Fuel pin discussion

[ellis93]

Ok.....since I'm screwing with injection pumps anyhow I'm going to start playing with the profile of out fuel pins. I hate idle haze and I can't turn a stock pin to the deep side without having it. And if I turn the thing toward the shallower side it can't allow the pump to fuel its hardest,you also can't grind on it there to achieve the full fueling either. I've spent some time with a mic and there's no way. You can remove the pin from any pump and the guide pin only moves out to a little less than half the pin bore.
One would guess that's where the fabled longer guide pin comes in,to take up the slack while using the pins natural profile on the deep side.

What I'm going to try to do is to use my mig machine and add material to the bottom of the fuel pin to let it push the guide pin back like the shallower side would. This way I could achieve little to no haze,while getting fuel fuel from a stock pin with a mild grind to the upper extremity.
I should also add that when yo grind a factory Bosch pin....there is no reason to grind at the very top of the tapper. The guid pin never sees the last 1/8" or so of ramp. If you doubt this,remove your afc diaphragm,drop the pin in its bore, and while holding the throttle wide open pull up on the fuel pin. The mark on its ramp will show you what im speaking of.

[oldestof11]

I put grease on my pin to check travel when adjusting the spring. I disagree with the last 1/8" comment. My pin uses nearly the whole ramp. I don't use as much of the bottom of the pin like I would like to. Where it's thinnest, it ususly stops there.

As for welding, I'd be afraid of ruining the heat treat.

I'll look it up but some one found that a certain drill bit size fits perfectly as a pin.

[ellis93]

Jon I'll snap a few pics. Unless your pump has a deeper bore or this non I/c'ed pin is longer than what your using,what I see is fact. Not trying to be argumentative,just so you know.

As far as ruining the hardness....I'm not worried,it's nothing quenching the pin while hot won't fix. I'm no expert on the hardening of steel but I've made a few knives and axes,and have had really good luck at hardening them enough to keep an edge.

[Remps]

When I ground my pin I took a little off the bottom as well, I don't recall if it allowed the pin to travel down any farther or not.

[oldestof11]

Jon I'll snap a few pics. Unless your pump has a deeper bore or this non I/c'ed pin is longer than what your using,what I see is fact. Not trying to be argumentative,just so you know.

As far as ruining the hardness....I'm not worried,it's nothing quenching the pin while hot won't fix. I'm no expert on the hardening of steel but I've made a few knives and axes,and have had really good luck at hardening them enough to keep an edge.

When I do my gov spring, I'll try to remember to snap a pic. They could be very different. Idk.

[ellis93]

I have a few different pins and until you said what you did I didn't think to compare them. I have three different pins....two ic and one non ic,then a m&h m2 pin.

[PToombs]

I have an alternate method for you. In the AFC top, grind off that ridge around the screw, the 1/2 moon thing. Then, grind the bottom of the cone just enough to make a nice taper so the fuel pin can slide from the ramp to the ring at the bottom of the cone. Grinding the top lets the cone come up, and then it pushes the pin in a little farther and defuels it more. I did this and it cut my haze and take off smoke by over 1/2. Remember with the valet I'm running on that spot all the time until I turn it on. Taco did it and I thought I'd give it a try. I was very pleased with the results.

[ellis93]

Already did that Pete. It helped some,but I'd like zero haze.

[AHineman]

Idle haze could be injectors/timing. A few degrees is the difference between mine killing mosquitoes or having invisible exhaust.

[AHineman]

Fuel Haze: http://youtu.be/87RPq0vDhBg

Clean Idle: http://youtu.be/Rdjog_kw_kU


It's been awhile, but I think the hazy idle was 18.5 degrees, but it could have been 16.5.

Clean idle is 22 degrees.


Your setup is different I know, but it shows the difference a few degrees makes.

[ellis93]

Andrew your on the money with the timing. When my pump gear was jumped a tooth and bumped an 1/8 I had no haze with the 7x10s or the 5x10s. Now that I have lost all the timing except the 1/8 it hazes cold....and some hot. I'm tempted to put the timing back just because of that but like the grunt the truck reclaimed as is.
I'm hopping that I can Dick with this pin thing and get the same results. If it doesn't work no biggie....when I install my resealed/rebuilt pump,I'll jump the timing again.

[ellis93]

Ok now for the pics of what I'm seeing with cut fuel pin I've doctored. First off,I'm holding the afc lever full forward with my finger and the pin fully in its bore.



And how the pin is ground. It's not what I've done at the top but the bottom is mine. I build up the bottom.

I still have to add to the sides of the new ramp but that'll come later,after it does what I want.
You can see the rubb line on the surface now.
And this is the amount of pin that free floats before it makes any contact with the guide pin.

No doubt there may be a line at the top of others ground fuel pins but it simply isn't doing any fueling. What I'm figuring is the internal fuel pressure is pushing the pin farther out and making it touch. I mean look at how far the lever will push out the guide pin

[RCCUMMINS89]

You are not seeing it use the full ramp because you are still using the factory nylon stopper.

The advantage to removing the stopper is to utilize a further ramp profile and therefore giving yourself more control through out the band (more afc adjustment if you will).

It is absolutely IMPOSSIBLE for afc tuning to affect AT IDLE haze or smoke. It has ZERO affect on the fulcrum lever position AT IDLE.



There is no way to gain as much control with a factory pin as a proper aftermarket.... the reason, diameter of the fuel pin. However one can turn to the shallowest side, remove the nylon stopper and gain full fueling with a factory pin.

[RCCUMMINS89]

That is also where custom slide pins come into play.


5/32" drill bit is .001" smaller diameter than our factory slide pin.... we can also grind A LOT of material off the defuel side of the afc top to gain a longer slide pin. My slide pin is over 1/4" longer than the longest factory slide pin that Bosch made.

[ellis93]

You are not seeing it use the full ramp because you are still using the factory nylon stopper.
brother there isn't a coller in sight on this,that line was made on the pin from me mashing the schit out of the afc lever and pulling like hell on the pin

The advantage to removing the stopper is to utilize a further ramp profile and therefore giving yourself more control through out the band (more afc adjustment if you will).

It is absolutely IMPOSSIBLE for afc tuning to affect AT IDLE haze or smoke. It has ZERO affect on the fulcrum lever position AT IDLE.

[bi disagree,I can remove the pin totally from the pump on my truck and and turn it completely around and it almost stops hazing at idle (m&h pin). If I didnt see that I wouldn't bother with all this. ][/b]

There is no way to gain as much control with a factory pin as a proper aftermarket.... the reason, diameter of the fuel pin. However one can turn to the shallowest side, remove the nylon stopper and gain full fueling with a factory pin.

I haven't had that spacer in a pump on this truck since I started messing with it. I threw that thing in a plastic bag in the glove box and there it stays.
All this has been done with a spare pump top,out on a bench.