Webers (What a Gas)

["Bruce Hevner" <scramblr@xxxxxxxxxxx>]

>So I have this 32/36 DGEV (two-barrel progressive) Weber carb on my 258.
I've got the main barrel barn-door dialed in. It was off a Jeep so it
>didn't have far to go.
>I bought the popular book on Webers (it's out in the car, too lazy to get)
which frustratingly leaves me in the dark on the two items I need to know:

There are literally HUNDREDS of variations on the "Downdraft Weber" type
carb. I used to sell new ones and have installed MANY used ones. I
CONSTANTLY saw different versions of them. The smallest was a 28-28 from an
850 Fiat, the largest is the 40-40 I am using on my son's truck. Most common
are the 32/36 and 38/38. The 32/36 is rated "about" 280-300 cfm, the 38/38
is "about 320-350 cfm (my 40-40 is 410!).  The cfm ratings vary due to the
choke design (some have bigger choke openings). 

>* ported vacuum?
Some DO have ported vacuum. It just depends on what requirements the donor
engine had.  I have seen them have more than one ported source,, and none.

>* adjusting 2nd-venturi issues?
This will be a combination of jetting AND accel pump issues. I have seen
them use accel pumps that only squirt on ONE side. Even though it "seems" to
run OK you might need to "squeeze" down on the sec air jet to get the fuel
to come in sooner. The real secret to getting good mileage with these carbs
is to use the double booster venture (has two rings) on the primary side. It
won't fit all the 32/36's but if you can find one that has it you will get
3-5 more MPG than the ones with out!

>It appears that Webers simply don't provide ported vacuum (eg.
>vacuum signal for the distributor picked off right above the closed
throttle plate). I've got the timing set statically to 5btdc, but then I
stick the hose >on and get 20 whatever btdc degrees.  Runs OK but I don't
like it.

>I have a huge bog when the 2nd venturi opens, plain and simple.
>Load or no load. The accellerator pump hasn't run out of stroke or anything
when it starts to open, so I don't think that's it.  If I ease through the
bog >region it flows OK and the motor pulls like hell, so the jetting isn't
too crazy. I assume all I can do is bend the linkage to determine pull-in.

E-mail me off the list and I'll help you if I can.
Bruce Hevnert