Stromberg metering needles

[gary1725]

Hi Folks,
I was told that at one time there were multiple different metering needles that could be used in the CD150's - searching the net has not shown anything that details these options or better yet a source!

I continue to have issues getting my car to run well - the engine was completely rebuilt and opened up and stroked to about 1805cc and I have good even compression across all cylinders and seem to have good spark and fuel delivery - it runs better at low revs but seems to lose breath and becomes hesitant at higher revs - I have the mixture enriched to the point that one more 1/2 turn and the adjusting screw is ready to fall out and leaks!

I have tried checking for air leaks with carb cleaner sprayed into all the joints and spindles and used a vacuum gauge looking for odd behavior and everything seems ok - The spark plugs look as though the mixture is on the week side which is why I keep coming back to mixture.

I thought a richer needle might give me more options to play about!

Thanks

Gary

 

[Ken Ellis]

I recall seeing a chart with chapter and verse on this, including variable tapers, etc. It was either online or in my carb book -- I'll try to find it this afternoon.

 

[gary1725]

Thanks Ken.

 

[Ken Ellis]

Ok, here's some light reading for you...

Google-up the following search string in Google Images (not just regular search): stromberg needle chart

So much stuff that this is the best way to present it. There's a lot of straight SU stuff mixed in there, but good to look at for theory, etc.

The larger lists I remembered are in the back of the Haynes "Stromberg CD Carburettors" book: ISBN 0 35696 300 3
(The updated ISBN number is 9780856962998, although searches on that number often return SU carb results.)

Three appendixes, covering Applications, Metering needles, and Metering needles cross-reference.

I would be happy to look up a thing or two for you, but I can't really scan out the whole thing and post it as the book is still available for purchase. I think I've seen it pop up at the usual suppliers. If you're stickin' with Strombergs, you should get one.

Used prices range from $30 to $120 (yikes) on Abe's books.
Actually, looks like no longer in print, but many used available on Amazon, etc.

I would think your prospective source for needles would have some performance enhancement information. Are you scrounging from other vehicles, or ordering fresh?

A quick scan of the appendix shows no Rootes vehicles with engines larger than 1725. They may exist, but they're not noted in the chart as such. Can you get hold of some 175 CDs? They show up on a 1850cc Saab.

You may have this sorted already, but these things don't always have a linear taper. They may have transitions of steeper taper, followed by shallower slope. The spec shows measurements every 1/4" or 1/8" down the needle.

To the performance problem, be sure to check any PCV valves, hoses, explosion dampers, etc. in the path to the intake manifold... and the manifold-to-block seal. Also look at fuel filters, and check for any flakes of crud at the rear gas connector pipe where the fuel line attaches. Debris there can limit fuel flow with similar results. It gets worse if not addressed. Hopefully that's not the cause, because the cure just sucks.


Let me know if there are specific bits of info I can share with you.

 

[beamdream]

Perhaps try a listing for Triumph 2000, not so far off your 1850.
The 2 litre Triumph 6 was fitted with CD150`s.

 

[RootesRooter]

What's the history of your Strombergs? Ever had a complete rebuild, including throttle shafts and bushings? Older Strombergs with worn bushings tend to run rich, probably rich enough for an 1850cc.
How about the ignition system? Are you getting full advance? Is the coil at 100%?

 

[Ken Ellis]

My mention of the Saab may have confused things. His displacement is 1805cc.

The 60s Triumph 2000 with 2x150s use either:
6J ('66-'69) Part# B.17316
7A ('64-'66) Part# 020691
Spring color is natural for each

+1 on RootesRooter and the choir. There are many, many things to be verified before one should dive into needlework.

On the distributor advance front, there's a plate inside under the cap with an oil hole that needs periodic attention too.

 

[George Coleman]

Here is a good parts source.

http://sucarb.co.uk/?utm_source=Bur...ail&utm_term=0_44190cdc60-63f2085778-78333145

 

[Hodee]

Just a thought other than the carbs... investigate the proper operation of your dizzy. Might find a fault there that could be the cause.

 

[Hodee]

oops, just saw post #7.

 

[gary1725]

Wow lots of replies..

