marinizing holley - grooving throttle shafts?? help!!!
 

I'm marinizing my own holley (I know nickerson can do it for me, but I have a machine shop - so I am going to modify the shafts my self). I just need to find out what holley (or nickerson for that matter) does to the shafts/bores of the plate to stop the fuel seepage. I have J-tubes already, and I am very versed in carb setup for the jetting, etc. I thought of machining grooves in the shafts for small o-rings, but thought of maybe grooving the shafts (without o-rings) and machining slots or holes in the base plate to re-direct the fuel and stop the fuel from wicking out the shaft????

anyone know what holley or nickerson does to them???

thanks guys!

ttt, anyone?

Ok, this is what I found on one of mine that I had apart a few years ago. The groove is machined into each end of the shaft where it passes thru the throttle plate. It is about 3/8" long and in effect at this point it makes the shaft OD smaller. Then they use a bushing that looks like Teflon to fill this void. The bushing seals any gap where the shaft passes thru the throttle plate.
If this is hard to visualize think about taking a soda pop straw and cutting off 3/8" from one end. This piece would then go in the machined groove.
That is the only thing different I found with the throttle shafts on my old Holley.
Hope it helps,
Dave

J tubes ... shaft seals .... what else is involved ? Where does the fuel pump tube enter the carb ?

Yup, j-tubes, machining a place the the fitting that the pump vents to - I'm good there. Just fuzzy about "sealing" the shafts. The one carb shop I talked to said they "no longer seal the shafts" due to problems with the shafts being "sticky" due to the seals. I'm curious to how Nickerson does it? From their site it says the "throttle shafts are grooved and slabbed". So what is "slabbed"?

I'm thinking if I can find some teflon rings/seals the proper size I can machine the shafts and do it that way....

Ok, found this on another post on this site from a member named "2112"

QUOTE: Just had an interesting conversation with Nickerson Carbs. From that discussion;

1) There is no such thing as a "sealed throttle shaft". It simply does not exist. If you have one, let the alcohol guys know about it, they would love to solve that dilemma.

2) The j tube is a Holley invention for marine carbs. The USCG has absolutely no requirement for these. They are more concerned about flame arrestors and SS braided lines.

For what it is worth. UNQUOTE

If they are not "sealing" the shafts, has anyone seen exactly what they are doing? maybe just machining grooves in the shafts to try lessen the capilary effect of the fuel out the shaft/plate?

u-really should not see fuel coming out @ the butterfly shafts exit point, if so find the internal leak, have seen dominator carbs with the wrong metering body gasket dribble fuel out onto the butterfly shafts @ shut down and create a puddle which can flow or dribble out of the shafts, this will also gen. cause a hard start cond. just 2 cents. ps: gas leaks bad news ! :eek: good luck

I agree, if a measurable amount of fuel is dripping from the shafts there is always a problem (gaskets, float level - causing fuel to drip from venturi after shut down and lead out shafts...), but all of the holley's seem to always have fuel stains on the base plate there. Maybe it's not enough to be worried about though.

[QUOTE=Josh Carr;2546933]Ok, found this on another post on this site from a member named "2112"

QUOTE: Just had an interesting conversation with Nickerson Carbs. From that discussion;

1) There is no such thing as a "sealed throttle shaft". It simply does not exist. If you have one, let the alcohol guys know about it, they would love to solve that dilemma.

2) The j tube is a Holley invention for marine carbs. The USCG has absolutely no requirement for these. They are more concerned about flame arrestors and SS braided lines.

For what it is worth. UNQUOTE


that's nice... i spent what , $25 for the j tubes for my 950:hitfan:

I agree and you can bet that those million or more Q-jets that have been used for years never had any throttle shaft seals either..at least none of the ones I ever worked on...Rob