CDSE150 Carbs - US/Sweden

[Qu1ckn1ck]

I have just bought a pair of unused NOS carbs for my 1971 GT6 and looking for some advice before I fit them.  They are USA/Swedish spec and of course have several differences from the UK spec ones that I currently have fitted.

 

1) The needles are different but my car seemed quite happy using the US needles and they are no problem to change, I already have a pair of correct new ones for my GT6.

 

2)  The US carbs have chokes fitted to both carbs and apparently in the US a very expensive single knob/dual choke cable operates both chokes in tandem.  Should I fit separate choke knobs and cable for each carb or would just choking one single carb be adequate for cold starting?

 

3) My existing crankcase emissions set up has the crankcase breather hose going direct from the rocker cover with a connection to each carb (see pics).  My new carbs have no facility to accept crankcase emissions.  Would it be OK for the crankcase breather hose and the brake servo hose to combine and share the centre tapping in the inlet manifold, either with or without a Smiths mushroom valve on the emissions side?  Alternatively, could the emissions hose be connected to the back of the air cleaner box?

 

4) The US carbs appear to have an extra hole on the inlet manifold flange.  Any idea what this is for and will there be a problem if they are covered by the gasket and spacer?  

[Pete Lewis]

question  ....why how bad are youre fitted ones   ...i dont remember .

 

if you  had found some CDS it would save a lot of stress  ha !

 

the us spec will have econostat valves and other add ons , you dont need , these measure/ breathe from the manifold via the ports in the flanges 

 

and probably outages for charcoal filters etc.

the dizzy would have two vac capsules in a pull me push me set up so extra outages for them

 

when we fitted  two cds both with chokes we got a hunter/sceptre choke cable with one knob twin cables quite cheaply.

 

if you change your breather you must fit the smiths valve to modulate the suck into the manifold 

 

Pete

[dougbgt6]

Yeh, my first thought was, can't the old ones be fixed? I would move the new ones on and refurb the old ones, if possible. It's not a difficult job fitting the refurb kit. Buckeye Triumphs do a very good piece on Stromberg overhaul.

 

Can't remember who first told me about Buckeye.    

[daverclasper]

Hi

 

I would refurb the olds if pos. The only bit of the bodies that can wear is the throttle spindle orifices I understand. (you can get them rebushed, but specialist job). If you have play in spindles, then often it is the spindles that wear most. A check is to remove the butterflies and slide the spindles along until the unworn section is in the orifices. If only a small amount of play then ok.

 

I had my breather tube running into air box and it used to oil up the filters after a while. Have since fitted an original PCV valve running into inlet manifold. This also appears to have made my carbs much easier to set up for mixture throughout the rev range! and no oil leaks from Rocker Cover/Filler Cap, now there is some vacuum in there.

 

Dave  

[Qu1ckn1ck]

Many thanks for the various comments and helpful suggestions.  

 

The existing carbs run very rich despite several attempts to lean the mixture, they even caused a comment about the petrol smell from a club member in the Raven car park recently.  I was considering refurbishing the existing carbs but made an opportunistic purchase when the NOS US carbs appeared on ebay.  I will probably try using them as they are, but if not happy with them, might cannibalise their critical parts into a rebuild onto the UK spec body castings.

 

Following another opportunistic ebay purchase, I do have a Smiths emissions valve to carry out Dave's suggestion regarding running the breather into the inlet manifold.  

[Pete Lewis]

The usa spec should be quite lean on mixture all be it you probably only have the carbs fitted and missing all the rest of the emmision clap trap that goes with it

 

pete

[Qu1ckn1ck]

The usa spec should be quite lean on mixture all be it you probably only have the carbs fitted and missing all the rest of the emmision clap trap that goes with it

 

pete

 

That was my thinking Pete - I have already tried the needles in my old carbs.

[Pete Lewis]

Do you know what your needle numbers are

 

if the idle mix is ok with a specified needle spec, but running is rich across the range then things like

float heights ,vent ports , damper weights and damper spring spec (there are thick and thin wire size)

 

From memory you shut the temperatue comps down, as these can cheat the idle mix to be over rich

due to the air bleed as can doggy sealed breathers being open to leaks

any extraneous air needs capping.

