I have two synchrometers (snail type) that each give a slightly different reading when compared to each other (a difference of a value about 1-1.5 units when measuring the same carburetor). I like to use a synch in each carb at the same time when balancing, but I have to allow for the difference of the synchs. Does anyone know how to calibrate one of these snails so they will respond the same?

Ansbacher

Since they're "analog" and not made to exacting standards, it's probably not practical/possible to synch them. Ironically .

If you're so inclined, you'd could probably open one up and either add or remove weight on the piece at the opposite end of the indicator until they're close. But I think you'll be more accurate using a single snail across all barrels to keep the measurement error consistent.

If you could put both of them in a clear acrylic tube in series, you could pull air through them simultaneously with a shop vac?
Note the difference and adjst...

But to adjust the snail type, you would have to add/remove tension from the internal spring

My solution when I had 2 snails. Sold 1 on craigslist for $20 and used the other to sync my carbs since I was only interested in balanced flow and not the actual numbers.

This falls under the heading, "A man with two watches never knows what time it is."

The snail has a flap with holes in it and a spring. I suppose you could drill more holes in the one reading high. You'd then have to verify that they both read the same at different flow rates. I like the unisyn for it's adjustment and simplicity.

The flow device is placed on each throat only momentarily.
When it is in place and indicating flow it actually impedes flow slightly.
The original proposal would only work if you had four (or 6!) flow matched units

Thanks all for your knowledge and suggestions. I wonder if I were to block off a few of the inlet vents on the body of the snail that is reading high, it might lower the reading. I might try an experiment...If it works it would be less invasive than opening it up to monkey with the mechanism.

Ansbacher

My old Motometer one impeded flow and caused issues when dialing in my 6 carbs,bought the tried and true SK meter,very little drop in rpm when using it.
Click to view attachment
I choose to use between 15 and 1800 rpm and got the same results,its not about the reading you use its about how stable and even you can get them.
My tacho is all over the place and will be changed out ,for the moment a will use my non-contact handheld to do a retime,hardly touched the car been doing a clutch in my sons GTI....now that's another story

Another problem that the proper amount of duct tape will fix. Add tape to the one reading higher till they match.

Sometimes calibration is as simple as shifting the scale.

Using one carb. Same Venturi. Determine the highest reading of the 2 devices. Turn the black base so the hole in it starts to meet the the one in the body. Adjust to achieve the same numeric value as the lower reading one. Switch back and forth a few times. Now confirm on a dif Venturi.

Rhodyguy:

I see there are two holes, a little smaller than a dime on each side of the neck of the snail body, but I don't see any hole in the rubber base that fits down in the carb. I have spun it more than 360 degrees and there is no hole to line up. Both snails have no hole in the rubber base. One is a gray colored "STE" made in Germany and the other is black colored no brand. WTF??

Ansbacher