Question about AFC mod

S

seancrete

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Jun 24, 2007
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I'm getting ready to mod my afc. My question is about the washers. I understand the concept of reversing and grinding off the lips.

Has anyone used smaller diameter washers that will move past the edge of the housing, where they currently stop, and end up stopping on the star wheel tube? It looks like this would give about 4-6 mm more travel. You would need to remove more material from the barrel/tube. It looks like there is enough extension left in the diaphragm so it wouldn't be stressed. This may not be useable travel.
 
Take a 1/4 inch washer as a reference and go to say ace hardware and find a couple of smaller diameter washers with the same hole size and put them under the inside washer to give you more forward travel, typically it will bottom out before you get into coil bind on the AFC spring, been doing this for a long time.

I do it mainly so I can move the AFC further back and cut low end fuel for smoke control then creep up on the low end with the low boost fuel screw to the desired level for response, I actually cut the fuel back so far that it creates lag due to lack of fuel, then I add turns on the screw till it acts like I want it too.

Jim
 
Anyone got any pictures of the washer method? I just got 1 fender washer stacked between the diaphragm & the afc housing..
 
Thanks for the confirmation Jim. I have been reading your posts since TDR. So basically two washers slightly larger diameter than the spring, and the correct inner hole size.
 
TDR days, dang that was a decade ago, no actually the tiny washers go inside the spring! You can use a 1/4 inch washer but it may catch on the spring as I have witnessed on the bench using shop air and a hand held regulator........that I have preached for years, use the smaller washers so they don't interfere with the movement.

It's funny, you mess with this stuff for years and then one day the light comes on and you learn something new, love these times!

Jim
 
After I posted I visualized what you were typing. Thanks, I'll do it this weekend.
 
If anyone comes here for me to work on their 12V I teach them as I do it, takes a bit longer but it is something they need to know, a hand held air regulator to simulate boost is a must with a 12V.......the most important tool! Timing is easy, running valves easy, trouble shooting easy.......it's all about communication, listen to the motor, pay attention to what is saying. I'll never forget the day that Piers taught me the index finger on the injection line to feel the pulse, are they different from the pump...no, injector side yes, problem is the injector.....worked everytime!

Jim
 
Jim Fulmer said:
If anyone comes here for me to work on their 12V I teach them as I do it, takes a bit longer but it is something they need to know, a hand held air regulator to simulate boost is a must with a 12V.......the most important tool! Timing is easy, running valves easy, trouble shooting easy.......it's all about communication, listen to the motor, pay attention to what is saying. I'll never forget the day that Piers taught me the index finger on the injection line to feel the pulse, are they different from the pump...no, injector side yes, problem is the injector.....worked everytime!

Jim
Click to expand...

And I just learned something from you again Jim. :bow: :clap:
 
No doubt. I've been using shop air but tuning my low end with the afc. Will be using your method next time.
 
Jim told me years ago how to set up a regulator and adjust the afc. I have to admit I have used it many times. Thanks again jim
 
TRUBBS said:
Anyone got any pictures of the washer method? I just got 1 fender washer stacked between the diaphragm & the afc housing..
Click to expand...

Bump, looking for a picture to see if I did it right or not ..
 
no pics, but Jim's method is (from front of afc to rear):

- shaft
- small washer(s)
- fender washer (or smoothed factory washer)
- diaphragm
- other fender washer
- wave washer
- nut

**I actually flipped the wave washer on mine to the opposite side before the first fender washer for even more forward travel when using the stock afc spring.... but ymmv depending on spring/rate/seated height/preload
 
Hurley said:
no pics, but Jim's method is (from front of afc to rear):

- shaft
- small washer(s)
- fender washer (or smoothed factory washer)
- diaphragm
- other fender washer
- wave washer
- nut

**I actually flipped the wave washer on mine to the opposite side before the first fender washer for even more forward travel when using the stock afc spring.... but ymmv depending on spring/rate/seated height/preload
Click to expand...


Thanks, I'll Amit it, im a very visual person so I'll probably have to tear the afc apart on the bench & put it back together as I read your post but can't mess it up with step by step instructions :lolly::thankyou2:
 
Really no need if the back washer is thin enough, when I turn the stock parts down I often have to advance the off idle fuel. Taking 0.100" of the barrel will also provide more travel than is needed again if the washer is thin enough.
 
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