Or your base mixture is rich across the whole range once you open the throttles

[Qu1ckn1ck]

The needles in the existing carbs are B5CF and the carbs are tagged 3432L+R which I believe are both correct for the later GT6 engine fitted.  Other than trying to adjust the mixture we have made no mods or changes to the carbs but obviously in a 46 year life a previous owner may have done .

 

The mixture appears to be too rich across the whole range.  The car starts with almost no choke and even when hot after a run, the exhaust smells very strongly of petrol.  If left to idle she will choke herself into stalling after 5 minutes or so.  

[Guest]

Hello.

 

This goes back to a similar thread about a month or so ago I think with Paul (bivvyman) who had similar issues with his Vitesse; I could relate to the problem having been in the same boat due to incorrect carbs being supplied by a well known seller / carb restorer. The carbs were "modified" emission units that allegedly had been corrected for non-emission deployment. There then progressed a fruitless to & fro with various needles wasting plenty of time and money. The downside of Stromberg needles is that the range is not as varied as SU, so it really does have to be match-for-match.

 

In the end, I had the original carbs restored by Gower & Lee (brilliant) never looked back and wish I had done that from the start. Sold the supplied ones at a loss but an acceptable payoff over further wasted time. 

 

Refurb kits are useful to a point, but when the linkages and bushes wear (especially the latter and Stromberg's are very susceptible) it really requires a proper overhaul, something that the refurb kit will not be able to deal with.

 

So the moral of the story is that if you want your car to run properly, get the correct spec / country carbs and have them restored to their original brief which in essence are the existing carbs that ST designated at the time for the car.

 

Unless your car is suitable for these overseas carbs you have and I do not mean "close to it", do not waste your time and money trying to find a solution that does not exist.

 

Good luck.

 

Richard.

[Paul H]

Hi - pretty sure I have the correct spec refurbed carbs ie CD150 SE currently on my Vitesse Mk2 though should be on a GT6 MK3

NB the emission control setup has been "closed down " with the help of Pete on this forum 

 

Regards

 

Paul ( Bivvyman ) 

[dave.vitesse]

I echo all the comments and will add - Before doing anything check the colour of the plugs after a run. White = Weak. Brown + OK. Black = Rich.

 

Dave

[dougbgt6]

Dave, I thought I already said that, but it was another current thread! Makes me wonder how often we repeat ourselves?  We should train a parrot, except they can't type, obviously.

[dave.vitesse]

Doug, I have the same thoughts, has it already been said and was it me! 

 

On your theme - I  must go down to the pet shop and buy a Norwegian Blue!

 

Dave

[dougbgt6]

 

Pete Lewis keeps parrots.

 

Are we really talking to Pete?

[Guest]

That sounds a great DVD Dave, can I borrow it afterwards !!

 

Richard.

[Pete Lewis]

Who's pretty boy then

[Gully]

The needles in the existing carbs are B5CF and the carbs are tagged 3432L+R which I believe are both correct for the later GT6 engine fitted.  Other than trying to adjust the mixture we have made no mods or changes to the carbs but obviously in a 46 year life a previous owner may have done .

 

The mixture appears to be too rich across the whole range.  The car starts with almost no choke and even when hot after a run, the exhaust smells very strongly of petrol.  If left to idle she will choke herself into stalling after 5 minutes or so.

 

The needles you have for the quoted carb set are correct according to the Zenith Stromberg workshop manual. However, as you have indicated, they are for the 1972 onwards GT6. My 70/71 GT6 ran rich and used to stall when hot idling until a certain Mr Lewis of parrot fame (amongst other things!) closed up the temperature compensators and reset both needle heights. Mine is on a 3335 R/L set and B5BT needles. Now likes full choke for cold start, with it rapidly pushed halfway in to prevent the engine choking itself and then progressively pushed home until completely in when the temp gauge starts to register - as you'd expect really!

 

Gully

 

Gully

[Pete Lewis]

fame a last  !!!

 

you can twiddle a carbatootie  but not a umbrella cockatoo  they just destroy your house, wiring, furniture telephone, and anything

4ft wing span  flying bolt cutter can get her beak on..  then  its re-homing time   the Grey went with her, just cockatiels nowadays 

[dougbgt6]

My brother live in Uxbridge, they are plagued by feral Parakeets, 100s of them, maybe 1000s, very pretty birds but, the noise! Nightingales they ain't! RSPB want to cull them because they are overwhelming native species.