3D"Courier 10 Pitch">gasket</font></f=
ont></li>
      <li><font size=3D"2"><font face=3D"Courier 10 Pitch">1/4&quot; insula=
tor</font></font></li>
      <li><font size=3D"2"><font face=3D"Courier 10 Pitch">gasket</font></f=
ont></li>
      <li><font size=3D"2"><font face=3D"Courier 10 Pitch">HS4 carb</font><=
/font></li>
    </ul>
    <p>The gaskets are all the same, shaped like the carb base with two
      holes for the carb mounting studs.=C2=A0 I have a reoccurring issue o=
f
      the gaskets tearing and blocking the air stream.=C2=A0 A couple weeks
      ago we found the two gaskets on either side of the heat shield
      were bad on the front carb.=C2=A0 <br>
    </p>
    <img src=3D"cid:[email-masked]">
    <p>Today it looks like the gasket between the intake manifold and
      the heat shield is bad on the center carb.=C2=A0 The first time was a
      couple of years ago.</p>
    <p>The only non-standard parts I have fitted are the 1/4&quot; insulati=
ng
      spacer and the nuts that hold everything together.=C2=A0 I got sticke=
r
      shock for the spacers - $40+/each.=C2=A0 So I made my own using=C2=A0=
 a 1/4&quot;
      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.=C2=A0 Had also fitted a PCV valve to the first inta=
ke
      manifold, but have recently removed it.</p>
    <p>Any thoughts as to why the gaskets are being destroyed?=C2=A0 <br>
    </p>
    <pre cols=3D"72">
Cheers,

Bob Haskell
Austin Healey 3000 BN7/BT7 registrar</pre>
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