Engine Specific Info and Questions > IDI Engine
How our injection pumps work, videos and service manuals inside
kaneb:
Hello fellow deezulers!
I just threw this video up on you tube i had collected. It shows the workings of our little injector pumps! I am not sure how to embed videos here so ill just post the link to my you tube page.
http://youtu.be/9-GSNR7W73M
This leads to my next question. So we can turn up the max fuel screw for more fuel, we can shim the governor spring for fuel in the top end. We can tweak and turn or get crazy and grind the boost pin for more fuel. This is all good help and gives us more ponies but i remember about reading a few years ago on here of a guy who machined down the cam plate on the front side of the pump for a wee bit more advance in the top end which gave gains too or so i thought i read it back a few yrs so could have my facts off. I'm still wanting to learn more about these pumps so hopefully the gurus chime in.
vanbcguy:
The advance curve can definitely be changed - it is controlled by shims, springs and the height of the cap on the advance. If you look at a TDI pump for instance the cap is much longer, allowing the advance piston to move further.
The problem is - change it to what? Without a pump dyno all you can do is guess and test. I don't believe there is really any advance above 4K with the pump in its stock form so in theory allowing it to do more would help it rev in to higher RPM ranges while still being able to burn the fuel in time.
At the extreme end, Giles apparently modifies the internal pump body to allow the timing piston to move even further (there is a limit to how much the roller cage can move before the pin bumps against the pump housing). But he's got a pump dyno so he can see exactly what he is changing, plus he knows what the settings are for ultimate power. :) Part of his "formula" is building a lot more dynamic advance in to the pumps.
If you are prepared to be a guinea pig, you definitely can play with the springs / shims / advance cap quite easily. The hard part will be measuring the results in a consistent manner!
nwcali6:
--- Quote from: vanbcguy on March 23, 2013, 01:59:44 pm ---The advance curve can definitely be changed - it is controlled by shims, springs and the height of the cap on the advance. If you look at a TDI pump for instance the cap is much longer, allowing the advance piston to move further.
The problem is - change it to what? Without a pump dyno all you can do is guess and test. I don't believe there is really any advance above 4K with the pump in its stock form so in theory allowing it to do more would help it rev in to higher RPM ranges while still being able to burn the fuel in time.
At the extreme end, Giles apparently modifies the internal pump body to allow the timing piston to move even further (there is a limit to how much the roller cage can move before the pin bumps against the pump housing). But he's got a pump dyno so he can see exactly what he is changing, plus he knows what the settings are for ultimate power. :) Part of his "formula" is building a lot more dynamic advance in to the pumps.
If you are prepared to be a guinea pig, you definitely can play with the springs / shims / advance cap quite easily. The hard part will be measuring the results in a consistent manner!
--- End quote ---
Said another way, you can put the money out and have Giles build you one, or you can spend far more money and time trying it yourself.. Or just go with the mods you can do and forget about advancing the timing past that point.
DogDiesel:
Thanks for posting the video. When I took Diesel Engineering 30 years ago, I remember my injector pump calibration class. Distinctly remember how clean we had to be when we moved a pump to the test stand. Also remember the price of the stand, and realizing there is a reason everyone cannot do pumps on their test bench.
Also, remember at the time, there were five types of injector systems. Part of the class leaned forward and described the future where there would be six more types with the onset of electronic injection. They provided a theory class of an engine without cams and rocker arms, all electronic solenoids, and an flat engine with a piston on each end and no cam. Today, that is all here.
A funny part of the class on Injector and pump calibration was the test. The answers were actually on the test. Behind the questions was shadowed writing and if you knew what to look for, the answers were there. I aced that test, but there were quite a few that failed in my class. The questions were tuff, and unless you attended class and studied, you'd blow it with the answers right in front of you. The advice posted on this forum has been sound.
Wayne
--- Quote from: kaneb on March 23, 2013, 12:58:01 pm ---Hello fellow deezulers!
I just threw this video up on you tube i had collected. It shows the workings of our little injector pumps! I am not sure how to embed videos here so ill just post the link to my you tube page.
http://youtu.be/9-GSNR7W73M .
--- End quote ---
8v-of-fury:
Figured I'd take this thread, add this;
http://www.fostertruck.com/Files/VW_diesel_77-83.pdf
and then sticky it so people can find it easily :).
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