So I took my pump top off today for something to do. I remembered leaving a bit of the AFC foot there and thought I'd take the opportunity to fix that issue

Anyhoo, while I had the top off, I got to looking at how all the AFC linkage relates. With the pump top off, one can clearly see the AFC lever pushing on the little pin by looking up though the bottom. I slid the stock cone in and pushed on the linkage while sliding the cone up and down in the bore. Even at the deepest setting, the stock cone limits pin travel into the bore by almost half a pencil width, which is alot when considering there's really not much movement there at all. So, I thought I'd check and see how much more travel my home grown pin gave me. Well, it's more than enough, that's for sure. Eventually, the pin is buried in the bore and the AFC linkage 'bottoms out' and my cut cone produces just that situation before it's even halfway down...

Soooo, if a factory cone can be cut deep enough to max out the AFC linkage on the pump internals, why spring for an aftermarket one? I'm not knocking the original Old Smokey pin--it likely has much smoother delivery than my hack job...but when it comes to all out max fuel, a buried pin is a buried pin, right?

On another note, my Bosch reman is a later model with the plugs for the AFC linkage...I was ready to grind the whole thing off, but thought better of it for the time being.

At any rate, every adjustment on my pump is set to 'kill' and I think the thing is just a pig. Even with the AFC grind, the 12cm lights quick enough to make smoke almost a non-issue. I'm plumbing in a FP gauge early this week and I'll have some video of how badly I'm likely starving my poor VE shortly thereafter....Blah blah blah...some pics for the hey of it


AFC grind and 366 spring:




Cone compar-O:

 

What keeps the cone from snapping off at the tiny waist??

What advantage is the 366 spring??

Thanks.

 

It's not cut as thin as the pic implies...and that is some crazy hardened material to boot!


The 366 spring AKA 3200 rpm spring is the best 15 bucks you'll ever spend on your engine. It allows the pump to fuel right up to 3k or so, making the wide spaces between Getrag gears more acceptable...and just making the little 6 scream. The first time I heard mine hit 3000 I got chills

 

SOOO that massive intercooler working so well that you looking for more fuel?


Again!


Flash.

 

Yes...

 

...........well ya haven't tried propane or laughing gass........yet!


na you need a lot more fuel reserved at the inj pump first!

Flash.

 

So your cover has the tin plugs over the AFC lever pivot shaft? I'm glad that is really where they are supposed to go.

I am a little surprised that your AFC is not leaking -- if the eccentric is cut too deep, fuel pressure can force the pin to extend far enough that the rounded end can pass the o-ring that seals it.

At this point of mods, there are only three things that I can think of that might make your pump "a pig". One is that there is not enough supply fuel. The second is that the plunger piston leaks escessively, and the last lies in a little shim that was brought to my attention the other day -- it is actually more a thrust washer that goes between the cam plate and the plunger. It might be possible that a thicker shim could reduce the effective plunger stroke, by changing the position of the relief hole relative to the control collar, but I haven't figured out how the shim thickness is determined by Bosch -- it is a non-serviceable part in the digram that Jim Lane posted.

Keep up the good fight!

 

Hey Alec, good point on the AFC leaking. So far, it's dry as a bone in there, save for the bit of grease on the pin. Now, however, I'm thinking about grinding my stocker so that the pin JUST gets buried to avoid potential leaks.

As for the PIG factor, I'm rounding up a FP gauge today. I've waited too long and it's really the first step in determining the state of my supply system. The shim is an interesting idea...my original pump with 300XXX miles felt stronger than this one .

All in all I'm pleased with the truck. Cowboy_Customs and I ran up to northern VT and back the other night on a bonzai mission and the ol gal pulled down 21+mpg running 70+ for 14 hours

 

Beats me, Greg. My truck made more HP with a borrowed Old Smoky pin than with a cut stocker. Maybe some pump tops are different than others.