BT7 triple carb question

[davidb]

As I understand it, this is a situation unique to the triple carb setup (naturally, because nothing in life is simple and straightforward). There are thin carb spacers between the carbs and the heatshield. In rebuilding my carbs, I was planning on using new spacers, and ordered a set of three as required, from AH Spares, because they appear to be the only provider. The spacer has a unique configuration on the tri-carb models. The replacement spacers that I received are about 1 and 1/4 inches thick, as compared to the originals, which are about 3/8 inch thick. In reply to my follow up query, AH Spares said that the Healey factory cut the thick spacers down themselves, to fit the triple carburettor application, and that I'd have to do the same. (Gee, thanks for mentioning it in your catalogue). Has anyone encountered this problem? Will a band saw give a decent cut? It has to be a pretty accurate and square cut as I see it. The spacer itself seems to be made of a fiberglass/plastic compound.

The reason for the new spacers is that one of the originals is nicked on one side, and is sucking in some air, which screws up the tuning. I initially tried some JB Weld where the air was being sucked in, but that didn't seem to work.

Any thoughts would be welcome, as greater minds than mine will prevail.

Cheers
D.

 

[Keith_M]

I'm surprised that filling the nick with JBweld didn't work. There are gaskets on either side of that spacer; maybe a little gasket sealer would help?
Keith

 

[davidb]

Thanks Keith,

Yeah, and of course the bad spacer is the one closest to the firewall, and difficult to get at (as you may know). I smeared quite a glop of JB Weld on the far side where it seems to be leaking, but it doesn't appear to have worked. Used one of those Uni-Syn carb synchronisers to try to balance the air intake. Don't know if more gasket sealer would work. Will be taking the whole tri-carb setup off this weekend, and replacing most of the worn gubbins (oversize throttles, needles and jets, etc.). We'll see what it looks like when apart. That could be the least of my problems. Come on over. We have beer and nachos.

D.

 

[dougie]

I sourced my triple carb spacers directly from SU Carbs in the UK, https://sucarb.co.uk/insulating-manifold-air-inlet-gaskets/insulating-gaskets.html
I have 2" SU HD8's on my vintage racer, but it appears they have sizes for the HD6 as well.

 

[davidb]

Thanks Doug for your suggestion on the SU Carbs website. I went to the website, and they are showing the identical spacer for the stock tri-carb HS4 carburettors, as I received from AH Spares (they may have the same supplier). Again, the "phenolic" spacer is too thick. I note that the spacers for other Healey carb applications seem to be the correct size (for example, my BJ8 has thinner spacers), but these stock tri-carb setups appear to be annoyingly unique. If I could borrow that spare black Healey of yours for the summer (you really don't need two), that would help, and I'll let you use my truck to move stuff.

D.

 

[rjc157]

When you say spacers are you referring to the insulator blocks ,I would give Joe Curto a call he has tons of everything or maybe he can make them for you

 

[davidb]

rjc,

Thanks. That's a thought too. Hadn't considered him, but yeah, that might be a good option, and I will look into it. As I mentioned earlier, I'm pulling the carbs, etc this weekend, and will have a look, and hopefully be in a better position to either fix the problem, or experiment with alcoholism as my new preferred hobby.

D.

 

[John Turney]

When you take the carbs off, you should have more luck with the JB weld. You should be able to fill in that nick and smooth it out so it won't be visible or leak. Cutting the new ones down would be asking for trouble. I bet they wouldn't cut straight.

 

[Keith_M]

Thanks Keith,

Yeah, and of course the bad spacer is the one closest to the firewall, and difficult to get at (as you may know). I smeared quite a glop of JB Weld on the far side where it seems to be leaking, but it doesn't appear to have worked. Used one of those Uni-Syn carb synchronisers to try to balance the air intake. Don't know if more gasket sealer would work. Will be taking the whole tri-carb setup off this weekend, and replacing most of the worn gubbins (oversize throttles, needles and jets, etc.). We'll see what it looks like when apart. That could be the least of my problems. Come on over. We have beer and nachos.

D.

Oh yeah, that third carb is a birch to get to. I think John is right though, once you have everything apart it will be lot easier to fill the nick. I've never been one to turn down a beer and a chance to play with carburetors; I'll be right over. If I leave now, I should just about be there for the weekend.

Keith

 

[DerekJ]

Just out of interest, why does the triple carb set up require thicker spacers?

 

[Brinkerhoff]

The thicker spacer is used on an MGB's HS4s. Check your three short hoses , their clamps and the balance tube carefully when you reinstall everything so you don't have any vacuum leaks at those points.

 

[davidb]

Once again, thanks to all who responded with suggestions and various options. As suggested, I may see if I can salvage the old spacer/insulator, because trying to accurately mill a new one may be more problematic. I gather from Brinkerhoff's comment that the MGB uses the full thick spacer on its' HS4 carbs, and the Healey factory cut it down to adapt to the tri-carb setup. I just wish that suppliers would make note of this in their catalogues.

I think we should all meet in Hawaii, and discuss this much much further, over little drinks with umbrellas in them.

Cheers guys.

D.

 

[mwagon]

You can buy the correct thickness tri-carb spacers from British Specialties for a very high price, & probably somewhere too that I never found. I purchased the MGB spacers( Moss ~$6.95) & used a bandsaw to cut in half. Then put in my milling machine to get the thickness exact to an original, plus a better finish then what the bandsaw left

 

[davidb]

This is by way of followup information for Healey tri-carb owners who are doing a carb rebuild and having to replace the spacers/insulators between the carburetors and the heatshield (and believe me, you will, because the gaskets are quite difficult to cleanly remove).

The new spacers/insulators that are sold by suppliers (AH Spares, in my case) are for the MGB HS4 carburetors, and must be cut down to the appropriate thickness (about 1/4 inch) for Healey tri-carb application. A buddy of mine has a good table saw, with a standard blade. He epoxy-glued the thick 1 inch insulator to a piece of scrap wood, as a guide, and so as not to lose fingers in the cutting process. He then successfully cut two thin slices of spacer/insulator from the one block with no problems, other than creating a lot of black dust. We dressed down the thin slices with sandpaper to size (about 1/4 inch) and they came out fine. Since we had ordered 3 large spacers to work with, we were able to cut 6 slices from them and used the best ones for our purpose.

Using a band saw may prove more difficult because of the thinness of the blade, but a table saw works quite well, indeed.

Dave.

 

[healeyblue]

Great "top tip". Never would have thought of that but it should work great and obviously did.

 

[Bob_Spidell]

Wonder if a planer would work?