[DeTomaso] HOLLEY GAS LEAK / Dick Ruzzin

[JDeRyke at aol.com]

In a message dated 10/24/07 3:32:12 PM, Dickruzzindesign at aol.com writes:

> Apparently the leak occurs when the accelerator pumps are activated. Are 
> the throttle shafts worn, can it leak when the accelerator pumps are activated? 
> What should I look for in terms of repair? Any similar history?
> 
Whats likely happening is, the base casting is worn egg-shaped where the 
throttle shafts touch. Positive pressure pulses in the intake are blowing fuel/air 
out along the throttle shafts. FWIW, Webers use sealed ball bearings on both 
sides of the throttle shafts. For U.S carbs, there were 3 fixes that I know 
of. The first involved removing the throttle plates and shafts, then drilling a 
small chamfer in the base casting on both sides and adding a small teflon 
o-ring & washer to each side, with a light coil spring to bear against the washer, 
forcing the o-ring into the chamfer. The soft teflon has practically no drag 
on the shaft and will quickly conform to the v-shaped chamfer, sealing it 
nicely. Clarks Corvair on the East Coast used to sell a kit; dunno if they still 
do. Tedious but practically no-cost and effective even for blow-through 
turbochargers. A second way was to remove the throttle plates & 
shafts as before, and bore each side of the base for a small bronze bushing 
that lightly press-fits into the casting, then ream to size. A little more 
trouble but more permanent. Finally, you can replace your worn base with one thats 
not; this involves only removing the throttle base screws & swapping over 
from a junkyard core. Good luck- J DeRyke



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