"Rare" carbs ?/ Rebuilding

[Zs-ondabrain]

Get the vido and the rebuild parts from Bruce. I bought the DVD 2 weeks ago and have watched it 2 times. I've learned a lot and put video to practice.

Here's the Carbs I'm working on this week.

Before and after. From Yuck to Yeah!!! Thanks bruce, did you get my email?

The pistons were stuck in the domes, the float bowls were full of white corrosion, Nothing moved before I got to it.

Dave

[ChrisZ]

Bling-bling

What did you use to clean them with, Dave

Chris

[tibZ]

Nice job Dave. At least I can move my pistons up and down. I like the finished product though. My main concern with taking everything apart and detailing it all is with re-assembly of all the linkages, can I assume that is covered in the video?

The wierd part of this is I have never driven this car, and I probably wont for another 2 years

Edited February 18, 2009 by tibZ

[Bruce Palmer]

The secret is to take one carb apart and do it while leaving the other together as a cheater.....

If it were me doing it, I'd drain the fuel system and get it all cleaned out and dry before letting it sit for two more years and go through the carbs just before reloading with fresh fuel and lighting it off. Time and static fuel systems aren't each other's friends. How long has the car been down now?

What else do you have going on with the car during this interim 2 year period?

[Zs-ondabrain]

As you can tell from the pictures, the domes were in pretty bad shape. Just pay attension to the STEEL items like the steel shaft in the piston. The picture below is of the piston that came out of that one. It was pitted too badly to reuse, so it will now be used an an alignment tool for the 4-screw carbs I have.

To bring the luster back, I found a long bolt (4.25" long) and 2 washers that were only slightly bigger in diameter, than the openings on the dome. (top one at 3/4" OD and the inner bottom one at 1/2" OD) both with a 5/16" bolt hole. Then give them both a 45 degree angle on the outer lip. This will seat them and center the bolt.

I put a nut on there and snugged it down. I use a small benchtop drill press. Once it's in and can spin without distortion, or wobbling, I use the red Scotchbrite on a medium speed. DON'T HIT YOUR FINGERS on the spinning bolt flange near the bottom of the dome.

I knock all the crap off with the scotchbrite pad and if it needs more surfacing, to remove fine cracks and such, I use 400 grit wetsanding paper, as it's a better quality than typical sandpaper. After the 400 grit, use the scotchbrite to clean a little more than I use Mothers Aluminum Wheel Polish on a soft cotton towel.

For the upper vent tube area, I use a buffing pad to get the hard to reach areas and also down by the feet, where the drill press method does not work. Takes a little time and effort but as you can see, it's well worth it. I top it off with Miguires Cleaner wax to keep it shiney.

The same process is similar for the piston but Do Not use anything stronger than the scotchbrite. If you take away too much surface from the rings on the upper part, the piston will not work correctly and be worthless. You can also use the scotchbrite on the inside of the dome. I obviously had to do that on mine. Clean everything with brakeclean and you can wipe the inside out with ATF fluid on a clean soft cloth.

Cleanliness is a good thing on the SU's. The Video covers almost every part of the SU and yes, the choke linkage has a few minutes of fame on the video. And Bruce hit it on the nose. DO ONE AT A TIME and use the other as a cheat. I personally know every part and where it goes but I still only do one carb at a time, until it's time to match the pistons and domes (fall rate) described on the DVD.

I'm sorry it took so long for me to get ahold of Bruce at ZTherapy.

Dave.

[tibZ]

Bruce, from what I was told by the PO, the car has been in his garage since 1984. He had it out in 2005 and put about 3K in various parts, floors, struts and tuneup. He never registered it and put it back in his garage until last August when I bought it. I started the restoration last fall and brought the motor into my basement to work on it all winter. This spring I will start the body work and stripping of the rest of the car, ie brake lines, fuel lines gas tank and front and rear suspension. If all goes well by spring of 2010 maybe I can start to put it all back together. Is there a problem with doing the carbs now and leave them dry?

Mike

[onuthin]

There may be a typo on the ZT site. The rare (or perhaps 'uncommon' would be better) carbs are early 4-screws w/o float bowl drains. Used on '70s only, probably the first 6-7000 cars.

I am fixing to rebuild a set of su's and have read all the threads.I still don't know which set would be the best to redo the 3 screw or the 4 screw?The PO did some mods to the engine and I am not sure what but it has a lot more power than any other Z I have had.The only visible mods are headers,electric cooling fan,oil cooler,and an R200LSD.I have a box of SU's both 3 and 4 screw so I will redo them before I take the ones off there now.I have the video so hopefully I want have to much problem.I would just like to know which set is best? Ronnie

[Arne]

There is no significant difference between 3-screw and 4-screw performance-wise, assuming you have the same needles and nozzles in both. The 3-screws have the ability to channel coolant through the base of the carb if you use manifolds from a '72-74, but other than that there's no preference, from what I've seen.

[Bruce Palmer]

Is there a problem with doing the carbs now and leave them dry?

Mike

There is no problem doing them now.