5521 IP rebuild instructions wanted

[simon]

i got a 5521 ip i want to try to rebuild , but i will need tear down and rebuild procedure and specs.

any body know where to get them?

[rameye]

call Stanadyne...I'm sure they'll be happy to help ;)

[gmctd]

Yep - that is the complete rebuild procedure, step by step, in detail: call Stanadyne or affiliated IP repair shop.

[Robyn]

I have had one of these pumps apart and replaced a couple things.

You really dont want to try and rebuild one yourself.

To do it right takes some special tools and of course a good test bench to run the pump on after you get it back together.

My honest opinion is take it to a good reputable pump shop and have them do it.
The results will be what you desire without the hastle of trying to do it at home.

Many people here I am sure are qualified to rebuild these pumps but we choose to let the folks who are in the bussiness with all the right tools do it for us.

If you are sure you want to try, be clean, go slow and mark or reference everything.

You will need to gauge a lot of parts for proper clearance so some mics and other fine measuring tools will be needed.

As far as replacement parts are concerned many of the pump shops will most likely have these and possibly sell them as needed.

Best advice on this subject I have.:)

Robyn

[DmaxMaverick]

Unless you have extensive experience rebuilding precision hydraulic pumps and servos (such as in aircraft), leave this to the Stanadyne shops. Robyn is right, tolerances are very close, and without the proper tools, you won't be able to measure those tolerances. You can do "testing" on the engine, but without a Stanadyne test bench, there may be extensive trial and error, and the pump comes out for adjustments, every time.

[simon]

Thank you all for your concern on this issue.

But when people say you should not, or you can't. than it just has the opposite effect on me. I'll have to find out for myself if i am up to it or not.
I did not get to where i am now by quitting before i started.

On this pump, I know I have to have it calibrated on a test bench and cannot do that cause i do not have one. but the mechanical part I know I can do, I have rebuilt several mechanical IP's over the years on other engines on my own equipment.

I do all repairs on my own and neighbors equipment of any kind for the last 30 odd years including welding and machining.

But I do not claim to know everything ,and every one needs some help on occasion.

I need to know how to take the damn thing apart without wrecking it, so the best thing is a manual, I just don't know where to get on

GRRRRR Simon

[DmaxMaverick]

I agree with you completely. But, how do we know which mushrooms will kill you? Someone must have seen the effect on someone else, and passed on the observation. There comes a time to just leave things to those who know. The DB pumps are mushrooms. If you are successful, attribute it to luck. I've had one success, and a bunch of paperweights. I do have extensive experience with aircraft servos, and it didn't help. Problem is, these pumps can be a total loss, and show no sign whatsoever of any defect, to the naked eye.

[rameye]

not to mention that the price of the bench test is halfway to a new pump!

I called wanting a suspect pump benched (I figured its like checking injectors) boy did I got an education!

apparently it gets broken down, component checked ,then ran on the machine for the finale!

[Robyn]

There is no disgrace in backing away from this one

This girl has built auto trannies for years as well as a lot of very intricate stuff. BUTTTTTTTTT, the material to do the job is available easily as are the tools

The fact is the books you seek are not available to the general scene and Stanadyne keeps it that way and rightfully so.
If every back shop was doing pumps there would be a buttload of junk out there that would give Stanadyne a real bad name.

You might find some books floating around on ebay or craigslist if you watch carefully but I would just let the pump folks do what they do best.

Nobody is going to point and snicker because "YOU" did not step up to the plate and do your own pump.

I wont back way from much but this is one area that I dont want any part of.
I have stood shoulder to shoulder with the techs in the pump shop when one of mine was being rebuilt and actually got my fingers into the mix.

This is an area that although not difficult requires special tools and they are not cheap to buy , even used.
You can pickup pop testers to do the injector nozzles fairly cheap and do that yourself.

Any way, this is my best advice and it seems to agree with the others who have added their opinions too.

Best to ya

Robyn

[simon]

Thanks for all the input fellows and the missus.

Its like standing on the edge of niagra falls with bystanders screaming dont do it, and all you wanna do is trow a pebble in the water to see how far it gets before it sinks.

Anyway if there ain't no info available then the game is over i guess,

but not yet.

[More Power]

Back when the DS4 first appeared, each authorized Stanadyne rebuild facility had to invest $20,000 to $50,000 to obtain the training and equipment necessary to rebuild/reman the DS4. We've tried to obtain rebuild docs for these and the earlier DB2 pumps, more for an informational excercise than an attempt to rebuild them. In these cases, the franchised Stanadyne shops refused to release that information for both business and franchise agreement reasons. I can't blame them.

So, unless there are bootleg and illegal copies floating around, the documentation simply isn't available.

I would suggest visiting a Stanadyne shop and ask to watch a pump rebuild, testing and calibration. I have... I consider myself to be very mechanically inclined, but I wouldn't attempt a pump rebuild in my shop.

Due to increased competition, the Internet has reduced the prices for pump rebuilds to a point that it really doesn't make sense to attempt a DYI unless you cut lots of corners and don't replace many of the parts that are always replaced (i.e. all electrical/electronic parts) as part of a DS rebuild.

I learned during one visit to a Stanadyne shop that a head/rotor replacement is the most expensive, and the shop makes no money on that pump (those with bad DS4 H/R's are usually scrapped instead of rebuilt). In many cases, the H/R can be reused after passing inspection.

Jim

[simon]

Being the stubborn guy I am, I tore the thing apart anyway, was not that hard to do afterall.

I inspected all the parts under a magnifying glas, found all parts in good condition.

