pump mods practice and theroy

[TestDriver]

.........
ok well all our pumps confuse us at times but something were familiar with can be used to explain them thats youre brake system. think of the pump as the master cylinder and the injectors as the wheel cylinders.
the pump with a bigger piston creates a force on the fluid which is transfered to the injectors with a theoretical smaller piston creating more pressure.

Interesting stuff here. I've got such a hookup to the advance/high idle circuit for my old, tired pump. On hot days, it's the only way it will stay idling with hot oil going through it. I use it at stop lights mostly.

As for the quote, you have this reversed. In a fluid system, for any given pressure, a larger piston will exert lower force than a smaller piston. If you consider that pressure is a unit of force over area, P=F/A, when the area increases, the pressure goes down. Likewise, if the area decreases, the pressure goes up. That's why we can jack up things with bottle jacks with pistons of about 3/8" diameter.

What you said about the DB4s is interesting. Do you know what the diameter of those plungers is?

 

[TestDriver]

Some Pics

I looked through this computer and found a couple of pics for you.

Plungers, one is new the other from a bad pump.

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Rotors that went with the two pumps.

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[subway]

or jred email it to me and ill put in my original post where needed pm me for my email

i am trying to find it, searched all my flash drives, might be on my othe computer.........it was posted here a while ago but i cant remember the members name.

edit:

the member was RKOCH, he claimed to have grafted a DB4 to a DB2 and have a powerstroke turbo grafted in (he showed pics of the turbo). he talks about the pump towards the end of this thread but not much detail
http://www.oilburners.net/forums/showthread.php?t=24177&page=2&highlight=pump

 

[88beast]

test driver i want to put up stuff like that in youre pics but with how to get the parts out
and youre explination works better makes more sense but thats what i meant in a wheel cylinder and master cylinder setup the mc may have 6 psi on it while the wheel cylinder (smaller piston) will have 12 psi
jred take youre time i got some stuff to come up with too

 

[TestDriver]

test driver i want to put up stuff like that in youre pics but with how to get the parts out
and youre explination works better makes more sense but thats what i meant in a wheel cylinder and master cylinder setup the mc may have 6 psi on it while the wheel cylinder (smaller piston) will have 12 psi
jred take youre time i got some stuff to come up with too

The pressure on both is the same. Even when there is flow, you can assume the pressure is the same on a closed hydraulic system with relatively short distances. The input and output, force, is what is different.

Wheel cylinders may be of the same size or slightly smaller or larger than the master cylinder. However, drum brakes require much less force to operate the shoes than the force needed from calipers on disk brakes. That's why you'll find caliper pistons are much larger than MC pistons and sometimes, there are multiple caliper pistons as well.

I have a pump already disassembled. If I remember to do so, I'll take more pics tonight and post them later.

 

[88beast]

sweet take tons of pics
i was talking output forces i guess that would be lbs not psi

 

[DeepRoots]

Wow..... so this is really enlightening to anyone here?
This is the biggest pile of feces I've ever seen. Not only did I not learn anything, I actually feel like I'm going to have more trouble spelling things for weeks to come.
If this becomes a sticky, would the mods PLEASE delete my account?

thanks,
Dp

 

[FordGuy100]

Wow..... so this is really enlightening to anyone here?
This is the biggest pile of feces I've ever seen. Not only did I not learn anything, I actually feel like I'm going to have more trouble spelling things for weeks to come.
If this becomes a sticky, would the mods PLEASE delete my account?

thanks,
Dp

To fully understand how to mod one of these pumps, you will need to know basic function. I would suggest to all wanting to do internal tweeks to learn how exactly a DB2 pump works. Not just high idle, gov. spring, etc. I'm talking about what happens from when the fuel comes in the inlet and exits out of one of the lines. Until then, modding is kinda a dumb idea.

I would suggest looking to 6.2/6.5 sites, those guys tend to know a lot more about their pumps then we do.

I still dont know exactly what happens in an IP, until then, I will leave modding to the pro's.

 

[hce]

Ever notice really good experienced mechanics can always tell you what not to do. How do think they found these things out?

 

[88beast]

one i want to take it apart and explain in pics thats why no mods have been posted except the easy stuff
deep roots im sorry for my spelling why dont you buy me a dictionary and send it to me
there is no reason to trash a thread this is to help explain how things work within the pump and to help people know whats happening if they change out the rotor or just turn up the fuel screw so if you can do it better heres youre chance school us all on pumps if not drop off this thread because up till you everyone was helpful or grateful for the info i posted
and im sure you would be too if you just bought youre truck and wanted to tune it up a bit

 

[88beast]

Ever notice really good experienced mechanics can always tell you what not to do. How do think they found these things out?

i talked to a guy a while ago who did nothing but mod these pumps he worked for a fleet when the trucks came out and found himself doing pump repair on them as the guys running the fleet opted for wmo diesel and wvo mix in the trucks and it was a messy pile of crap going into the fuel system
then he started his own diesel shop years ago and recently retired but he rebuilt these things all the time when they were 10 years old they were in every local fleet and some still are
also he has messed with chevy motors and dodges too along with big trucks thats how i got everything explained to me he pulled out a service manual from 92 with pictures and everything clicked while the one linked eariler is not quite good enough for me
so yes he has modded these things and has done a lot more than i mentioned and he gave me his two cents on it good or bad

 

[phazertwo]

GREAT THREAD! good information here! However I am with deeproots (just not that mean), it could be displayed better.

Also, in any pneumatic, or hydraulic system, the pressure does not change change from the pump to the piston (or injector in our case). So saying that the larger piston puts more pressure on the smaller piston is actually wrong, the pressure is always equal. It is only the force that changes. The pump has a large piston that puts pressure on the system, the injector has a small piston so the force is actually smaller. However the same amount of fluid that the pump displaces needs to pass through the injector (since diesel does not compress like air), and it needs to pass through it in the same amount of time that it takes the pump to move it. Since the hole in the injector is MUCH smaller than the piston in the pump, the fluid must increase velocity, which makes the fuel atomize on its way out the injector nozzle.

I think you were headed down the right path, just need to straighten up some terminology

Edit it up, and it should be a great read!

PZ

 

[88beast]

well ya the display sucks i will admit but the info is good i will rearrange the info and edit to make more sense i threw this together at like 3 am

 

[Agnem]

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[88beast]

now do you have a exploded view mel and a labeled one to tell what everything is?
thats the pic that inpspired me to put something like this up because at first i looked and said um ok thats an ip and had no idea what did what