Ok so my SU round top carbs need to be rebuilt, has anyone rebuilt them before themselves? If so how hard was it, and how lond did it take? Or should I take it to a shop for them to rebuild them, and how much would it cost? Thx Ian

I recommend the kit from ZTherapy. I did mine (with a cheaper kit, basically replaced the seals only). Before I did them I had zero experience. They are working well at the moment and I think that as long as you are organized you should be ok. Just do them one at a time. That way you don't mix up the parts and you can use the other as a go-by. I also recommend the video from ZTherapy. You can do it without it, but it really helps, especially if you are new to SUs.

Good luck.

At the very least get the video-you will learn all about the cars and feeding of a pair of SUs.

Will

Well... there is "rebuild" and then there is "rebuilt"...

As suggested, if you simply need to take them apart, clean and adjust them.. then replace the seals and fuel line between the carb and float bowl... ie "rebuild" them... then yes.. get the video and the kit...

On the other hand - if the throttle shafts are worn, and leaking - as well as being sloppy, . . . thus all but impossible to tune them out... You may have to buy a REBUILT set from Z-Therapy. In that case you also get re-plated Cad parts along with the new throttle shaft bushings etc...

There is a primary reason that Z Therapy exists.. and that is because by now most sets of the Z SU's need new throttle shafts and bushings..

Nonetheless, get their video... and start there...

FWIW,

Carl B.

I'll 3rd (or is it 4th) the recommendation for Z Therapy. I just got my roundtops for the '73 rebuilt by Z Therapy (actually you send yours in and they send you a replacement set) and they are terrific! Highly recommended, and well worth the $$$. Cost is around $600 if I recall correctly.

I have a set of Ztherapy SU's with about 1500 miles on them, they look great and run great. I switched to tripples with my new motor and no longer run them, I am interested in selling them. If you are interested PM me.

Ian, You can add my name to the Ztherapy band wagon. They did my S.U.s and even jetted/needled them for my altitude(5000 ft.). They made a MAJOR difference in the way the car performs. they were definitely worth the $$$. FWIW you can't know how many miles have been put on the carbs...my car only had 69,000 miles on it, but because it is a 73 the old flat tops had been replaced w/ 71s and I had no idea how worn out they were. I know that $600 sounds like a lot, but believe me it is a bargain. Cheers, Mike

The part that you can't do yourself is replacing the throttle shaft bushings. And that is exactly where they wear out. All the kits and fine-tuning in the world won't help a pair of SUs that are leaking air in at the throttle shafts. You can't really tune that out.

If $600 is more than you can afford, or you simply don't need the beautiful concours-type job that ZTherapy does, consider just having them do the carb bodies instead. That runs $225 exchange and takes care of the throttle shafts - the rest is then up to you.

Thanks guys, I just bought custom forged pistons with valves reliefs, pop ups, and there 40 over, and they raised the compression to 10.5:1 on the N42