Re: Anti pullover fixes for Holley 4412...
[Re: tsanchez]
#1325954
10/25/12 04:44 PM
10/25/12 04:44 PM
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Posts: 6,840
The Swamp
Sixpak
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Quote:
Have you tried an anti pullover nozzle?
Yes, had ones from an old 4165 / 4175 trick kit, like a small rectangle cast into and all the way up the sides of the shooter, open at the top, spill hole at the bottom, did not help. Shooter hold down screw is solid. Wondering if the right size spring between the needle valve and shooter screw would cause it to better stay seated and only open when the pump arm is moving. Or else adding more weight in the form of a check ball on top of the needle valve and reducing the space between the shooter hold down screw and the needle, etc.
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Re: Anti pullover fixes for Holley 4412...
[Re: oldtimer5151]
#1325956
10/25/12 05:07 PM
10/25/12 05:07 PM
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Quote:
Make sure that you install the gasket between the screw and squirter and the base. You are getting a large vacume leak around the squirter and it will lift the needle.
Definitely installed the gasket between the screw and shooter, and the shooter and the carb body. Pull over is causing gas to come out the shooter holes/nozzles. Carb sits off to one side on this inline 4, like a slant six, so I am thinking the intake is like a lever and multiplies the vibrations the carb sees at like 5 grand and higher. Same 4412 did not seem to experience pull over on a V8.
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Re: Anti pullover fixes for Holley 4412...
[Re: mcat4321]
#1325960
10/26/12 02:13 PM
10/26/12 02:13 PM
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Joined: Jun 2003
Posts: 9,225
Charleston
sixpackgut
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how do you know this is happening? do the intake ports and exhaust ports come out on the same side of the head?
Gen 3 power 6.22@110, 9.85@135
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performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: Anti pullover fixes for Holley 4412...
[Re: sixpackgut]
#1325961
10/26/12 10:14 PM
10/26/12 10:14 PM
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Quote:
how do you know this is happening? do the intake ports and exhaust ports come out on the same side of the head?
You can stand over the top of the carb, with the car at rest, and rev the motor to 5000 rpm and watch it. Apparently it's a pretty prevalent problem. Here is a video I found online of this very scenario...and the intake is on the drivers side, header on the pass side..Sorry to the earlier poster but I can't see how Holley would make this how a carb should work - there's no way to control the mixture if it did because the RPM that it happens at is not consistent. When the throttle isn't being worked the acc pump should stop dead and not shoot any more fuel in. You crack the throttle and air can enter faster than gas can flow thru the jets, due to the drop in the vacuum signal to the venturis. The acc pump circuit is just to cover any flat spot til the venturis can create enough of a signal to start pulling gas thru the main metering jets.
http://www.ryanbrownracing.com/video/4412_dyno_hires.wmv
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Re: Anti pullover fixes for Holley 4412...
[Re: Sixpak]
#1325962
10/27/12 12:17 AM
10/27/12 12:17 AM
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Joined: Jun 2003
Posts: 9,225
Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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Quote:
Quote:
how do you know this is happening? do the intake ports and exhaust ports come out on the same side of the head?
You can stand over the top of the carb, with the car at rest, and rev the motor to 5000 rpm and watch it. Apparently it's a pretty prevalent problem. Here is a video I found online of this very scenario...and the intake is on the drivers side, header on the pass side..Sorry to the earlier poster but I can't see how Holley would make this how a carb should work - there's no way to control the mixture if it did because the RPM that it happens at is not consistent. When the throttle isn't being worked the acc pump should stop dead and not shoot any more fuel in. You crack the throttle and air can enter faster than gas can flow thru the jets, due to the drop in the vacuum signal to the venturis. The acc pump circuit is just to cover any flat spot til the venturis can create enough of a signal to start pulling gas thru the main metering jets.
http://www.ryanbrownracing.com/video/4412_dyno_hires.wmv
edelbrocks have a spring and check ball that might stop the problem
have you tried a tube type squirter? that is a great video
Last edited by sixpackgut; 10/27/12 12:21 AM.
Gen 3 power 6.22@110, 9.85@135
Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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