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MG TD TF 1500 - Carburetor Insulator

Hope that I'm not wearing out my welcome with my continued "newbee" questions. Here are six questions regarding the carburetor insulators on my TF-1500 with AUC6020 carbs and 168434 (168454?) intake manifold:

1) How do I remove the glued on gaskets from the carb insulators without damaging the insulators?

2) Should I chip off the old insulators and replace with new reproductions? Looks like my insulators are glued on both sides. Are modern insulators made from hard plastic? Do modern insulators seal as well as original insulators (without gaskets)? From whom should I purchase insulators?

3) Should gaskets be used between the carb and the insulator; and between the insulator and the intake manifold? None are shown in the Workshop Manual or in the Service Parts List. However, gaskets for both sides of the insulator are included in the SU Carburetor Master Rebuild Kit from Moss, and are shown on the Moss diagram.
FYI - no gaskets are required on either side of the insulator on my 1954 Chevy pickup.

4) If no gaskets are required, should I glue the insulator to the carb and to the manifold? I am usually reluctant to glue items that may need to be removed.

5) If gaskets are required, should I glue them? If so, glue on all surfaces ... carb / insulator / manifold?

6) If you recommend gluing the insulator and/or the gaskets, what type of gasket glue should I use?

Thanks for your continued help,


LM Cook

A gasket is shown on the exploded view, (Moss), no glue should be used,,,, They might seem to be glued because there were on for soooo long and they are "frozen" together,, or the PO used a a gasket cement,,, try tapping with a hammer,,,if they break, replace with new ones,,,
They should be easily removable,,,


You could try to soften the cement with some lacquer thinner then split it off with a blade. As Steve points out, if you break it, just replace it. There's nothing wrong with the new ones.
JE Carroll

Well, I got the insulators off ... all four of them. There were two on each port. Each a couple of thou under two-tenths of an inch thick.

How thick is a new insulator? Any reason for using two on each port? Perhaps to reduce gasoline boiling in the float bowl?

Should I seal the edge of the insulators with paint when I install them to keep them from swelling and shrinking with moisture? Or is all of the oil flying around in my engine compartment enough?

I split them off and scraped the surface of each port with a wood chisel. I was expecting a hard bakelite insulator. They are like fiberboard. If they are fiberboard, then I still don't see a need for gaskets on each side. Guess I'll figure that out when I receive the new insulators.

Wiped the surfaces with lacquer thinner. Cleaned the studs with a wire brush. Everything looks good. (Except for the thick build up of varnish inside the manifold.)

Thanks for your help.

LM Cook

The originals were constructed in a laminate fashion with some fiberous material. Most likely some asbetos involved. The replacements are made from a cast resin..similar material as was used in the later MGB. No need to paint them but you should use a gasket on both sides. It sounds like you did not have 4 spacers but that they came out in 4 pieces.

MG LaVerne

I personally always use some type of gasket sealer, as the faces are often not very smooth or flat. An air leak here can cause problems and can be very hard to diagnose. While the carbs are off, lay a straightedge along the inlet manifold mounting faces top to bottom and make sure they are flat. I have run across a couple that were really bowed, which would cause a major air leak. George
George Butz

I'm With Laverne
Use a casket on both side of the spacer. It assists in a good air seal and possibly helps prevent some heat transfer to the carbs as well.

Check the clearance at the bonnet side though. When the engine rocks just a little on the Stay to ensure it does not hit either the rad stay tube or the bonnet. Rocking by hand should be good enough to test this. If you are adding to the spacer distance. It should not be an issue.

My air Plenum has a flat on the front corner it to help clear the bonnet. Some don't I have heard.


R D Jones

Plenum Pic

R D Jones

Is your car a TD or a TF Rod? Cheers.
Peter TD 5801
P Hehir

TD :)
Sorry, I did note that Lonnie is working on a TF. Der
So the plenum is not an issue for the TF.

But if you increase the distance of the spacer, which I do believe is the same as a TF, I would still check all the clearances just to be sure.

R D Jones

Thanks Rod. Don't wish to divert the thread but one of the reasons I asked is there are no spacers on my car. Given the problems with fuel vaporization it obviously seems prudent to fit them. Only restrictions I can see are to ensure clearance (your 2nd pic shows why the radiator stay should be bent) & to ensure that the carby securing bolts are long enough to accomodate the spacers. The other reason was I note, you, like me have handed float bowl lids. I can't tell from the pic if yours are 1 1/4" or 1 1/2" SU's? I'm guessing because of the oil bath air filter they are 1 1/4"? Cheers.
Peter TD 5801
P Hehir

In the pictures, LaVerne's is his TF with 1½" SUs.Rod Jones' SUs are 1¼" of his TD, and as you have noted, use quite different air cleaners.

And yes, the float bowls are handed. Just don't get them mixed-up or the floats will not rise and the car won't start (or run).

In any event, its a mistake you would quickly identify.

Gord Clark
Rockburn, Qué.
Gordon A Clark

Hi Gordon. Can you jump onto the other thread that Rod started, (directed to me) & enter the handed debate? Cheers
Peter TD 5801
P Hehir

Here's the conclusion to my insulator question ...

I bought new carb insulators from Moss. They are hard plastic instead of the fiber material that I removed between my carbs and manifold. They are about the same thickness as the insulators that I removed. I used gaskets on each side of the insulators with no sealant.

I lapped both sides of the insulators with a piece of Norton p220 paper on the bed of my woodworking jointer. Took a while to get them flat.

Thanks for your help,


LM Cook

This thread was discussed between 26/02/2014 and 07/03/2014

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