Mill out the AFC top

[thechoochlyman]

It only smokes bad until I reach a high RPM - but by that time the boost is gone.

I've never heard of that valve you're talking about. I'll have to look into that!

[RATROD92]

Put a ball and spring style boost controller in the boost reference line, and set it for ~20psi or so, that way there won't be any additional fueling until you reach that set pressure.

Yes this sounds fantastic...your talking about the line coming to the banjo bolt on the AFC...Correct? This sounds like something I am going to need also.

[Tacoclaw]

Look up a "Gillis" valve if you're wanting to see the basic design.

You can make them yourself pretty easily out of a brass T, a ball bearing, a set screw and locknut, and a spring.

[thechoochlyman]

Thanks guys, I'll check out some o' this.

[dvst8r]

Put a ball and spring style boost controller in the boost reference line, and set it for ~20psi or so, that way there won't be any additional fueling until you reach that set pressure.

...your talking about the line coming to the banjo bolt on the AFC...Correct?

Yes. Replace with barbed fitting, and line, or push lock fittings and line, and boost controller. Use shop air to preset the controller, install and fine tune.

http://cgi.ebay.com/ebaymotors/NXS-MANU ... ccessories

That inline. Bottom port to intake manifold, side port to AFC housing.

[cougar]

Based on the picture and original description:

Boost pushes the pin down. So if you have the star wheel all the way up it will keep the pin from going all the way down.

The smoke screw sets the starting point for fueling when the pin is all the way up. From the mark on the pin. lifting it further will cause the follower to slip under the pin.

The groove on my M2 starts a little higher than the Denny T, so I was able to install a spacer to lift the cap and still have lots of room on the bottom of the pin.

[JBradley500]

on my pump you could raise the starwheel all of the way up and still not limit the travel of the AFC lever with a denny t2 pin. i flipped the starwheel over and then i could limit the travel. you have to take off your pump top to find out when your starwheel is too high by messing with the internal lever.

[thechoochlyman]

I recently finished up this project and made an adjustable valet valve for it. I'd still like to look into the "gillis" or ball-and-spring valve like was suggested earlier. Upon closer inspection of my pin, the movement didn't go quite as low as it appeared. I went ahead and milled out the underside of it so the pin could come up a bit more.

I didn't take a before picture, but I cut it about a millimeter past the slots on the side of it.


And here is how it looks on top. I machined a thread adapter to go in the AFC cap so I wouldn't have to drill and tap that itself. I also milled off the lip around the smoke screw so I could actually get to the jamb nut.

[cougar]

I was just thinking about how much you can machine off of the inside of the cap. Measure the distance between the large area washer that holds the diaphragm on to the fuel pin and the top of the nut, or the top of the fuel pin whichever is higher. That is how much you can take off that flange. You can do a combination of machining the flange and the bottom of the smoke screw pocket to get more. I opted for a .120" spacer between the AFC and cap.

[thechoochlyman]

The way I "calibrated" mine was simple. I just set the pin in the AFC housing, and left it where the naturally rested on top of the spring. (with the wheel all the way down) I moved the throttle a few times to extend the pin in the housing, and pushed the fuel pin down to make sure the bottom of it wasn't over top over the small pin. I then put the cap back on and adjusted the smoke screw to where it would barely touch the top of the fuel pin as I put the cap on.