Help me understand how the injection pump works please

[franklin2]

I was reading with interest the other thread where the guy put new injectors in his engine with a old pump. It was discussed that he should replace/rebuild the pump since it's not up to making the new injectors work.

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What is exactly done to a pump to make it "new again? If I am figuring this out correctly, the plunger(there are really two I think) in the above picture are what develop the high pressure to the injector correct? Are these replaced? If I am right, how is the bore where the pins ride refurbished?

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The piece in the first picture goes around inside the piece with the "bumps" or cams on the id correct? And a pump for the 4 cylinder would have 4 "bumps", a 6 cylinder 6 "bumps", 8 cylinder 8 "bumps". Do I have this figured correctly?

 

[RLDSL]

An injection pump is kind of like a tiny engine or compressor. It takes the fuel and squeezes it from a larger area into t smaller one and using hydraulic principals increases the pressure a whole bunch in teh process. The little parts inside have things similar to piston rings to hold the pressure and they wear over time and won't build as much pressure as when new.
a new set of injectors has a tight set of springs and when old and worn they get old and soft and dont' require as much pressure to open, so they wear along with the pump that puts out less and less pressure over time, but it's so gradual that you barely notice it ... till you get in someone elses truck and go, man, I've got a real dog..... then it's time for a new set.
Problem is if you replace teh injectors, you have nice tight injector springs, and a poor tired old injection pump , so it will be giving it's all, but in trying to keep up with the extra resistance, it will eat itself up before long.

THat's the not so technical nutshell version

 

[franklin2]

I appreciate your reply, but apparently no one knows how the pump works inside? It's sort of like a auto tranny. I don't see myself ever rebuilding one myself, but I like to have knowledge of how it works inside so if I ever it get it repaired I can talk to the tech with some knowledge about it.

I read some threads awhile back that when you send your pumps to be rebuilt, that they come back and any hard parts that are replaced are in a baggy with the pump. Have you guys ever wondered what those parts are or what they do and how they fit in to the whole picture?

 

[Dieselcrawler]

works like this....

http://home.comcast.net/~steveham21/turbo.mpg

 

[icanfixall]

Let me be the first to fly the flag...... I'll bet that guy was running for office with all that bs squirting out of him..... Sure made me giggle....

 

[KyleQ]

Problem is if you replace teh injectors, you have nice tight injector springs, and a poor tired old injection pump , so it will be giving it's all, but in trying to keep up with the extra resistance, it will eat itself up before long.

THat's the not so technical nutshell version

So you are saying if I replace the injectors and pump on an original 160K truck I'll be able to break 60mph on flat ground towing ~7Klbs?

 

[franklin2]

I guess Stanadyne has this all wrapped up. Thanks anyway.