I ended up talking to a technician at northern diesel in dawson creek [ BC].
who does a lot of these pumps.I told him my findings,

He agreed it ain't that hard to rebuild them. Biggest issue is setting he fuel solenoid at 5 thou on the poppet valve, this is acompliced by a thin crush ring between the body and the solenoid, ever noticed the toothed cam with small allen bolt on the side of the solenoid?. The rest is all electronic, There is notting mechanicly adjustable inside the pump.

if I would have left that sol in place he could have bench tested the pump for a couple hundred bucks

He also said that the majority of pumps he gets to do are mechanicly sound, the electronics are the problems

so it appears it is the lack of info that prevents some one from getting into the nitty gritty and not because of needing extraordinairy skills. beside the test bench ofcourse.

So there you have it.

mission acompliced Guys and gall, i ain't get to do a rebuild afterall.ah maybe
Now don't say, I told you so.

At least I know now how things work in there, its pretty simple.

A PMD is another story, I tore that apart to, that thing is tottaly beyond me.
The aliens that figured that thing out must be either nuts or genius, or both.

Simon

[Robyn]

Most of the later DS4 pumps will mechanically live a good long long life if the fuel is kept clean.
The issues are usually electronic.

The PMD is a set of high power driver transistors that convert a small electrical signal from the PMD into enough power to run the fuel solenoid and that controls the fuel delivery to the mechanical parts that actually deliver the fuel under high pressure.

The DS is a little too frail in the electronic dept to suit my taste BUTTTTTT its about the only tune in town that really gives these trucks great driveability.
The DB2 can be retrofitted and the TPS modified to work with a cable system, BUTTTTTTTTT getting the tranny to act right can be a challenge.
Also getting the computer to keep quiet can also be anoying if it sees that its buddy the DS4 is no longer up front doing the fueling job.

[More Power]

Being the stubborn guy I am, I tore the thing apart anyway, was not that hard to do afterall.
so it appears it is the lack of info that prevents some one from getting into the nitty gritty and not because of needing extraordinairy skills. beside the test bench ofcourse.

So there you have it.

mission acompliced Guys and gall, i ain't get to do a rebuild afterall.ah maybe
Now don't say, I told you so.

At least I know now how things work in there, its pretty simple.

Simon

Congratulations.... I've got a couple of DS4 pumps that I use for show-n-tell. I took one of them apart as well. (even as a little kid I would take my toys apart to learn how they worked...)

Did you remove the Optical Encoder Sensor? That's one part that, I'm told, you can't re-install and get it right without the bench test equipment. :)

Jim

[Slim shady]

Congratulations.... I've got a couple of DS4 pumps that I use for show-n-tell. I took one of them apart as well. (even as a little kid I would take my toys apart to learn how they worked...)

Did you remove the Optical Encoder Sensor? That's one part that, I'm told, you can't re-install and get it right without the bench test equipment. :)

Jim


I have done a DS4 pump and the optical encoder sensor has a boss inside the case where you place a gauge to center the sensor in the housing. The rotor is centered by the retaining screws on the side and bottom of the case. This centers the optical encoder with the rotor. The encoder is adjustable though (HUMMMM) maybe I will try to break it, play with the optical encoder adjustment for fun.

If you want to turn up your transfer pump pressure there is an allen screw in the fuel intake fitting that will set the transfer pump pressure higher. Even with the screw bottomed (clock wise) the transfer pump still bleeds pressure. GM states the transfer pump pressure is from 25 psi at idle to 125 psi at 2000 rpm. This transfer pump feeds the spill chamber and the four roller pumps that then create the high pressure fuel feed to the injectors. As long as the solenoid is off (Normal state) the pressure continues to build until the rotor passes the outlet hole in the rotor head or the pump rollers go past the high point on the cam ring in the pump. However GM doesn't let that happen. They control the amount of fuel by bleeding off the high pressure feed to the injectors before the pump has reached it's capacity by using the FSD.

The fuel solenoid controlled by the FSD and ECM then opens or bleeds pressure from the high pressure fuel feed to the injector to a spill chamber to control the amount of fuel metered to the injector. SO if you could increase the solenoid off time you could increase fuel flow. Relative to the programed fuel table (is this the TDC offset we adjust) Or the ( FSD resistor) we change)

I received a GM Stanadyne manual from a friend that was trained to repair, adjust these DS4 pumps at the GM dealer. The hydraulic passages are cast in to the housing and there is nothing to adjust anywhere in the pump except the afore mentioned crush ring for the poppet valve driven by the electronic solenoid.

Heck it took me a week of looking at the manual and the disassembled pump to figure out how to get a little more fuel out of it by upping the transfer pump pressure. I also picked up about a half mile more to the gallon. Coincidence maybe but I will take anything I can get.

Now the disclaimer, all of what I have stated is my own observation and is not verified or considered accurate information. I am NOT a certified re builder or do I have any knowledge of precision fuel pumps. GM taught me how to rebuild the old db2 pumps in the 1980's and I made good money for a long time doing it. The rest is basic hydraulics which is what the DS4 pump is all about.

[simon]

Congratulations.... I've got a couple of DS4 pumps that I use for show-n-tell. I took one of them apart as well. (even as a little kid I would take my toys apart to learn how they worked...)

Did you remove the Optical Encoder Sensor? That's one part that, I'm told, you can't re-install and get it right without the bench test equipment. :)

Jim

No jim, I got the pump with the top plate with the OS allready removed by the former owner, he had taken it as a spare on a long trip. It came with the pump though.