Starting Carb Conversion: Flat Tops to Paltechs

[Captain Obvious]

That old flat-top part should get you out of the woods for now. It really wants a bearing support closer to the end, but I think it should be OK for now.

So here's what I have. Question is... Will the pivoting mechanism mount to your firewall? Are the mounting holes in the same location(s)?

 

[Dadsun]

Wow,.that's nice. And yes, I'm wondering about the support on the carb side with that longer arm. Here is a picture of the underside. Looks like the middle hole is flipped, but the two outer holes line up. 

[Captain Obvious]

If I get a chance, I'll take another pic today with a tape measure up against the bolt holes so you can see if it's the same as what you currently have.

[Dadsun]

Center to center distance on those two mount holes is 1 9/16". 

[Captain Obvious]

It looks like the newer design will bolt up. I'm kinda surprised.

Here's a pic of the dimensions on what I have:

Send me a PM and we'll see if we can reach an agreeable agreement.   

[Dadsun]

Well, the carbs are on, no leaks, and it starts every time. Progress!

Now I need to tune them. I have a Uni-Syn tool that came with the car. I'm getting no air draw on the front carb, just the back. Is that normal?

I have a service manual and saw some old threads here on tuning/balancing, but if y'all have a go-to reference please pass along. 

[siteunseen]

Edit: That looks damn good!

That front one has a nipple on the backside for distributor vacuum advance. Is it open?

Here's what I used to begin a basic tune. Thank you! @240260280

 

 

Edited January 13, 2021 by siteunseen

[Dadsun]

I have a line from that nipple to the distributor, so I think that's the correct setup. See pic.

[Dadsun]

Ok, I'm looking at the Quick and Dirty SU Tuning thread. For balancing it says: "2. Warm up car and remove all linkage connections so that the carb's throttle plates are resting on their set screws.
3. Adjust each set screw so that the suction felt when you put your knuckles against the throat of each carb and feel the air flowing between your fingers is the same on both carbs."

... Is the set screw the same as the throttle adjusting screw on each carb?

Also, my setup came with no screw in this place (next to zip tie in pic) that looks to be opposite the balance screw. The guy who refurbished them said no screw necessary there.

 

[siteunseen]

I think that missing screw is what adjust the throttle plates. As in your 2nd sentence, #13 on the diagram.

I always unhook that top plastic marble to release the linkage during adjusting. Closest to #8.

Here's the spring loaded screw you need. Probably easiest to get one at motorcycle shop. They're on bike carbs.

[Dadsun]

So, if I understand that correctly, the missing screw is needed for the air intake balancing work? Argh. 

[siteunseen]

It's been awhile but the airflow sync I use to balance air flow I turned #10 screws on my '72 SUs.

That spring loaded screw you're missing keeps the linkage tight and snug for butterfly respose. It's not really used to balance them but keeps them responsive to your foot on the pedal. 

I would watch a few YouTube videos. There's some pretty good ones now. Good luck.

Edited January 19, 2021 by siteunseen