Carburettor I.d help (pictures included)

[qed296]

Evening all, picked up these carburettors to replace my very tired 150 cds's on my mk2 vitesse(as noted I was looking to get them reconditioned in an earlier post).

I've bought them as 150cd items, but straight away I've noticed a few differences.

As ever onto Google to find out what they really are (just say "CD" no numbers)but I've  ended up more confused.

Any ideas..150 cdsve from tr250 or tr6 seems to pop up, but I thought 175 cds came on the tr6?? (Got some of them, but need refurbing)

If they turn out to be gt6 carbs and they an improvement on the 150 cds originals? ?

Any help, info or pointing and laughing welcomed.

[Steve AKA vitessesteve]

You can read about Stromberg CD carbs: https://app.box.com/s/qnc1py2hx8hkro9f8o8a

http://zenithcarb.co.uk/technical/

Yours look to late models with emission control mechanism on the sides.

[qed296]

That's interesting.....
Just noticed something,

The air valve body on one of my carbs is showing the metering needle through the inlet. Is this correct, my others 4 x150 cds & 2 X 175 cd units are not visable, could I have an issue or is it an easy fix or is this correct?

[Steve AKA vitessesteve]

Seeing the needle is normal - you should be able to raise/lower the air valve and see more/less of the needle. The valve raises and falls as the air pressure caused by the induction changes as the engine sucks in the fuel/air mixture.

[qed296]

Appreciated info Steve.

[RobPearce]

As others have said, those look like later model CD3 carbs with (partial) emission control. It's possible they're from a Mk3 GT6, which had that type.

My personal opinion, having both a Mk1 Vitesse and a Mk3 GT6 in my fleet, is that the CD3s are a pain in the posterior and the early type are much preferable. However, once properly set up, the CD3s ought to work on a Mk2 Vitesse.

As to your "visible metering needle" - the photo doesn't appear to show the needle. It does have a black circle (almost certainly an allen head grub-screw) showing on the side of the piston - which is the screw closest to the words "metering needle" on the exploded diagram. I can't remember off the top of my head whether that should be visible or not, but I wouldn't expect it to be located there. If it's not visible on the other one of the pair (no use comparing with the earlier type as they're different) then it suggests at least one of them has been assembled wrongly and won't work. The piston on Strombergs is held in its correct orientation by the rubber diaphragm, which is located by a fairly small tab that could be easily missed by somebody more obsessed with polishing the visible bits than learning how to put it together correctly.

[glang]

Quoted from RobPearce

As others have said, those look like later model CD3 carbs with (partial) emission control. It's possible they're from a Mk3 GT6, which had that type.

My personal opinion, having both a Mk1 Vitesse and a Mk3 GT6 in my fleet, is that the CD3s are a pain in the posterior and the early type are much preferable. However, once properly set up, the CD3s ought to work on a Mk2 Vitesse.

As to your "visible metering needle" - the photo doesn't appear to show the needle. It does have a black circle (almost certainly an allen head grub-screw) showing on the side of the piston - which is the screw closest to the words "metering needle" on the exploded diagram. I can't remember off the top of my head whether that should be visible or not, but I wouldn't expect it to be located there. If it's not visible on the other one of the pair (no use comparing with the earlier type as they're different) then it suggests at least one of them has been assembled wrongly and won't work. The piston on Strombergs is held in its correct orientation by the rubber diaphragm, which is located by a fairly small tab that could be easily missed by somebody more obsessed with polishing the visible bits than learning how to put it together correctly.

+1 yes you need take off the top cover of each carb to check the diaphragms are correctly located on both the pistons and carb bodies. Hopefully the diaphragm itself hasnt been damaged. Also just noticed that on my carbs (admittedly early version) the covers are installed 180 deg round the other way.....

[GT64fun]

My money would also be on late GT6 Mk3 carbs.
There is a serial number visible on the side view. It might be worth quoting this to Gower and Lee (Geoff) or to Burlen and they might be able to help with identification.

The float bowls have the blanking piece in the base, so they will have top adjusting needles, rather than the fixed needle and adjusting jet of your original Vitesse carbs.
The gubbins on the side with cream coloured plastic covers are the temperature compensators (can be troublesome, but probably best left alone)
Looks as though there is a choke on the front carb only, in which case I would expect to a tube between the carbs to dribble some fuel to the back carb, although there is a bracket on the back carb, that looks as though it is intended for a choke cable connection as well.
The carbs look cleanish and the covers have definitely had a polish (to bling them up a bit for sale)
I have a section in my Autobook manual covering the 150 CDSE carbs which I can scan and e-mail and there is probably a section in the red Triumph workshop manual as well (I'll have a look this evening)
There is also a lot of information on the Buckeye Triumph website covering refurb of US spec carbs, which would probably be relevant to your units.

I'm pretty sure that TR250s and US TR6s would have had CD175s.

PS:-I actually have 175 CD2s on my GT6 (non original-possibly from a Volvo) and they are a hybrid with fixed needles, choke unit on front carb and temperature compensators.

Hope this helps

Ian F

[qed296]

Thanks for the replys.
So a inspection of number 1 is advised then before fitting...got it...

Only a few minutes from Peter Burgess garages so if all else fails ill get it booked in for a rolling road and tune.

[Pete Lewis]

Temperature compensators have a set of tests to correctly set them
they  are an attempt to aid emissions especialy to lean the idle mix when the engine bay is very hot  it will also speed up,the idle a little

Its imprtant these little devices are closed at normal temperature or you will never set the idle mixture if they are partly open
so  undomthe 2 screws and remove the unit, there should be 2   0rings to seal the  inserted end to the carb body   the small plastic plunger must be seated in its case, so tighten the small nut to re load the bimetal operating stripmto get the littel sod closed, if it never opens its not a problem
you just dont want it open when it should be closed as this bypasses the throttle plates
through a small drilling direct into the manifold, the gaskets have a port that must align

putting the gasket on upside down will stop  its operation and also make it sealed and inoperative

easy to check and sort