Spit 1500 engine and 1.5 CD Strombergs

[Peter Truman]

Trying to find reasonable 1,5 HS4 twin carbs is very difficult esp here in Aus, I have several 150CD Stroms which unlike SU's aren't handed so I was wondering what the pitfalls of adapting the Stroms to a 1500 Spit engine are. Just thinking here.

I've modified a spare Spit Mk3 inlet manifold I had from 1.25 to near 1.5in throat size & can easily make an aluminum  adapter plate to go from the vertical 1.25in flange to the 1.5 offset bolt arrangement.

I prefer the Stroms to SU's as their a later better and simpler design, I find easier to tune & less height so fit easier.

Has anyone done it if so what are the issues and what needles are best.

I should go to bed to sleep not dream the impossible or impracticable!

Regards

Peter T

[Pete Lewis]

There are few options for needles on stroms 

I agree about  their better design  both can do a job but laying the components out  and compare what you you  get the stroms have to win.

I would think nearest off the shelf needles would be  ??  the 1600 vitesse ,    a 7B    this needle does not have a piston spring but a thick heavier Diaphragm ring 

Adding  a spring makes it rich across the range,

Pete

[Peter Truman]

Thanks Pete I haven’t seen one of those thick/heavy diaphragm retaining rings before.

I’ll have do some searching re local carb suppliers firstly then UK.

I don’t think there’s any Vitesse 1600’s here in Aus, there’s only about 25 in total in Aus, NZ more as sold/assembled there.

there’s a Chris Witor tome on Storms that shows the retaining ring with part No. so that’s a start

Thanks

Peter T

 

[Pete Lewis]

i guess if you have the lighter weighted retaining ring then keep  the spring , but  reckon you dont want both 

as far as i remember its one ..........or the other   not both 

Pete

 

[mark powell]

I have a pair of Stromberg 150's on an SAH inlet manifold on my 1500 Spit engine.  I'm fairly certain they have the Vitesse 1600 needles.  The engine combo is in my Herald pick-up special. 

I can't give you any data, but it certainly pulls like a train with excellent acceleration. 

[Peter Truman]

Thanks for the info both of you. Pete I have 4 spare 150CD carbs all 3116 models (F & R, and FN, RN) 2 ex saloon 2000 model which have the light weight diaphragm retaining ring with dashpot springs of the other 2 rough spares both have the heavier retaining ring one with and one without the spring? so with Triumph as usual anything goes!

I checked the Burlin model specifics pages and for the later 1600 Vitesse it quotes 3027F & R model carbs, with the heavy weight diaphragm (damper) and no spring, as you quoted Pete the metering needle is a 7B & quotes a B16837, so that's  a starting point.

I'd be interested what is the difference between the 150CD models 3116 and 3027.

Regards

Peter T 

[Pete Lewis]

Pretty  much all stroms have common bodies with evolution changes of

CD thames barrier choke 

CDS  starting valve choke on frnt carb

CDSE  starting valve top dashpot adjustment can have temperature idle bypass

CDSEV  has more  emission  add ons 

Much can be mixed and matched , 

Will have a look,at the numbers later (on silly  tablet with early cuppa just now )

Pete

 

[Pete Lewis]

both are early 3027 is 1600  3116 is mk1 2000 

both have what i call thames barrier choke ( rotating ramp )   the variance is just needle spring and damper weights 

Pete

[Peter Truman]

I like the description of Thames Barrier Choke, my wife was Sec to the MD of the company in the NE that I believe made the gates" Head Wrightsons" & I worked for the opposition, where my father was an exec "Power Gas/Ashmores" interesting when we were both quoting on the same job! I think it's called  "Sleeping with the Enemy"!

I have good condition 3116F & R carbs with 0.9jets, two heavier diaphragm weights, I need the metering needles 7B/ B16837. I did find an Aus outfit selling all different Strom needles (from Ford falcons & Holden Torana;s & Kingswoods) on ebay, but am having difficulty locating them again, if not I'll chase Burlins.

Thanks for the help

Peter T 

[Pete Lewis]

Lets hope it works  ???

Pete

[Peter Truman]

It'll be a little time to I get to try the mod, but whilst cleaning and replacing parts on the 3116 carbs I decided to check the difference of the 7B (Vitesse 1600) & 6J (Mk1 2000 saloon)  metering needles, the 6J is slightly larger (see table attached) meaning the orifice annulus between the jet and needle is smaller with the 6J needles could this therefore be a better starting point for the smaller capacity Spit 1500 engine?

My query is simply the availability of the 6J needles I have 4 from my old store of 150CD carbs.

Comperison of Stromberg 6J & 7B Metering Needles.xlsx

[Pete Lewis]

well a trial  of 6j    will soon show if its near enough to make a good job  dont spend on whats a guess,

use what you have , work from there on.

got to be worth a go  unless you want........... utopia 

Pete

 

[Peter Truman]

I've been doing some more searching re the compatible Twin 150CD Stromberg Carb  Needles as an alternative to the usual HS4's fitted.

The attached graph shows the usual needles fitted to  the HS4's on a Spit 1500 ie ABT or ABN, with similar profiled needles for the Stroms.

In my mind it appears the 5P Stromberg  Needle looks the nearest, any comments? am I on the right track. I'll try the 6J's first as I have several!

The graph is adjusted for the difference in measured points between SU (16) and Stromberg's (13), that's why there are 30 steps on the X axis.

Interestingly the 7B needle fitted to the 150CD Vitesse 1600 appears richer than that fitted to the 2000 Saloon Mk1 needle 6J?

The jets on both the SU & Stromberg carbs were 0.0900in so compatible?

Its a cold, cloudy, damp winters day here in Melbourne with a max temp of only 14C so playing on the computer in a heated house was appropriate.

Regards

Peter T

[Pete Lewis]

wish we had 14c in winter 

there is minty lamb automotive that  give needle comparatives but only su.

Club has a needle lathe in the museum ,   wonder if they could hire it out 

Pete

[Peter Truman]

Seen Minty Lamb's site but I used the Telgez** site for the step point measurements. I have access to a small lathe (heart surgeon friend! who doesn't have time to play) but by the time I finished with it bet it would be hour glass shaped!

Think I'd do better with a drill and emery paper.

The 5P has an interesting profile up down, richer, weaker, richer? Will try the 6J first daughter already working on how to run engine out of car.

Had to get my daughter (aerospace engineer) to produce the graph, I initially did it old hand "Drew it".

Re weather all relative as anything < 10 bloody cold, sometimes 14 can be nice all depends on wind and sun, Sat 16C BUT windy! Cleaning the pool at 10C gives you chilblains. I have a cousin in Winnipeg Canada now that gets cold. I've lived twice in Canada and that's why were in Australia.

Peter T