Fuel System: Drilling holes in super charged stromburg

[Gold Hawk Doug]

Hi y'all.
My '57 GH has always had a problem starting when hot. It takes quite a bit of cranking if it sits for more than a few minutes.

I found in a old thread a service bulletin that says to drill small 5/64, and 7/64 holes in three of the throttle body air passages, for "considerable improvement"

My question is, has anybody done this, and did you like the results?

According to the old tread, Studebaker started doing this on all later production models, but I can't find any evidence of that.

Thanks, Doug

[Gold Hawk Doug]

Additional Info: Here is the service bulletin #325. Look to the second page under "Hard starting with hot engine"

http://www.packardinfo.com/xoops/html/downloads/SC/SB-325.pdf

Thanks again,
Doug

[Gold Hawk Doug]

Bump

Anybody? Or will I be the guinea pig on this one. I guess if I did this and it didn't work I could seal the hole back up with some JB Weld.

Doug

[gordr]

Had to root around in your link, but I found it. Great resource page! Well, if the factory recommended it, I can't see any harm in it. I'd want to have the carb in hand to try and figure out where the two 5/64" holes go to. Do they enter the venturi, or do they intersect the throttle shaft bores?

The root cause of the issue is fuel boiling in the carb bowl during a hot soak, forcing liquid fuel to dribble into the intake manifold and flood the engine. Since today's fuel boils more readily than good 1950's gas, the fix that worked back then may not be "much" use now. Probably, blocking off the heat riser passage in the intake manifold would be the best single thing you do to relieve the problem. Of course, warmup after a cold start in cool/cold weather will take a lot longer. That may not be an issue if you don't drive in winter.

[DEEPNHOCK]

This should help.....
Jeff

http://tinyurl.com/Drilling-Throttle-Blades

[gordr]

Heh! Drill enough holes in a Holley, and it will kinda-sorta work right.

[Gold Hawk Doug]

I think that in drilling the holes they were looking to allow accumulated vapors from the boiling fuel a place to escape from.

The trick here like you said would be to determine where the passages go, and what effect this would have on over all running. I sure wouldn't want to create a lean condition, from what could be essentially be a vacuum leak on a supercharged engine.
Can you say melt down?
I was hoping that some one here had done this, or had found a carb that had already had this done to, as in the later production cars, and tell us what the results were.
Ah well, more research I guess.

Doug