Synchrometers

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David Jones
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Synchrometers

#1 Post by David Jones » Mon Jun 27, 2022 4:22 pm

I just repaired my original STE synchrometer and compared it to my newer (EMPI) version. Results pictured. Closer than I expected. Knowing the difference will allow me to use both at the same time and get as close as I need I am sure. The results on Solex 40 PII carbs will maybe show a smaller difference with a lower draught.
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Wes Bender
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Re: Synchrometers

#2 Post by Wes Bender » Mon Jun 27, 2022 7:19 pm

David, a bit of fiddling and you might get them closer. At least it would be an interesting exercise.
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Re: Synchrometers

#3 Post by David Jones » Mon Jun 27, 2022 7:55 pm

I used a 0.22 air rifle lead slug as my replacement weight but had to estimate the final balance point. I ran short on patience as I was carving tiny slivers off then placing the slug on the anvil of the balance arm until it read zero but my final estimate was a tad off. It would have been easier perhaps to leave it a little light and add more weight. It will be difficult to remove material in position.
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Martin Benade
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Re: Synchrometers

#4 Post by Martin Benade » Mon Jun 27, 2022 9:35 pm

Wouldn’t slicing a piece of solder have been easier?
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David Jones
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Re: Synchrometers

#5 Post by David Jones » Mon Jun 27, 2022 9:46 pm

Not really, I started down that road and quit quickly.
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Harlan Halsey
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Re: Synchrometers

#6 Post by Harlan Halsey » Tue Jun 28, 2022 5:20 am

My understanding is that a screen to catch the parts that fall out of a Synchrometer is desirable. I've used a Unisyn for decades. Accurate enough, and nothing to fall into the engine.

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Re: Synchrometers

#7 Post by David Jones » Tue Jun 28, 2022 7:43 am

If any of the small plastic parts should fall out of the synchrometer I really doubt they would cause much damage and after examining both mine very closely I do not believe that there is not much likelihood of any such thing happening.
It is also way more convenient and easier to use than the uni-syn of which I have two and now gather dust.
Last edited by David Jones on Tue Jun 28, 2022 9:53 am, edited 1 time in total.
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Al Zim
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Re: Synchrometers

#8 Post by Al Zim » Tue Jun 28, 2022 9:49 am

The numbers on your synchro meter are arbitrary. Your only concern is that the air flow through the fuel delivery device is the same on both sides. They should have used letters on the dial that way this discussion would never have transpired.
September 1, 2022 would be the start of the model year if the 356 were still being produced. But they are not and the cars are all now over 58 years old because production stopped at the end of April 1965.
I can assure you that like life everything wears out! YOU KNEW THAT. Experience at ZIMZ has indicated that a plethora of other situations exist in your engine (vehicle) that may cause it to falter. THING BEFORE YOU START AND KEEP A SHOP MANUAL NEARBY, zim
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Re: Synchrometers

#9 Post by David Jones » Tue Jun 28, 2022 10:00 am

What THING before I start Al? There are many THINGS I consider before I even get dressed let alone pick up a wrench. You are of course correct about the numbers being arbitrary unless all synchrometers are calibrated to read the same which is obviously not the case. Just like speedometers, unlikely any two random 60 year old cars will show the same speed indication.
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Re: Synchrometers

#10 Post by Mike Wilson » Tue Jun 28, 2022 10:55 am

I don't know the size of the weight but I was thinking a split shot lead sinker. They come in many different sizes.

Checking the delivery of both synchrometers would be fairly easy. Test both on one side to see if they measure equally. If not, you should be able to figure out the difference.

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Re: Synchrometers

#11 Post by Kevin Wills » Tue Jun 28, 2022 11:27 am

I bought a pair of the SKE snail synchrometers years ago and they do match in reading. Super handy having two instead of swapping back and forth, so I totally get where you're going trying to make them match.

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Re: Synchrometers

#12 Post by Wes Bender » Tue Jun 28, 2022 12:30 pm

I used two lengths of plastic hose, extending from my ears to the throats of each carb. Never knew why the engine ran rough until I had my hearing checked. (In addition to the cars getting old, Al, some of us are ageing alongside them.) All kidding aside, the Unisyn was a necessity on the Healey with side-draft SUs. There wasn't room for the Synchrometer. I gave the Unisyn to my friend who bought the Healey and have used the SYnchrometer ever since. Back in about '59 or so, I built a synchronizer by mounting two glass U-shaped tubes on a slanted board. A hose went to each carburetor and was terminated with a small nozzle to measure draft across the ridge just below the piston. Filling the tubes with colored water and sliding one tube so the levels were the same allowed me to balance the SUs quite nicely. It was a fiddley thing at best though and the Unisyn was a welcome improvement and much easier to set up.
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