The carbs were rebuilt by me with new shafts, butterfly's seals, float needles, metering needles and jets and diaphragms etc before the car went off the road for restoration and everything was running great - I started the car with the carbs as they were just to get it running quickly and then removed, cleaned and replaced all the rubber parts because they had sat for 5 years during the rebuild - again at idle and without any real load the car revs ok.

The distributer is a pentronix and its associated flame thrower coil that has only done 10K at most and again they were running great before the car went off the road, I did replace the cap and rotor when I rebuilt the engine - when I rev the engine the advance takes place - I am simply basing this with vacuum disconnected and reconnected with a timing light watching the timing marks - am I getting "all" the advance - no idea I can look at that this weekend as the timing light has the advance adjustment on the back..

I think I covered everything..

thanks again
Gary

 

[Ragg Mopp]

I had problems with my carbs running lean after rebuilding them and replacing jets and needles. I struggled for several years until I acquired a used set of carbs and switched needles. Suddenly the problem went away. The needles that ran lean had no markings but the used ones were marked 5M. If you have unmarked needles, there is no way to know what they actually are. I eventually bought new matched needles and jets from Apple hydraulics and the engine ran even better.
http://www.applehydraulics.com/carbs.htm

 

[Ken Ellis]

If you're industrious, you actually can tell basically what you have, even if they're not marked. The book I've been referring to has a section which gives the measurements to be expected every 1/8" down the needle, from the shoulder.

Later on, I will look up what should be in it, number-wise, and post an image of what those measurements are. Get out your digital caliper, hot up the coffee, and stay tuned...

Actually, skip the coffee because you wouldn't want to scratch the needles with the calipers.

And while you're waiting on me, look over the procedure for centralizing the needle (which you might want to verify before the whole measurement thing) and how to pull the spring so you can check the color (if any) painted on it.

Also the flow, with a manometer or two, and the linkage for synchronicity throughout the throttle range. And the resting gap of the butterfly. And... well, check my sig for which carb I use now.

 

[hartmandm]

Another ISBN

...

The larger lists I remembered are in the back of the Haynes "Stromberg CD Carburettors" book: ISBN 0 35696 300 3
(The updated ISBN number is 9780856962998, although searches on that number often return SU carb results.)

Three appendixes, covering Applications, Metering needles, and Metering needles cross-reference.

FYI - I picked up the book Ken recommended, but a different revision it appears. It has a 1986 copyright. Printed in England. It has the 3 appendices Ken mentioned. Two ISBNs are listed.
ISBN 1 85010 060 8
ISBN 1 85010 019 5 (US)

I expect to have a bunch of fun with this book!

Mike

 

[gary1725]

Thanks Ragg Mopp,

Apple Hydraulics provided a pair of 6J needles that I fitted yesterday morning - leveled the jets and backed of 2 1/4 turns and she fired right up - the difference is unbelievable! Hesitancy has gone and throttle response is simply night and day! I have only driven it a short distance as it started snowing so I quit for the day...

I will tootle about as best I can over the next week or so how it runs...

thanks to all!

Gary

 

[hartmandm]

Thanks Ragg Mopp,

Apple Hydraulics provided a pair of 6J needles that I fitted yesterday morning - leveled the jets and backed of 2 1/4 turns and she fired right up - the difference is unbelievable! Hesitancy has gone and throttle response is simply night and day! I have only driven it a short distance as it started snowing so I quit for the day...

I will tootle about as best I can over the next week or so how it runs...

thanks to all!

Gary

Great news Gary. I think I have a similar issue with my carbs. Anxious to hear more feedback after you have run for a bit longer.

Mike

 

[hartmandm]

I followed suit and bought 6J metering needles from Apple Hydraulics. During installation of the metering needles, I discovered my Strombergs had blue colored air valve return springs! They must have been installed during the carb rebuilds. I replaced the blue springs with natural colored springs.

Set the jet adjustment screws to 2-1/4 turns out. Fired it up. OMG! The difference is night and day. I can remove the choke after a short bit and it will idle smoothly when cold. Stumbling and stuttering is gone when cold. Much more power. I'll run it a bit and check the spark plug condition and fine tune the mixture.

Thanks all so much for suggesting to swap the metering needles!!

Mike

 

[gary1725]

Hi Mike,

I honestly can not take the credit! someone else suggested that I look at alternate needles and it was suggested here that I try the 6J's! I was amazed with the way they transformed my car and am delighted that they are working well for you too!

take care

Gary