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Holley Carb Rebuild. Help!

5K views 10 replies 5 participants last post by  cobalt327 
#1 ·
Hey gents. I have torn down a Holley 3310 750 VS almost all the way (been YEARS since I have done this and am relearning the hard way lol). Basically all I have left is to pull the shafts out of the base plate. Obviously I have to remove the butterflys before doing that.

I want to install new butterfly screws and I will probably be giving this same treatment to a couple of other carbs that I have laying around.

My question is this, does anyone know what size those butterfly screws are and if so what are they made out of? I want to buy some of them in bulk (probably have to order them) from my local nut / bolt / screw supplier? Is there a more desireable type of screw to use other than what Holley puts in from the factory? Again I want to buy them in bulk and hopefully cut down on the cost of redoing three or four carbs. Thanks!
 
#6 ·
for sale 2- holley 660/s, not even 6months old 4 sale

31fordcoupe said:
Hey gents. I have torn down a Holley 3310 750 VS almost all the way (been YEARS since I have done this and am relearning the hard way lol). Basically all I have left is to pull the shafts out of the base plate. Obviously I have to remove the butterflys before doing that.

I want to install new butterfly screws and I will probably be giving this same treatment to a couple of other carbs that I have laying around.

My question is this, does anyone know what size those butterfly screws are and if so what are they made out of? I want to buy some of them in bulk (probably have to order them) from my local nut / bolt / screw supplier? Is there a more desireable type of screw to use other than what Holley puts in from the factory? Again I want to buy them in bulk and hopefully cut down on the cost of redoing three or four carbs. Thanks!
for sale 2- holley 660/s, not even 6months old 4 sale
 
#7 ·
31fordcoupe said:
Hey gents. I have torn down a Holley 3310 750 VS almost all the way (been YEARS since I have done this and am relearning the hard way lol). Basically all I have left is to pull the shafts out of the base plate. Obviously I have to remove the butterflys before doing that.

I want to install new butterfly screws and I will probably be giving this same treatment to a couple of other carbs that I have laying around.

My question is this, does anyone know what size those butterfly screws are and if so what are they made out of? I want to buy some of them in bulk (probably have to order them) from my local nut / bolt / screw supplier? Is there a more desireable type of screw to use other than what Holley puts in from the factory? Again I want to buy them in bulk and hopefully cut down on the cost of redoing three or four carbs. Thanks!
Screw size is 8-32 from my notes. You can use a button head allen screw for the least air flow disruption, but truth be told, there's virtually no difference between the button head and a regular screw until you get into shaved blades and thinned shafts, etc.

Are you 100% the shaft needs removed? Holley carbs aren't known for wearing the throttle shafts or plates...

Be dam sure you grind or file the exposed ends off the screws before you attempt to remove them. They're peened or staked at the factory, if you try to remove them w/o grinding the ends they WILL break off. Use staking or loctite 290 or similar to hold them in place.
 
#8 ·
Cobalt,

Thanks for the info sir.

I am not ABSOLUTELY certain the shafts need to be removed, but one does have a LITTLE slop in it. My machinest who rebuilds them all the time said it could go either way. Guess there is a possibility that I could get a vacuum leak if there is too much play in the shaft? What do you suggest? If I don't have to pull them I'd rather not.

Thanks.

Brent
 
#9 ·
31fordcoupe said:
Cobalt,

Thanks for the info sir.

I am not ABSOLUTELY certain the shafts need to be removed, but one does have a LITTLE slop in it. My machinest who rebuilds them all the time said it could go either way. Guess there is a possibility that I could get a vacuum leak if there is too much play in the shaft? What do you suggest? If I don't have to pull them I'd rather not.

Thanks.

Brent
I'd be rather surprised it it was bad enough to cause problems. The shaft should have some "slop" to it, and in my experience if the butterflies aren't contacting the throttle bores of the baseplate from the wear, you are fine.

So my advice it to leave it alone. If you find you cannot get a good idle, you can always pull the carb and remove the baseplate to work on it.
 
#11 ·
31fordcoupe said:
Thanks again Cobalt. I will probably leave it as is then.

However, if in the future I want to remove one, is it ok if I use stainless steel screws in the 8-32? Or does it need to be some other material? Thanks.
I don't see a problem with stainless steel, as long as they're good quality screws- but I wouldn't go out of my way to find them in SS.

But whatever type screw or material you use, with that small of a screw just don't over tighten them, or else... and be sure to stake the exposed ends and/or use loctite to keep them from ever working loose. ;)
 
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