Stromberg 150 type identification

[Paulfc]

Hi,

Sometime ago I acquired a pair of Stromberg 150CD carbs with a manifold. I've been able to  verify the manifold via its Stanpart reference as correct for the car. What I haven't been able to do is identify if the carbs are CD or CDSE. Can anyone please enlighten me as to how to tell the difference? Many thanks,

Paul

[Guest]

Paul.

Have a look at this link, which shows CDSE carbs: http://joecurto.com/triumph-tr250-zenith-stromberg-175-cdse

Regards.

Richard.

[Pete Lewis]

CD has a thames barrier type choke which lifts the air piston and blocks the throat at the bridge /jet platform

CDS has a starting valve choke enrichment on the side of the front carb and a tube to pass fuel to the rear carb 

Both have easy jet adjustable from below the float bowl

CdS is probably the easiest   best of the 3  for diy adjustables.

CDSE > cdsev  has the same starting valve , with  temperature compensators and mixture adusts from down the air piston dashpot

Via a allen key tool  or offset slot device,   should have biased  sprung needles old style adjustment blanked witha cap and O ring

All have fast idle controlled by a cam and adjustable tappet screw

If thats a help,

 

 

 

[Paulfc]

Thanks both for the information. Much appreciated. Life's never dull with a Triumph!

Paul

[steveweblin]

You can read about Stromberg CD carbs in   Tuning Stromberg CD Carburetters  which is available from my website at: http://vitessesteve.co.uk/Other-manuals

[Paulfc]

Thanks Steve, much appreciated. 

Paul

[Paulfc]

Hi, 

I'm starting to get boggle eyed and just a little confused..... can someone please confirm for me what model Strombergs would have been fitted originally to my early (1971 manufactured) Mk3?

I've read loads of info but find conflicting references to CD and CDSE variants.

Thanks,

Paul

[dougbgt6]

Paul,

is this any use? I think yours should be 3369L/R 

http://zenithcarb.co.uk/cf/vehicle/list/?manufacturer=Triumph&vehicle=GT6

Doug

[dave.vitesse]

Mk3 GT6 - up to engine number KE10000 should be 150CDS carbs. Which are the same as the Mk2 GT6.

Mk3 GT6 at engine number KE10001 and after the carbs should be 150CDSE.

The picture is of a 150CDS

dave

[dougbgt6]

This is a 72 so should be CDSE

db

[Paulfc]

Thanks to you both for coming back to me. My commission number is KE16 and the engine number is KE84. A previous owner has put a pair of SUs on and I've now acquired a pair of Stromberg 150CDs. I'm minded to refurb and install the CDs as part of my restoration plan and I'm assuming it won't really matter if they're not CDSEs as my understanding is these are just emissions reduction improvements and with my likely annual mileage I don't think I'll be doing too much additional environmental damage!

Paul

[Guest]

Paul.

Does there appear to be any type of emission control on your old set-up with the SU's ??

If not, then the CD's will be fine with the correct needle and spring.

The only downside with Strom's is the needle range is limited compared to SU's; however that said Strom's are an excellent carb and very underrated - generally as a result of wear. I had my Strom's overhauled fully and the transformation is excellent - well worth doing.

Worn carbs always remind me of the famous cricket dictum: you cannot set a good field with bad bowling !! 

Regards.

Richard.

[dougbgt6]

6 minutes ago, classiclife said:

the needle range is limited compared to SU's;

Indeed, early, late and pancake filters! 

db

[Pete Lewis]

But if all is  std then everything strom is available , its only if you mess with intakes that needle choices are limited

Exhaust changes  have a lesser effect on mixture

A pair  of cds will be a good choice 

Most ive come across who have misguidedly   fitted SU to the  Vitesse  Gt6 run into some poor running , and end up reverting to what triumph specified

The std air box and  piped cool intake air works as designed 

 

[Gully]

According to the Haynes Zenith Stromberg bible...

Mk 3 GT6 (UK):

1970 Set 3369R/L 150CDSE (as Doug indicated) Needle B5AJ

1971/72 Set 3335R/L 150CDSE Needle B5BT

1972/74 Early Set 3426R/L 150CDSE Needle B5CF

1972/74 Late Set 3507R/L 150CD-SEV Needle B5CF

My 1970 produced, Jan 71 registered car has the 3335R/L carb set - KE83 commission, engine KE154.

Gully

 

[Paulfc]

Thanks one and all for the information and advice. If I can push things just a little further - is there any way of identifying the different set types from the serial numbers on the carb body? 

Paul

[Gully]

32 minutes ago, Paulfc said:

Thanks one and all for the information and advice. If I can push things just a little further - is there any way of identifying the different set types from the serial numbers on the carb body? 

Paul

The set numbers are on the small brass tags attached to the top cover screws. No idea about casting numbers - sorry.

Gully

[Guest]

Yes there is, check the link out which is an excellent and informative spreadsheet: http://www.carburettorspecialists.com/CHLAUG2016.htm

Regards.

Richard.

[Pete Lewis]

The casting numbers  reflect the family of design and nothing to do with the specification of settings (brass tag) details the 

Needles , jets , springs, damper weights are all pretty interchangable where as the  body with their casting numbers are fairly common for each evolved family  .

Pete

[Paulfc]

Thanks everyone, replies are much appreciated.

Paul

[dave.vitesse]

The first picture shows 150CDS on a Vitesse. The layout is the same as the early GT6 Mk3 except for the location of the throttle cable. Note the use of a Smiths emission valve, this is not present on the late GT6 Mk3 which uses the 150CDS carbs. Instead the rocker cover breather is fed directly to each carb. The second picture shows the 150CDSE set-up on a Triumph 2000 which is similar to the late GT6 Mk3. 

Dave

[Guest]

Dave,

Looking at the photos - was there an advantage, one over the other or was it just design led ??

In essence the fumes go from the rocker to the manifold or carb, depending on the set-up all being recycled to the pistons eventually.

Regards.

Richard.

[Pete Lewis]

the rocker breathing was changed from a semi sealed with a vented cap  with a flap valve and smiths valve , the valve kept the inlet sealed until any crankcase compression was detected ,it opens and the oily fumes get reburnt

the later has a fully sealed system  sealed cap,   so once the manifold vacuum has sucked the crankcase  empty and  no more air gets let in, it doesnt need a valve to control ,

 in general all covers have a gauze flame trap in the cover  behind the outlet stub,  its not on alloy covers  !!! which really need an external one 

well something like that

Pete

[dave.vitesse]

Echo Pete. Plus the point where the breather is fed into the carbs is said to be a constant compression point hence this was the reason why the Smiths valve was not required.

A cheaper set-up and maybe reduces pollution. 

Dave

[dougbgt6]

Mine doesn't have gauze, it has a series interleaved plates located in that "lump" on the top of the rocker cover. I've seen quite a few alloy covers with no fire trap, as Pete says theses should have reverted to the Smiths valve.

db