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Triumph TR6 - Carbon Canister?

I've a USA spec 71 TR6, which has been UK speced...before I brought it.

On opening the boot, on the right inner wing there is a covered area with two metal pipes coming from the area of it rear the petrol tank, two flexi pipes go off around the top of the tank, BUT were not connected to anything, accept fot a plastic 4 way junction. Would this be the USA spec carbon canister, with the four way junction sending pipes to the engine?

On the same note, it stank of petrol (the rear of the car), I noticed a hose coming from an output at the top left of the tank and going through the boot floor, it simply vented the tank to the outside! I've plugged this as it was causing worries over explosions at the office garage it is currently at.
Question is: What should the top left pipe output go to? I presume originally...the carbon can.

Any ideas Lads?

aj mcmurray

Check the TRF catalog if you have 1, there is a fairly good picture of it's start and finish, yes it goes all the way forward to the carbon cannister,(rubber tubing along the frame rails).
Regards, Keith
KBD Dixon

You have a unique set up for the emission tank assembly. I have the same. It was only done from CC55030 to approx. CC75000 (1971). It at least went up to CC65060L. The TRF Catalogue (or any book for that matter)does not show a picture of this set up but does mention all the parts. Alistair u probably do not have these books so will go into detail in a moment. Now here may be why u had the disconnected pipes. The gas tank (oops ...sorry petrol tank :) that came with this set up had 3 connections on the top. An angled pipe out of the back left top (which u mentioned), an angled pipe out of the front right top of the tank ( do u have this pipe??), and a connection at the filler neck. You also had the 2 connections to the emmissions tank at the right side of the boot. You should also have a black plastic hose that runs around the inside of the entire boot area. Before I continue a note on this tank. It can easily be removed by drilling out the pop rivets and checking to see if it is rusted through or not...probably not as it was never exposed to salt because of being inside the outer body. Clean the tank out with some degreaser. You might find you have some "original" fuel in the tank which would account for the stink.
OK..The Connections:
1: from front carbon canister through a metal pipe (mine is metal not plastic Keith that runs along side the fuel line at the frame) through body front left side of fuel tank up then across the front edge of the fuel tank and then around the entire boot back across the front edge of the fuel tank then to one of the connections of the small emissions tank.
2: From the second connection of the emissions tank to the "4 way connector" (mine is a copper 4 way connector pipe).
3: Off of the 4 way connector with the remaining 3 connections go to the 2 pipes off the left and right of the tank and to the filler neck.
Thats it.
Alastair I do not have a scanner so can not e-mail you a drawing but do have a fax machine if you give me a fax number off line this BBS. Also edit my e-mail address to

Hope this helps... I am curious if you have the other pipe on the top of the fuel tank.
Rick C
Rick Crawford

Thanks Rick, for all that detailed info.

The car has been totally restored, chassis (frame) shot blasted ...the lot, I guess the chap simply didn't bother removing the little tank (whats in it?) and associated tubing as there isn't a carbon can fitted :-)
I will remove all the piping and join the three tank top pipes together to plug them. However how does a UK spec tank breathe? I thought it was integral with the filler cap....I don't want to create a vacuum!

aj mcmurray

You are welcome. Sounds like you have a very nice lookin' 6. I did a full tub off restore so that is why I know the emission set up so well. You ask what's in it? I said, some "original" petrol thus the stink. In theory, If the tank was filled to the top and you had petrol splash up the filler neck through the breather emission plug screwed into the filler neck it would travel through the 4 way connector to the little "extra " tank and just sit there.
Alastair, not the name of all these connections...BREATHER. I do not know if you would create a great enough vacuum, if all 3 fittings where pluged, to starve the engine of petrol.
The P.I. UK spec 6s did not have an evaporative loss system. How did the tank breath? The P.I. system has an electric fuel pump ( slight pressurized fuel system) with an inline pressure relief valve connected via pipe back to the tank thus any sort of potential vacuum was not a problem thus no "extra" connections on top of the tank or the filler neck.
If u have no carbon canister then the emission breathing system must be currently pluged at the carbs also. If this is so then these plugs must not have a leak at all or you will get rough engine performance (vacuum leak). If the pipe off of the valve cover is pluged then you have the potential of pressurizing this area. The carbon canister had 2 inputs... 1 from the carbs (and valve cover) the other from the petrol tank. So you have both areas affected by pluged pipes. The problem is that the carbon canister is like the proverbial neddle in a hay stack over here and probably worse on your side of the pond. You should try to see if you can get on or if anyone else knows of where to get one please jump in. This will keep the car original and will not affect engine performance at fact..might help.
Good luck Alastair.
Rick C
Rick Crawford

Rick C. It may not be as simple as just hooking all the tubes together as the carbon canister design allowed a quantity of air to be vacuum dragged to the carbs, even if the petrol tank vent was plugged. The bottom cover of my carbon canister has an open nipple which draws air up through the fiber filter and carbon to the carbs. You'll notice the petrol line at the canister has a brass flow restrictor installed to limit the amount of air being drawn from the petrol tank; the rest of the air came through the nipple. Later TR's had a solenoid valve installed on the nipple that closed this air entry point when the engine was shut down to prevent run-on.

Anyhow, my point is that hooking the tubes together eliminates a source of carb air/increases vaccum that may or may not cause performance problems. Any insights anyone?
Rick Orthen

Ha RickO
I am not sure where u got the idea that I was suggesting that Alastair just hook up all the pipes/tubes...that is why I said try to find a carbon canister (CC). The 70/71 system did not have the brass restrictor inline from the fuel tank. There is/was a restrictor on the inlet pipe from the carbs/valve cover. Look at TRF Plate AR and from plate #AR4 down that side of the page there is no numbers...this is all 70/71 and is not illustrated. The 70/71 also had the nipple bottom of the canister. My point of "must be currently pluged at the carbs" is maybe where u mis-interpreted what I was saying. Alastair does not have a CC and those breather connections (with restrictor) at the carbs better be pluged or he will be drawing in to much air at this connection. Alastair did not say how it is connected but They are either pluged or are connected to the valve cover and the canister has been eliminated. I would think the later is the case.
Sorry Alastair for going off on a tangent here but I think the point is made by both Ricks that the lack of a CC might affect engine performance. Maybe the carbs can be adjusted so that the direct connection from valve cover to carbs less CC will work. I have not done RickO says...Any insights anyone?
Rick C
Rick Crawford

How about a photo?
Try at the top ate a few photos taken last month before I stored the car so I can sell the spitfire.

As you can see the rocker cover pipe is fitted to just the front carb and the rear carb has this inlet plugged. The motor runs fine at TO so I guess the emission control fittings have been sorted.

I know SUs back to front, so I'm fitting a pair of 1997! units HIF44 to replace the strombergs ASAP as the exhaust blows and I will be fitting a stainless 6-3-1 manifold with richer needles, so I can go TR6Pi chasing :-)

aj mcmurray

This thread was discussed between 14/07/2002 and 16/07/2002

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