Carb Sync tool

[Tinster]

Strombergs 175 CD-2
idle now at 900 rpm
carbs leaned out some (I hope)
Vacuum at intake manifold is -21 psi, steady
Carbs rebuilt by Jeff Palya.

When I place the Unisyn tool over a carb throat,
the red cup rises quickly to the middle and the
car engine dies. This happens on either carb.

Is it normal for the Unisyn tool to kill the engine?
It makes it difficult to balance the carbs.

It really takes fast reactions to spot the cup
before the engine dies.

Any thoughts?

d

 

[SilentUnicorn]

Dale is your tool like this one

if so then you can adjust the center spinner to control the amount of air being drawn into the engine when the tool is in place over the carb throat. Un screw it ( so the gap is large) then while the tool is over the carb you can slowly screw it down till you can get a reading. Its is not how high the float on the tool goes but how even they are.


mark

 

[Tinster]

Many Thanks, Mark !!

Yup that's my tool.

Thanks for the instructions on how to use it.

Much appreciated.

dale

 

[AltaKnight]

Dale....
I have the same balancing tool.
Here's how I do it.
I just increase the RPM's while I'm doing the test so the engine doesn't stall.
After loosening one of the folded metal shaft connector screws (so the carbs work independently) use the idle speed adjustment screws on each carb to get the engine idling about 2000rpm; then check each carb with the balacing tool; adjust one of the carb idle speed screws to get the balance right; make sure you give the engine time to recover it's rpm's and smoothness before testing the 2nd carb.
When you have them both even on the little red thingie,tighten the folded metal shaft connector screw and recheck the balance; repeat above if required.
When it's balanced ok with the screw tight, then adjust the idle speed to the right level using both idle speed adjustment screws and you're done.

 

[poolboy]

Although these things have been around since forever, they do have to be used with utmost attention as to making a consistant and repeatable placement on the carb.
A 1/4 inch deviation from one carb to the other in itself will cause a different amount of air passing into the carb thru the Unisyn, which is what your reading is based on.
I've taken to using a stethoscope with the amplifyer removed. If you place that open tube in the same relative place on each carb, your ear will tell you if they are in balance.

 

[TRDejaVu]

I use a pair of space-age plastic tubes; one in each lug hole. I don't thrink thet itt hes sicked ny brane oot yettt.

 

[AltaKnight]

I use a pair of space-age plastic tubes; one in each lug hole. I don't thrink thet itt hes sicked ny brane oot yettt.

I'm just visualizing the tubes in your ears; heck of a wax remover!
Love it!

 

[TR3driver]

The other point that I overlooked at first with the Unisyn : The tube is to be tilted until it's nearly horizontal, rather than vertical. That gives more ball movement for a smaller vacuum signal; letting it work with the opening large enough that the engine doesn't die.

It's a shame that the synchronizing tool from the "SU Tool Kit" doesn't fit ZS carbs. It's much simpler to use, and best of all, allows you to check synchronization with the throttle partially open as well as at idle.

 

[Brosky]

I really never liked the Unisyn. I have two of these and they work great IMHO.

 

[poolboy]

I haven't tried that one,Paul, but it looks like it eliminates the problem of placing it in corresponding identical locations on each carb.

 

[Brosky]

You can't screw up the locations and you can have one in each carb if you push them in snuggly and that makes it easy to set them perfectly at the same time.

 

[poolboy]

Sounds very "luxurious". Is there an adjustment to vary the amount of air passing thru it?

 

[Brosky]

PB,

I have the SK unit in my hand, made in Germany and there is no adjustment for the air on it. The other I bought on ebay, but it's not here at the moment. It is not an SK, probably a knock off, but it looks and works exactly the same and gives me the exact same readings.

I don't know if I'd call it luxurious, but I am basically lazy, so I guess that I would choose calling it an easier more efficient unit for the labor required to do the job.

 

[poolboy]

Just kidding. The fact that there is no adjustment for air and the plug in installation does eliminate the 2 biggest source of errors when using the Unisyn.
Next car show, I'm going to see who has one that I can bring over to my car and see how it compares with my sthethoscope.

 

[toysrrus]

Hi Paul,

I`ve never seen this thing before!

It looks like it would work quite well.

Where the heck did you get it?

I believe I may be speaking for a bunch of us here? Then again; Maybe just myself?

Thanx for the Hds-Up,

Russ

 

[Brosky]

Russ,

These were quite popular years ago for VW, Porsche, Weber stacks, etc. See, I am an old fart! They make setting Weber's really easy.

Ar any rate, here are a bunch of them. Just make sure that you get the one to fit the TR6 air opening.

Oh and for the record, the SK models do feel a bit heavier than the others and seem to be a bit more robust, but except for thinner plastic, they look and read the same as each other.

Synchrometers on sBay

 

[2wrench]

How much more involved does it get after synching the carbs?

 

[poolboy]

The proper order of things are: Valve clearence, Ignition timing, Carb mixture, and last, Carb sync.

 

[2wrench]

If I remember right, with my BP270 cam from bpnorthwest, I set the
intake at .012 and the exhaust at .014.

So by "valve clearence," do you mean resetting and/or verifying the
valves to these same specs?

When/how soon is this to be done?

Valve clearnce and timing I think I can get past; but carb mixture and
synch could prove a bit more of a challenge. I am willing, of course,
to go for the synch tools heretofore mentioned as A: It would be great
to know how to tune the car in toto; and B: Any investment would pay dividends
by not having to pay shop fees at roughly $100.00 per hour.....

So I'm willing to learn. Do I qualify a worthy student??? Kind of like the
tranny, though -- if it is likely to be way over my head, I'm willing to
concede. Only you experts can clearly discern. Your input, please.

PS: Still waiting till tommorrow to order my rotor parts.
PSSS: Don't mean to hyjack the thread.

 

[TR3driver]

IMO, 2wrench, save your money. The "hose to the ear" technique works plenty well enough, and only requires some old heater hose.