Non-Smog Needles?

[eastmedia]

After reading all of the various material about de-smogging, I can't find any info about non-smog SU needles.

I pulled my needles out and they are M70. I have another set of carbs with M39's (one needle bent).

So which ones are the non-smog? And where can you get new needles?

Thanks All.

Ron

[S Allen]

Ron,

I am not sure which needle set is the smog type. Many people including myself have used ADQ(British Needles) for a non-smogged 1600. Joe Curto is an SU guru on the east coast. I know he could get you a set of ADQ's. He has a website http://www.joecurto.com or you can call him at 718-762-7878. I am sure Dean could sell you a set of M non-smog needles. If you find out which one is which let me know.

Steve

[itsa68]

Ron:
M39 and M43 are the non-smog type used with the 38W-3 carbs.
The M70 needles are the smog type that were used in the 38W-6 carbs (also used for the L16 engine in the 510SSS).

After trying both the M39 and M43 on my 1600, I stuck with the M39's because they were much more responsive throughout the power band and they did not seem as thirsty as the M43's.
M43's were also used in W38-4 su carbs for the 411 SSS, most of which had automatic transmissions, so that might explain their thirstyness.

This link has some info on needle station measurements.
http://www.jetlink.net/~okayfine/SU/suneedles.html
This link has the usual carb set-up tips.
http://teglerizer.com/sucarbs/techtip6.htm#TROU

Hope this helps
Ray B.

[eastmedia]

Thanks Ray,

A couple of questions: How do I tell if I have the 38W-3 or -6 carbs? Can I put the M39 needles in the 38W-6 carbs safely?

What's the difference between the -3 and -6 carbs? If I have the 38W-6 carbs does that mean they were from a different engine than the R16 or were those also used on the 69 1600s?

I think I have the carbs correctly adjusted, as my performance is usually pretty good. What kind of benefit will I get with the non-smog versus the smog needles?

Ron

[SLOroadster]

The engine will run differently due to being a little more rich at low rpm. It might bog a little off idle, it might not. It might have more in the upperend, it depends on your engine. They seem to be very sensitive to individual engine setups. Try them and see what happens.

Will

[itsa68]

Ron:
The float bowls have the carb number electo-etched on the side of the float bowl.
I believe the main difference was the smog type -6 types came with a vacuum fitting that hooked up to the smog vent on the manifold.

The M70 needle was orginally designed for the 1970 smog model year as indicated by its part#. The M70 needle part# is 16354-A7710 where A77= spl311U 1970 model with emmision control. However, this part could be used widely over other car models (such as the 510sss) after its original design intent.
The -6 carbs were used on both the roadster R16 1600cc engines and the L16 1600 engines.

The pairs of M38m M43 and M70 needles can all be put in. You have to have to re-center the jet nozzles to the new needles and totally re-adjust your fuel mixture again.

In terms of benifits, as Will mentioned in the previous reply above, it all depends on your particular set-up and what you are trying to achieve.

In my case, I was not getting the throttle responce at the low end and the tailpipe and plugs were always carboned up and my gas mileage sucked. After making sure I didnt have leaking fuel from the float needle valves and everything else was tuned up, I tried all the needles sets to find out which worked best for my set-up. I am now quite happy with the throttle responce and the carbon up problem has gone away.

If you're happy with the performance your getting now, I recommend leaving things as they are, otherwise you might spend more time dicking around with the carbs than out driving around and enjoying your roadster.

Hope I did not make things more confusing for you.
Ray B.