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TR2/3/3A Carb. Heat shield location?

GTP1960

Jedi Knight
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I'm wondering if I have my carb heat shield positioned correctly?
I've got it positioned after the spacer.
however, I've been told it would be more effective if it were located before the spacer (intake manifold/carb junction) & not in direct contact with the barrel of the carbs.

Your opinion is appreciated.
 

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Merlin63Tr4

Jedi Trainee
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Should be; intake manifold, gasket, heat shield, gasket, insulator (spacer), gasket, carburetor.

M.
 
OP
GTP1960

GTP1960

Jedi Knight
Offline
My heat shield has a cut out where the throttle linkage passes for the forward carb. ( see close up pic).
i don't think it would fit if I located the heat shield before the insulators.
could I have the heat shield reversed?
Should I flip it around? Currently , The shelf is facing out

Thx for your input
 

Merlin63Tr4

Jedi Trainee
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I had to trim my heat shield back in the same spot in order to clear the interference with the throttle linkage.
Looks like you are going to have to do the same.
If you locate the heat shield after the insulator (spacer) it will not be very effective since the radiant heat it is adsorbing from the exhaust manifold will be directly transferred to the carb bodies/float bowls. Locating the heat shield before the insulators (spacers) will help to minimize this transference.

M.
 

NHinNC

Freshman Member
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Should be; intake manifold, gasket, heat shield, gasket, insulator (spacer), gasket, carburetor.

M.

I am not speaking from any experience, and maybe should just keep quiet, but...

Shouldn't the shield be outside the insulator from the manifold? More heat from the manifold would be transferred with the order as listed.
 

Vila

Jedi Hopeful
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I would call or email the supplier and get their opinion on how it should be installed.

They sold it to you so they should know the correct way of installing it, and if it does not fit properly as supplied they need to correct the design.

I hate it when I buy something like that which could be installed several different ways and they don't provide directions for proper installation.
 

NHinNC

Freshman Member
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I am not speaking from any experience, and maybe should just keep quiet, but...

Shouldn't the shield be outside the insulator from the manifold? More heat from the manifold would be transferred with the order as listed.

Maybe I should have kept quiet. After thinking further, if it is the heat from the exhaust manifold, then putting the shield on the carb side of the insulator give a path for the heat to get to the carb.
 
OP
GTP1960

GTP1960

Jedi Knight
Offline
I would call or email the supplier and get their opinion on how it should be installed.

They sold it to you so they should know the correct way of installing it, and if it does not fit properly as supplied they need to correct the design.

I hate it when I buy something like that which could be installed several different ways and they don't provide directions for proper installation.

I've never had much luck getting detailed instructions from the usual suspects (TRF, Moss, etc.), we are usually dealing with clerks & sales people there, who try, but I suspect only have 2nd hand product knowledge.
but I can understand why too.
Since almost every part for our cars are now "aftermarket" getting detailed accurate specs & instructions is that much more difficult.

having said that: I took your advise and researched Joe Alexander's heat shield ( which is the type I have):

here is a quote from his webpage :

[SIZE=+1]Stainless Steel Carburetor Heat Shields[/SIZE]

A.R.E. is producing a line of Stainless Steel Heat Shields for 1.75 SUs & Strombergs, specifially for Triumphs. These are assembled to each pair of carburetors with existing hardware, typically with no modifications, with the addition of gaskets (not included).
TR3/TR3A/TR4For SU H6 and early Strombergs (1.75)
TR4A/TR250For SU HS6 (TR4A) and TR250 Strombergs


I also also found an old forum post, with a quote from Joe A. Stating the heat shield is sandwiched between insulator & carb. (Note: it does fit nicely: plug & play)

However, having said ALL that: I think Merlins & Hawaii's retrofit makes more sense, if you have the know how & skill to modify the heat shield so it fits between intake manifold & insulator.

thx guys.
 

TR3driver

Great Pumpkin - R.I.P
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I have mine installed as Joe A intended, and it certainly helps a great deal over nothing at all. Might be an interesting experiment to move it to the other side of the insulator, but I'm guessing the difference would be minimal. The main purpose as I see it is to block radiant heat from the manifold getting into the fuel area (float bowl and jets). The shield has a lot of surface area, so it isn't going to get nearly as hot as the manifold, so IMO the conducted heat is much less of a concern.
 
OP
GTP1960

GTP1960

Jedi Knight
Offline
It will probably work fine either way, if the purpose is to shield the float bowls from heat.

This gave me a good reason to go for a spirited drive.
i put a laser thermometer on various parts immediately after a 45m fast drive.

The front float bowl was about 122 deg. On the inboard side closest to manifold.
(only warm to the touch). The back bowl was even cooler.

the lower base of the carb barrels, in contact with the shield where the stud passes, registered about 130.

the lowest part of the shield read 150-155; upper read 120

intake manifold averaged 180-190
exhaust 250-280 with a spike of 312 on #2 cylinder for some reason.

so you are probably right, either way should work. Because those #'s aren't bad.
 
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