squirter pullover,,dominators

[pont2000]

this is a comp type motor, at 6500 rpm iv'e got two sprinklers,just hoseing, even with the pump arms off,,part throttle no load, the secondaries are'nt even open, wierd as.
anyone got any answers?

[Procision-Auto]

Are you sure you're not looking at the boosters?

The squirter nozzles have a direct path through the metering blocks to
the accelerator pumps.

I can't understand how the squirter nozzles would be flowing fuel unless
the gasket was broken and the low pressure in the venturi was causing
the fuel in the bowl to flow out?

If not, you might want to try a short nose squirter to get the nose out
of the low pressure area.

[bill jones]

-you might want to look at this:
http://www.stockcarracing.com/techartic ... etor_cures

[Blacktrack]

I had the same problem with my engine, every time i reved up the engine to 2000-2500 plus revs it would start dribbling/running fuel out the pump squirters.It ended up being a engine balance problem.Long story but how i found out was i fitted a jesel belt drive and on the first burn out i did, the 4 nuts on the jesel belt drive came loose and the cam timing move and bent the exhaust valve.
So i asked the guy that balanced the engine and he said KNOW WAY could it be out of balance.Well i had it re-balanced at another shop.To find out that this crank was so far out of balance that the guy said come and see for my self.
Once i had the engine back together the pump squirters stopped leaking.

[ProGSX]

this is a comp type motor, at 6500 rpm iv'e got two sprinklers,just hoseing, even with the pump arms off,,part throttle no load, the secondaries are'nt even open, wierd as.
anyone got any answers?

My friend has a 472" sbc with a pair of Domintors that had a squirter pullover problem. Davinci shaved the nubs off the squirters. Very little pullover now.

[shawn]

Hi,
go here-

http://www.blp.com/processtype.asp?Main ... cessType=2

Mike Laws is one of the forum members. BLP sells what you need.
shawn

[RL]

Is this what you mean about pullover

This is a video of our new 850 Demon, you can just see the 4 squirters fuel being pulled out(poor video quality. original is clearer), Our AF has always been very good out of the box, so we don't worry about it, Should we

http://www.livevideo.com/video/98637155 ... rters.aspx

[Procision-Auto]

Wow, that's a crazy amount of fuel dumping into the venturi.

What RPM did you pull to?

I wonder if the amount of fuel would reduce if a different style squirter
was used.

I read through Bill Jones' link and found the troubleshooting to be quite
fascinating. I didn't realize vibration could do such a thing. I guess that's
part of the game when you build 7 second /8000+ RPM motors!

In your case, it seems the low pressure in the venturi throat area
is causing the fuel to be pushed out of the accelerator pumps.

It's giving me an idea to draw up a possible solution.

[RL]

I think it's about 5000-7800 rpm

The AF are very steady using the Demon so we usually buy them

[shawn]

Ryan Brown has a good video of what is happening here-

http://www.ryanbrownracing.com/video/44 ... _hires.wmv

this is a two barrel but it gives you the idea. The problem with fuel pullover is not that you can't meter for the correct fuel ratio, it's the quality of fuel. You don't have quality, emulsified air coming out of a squirter. You can't control it. I would rather use the metering in the block and bleeds to control the curve. You can have the same a/f ratio and make better power with an opportunity to control fuel emulisification and drop size.
shawn

[Procision-Auto]

It's times like these I wish I had a patent! If anyone runs with this idea
and makes a few million, remember where you found it!

Excuse the cheap drawing, but imagine the concept:

An aluminum, or "rubberized" shroud that slips over the vent tube and is moulded around
the nozzle (sort of like a spark plug boot, but a thinner cross-section).

The shroud could also incorporate snap clips to secure and stabilize itself to the nozzle.

The mating edge of the shroud should be air tight against the vent tube and
carburetor main body.

The idea is to keep the area under the shroud at ambient pressure, as
opposed to a negative value.

[Mark R]

This is very enlightening!(sp?) Do you think the same thing happens with the side hung float bowls that use the check ball instead of the red rubber diaphragm? Could it help solve this or make it worse?

[shawn]

Just buy the anti-pullover squirters from BLP I linked above and you don't have to do anything.
shawn

[Barry_R]

The anti-pullover squirters will eliminate the issue. Holley makes them for a reason.

At the same time you should be aware that pullover is a legitimate tuning tool - and can be used to fatten the upper end of a fuel curve if needed. You can tailor it a bit with a heavier pump check (which will delay the start of pullover). You can lean it out by drilling an accessory hole in the pump cross channel that faces the float. Ford used a similar .013 hole in the model 4180 mustang GT carbs - - that hole also reduces the tendency for pump cavity fuel boiling to load up the motor on hot soak.

[Mike Laws]

Thanks Shawn.

There has been excellent information presented on here about this issue. We have a lot of time invested on this situation and still do not have it completely figured out. The bottom line is that fuel exits the squirters pretty much all the time. Many engine builders utilize this excess fuel as part of their calibration while others prefer to eliminate as much pull-through as possible.

We manufacture a nice billet squirter-kit for the 4150 and Dominator carburetors that eliminates most of this siphoning-effect. Price is around $12 ea. Please PM, email or call me for more info.

ML

mlaws@blp.com