Set me straight on fuel cones, please

[Begle1]

I thought that there was a limit to the amount of AFC travel that could be gained by extending the fuel cone profile, due to the AFC lever contacting the case.

I thought that limit could be reached by simply grinding down the stock fuel cone?


How is it that a DennyT pin can give you travel beyond what a ground stock fuel cone can give you, yet you can't gain the same results by grinding a stock fuel cone and shortening the rod that rides against the fuel cone?


To actually take advantage of the profile of a DennyT, don't you need to go to a longer rod and grind down the AFC lever accordingly?

[crewcabxlt]

i noticed this when ive had pump tops off, even a longer rod wont add more fuel, ive posted about this before. i grind afc lever a little and grind my own pin so i still have afc control. i think alot of fuel leaks out the afc occur with pins cut too deep. the stock pin can be ground to fuel als much as the afc lever can move.

[burnt_servo]

i've noticed the same thing playing around with vw ve pumps , a person can grind deep enough into the stock fuel cone , to the point where the pin no longer rides on the cone ....

[Begle1]

i've noticed the same thing playing around with vw ve pumps , a person can grind deep enough into the stock fuel cone , to the point where the pin no longer rides on the cone ....

I would also imagine that a witness mark on the cone might falsely indicate contact, because the fuel pressure in the injection pump could continue to press the rod against the cone even after the AFC lever reaches its limit of travel?

[burnt_servo]

i've noticed the same thing playing around with vw ve pumps , a person can grind deep enough into the stock fuel cone , to the point where the pin no longer rides on the cone ....

I would also imagine that a witness mark on the cone might falsely indicate contact, because the fuel pressure in the injection pump could continue to press the rod against the cone even after the AFC lever reaches its limit of travel?

is the fuel pressure behind the pin significant enough to push the pin into the cone ?

what i have seen is this ;

i use white lithium grease on the cone , there will be dark marks in the grease roughly 1/8 to 3/16 of a inch higher up the cone than the actual wear marks in the metal .

what i'm thinking is the afc lever has limited out and is no longer putting any pressure on the pin / cone where it stops marking the metal on the cone it's self .

but the dark marks in the greas might be the fuel pressure pushing the pin into the cone ?

[dpuckett]

Fuel pressure inside the pump will move the pin past the sealing point- I saw it in my own truck with the fuel cone removed just to see what it does.

Daniel

[cougar]

If you haven't been to
http://www.dieseltruckresource.com/dev/ ... p?t=231863
and here
http://www.dieseltruckresource.com/dev/ ... p?t=200901
yet, this may answer some of your questions.

A guide pin follows the fuel cone. In turn, the guide pin controls how much the AFC lever moves. Shortening the guide pin will only move the location of were the lever travels, not how much. The same is accomplished with the fuel screw. A fuel cone/pin with a different profile however, will change how much the AFC lever moves. More travel. There are 3 different guide pin lengths that can be used to keep the pin on the o-ring. Yes there is an overall mechanical limit to how much travel the AFC lever can attain.

Hope this helps.

[Ace]

I'm pretty sure the guide pin is doing it's thing on my BD fuel cone, because it's digging in there deeper and deeper and starting to get pretty aggressive.

[cougar]

BD and Old Smokey pins have a history for being too soft. M&H and Denny T are reported as hardened pins/cones for longer life.

[cougar]

I'm pretty sure the guide pin is doing it's thing on my BD fuel cone, because it's digging in there deeper and deeper and starting to get pretty aggressive.

I was just thinking.
If you know a gun smith, they should be able to clean it up and either heat treat it or case harden it.

[Ace]

I'm going to tap it with the MIG a few times, quench, re-surface with a slightly modified profile and see what happens.

They appear to be case hardened from BD, not enough. Once it got through the surface it was all over.

[noseamum]

What is M&H?

[Begle1]

Yes there is an overall mechanical limit to how much travel the AFC lever can attain.

So what is required to reach that limit?

Is that limit reached with a ground stock fuel cone?

[Swaggs]

I saw a dyno run on youtube with a ground stock pin, and right after they installed a denny2 it gave it like 26 hp and 31 tq... So, i dont know if the lever does reach max with a ground stock, or do you think maybe it just reaches max earlier and stays there.. i dont know..

[cougar]

Yes there is an overall mechanical limit to how much travel the AFC lever can attain.

So what is required to reach that limit?

Is that limit reached with a ground stock fuel cone?

To give you some exact numbers I would have to take one apart and measure it. Researching other posts here and other web sites you can attain quite a bit (relatively). Some people will grind their AFC lever to get more travel. Some have removed it all together to get max performance period. Before you ask, the AFC meters fuel based on boost and the pin/cone is just to profile fueling in relation to. Remove the AFC and you no longer have "boost based" fuel profiling, just straight throttle position.