Which synchronizer is best?

I could teach you to do it in 20 minutes!

Especially if you have perfect pitch. My ear isn’t so well attuned so I use a Uni-Syn. It works well for me. I can’t remember the last time I had to re-tune the SUs.

Paul - I don’t think so.
In addition to being tone deaf, I have tinnitus in both ears AND I was rejected out-of-hand when I tried out for monotone in the school chorus

Yer on… you forget, I have severe tinnitus, and nope! No perfect pitch.

“I could teach you to do it in 20 minutes!”
Paul - Is that an open invitation?
I have tried using a hose, and can hear some
differences, just can’t get them to all sound the same.

Sure! Now we just have to figure out how to do the meet-up… :slight_smile:

Whenever I try to use the Uni-syn - when I set it to get the bubble to rise above the bottom 1/4 of the gauge, the flow chokes the car and it stumbles and dies. I haven’t been able to figure this out.

If the other flow meters are just plug over the throttle body and measure, then I’d like to try one of those.


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Unisyn is itself tunable…screwing the cone in and out will adjust how far the bubble will rise in response to airflow. It sounds like yours needs attention.

I probably need to study a YouTube video to figure out how to properly use the Uni-syn. As I recall, that’s what I was doing. When I turned the adjuster to get the bubble to rise, the engine stumbled. I could never get it to rise more than 1/4 above the bottom, often less.

Maybe mine is defective, too.


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This link to the printed instructions might be helpful.

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My problem was with step 4 of the instructions. I can’t see that there is much scope for using the device incorrectly, and it looks rather simple so I can’t tell if it has a defect. The neoprene-like gasket\seal seems fine. I got the Uni-syn from my brother who had it for tuning Datsun 240Z Hitachi carbs.

If I recall correctly, closing the screw and narrowing the airflow gap is what makes the ball rise in the gauge, I guess from strengthening the venturi effect by increasing flow velocity? That’s when the engine stumbles and stalls for me.

It’s mostly likely user error on my part though so time to study how capable people use the device (or get a more fool proof type, proof against this user at least…)


Try setting up a carb without the Unisyn. Use a hose, use the lean roll method, use your mechanics sense, whatever. Then adjust the cone so that the bubble is around the middle of the tube. Then never touch the cone again.

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I have exactly the same problem with a new Unisyn. For the moment it runs well enough to sit in the shop and work on upholstery! But someday I will have to do better. @Wiggles can we stretch a hose from Colorado to Florida?

Rick OBrien
65 FHC in FL


Meh… buy me a cheapo ticket down’n back, lend me a sofa, stock up on Coke Zero, and we’ll make it a party!