SU needles

[deliver]

I have a stock 66 1600 with SU carbs. I am having problems getting the fuel mixture set. At idle I am rich and of course at speed I am lean. I removed the needles to find a ADQ written on the needle. I am lost as to what the car should have in it. I was wondering what needles you guys are running in your 1600s and where I could find new needles? I have not heard of a ADQ needle. Thanks.

[twinight]

That's a british needle that Keith Williams uses on his rebuilt 1600 carbs.
You can compare it to others here:
http://www.teglerizer.com/suneedledb/09 ... tjava2.htm

[spl310]

Keith Williams does a sort of "lend/lease" program with the needles. He basically sends you an assortment of needles and you try them out. When you find a set you like, you mail the rest back with a check for the set you keep. Drop him a line to see if he still does that...

[Linda]

I'm sure Keith will show up to add info, but basically the ADQ needles were determined to be an excellent fit for the Roadster to give it a reasonable idle but enough power at speed. They need to be set at the right height for whether you have smog or no smog, and they of course need to be centered so they don't hang up.
I have them in my car and could notice an improvement . Keith can explain it much better since he did the research.

Linda

[keith0alan]

Hello all,
The ADQ is better than the Nissan needles for the rich at idle and lean at the top end problem. Here are some things to check. Needle and nozzle wear, are there shiny spots on the needle, particularly near the base? The needles come with a satin finish, shiny is wear. Check for nozzle wear. The holes should be .092" in diameter. I've a pin gauge that I loan to measure them. The ADQ needs to be set out from the face of the slide rather than flush like normal. I normally suggest .012" but you can go to .020" or even .030" to lean out the idle. Moving the needle out has a lot of effect at idle and hardly any at high speed. Here is a trick from way down in the bag and not for the casual tweaker. Get the mixture set at high speed then start moving the needles out a few thousanths at a time till the idle comes into line. Check the float level also. Let us know what you find and post again.

keith

[deliver]

Good info. I have synchrinized the cards at idle, 2500 and 4000 rpm. Timeing set at 16 with Boone dist. I am 20 thousandth down on the mixture screw. I have several hundred mile runs I can make in the car. Will try moving the needle out 20 thousandth. Did not notice any shiney spots on the needles when looked at them. Metering nozzle appears to be round. Will report back with results. Oh yes floats checked and fuel pump pressure.

[keith0alan]

To adjust the mixture set the engine speed to 2000 or a little more and adjust the mixture knobs for maximum RPM. That will get you real close, then start checking plugs. Also, with it running at 2k lift each of the slides just a little, this leans that carb. If it speeds up then that carb is rich. With a little practice you can push the slide down. This richens the carb. If it speeds up it's too lean. You want it where raising or lowering slows the engine down. Once you've done this at 2000 RPM try it at idle. If raising the slides a little speeds the engine up then set the needles out just a tad more to lean it a bit. For those uf us saddled with the smog test you can dial in your high speed and idle mixtures this way. You can actually get it to pass and still be drivable but it really likes being just a bit richer.

keith

[deliver]

Thanks for that info. I am planning to run to the mountains Sunday, 150 miles or so. I will have time to play with it as I go. Set the needle .018 from being flush. Metering nozzles set at 0.87, read that somewhere, but hear goes. David

[GeoffM]

OK, I am performing thread necromancy and reviving this one from '06. It has some great advice from Keith so instead of starting a new one...

I recently changed out my needles to the ADQ and wanted to lend my thoughts.
I have had M-43's installed since I purchased the car (don't even see them on the chart above). I don't know where they came from, but they are much shorter and wider at the first station. These got me through the local emmissions testing so that I could get my collector licence plates and the cheap insurance. I only needed to pass once and now I am free to tune it to how I want.
I installed the ADQ's but I wish I would have read this thread before I buttoned everything up, as I set the needles flush, which has resulted in a rich idle. An easy fix.
I am suprised that the ADQ's make such a difference in mid/high end power. It may be the plasebo effect but I find that accelleration is much more responsive. WOT accelleration is progressive right up to 5500, without the lean (over the hump) feeling I was getting after 5000 previously.

A note: The ADQ's come with a top-hat arrangement that the british cars use in their SU's that must be punched out. I used a punch with the top hat collar supported in a loose vice. Put a rag or something under the vise to catch the needle. I also found that the ADQ has a knurled top, which makes it difficult to fit into the piston bore. I ended up delicately filing a chamfer to help the needle lead-in.

On the down side, I noticed that I set the back carb nozzle to ~.090 and had to set the front carb to .010 to get optimum mixture at 2500rpm. I guess I must have a worn throttle bushing on my front carb. Oh well, another winter project.

[keith0alan]

Thanks for the feedback.

Your nozzles may also be worn or your float level incorrect. All of the Nissan needles I tested ran rich at idle and lean through the middle and top. The ADQ fixes this. The acceleration at cruise is much crisper. When I purchase the ADQ needles I remove the cap and turn the knurling down in the lathe so they are ready to install.

keith williams

[Linda]

I like the idea of thread revivals...
I wondered about the nozzle setting with ADQ needles. The conventional advice is .087 as a starting point for regular stock needles but they are shorter too. With the ADQ needles would .090 be a better starting point?
I suppose it would depend on how far out the needle itself was set.
Having tried other methods of carb adjustment I like the measurement approach best. At least for me using the digital caliphers.
With .087 and ADQ needles the carbs on my car seem to be synced well but still a bit rich.
The nozzles should not be worn as they do not have that many miles on them.
I will have to try some of the suggestions here.

Linda

[keith0alan]

If the ADQs are still a bit rich at idle you can set them a bit farther out. Move them a couple thousanths at a time. This way you can dial the idle in so the mixture remains correct from idle to top end.

keith williams

[GeoffM]

I set them out .020" from the bottom of the piston (not the needle bushing) and it helped a bit with the rich idle. But yeah Keith, I could probably set them out further and see what happens.

I also bumped the timing another 5 degrees. I can't get it to ping even under heavy load...but it ran too hot. I guess I need to set timing back to 16 degrees and maybe try running 89 octaine and see if it pings.

Hey Linda, I don't know if the initial set-up matters too much going from .087 to .090 because you are going to tweek the adjustment once its running anyway.

[23yrRebuild]

The ADQ's from Keith work great in a stroker.

[ppeters914]

Keith Williams does a sort of "lend/lease" program with the needles. He basically sends you an assortment of needles and you try them out. When you find a set you like, you mail the rest back with a check for the set you keep. Drop him a line to see if he still does that...

So, Keith, is this still the process, or does one just go with the M43's in a stock R16?