Hello all,

I recently rebuilt my 3 screw SU carbs on my 240z with the Z therapy kit. It was a good experience.

At the same time I installed the MSA premium exhaust. I've noticed a very strong gas smell when driving the vehicle now. Is this normal with the SM needles? From my understanding they were overly rich during idle only?

My 240 is basically stock, with the 2.5" exhaust and 280zx distributor coming soon. The smell is so strong I'm thinking of switching back to stock needles because it is so bad. I forget who I spoke to on the phone at Z therapy, but I asked if they were ok for a basically stock engine and they said yes.

Secondly, when tuning them, one carb required 2.5 turns, and the other 3.5. Should I adjust the other float to make them exactly the same, or am I ok leaving it this way?

Colten

SM are too big for a stock L24. They were to big for my cammed L24. Put the stock ones back in.

Ok. I had heard mixed opinions about them for sure. I also noticed a slight leak from one of the fuel hoses from the float bowl to the nozzle. Ice tried adjusting the little clamp and see if that stops it. I'll put the other needles in, in a few days and see how that goes.

Any suggestion on the float height with the difference in turns required?

If anything, SMs reverse what the stock needles did. They lean things down at idle and richen things up up top where your engine will be happier. With all the happy owners out there liking what they get with SMs I have to believe you have other issues...

Which Vancouver are you in?? If it's WA, drive down and I'll bet lunch Steve will have you running in relatively short order. BC, not so much

I've got 'em on all five of mine......no problem what so ever.

Your nozzles OK? Worn ones make it richer, sometimes much richer. One could be worn more than the other. Had to replace mine. Ztherapy has rebuilt if necessary. They also have various under and over sized nozzles; I was wondering about those.

I'm happy with my SMs too. Floats should be .55" from the lids.

Stock L24 with small valve E88.

Edited April 7, 20159 yr by siteunseen

My judgement was made based on what I saw on my AFR gauge using SM needles. I still believe stock needles are more than adequate for stock L motors.

The nozzles are brand new which came with the Z therapy kit.

I believe I had an exhaust leak at the manifold, which is part of my issue. I installed the exhaust at the same time as the carb rebuild. I'm going to try and fix that first and go from there. It is definitely a strong gas smell.

Any recommendations on the float level? I set them both to the recommended level, but to get the best idle/performance I had to enrichen one more then the other. Obviously the float levels weren't exactly the same. It was tough as the needle valves supplied were the same length when both carbs came with a different length from factory requiring a different curve on the float tab.

Oh and Bruce, I'm in BC.

I was happy with SM needles in my SU's back in the day. Now i only wish i had SU's....

Mr Palmer will send you a set. I may get some new ones myself. 8)

Oh and Bruce, I'm in BC.

Colten. I've sent you a PM. I'd be happy to help you tune and set up your SU's. Contact info in PM. I'm local in Metro Vancouver. We probably know some of the same people in local Datsun clubs. Richard.

Edited April 10, 20159 yr by Chickenman