Holley float level specs

[Michael]

Manuals for adjusting the float level of center-hung floats in 3310-style carburetors mention two methods: the first is in the car, where the sight plug is removed and the float level adjusted to where the fuel level is low enough so that fuel isn’t flowing out!; and the second involves removing the float bowl, turning it upside down and adjusting the float level until the gap between the float and the bottom (now on top) wall of the float bowl is at some level.

 

I much prefer method #2. Trouble is, I can not find the spec for what that gap should be. I have not been able to find it in scanned Holley manuals on-line. Holley’s own manual for this model (http://www.holley.com/data/Products/Technical/199R9934-3.pdf) does not even mention method #2.

[kcelectronics]

Why??? Just pull the sight plugs and adjust and your done, don't make life difficult for yourself:grin:

[blueovalz]

#1 (which is why this hole is there in the first place). Adjust the level so that fuel just barely trickles out of this hole with pump running.

[jnjdragracing]

I have always done the 1st step, the second option I have read before but you do it that way if you are running alky.

 

John

[kcelectronics]

I have always done the 1st step, the second option I have read before but you do it that way if you are running alky.

 

John

 

Why do you need to run alcohol at a different static fuel level? should it be higher or lower than gas?

[jnjdragracing]

I read an article in carcraft, they were talking about running ethanol and what you needed to do to the carb. They mentioned turning the floats upside down. You will need more fuel in this application because it is like a 2 to 1 ratio when running alky or ethanol.

 

Why do you need to run alcohol at a different static fuel level? should it be higher or lower than gas?

[kcelectronics]

Thanks for the reply, There is a spacer to increase the capacity of the float bowls

 

But the static fuel hight would need t be set the same as this is what sets the fuel "tip in" and is well documented in the holley carburetor manuals.

Just my 2¢ worth

[dr_hunt]

I run alky and I do neither. No bowl extensions, floats set as normal. The trick is to have proper fuel delivery. High flow .150 4 port needle and seats, 11psi fuel pressure at WOT and about 3psi at idle, proper fuel lines, I run -8 to each fuel bowl off of a -10 line for NA applications, jet extensions on back if your 60 foots are lower than 1.64 or so.

 

IMO if your running the bowl dry and think you need more volume in the bowl, then your needle and seat doesn't flow enough and increasing the bowl volume only delays the problem. What happens then is you go lean and run out of fuel at the 200 ft instead of 100 ft off the line. Motor lays down, has good 60 foots but nothing after that. But that's my experience on the track.

[kcelectronics]

Thanks Doc, well said, enough fuel flow is the answer.

 

 

and here is a link to Modding Holley Carbs for Alcohol:-

http://www.hardtail.com/techtips/alcoholconversion.html

[dr_hunt]

Well, that's an old skool link, seen that in the past, problem is that you don't have any idea what the fuel flow through the carb will be IMO. The reason I say that is carb size and booster type will alter the "signal" that the carb sees, that and cam, heads, intake, etc. This guy is mandating drill size which dictates flow.

 

C&S offers this type of modification for circle track applications, not for drag, the holes above the jets in the back are uncovered during hard luanches and the carb goes lean.

 

In my experience it's better and less headache to buy a good alky carb and go faster.

 

I bought 2 alky carbs from "People like this guy in the article". One on ebay that said his carbs make more power than the big name carbs for $800. I was running gas, switched to alky with his carb, picked up 3 tenths. Ok, took out hydraulic cam, ported my heads, installed solid roller, and it ran the same time! WTF? Talked to a different guy, he said your needle and seat are maxed out for flow and therefore HP so your running lean. 60's improved but that's it. So, popped those out, sure enough .130 needle and seats. A check of flows for needle and seats at 8psi indicated that they would only flow enough alky for 450HP which is what I was making. Damn, so I sold that carb on EBAY for $350, bought another FROM THE NEW GUY FOR $650, had bigger needle and seats but, would run you out of the shop at an idle, way rich on the bottom end to get it close on the top end so fuel metering circuits were all out of whack (READ AIR BLEEDS AFU and passages wrong size). BTW, drilling out an air bleed leans it out not the other way around. So, I sold that carb on EBAY for $400 and bought a C&S aerosol billet with a 30 day money back guarantee. Now I have 2 of those and never been happier. Oh, they are about $1000 or more and you "GET WHAT YOU PAY FOR!"