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Triple Weber DCOE40 with TWM Manifold and linkage - Assembly Instructions

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Hi All

I have a Moss Carburettor Conversion Kit, Triple Weber 40 DCOE with linkages.

https://www.moss-europe.co.uk/shop-by-model/triumph/tr5-6/performance-tuning/fuel-system-induction/carburettor-conversion-kit-triple-weber-40-dcoe-fast-road-ttk1259.html

image.png.2d72c87c8c24889f883da6345d7be48c.png

  • Can anyone assist with assembly instructions, or alternatively have any pictures?

Many thanks

Dave

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Hi

First of all you have the bell linkage ie rod ( not good) however you also have the cable option there also use that,the three mounting rose jointed rods need a lock nut and last but not least the inlet gaskets are no good find misab ones. 

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Hi Dave,

Can't say that I agree with Neils' opinion on the rod and bell crank system that you have with your kit. I've used it successfully on my race car for several years now without ANY problems at all. Just ensure that the bell crank fixings are securely tightened onto the rod. I'll try to remember to photo mine and post it tomorrow.

Yes, the rose jointed rod mounts need a lock nut to secure them once they are all aligned, but it's only a straightforward 5/16" or 3/8" UNF nut, so not a problem.

You will need to provide a "buttress" on one of the carbs to secure the end of the throttle cable so that it has something to pull against when you depress the pedal. I made up my own as I couldn't find anything in the Weber standard parts list. I provided 2 cables just in case one broke, but that was really belt and braces for a race situation to avoid being unable to finish a race. Don't forget to adjust the bolt stop on the back of the accelerator pedal to avoid stretching the cable and breaking it.

Yes, Misab plates which are a metal plate with an O ring between each carb and the inlet manifold, are better than the flat gaskets supplied. They allow the carbs to be inclined/rotated on their mountings to provide a good seal, while enabling the rod mounts to be aligned properly so that the linkage rod rotates freely. 

See link - https://fastroadcars.co.uk/store/index.php?route=product/search&search=Misab Plates

If you do decide to go for a cable option see link https://fastroadcars.co.uk/store/index.php?route=product/product&path=60_80&product_id=528

I'll try to post a photo of the cable system tomorrow.

Before assembling anything together on the car it is advisable to :-

  1. Offer the carbs to the inlet manifold, which looks like a TWM in the photo. There are sometimes slight misalignments which just need opening up to allow full orifice flow.
  2. Offer the manifold to the cylinder head. Sometimes the fixing holes need slight relieving to ensure a good fit.
  3. Depending on what type of exhaust manifold you have, check that you can fit all the nuts on the projecting studs. With a tubular steel performance manifold the nuts on the bottom studs at cylinders 1 & 6 cannot fit on. Remove the studs and use a Cap Head Screw (Allen Key Screw) instead, which can go in after the inlet manifold is fitted. It has even been necessary sometimes to grind down the sides of the head of the cap head screw for clearance.
  4. Consider the need for a choke. The TR6 starts fine without a choke. Just press the accelerator pedal 3 or 4 times before you turn the key to pump fuel in and it starts ok. If you are happy doing that you can cut off the triangular plate from the inlet manifold under the back carb which forms the mount for the L shaped bell crank in conjunction with the long turnbuckle to operate the choke. With that plate cut away it is VERY much easier to get to the bottom manifold fixing bolts with the "slugs" which fix both inlet and exhaust manifold. Ask me how I know??!! Don't take my word for this before you start cutting. Ask others for their opinion.

After this I found it best to assemble the carbs onto the inlet manifold and set up the linkage rod mounts, etc on the bench. I then offered that whole assembly to the cylinder head to bolt it into place. Depending on what length inlet trumpets you have, you may find it easier to remove them at this stage to enable access to the bottom studs/nut/"slug" fixings underneath and then put the trumpets back on later.

Hope that helps.

Dave McD

 

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Good advice from Dave there.

With regards the bell crank rods.   With the kit i purchased they came without any circlip type fitting on the ball end to stop the ball from pulling out.If you check diagrames on webber sites .you will see them .  Check yours have these . Caused me a breakdown.

ROY

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1 hour ago, ntc said:

Hi Dave

Race conditions are far different from road use ask Stan in the states B)

My main issues with the dcoe's on the TR6 have been with the bell crank. This is probably worse on the LHD cars because there are more moving parts but in my case with the Canon manifold the pivot for the bell crank ends up very close to the exhaust and the combination of heat and dirt and probably cheap materials causes the bell crank to start binding/sticking after a while. I have tried converting to a cable system but that had its own issues so I struggle on with the bell crank. This winter I have a new one with what I hope is a better bearing.

I am also going to block off the balance tube in the Canon manifold. I notice that the TWM manifold doesnt seem to have one and I assume the brake servo works ok with the vacuum from just that one carb.

Stan

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Bronze bushed bell cranks are not the best, though I've done fine with one on my concourse car for 6500 miles. My driver has a ball bearing bell crank which I see in the top photo; these shouldn't give any trouble ever - 130K miles and counting on mine. I use the factory mechanical linkage all the way to the bell crank on both cars ( LHD ). A bit touchy, granted but I got the knack of it pretty fast.

I'm quite content with the CANNON manifolds on my cars; as is the brake servo barely gets the vacuum it needs at idle, and if touching the pedal repeatedly I'll rev to boost it. The balance tubes may help balance the idles better than fully independent runners like the TWM. My carbs are vintage Italian without the throttle bypass adjustment screws which I would definitely want if using a TWM. I can get mine to idle pretty low with what they have:

 

 

 

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