Q: dual carbs on a 1776 Bug motor
John William Kuthe
I'm seeking people's experiences with any type of dual carb setup on
Bug motors. I've been driving aircooled VW's for quite a while, have
been working on them for almost as long as I've been driving them (my
first one ran for a while before I had to work on it! ;-)), and have
experience at rebuilding motors, front ends, general mechanical stuff
of every degree.
I am currently driving a professionally built 1776, mild cam mill
/w/ a CW crank, full flow oil filter, stock exhaust and a Weber
Progressive carb. I think I have a vacuum leak somewhere, but the main
reason I'm thinking about dual carbs is because it has recently turned
real cold here in St Louis, and I am under the impression that dual
carbs, because they are situated so close to the cyl heads, are much
better about 'warming up' (i.e. not needing preheat air), etc.
Having never run duals before, a few questions come to mind:
1. If I want to install 'em myself, can I do it without removing the
engine from the car? I *can* remove the engine, but I'd rather not.
2. How well do they perform in cold weather, *really*? From personal
experience.
3. How bad is it getting to the front spark plugs? (replacing them,
etc.)
4. How bad are duals to set up, adjust, etc., for tune-up purposes?
(Yeah, I know about those sync devices to balance dual carbs). How
easy is this to do?
5. Any gotcha's those of you who have run dual carbs have found that
the uninitiated should know about?
Please include what type of carb setup you have experience with, and
on what type of motor.
I follow this group daily, so followups are fine, but if you want to
email me directly, that's OK too.
Peace,
--
John Kuthe, aka jw...@cec.wustl.edu, St. Louis, Missouri |MWA Homepage: |
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Paul Cleve
My '71 Super only has a single carb, but I've got a '71 MG Midget as
well. It's got twin SU HS-2 carbs.
>2. How well do they perform in cold weather, *really*? From personal
>experience.
From my experience, I just love my manual choke. It's a small thing
to remember when driving, but MUCH more reliable than any old automatic choke.
I'd opt for one (if they're around) if I were switching carbs. I've never
had a problem starting or idling in cold weather with the MG (believe it or
not), even when it's badly tuned.
>4. How bad are duals to set up, adjust, etc., for tune-up purposes?
>(Yeah, I know about those sync devices to balance dual carbs). How
>easy is this to do?
I've always tuned these with a length of rubber hose. Tune the carbs
while listening to the hiss from the intake of each carb in turn. When the
volume is the same, and it's smooth, you've got it. There's also a real handy
tool I've seen (although now recently) for balancing/tuning engines. It's a
sparkplug witha little window in it. You can look down into the cylinder
while the engine is running, and tune the engine by flame colour. Pretty
smooth. It'd be kinda hard to see down it with the plug locations of the bug,
but it works great!
Hope this helps a bit.
Paul
Dean Bolton
I am biased towards Dellorto's (either Baby's or preferrably DRLA's -
dual two barrels) I have run a set of 40mm DRLAs on a Type 1 1776
similar to the one you describe and it ran like a stripped #ss ape
(scuse the french). I also ran a set of 36mm DRLAs on two different
Type 3s. One had a 1776 similar to yours, the other had a 2110 that
was pretty radical. Both setups ran EXCELLENT, but the only thing I
would have changed was that I would have stepped up to 40mm or 45mm
for the 2110 since the power seamed to fall off above 5000rpm.
>1. If I want to install 'em myself, can I do it without removing the
>engine from the car? I *can* remove the engine, but I'd rather not.
You should have no problem installing them without removing the
engine, the tough part is getting to the front intake nut. At the
most you may need a universal joint or a wobbly socket and you'll get
it.
>2. How well do they perform in cold weather, *really*? From personal
>experience.
With the first engine I described, I lived in Klamath Falls, OR where
the temps dropped to 10 or 20 degrees F regularly in the winter. I
usually started the car, revved it slightly for about two to three
minutes, then it ran perfect until it was warmed up. I think (been a
long time) that one time when it was around 10 or 20 F at night, that
I noticed that the manifolds got slightly iced just under the
carburetor, but it never affected the driveability like it does with
the single carb setups.
>3. How bad is it getting to the front spark plugs? (replacing them,
>etc.)
It can be a little tough getting to the front plugs, but not even
close to tightening the upper left engine mounting bolt on an engine
with a dog house shroud and no blind nut attached to the case (thats
probably another story). Anyway, its not that tough.
>4. How bad are duals to set up, adjust, etc., for tune-up purposes?
>(Yeah, I know about those sync devices to balance dual carbs). How
>easy is this to do?
Just get the tuning book for Dellorto's (or for Webers if thats how
you go) from CB performance, and that will give you all the info. you
need. It takes a little reading, but its pretty easy after you've
read about it a little.
>5. Any gotcha's those of you who have run dual carbs have found that
>the uninitiated should know about?
You'll have to relocate your ignition coil if you currently mount it
to the shroud (the carb kit should come with a new mount or you can
buy one separately if you get the carbs used).
P.S. I pitted for an offroad racing crew that ran Webers, and I
really became attracted to the Dellorto's for the following reasons:
1. Dellorto's have better throttle response
2. The idle jets on the Webers got clogged easier
3. The Dellorto's have sprung needle and seats which means
that they handle offroading and rough terrain and hills better.
4. And I just thing the Dells are better (IMHO)
If you need any additional info, feel free to send me some mail at
tal...@calweb.com. Good Luck.
**************************************************************
Dean Bolton 64 Killer Baja
tal...@calweb.com The Duke of the Baja World
(at least Sacramento)
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