John,
I was having the same difficulty on a 79B. I used two or three
thicknesses(?) of a manifold gasket material that was designed for motor
homes. It has a piece of metal sandwiched inside gasket material. I riveted
a washer or two between each layer and attached this to the heat shield
metal frame. Two years and no overheating problems.
Monte
79B, Carmine
67B, BRG
74 1/2 Rust, parts car
From: "John Graham" <theklube@hotmail.com>
To: <mgs@autox.team.net>
Sent: Monday, April 26, 2004 1:55 PM
Subject: Need Carb heat shield backing material
> Last year I replaced my carbs on my 70 MGB. In doing so, I discovered
that
> the original insulating material on the engine side of the metal heat
shield
> was crumbling off. I think that it was probably asbestos based so I went
> ahead a took it all off. I hunted about for a replacement and ended up
> using an adhesive backed material that I purchased from an online source
> (can't remember the name now).
>
> Well this insulating material hasn't held up very well (it's peeled of to
be
> precise) and it seemed that it didn't do that great a job anyway. When I
> would run the car long enough to get things hot and then park it for a
> while, when I started it, it would behave like it was flooded if it was
less
> than an hour or so since it had been run. If I waited til the next day it
> started better, but in either case the fuel pump would pump like mad for
> about 10-15 seconds like the bowls were dry. So my guess is that what I
> have for a carb heat shield isn't working very well and the heat from the
> manifold was heating the fuel bowl and probably boiling off the gas. Both
> carbs have bowl overflow tubes that just go straight down exiting near the
> top of the crankcase oil pan.
>
> Some time last year when I visited this question on the list, there were
> suggestions of using a kind of board like material that might be used in
> wood stove insulating panels or a shield for welding. Do any of you have
> success stories to pass on as to what will work well?
>
> TIA
>
> John Graham
> '70 B
> Charlotte, NC
|