View Full Version : Vacuum guages and carb balancing
08-08-03, 06:27 PM
Following on from the other vac guage thread, what guages are available to balance a pair of carbs (webers in this case)
I have been to all my local parts places and noone sells vac guages anymore. The ones i have been looking for are quite a large sized guage that resemble a common compression tester. They used to retail for around 100 dollars but NOONE stocks them anymore.
I've been making do with a mate's boost guage, but had to give it back. What else can i use. I have heard of something called a "carbalancer" (brand name), it's some plastic thing with hoses and balls that rise and fall representing balance.
Where can i get these? Are they any use? What other options do i have?
08-08-03, 07:21 PM
Hey mate, im not sure about this, but is this what your after? http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=2426911426&category=32053
09-08-03, 07:38 AM
The very best way to measure inches of mercury manifold vacuum is with a proper mercury manometer. They are just a U shaped tube part filled with mercury. You could make two, (or more) to compare manifold vacuum between cylinders, or just one with each leg connected to a different intake port will show the difference in idling vacuum.
Four on any multi cylinder engine, this is the very best, quickest, and most accurate method possible. The older motorcycle tuners know all about this.
No doubt someone is now going to say how mercury is extremely toxic, and even looking at it is going to strike you stone dead.
Just treat it with the same respect you would household bleach, drain cleaner, weed killer, rat poison, or petrol, and you will be fine.
09-08-03, 01:17 PM
Yup, that's how the old man used to do his bike carbs. But not having access to one we tried using huge lengths of clear plastic hose and water and it never really worked too well.
Where does a person actually aquire mercury ?
09-08-03, 01:43 PM
You could look in the phone book under Chemical Suppliers.
There is a company up your way called Alpha Chemicals, in Dee Why 02-9982-4622. They advertise in the yellow pages here in Melbourne as being stockists of a wide range of metal based inorganic chemicals. They should either have the stuff, or will know where to get some.
I have no connection with Alpha, and do not know if they can help, I just picked them out of the phone book?
If you locate a source, post it here, it might help others.
09-08-03, 01:50 PM
Cool, they are just down the road!
I'll call them on Monday,
thanks for the help.
09-08-03, 05:42 PM
Forget stuffing round with mercury and u-shaped tubes...
simply get a length of hose, stick one end at your carby inlet... other end near your ear. Providing the carbs are identical, and that you position the hose end at the same spot on both your inlets (make up a bracket or something if you are fussy), you can balance the carbs with sufficient accuracy by simply lisenting to the sound of the passing airflow and adjusting accordingly. Try it... you'll be suprised how accurate it is.
Note: make sure the end of the hose does not completely block the inlet, otherwise your in for a rather unpleasant and instant ear *dewaxing*.
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