Carburetor Accellerator Pump Cams Video - Holley Carb DVD

Buy the "Holley Installation & Tuning" DVD http://store.boxwrench.net/Holley-Install-Tuning-DVD_p_0-12.html

Holley Installation & Tuning DVD: Accelerator Pump Cams

Their are lots of pump cams to choose from. This section will show you the difference and set up procedure to help you choose the right one for your particular application.

If you buy a brand new Holley 4-barrel, this DVD now comes in the box with every purchase. If you already own a Holley carburetor or would like to learn about the internals of the all-time, most popular modular style carburetor, this is the DVD for you.

It's the ultimate installation, tuning and troubleshooting guide for the Holley modular style carburetor. This disc will also help tune and troubleshoot any other brand of modular style and some one-piece style carburetors.

Menus are full of bonus information and detailed animated tours of carburetor
internals and accessory kits.

Get the full DVD with all of the interactive menus, detailed animated tours of internals and accessory kits here...
http://store.boxwrench.net/Holley-Install-Tuning-DVD_p_0-12.html

Don't forget our Basic Engine Building DVD.This video is great for people interested in car repair, car care, and restoration. As well as hot rods, muscle cars, performance parts, and boosting horsepower. It can also help you to gain knowledge for increasing fuel economy, how to lower your emissions, and covers preventative maintenance to avoid little things like overheating.

Sample clips on our YouTube page and at our store here...
http://store.boxwrench.net/Basic-Engine-Building-DVD_p_14-8.html

BoxWrench.net is a community and resource designed for automotive enthusiasts.

New Transmission DVDs and a Differential Rebuilding DVD just added.

BoxWrench Store:
http://store.boxwrench.net/

http://www.boxwrench.net
Educating the Automotive Enthusiast

BoxWrench on Facebook:
http://www.facebook.com/boxwrench

Category:

Autos & Vehicles

Tags:

• engine
• rebuild
• carburetor
• holley
• carb
• accelerator
• pump
• cam
• tuning
• building
• V8
• 4150
• Double
• Pumper
• repair
• video
• dvd
• instructions
• tutorial
• software

[joness105639]

Always wondered what an accelerator pump looked like. My carburettors dont have one!

[BoxWrench]

You very likely do have an accelerator pump of some kind, it's design is probably just different from Holley's.

Without an accelerator pump shot of fuel, the engine will experience a brief hesitation at the moment your foot presses the gas pedal.

[joness105639]

When you hit the gas, the piston rises but is slowed by a damper in the dashpot. Thus there is a smaller than usual venturi for the trottle position, and with faster air moving accross teh jet, the mixture become richer mommentarily. If one forgits to ensure that the damper is full of oil, the engine ill hesitate just as you said. This is the principle that SU, Zenitch Stromburh, and even some Hitachi carbs work on.

[BoxWrench]

Would love to see some video of the carbs and/or some graphics of the theory of operation...

Sounds like an interesting design. How is reliability and tuning?

[heckeng1234]

When do you use the hole #2 in the throttle bracket? Is it whenever you use the cam hole #2 or #3? Do you ever use the #1 cam hole with #2 throttle bracket hole or vice-versa?

[BoxWrench]

Multiple holes in the throttle lever and in the accelerator pump cams allows you two tuning positions for each cam.

You would normally line up hole #1 in the lever with hole #1 in the pump cam. The same matching of the #2 holes as well.

This will allow you to match the profiles to the factory determined flow ratings and profiles designed for each accelerator pump cam.

[rotaxtwin]

Gotta love the adjustable nature of a Holley. It just rocks!

[DrFiero]

@BoxWrench : the metering rod mostly plugs the main jet. As you open the butterflys, manifold vacuum is metered to the top of the piston. It pulls it up, letting the piston rise, feeding more air and fuel, but only as the engine needs it (just like a vacuum secondary on a Holley).

[DrFiero]

@BoxWrench : Can't believe nobody's touched on this in a year! The design above is a "CV" or constant velocity carb. Most bikes use the same principal. My 50's & 60's british cars also used them (SU carbs). They're very simplistic, and easy to setup and maintain.

There's a throttle plate near the manifold. A large'ish piston in the bore blocks about 80% of the opening. There's a metering rod attached to it. At idle, it stays down, mostly blocking air flow.

[VinnyMartello]

@swordfishmatador

Rip out the jets and dip them in some chem-dip or something.

[swordfishmatador]

@TheBlueToyota Yeah I checked the jets as well. the problem was the front metering block. I changed it and it stayed running.

[TheBlueToyota]

the jets up from the bowl may be clogged to have you checked them as well?

[swordfishmatador]

Ive got a huge problem. I have a 650 holley carbarator double pumper. A few weeks ago I ran out of gas snd the fuel filter and carbarator got covered in gook. I cleaned the filter and inside the carbataror bowls and still it wont stay running. What could be wrong?

[joness105639]

Tuning for more power? Not sure, never tried it. Tuning for good running is reletively easy. You have a mixture adjustment nut, an idle screw and a "fast idle" screw (the fast idle sets the idle speed when the choke is out.  Once they are set, they dont need to get touched again for a LONG time. I'll send you a PM with the vids etc.