The Stovebolt Site Forums The Shop Area Engine Shop Uni-Syn help

Alright, I finally got myself a Uni-Syn carb syncronizer (got a good deal from the Matco dealer), and I think I have a grasp on how to use it. However, if anyone has any good tips on how to use it to get the best results, I would greatly appreciate it.
TIA

The cone-shaped restrictor in the air horn section is screwed down until the floating indicator rises to about midrange of its travel on one carb, then it's transferred to the other one(s) and the idle speed and screw is adjusted for the same amount of air flow. The see-through tube with the floating ball in it needs to be straight up vertical for the best results. Adjusting the idle mixture screws should have little, if any effect on the air volume, but if it's necessary to make a big change in mixture, double-check the air flow.
Jerry

I synchronized the duals SU carbs in an Austin Healy Sprite with an original UniSyn, but didn't trust the results. Bad mistake. I took it to a Healy dealer and had them adjust them. It took about 300 miles for the two rear exhaust valves to burn up. Sodium filled valves $60 each in 1972 dollars.

Have a little faith in yourself when you use a Uni-Syn. It's really pretty easy to see what's going on.

Try here:

http://www.thecarburetorshop.com/Dual1barrelcarbs.htm

Jon.

Depending on the condition of the carb throats,a little vaseline,
don't glop it ,on the rubber seal can help. Then just wipe it clean.

Make sure you loosen the linkage between the carbs before you try to adjust the flow or you will adjust one and the other will be off again. Dont forget to tighten the linkage back when you are finished. Would want you to go off half carbed.

Thanks for tips, guys.

Has anyone ever used two Uni-Syn's, one on each carb, with any good results? Would that make the job easier?
Joe

Joe, The Uni-sync is adjustable so if you could set them the same, you wouldn't need them, just set the carbs the same!

The uni-sync has a movable stopper that plugs the inlet hole and creates a slight vacuum. The vacuum pulls the small indicator ball up a tube with a scale on it. The idea is to adjust the gauge so the ball is midway up the tube, then move to a second carb. With out adjusting the gauge, set the idle speed till the second carb is pulling the same amount of vacuum on the tube. Once both are set for the same vacuum, you know the throttle blades are open the same amount, now its a matter of jumping back and forth to set the idle speed. Each adjustment of the throttle blade will require a uni-sync check of all the carbs.

Joe

Joe I did use 3 unisyncs on a 54 corvette a few years ago. Had to borrow 2. But I was looking for some trickey acceloration problem that had me baffeled. I thought 2 carbs were pulling more than the other on acceloration. http://rides.webshots.com/photo/2326100990093759043wLJqQR
But as a normal adjustment process it is just over kill.

I'm not sure, but I think the unisyn needs to be the same one on both carbs! I think that the unisyn is measuring the carb its on, and placing it on the other carb enables you to duplicate it's airflow/vacuum. Using two would give you a benchmark for the other! What I'm saying is sticking to one removes a variable, and is the intended means of EQUALIZING the carb settings. I have yet to use it on my 261 dual carb, but used one on a motorcyle years ago, so I may be remembering wrong ( insert grain of salt here.)

You are correct blackjack. You set up the meter on one carb and then match it to the other. When i used 3 unsync units i took all three and set them up on #1 carb. then taped (duck tape) the units to the 3 carbs.

I wouldn't have thought of that, setting three using one carb! It would make it easyer to set all three at once. Joe

Joe I was checking for a differance in carb. opperation under acceloration not setting idle flow. The carbs were in sync. at idle. As it turned out they were all pulling the same on acceloration also. My problem was timing advance and fuel. We found that if you mix premium unlead and aviation (110 octain) fuel together it ran 200% better.

Yep, the problem with using more than one Uni-Syn is that each of the two or three you use would have to be set exactly the same to match the other two or or three. Therein lays the problem. I don't see anyway that you would know that each Uni-Syn you used matched the sttings of the others. I never thought of it in those terms. Duh!
Joe