base line settings for pump

[nuthugger]

I just resealed the pump and I noticed there are a lot of little adjustments that could be made. The most important being the governor shaft that is blocked from adjustments once it is installed on the engine. The rest I can figure out later but I cant install this until I adjust the governor shaft first. Any ideas? The fuel screw I marked so that is ok. The linkage oops I did not mark any of thoes either but I can play with that later. And how about the "star" wheel? What does it do? I understand it changes spring pressure on the diaphram above it and boost pushes back but what does all this control? I assume fuel enrichment that is needed as boost increases. Is there a manual that gives these base line settings out there? What do the rebuilders use? And why is it important to lock the pump to install it?



Thanks for any help

Jason

 

[dpuckett]

The pump lock is for when the pump is bench timed and needs to stay EXACTLY where it was put. Otherwise, just put it on the engine and retime it if you ahve the tools, or line the marks back up.



The governor shaft- I'm not sure. Greenleaf said in his class to leave it alone, or put it back where it was. I was looking at my other pump yesterday, and it seems to me like you could gain more fuel by moving it inward, though I could be wrong.



The AFC is a smoke control device. There is information in the stickies at the top of the forum.



There is a manual out there, but I've heard it is expensive ($400?)



Daniel

 

[nuthugger]

Where is this manual I want to learn more on this pump. Does anyone know the name of it so I can search the net or EBAY? I found the AFC on other posts so I am ok with that. That manual would really help. I did the most amature move by removing everything with out marking it or toking any pictures.



Thanks so far for the help.

 

[PToombs]

GL says " The end of the governor shaft should be even with the end of the nut. Turning it in or out will not affect fuel unless you move it a long way. The best way to play with this adjustment is on a test stand where it can be easily adjusted. " The only thing I got out of pump class! Sorry Scott, I'll pay more attention next year. The AFC gives the engine more fuel as boost goes up. Turning the starwheel down relieves pressure thus giving more fuel at less boost pressure.

 

[Greenleaf]

It's a timing thing, indirectly. The setting of the screw will net the internal pump pressure cut-off. The shaft contains a passage that is uncovered by the sliding sleeve. Load compenstion.



If the shaft is backed outward, then the internal pressure would cut-off sooner becasue the port would be uncovered sooner. Just the opposite is true if you threaded the governor shaft inward.



Don't confuse the cut-off port with the one on the pump's plunger.



Get all that?



There is a manual you can obtain for nearly free from this site. One is "Theory of Operation" and another is a link to the step-by-step picture manual on a web-site for VW engines.

 

[dpuckett]

... . The only thing I got out of pump class!...

Yeah, that's because we tried to have timing class over at my and Jeremy's pickups and found we had wrong adaptors. . :-laf



I came to my conclusion based on the thinking that everything else in the pump increses by turning in, why not this adjustment, too?



-DP

 

[nuthugger]

Thanks for the info guys. I decided as an ASE master mechanic with absolutly no expierence on this pump it would be better if I had it set to factory specs by a pump rebuilder. I am using Midwest Fuel Injection for this. Once the factory specs are set and the truck is running I will tweak it for a little more power. I do want a copy of any manual for this pump if available and I do not want it from a website. I am looking for a publication from Cummins or Bosche on this. If anyone knows where to get this I would appreciate it.



Thanks Jason

 

[MMeier]

What's to be gained by playing around with the screw and locknut under the stamped cover... (under metal cap)?

 

[nuthugger]

I think it is the fuel screw. I will have to look into this better before I play with it.

 

[Greenleaf]

Listen close..........there will be a test.

It is one of the adjustments to change the fuel injection rate. Used to fine tune flow rate during a bench test. Some folks will turn this screw IN to increase delivery of fuel injected to increase the power band. There are other methods as well, all of which will serve to increase the HP of said engine.



There will be a point at which the engine can recieve more fuel than it can burn so air adjustments are needed to utalize the increased fuel rate and prevent large quantities of black smoke and possible overheating the pistons.

 

[dpuckett]

What's to be gained by playing around with the screw and locknut under the stamped cover... (under metal cap)?

That is the "smoke screw" I forgot they came from the factory covered up. I have never noticed much difference in messing with it. I back it out as far as it will go and still clear the cap (if I still have one on a particular pump), and leave it just in case it smokes.



DP

 

[JLEONARD]

Jason,

I am not answering anything in this thread until you come clean on why you chose "nuthugger" as your screen name.

We wants to know.

Jay

 

[MMeier]

Jason,

I am not answering anything in this thread until you come clean on why you chose "nuthugger" as your screen name.

We wants to know.

Jay

Maybe YOU wanna know, some of us do not !

 

[nuthugger]

I was under the impression the smoke screw was a star wheel just under the diaphram on top of the pump. Or do they call the fuel screw the smoke screw because it has the ability to dump a lot of smoke out when turned in. The screen name was given to me by my "friends" a long time ago since I have a habbit of adjusting the large package :-laf