[JAGNUTS] Balancing Carbs using Dial Indicators

[Bob England]

Here is something off the E-Type Jaglovers list that might be of interest to
those with ZS carbs and are looking for a different way to balance the
carbs.  The YouTube video shot is from a V12 E-type with 4 of these carbs.

Bob

-----Original Message-----
From: owner-e-type at jag-lovers.org [mailto:owner-e-type at jag-lovers.org 
Sent: November 04, 2007 5:32 PM
Subject: [E-Type] Balancing Carbs using Dial Indicators

Hi All,

I said I'd report back on my 'experiment' using dial indicators to 
measure the piston height in Stromberg or SU carbs.

I would say it was worth the effort of getting the adaptors made:

1) I was able to balance my four carbs whilst 'seeing' the flow on 
all four simultaneously (rather than running around with my 'hiss 
pipe' or flow gauge).
2) I didnt need to to do any dis-assembly of aircleaners - just 
slacken the linkage and start balancing.
3) I was able to diagnose a fault on one carb where the piston 
is 'sticking' or is 'lazy' compared to the other three.

I used standard Dial Indicators like these
http://www.mitutoyo.co.jp/eng/products/dialgauge/dialgauge_01.html

In my experience of using the flow-gauge method, I would have 
difficulty seeing the effect of 1/8th turn of the idle screw. With 
the Dial indicators I could easily see flow/lift effect of 1/16th 
turn.

I nailed-together a quick youtube clip so you can see what I'm 
trying to say!  
http://www.youtube.com/watch?v=3_1S-izfXMk 
I hope the clip is clear enough for you to see the gauges react as 
I blip the throttle

The return springs in the indicators must have some effect on the 
piston height, but flow gauge methods also restrict flow and need 
to be done without the restriction of the air cleaners... so I 
don't think this is a major concern.

Overall, I'd say it's easier to use & more accurate than the other 
methods I've tried.

--
Dave