Pump Element: Don't Touch That Dial!
 

I don't want to.

BUT, it looks like the p.o. used some hokey-pokey copper washers, which are now seized in the bores of the pump elements. And leaking.

I'm aware that the seals need to be fished out -- normally -- due to expansion from compression stresses. I typically carefully pry them out with a stainless dental pick.

These are much worse than that.

http://franklynb.home.mindspring.com...mp-element.jpg
For clarity, here's the style of element/delivery valve arrangement I have on this MW pump. Valves are #50, washers are #47. #53 is pump element. #62 is a shim.

The washers I'm considering R&R are swaged into the pump element counterbore so badly that I need to put them ON A MILL and machine them out for removal.

Obviously, this will require that I remove, and restore the pump elements.
As an aside, one also has a leaky o-ring. I'll replace them all "while I'm in there".

I know, I know. This also means that I should send the pump out for alignment. BUT, this is my "go ahead. make my day" rusty, trusty winter beater. Our four lane city streets are down to 2.5 lanes with ice encroachment. It doesn't pay to park/drive anything you aren't ready to lose to a snow plow.

A pump alignment will cost more than the car is worth, as my local bosch dealer can only tune <send to a stand> a repaired pump.

Call it $1200 +-$1K.

So. To the experts. There is no need to repeat the time-honored mantra "you could screw the pump, and the engine, beyond recognition!"

I get that. On to the question of the day:

Can I use the drip method, in sequence on each port, to tune the pump element positions?

In other words: drip test to spec; pull #2; fix it; restore it; crank to 24d + offset where required. set element position to the measured drip rate;
ibid #3, #4, and finally, #1. Repeat as required to get uniform readings.

I'm posting this in the "less travelled" Perf Tuning board in the hopes of having hard-heads weigh in. The thread on glow plug "tuning" got me to thinking. I'm not convinced that a glow plug is linear enough to compete with an EGT sensor, but thats another matter enitrely.

At a glance, the drip method would seem to be a technically sound predictor of "initial fuel rate" -- if carefully performed. I'm talking stopwatch, and perhaps a fuel pressure monitor. I'm not planning to change the shims, as I have no way to re-shim the pump elements correctly. <I suspect this is problematic, as the shim and pump element are a performance-matched tuned set, right?>

However, the leaks are progressive, and bad enough that I can't get a drip test to accurately predict fuel rate anymore -- so I'm forced to do something before spring.

Which ain't anywhere near Wisconsin.

Weigh in, please.

--frankb

I assume this is for an OM617? If so, I have a good injection pump that I can sell you. PM if you are interested.

If you don't go the used pump route, I would very carefully mark the position of each element before removal. If you put each element back where it came from, along with the corresponding shims etc, and line it up, you shouldn't need a calibration...

Find a used injection pump and replace your pump.

Don't even think for a second that anything you do can properly time it like a $100,000 bench machine. Its a RPITA to get them flowing evenly with a bench machine. Fractions of an inch make a significant difference.

I am so going to prove you wrong one day FI.

I'll be too elderly to prove you wrong by then. ;)

Ummm .... and how does one validate that the pump elements on a used pump haven't been disturbed since last setup, exactly?

And I get that a drip test will probably not out-perform four figures worth of service, by a professional on a six figure test stand.

However, that is not the question. I'll try to re-state it more clearly:

On my 616, can I expect to restore its present performance by carefully aligning the elements using the drip method?

Here's an observation: The Factory, in volume 1, suggests that one should check the drip on port #4, validating whether the pump needs service.

<Note: There are precious few objective measures of pump serviceability. Especially field bench tests. See first question above.>

So, if I check all four, and they are closely matched to an accurately projected set <pair, which simplifies matters greatly> of timing marks:
can I make the reverse inference --- plausibly infer that the pump can be restored to previous service levels?

Thats what the yellow paint on the nuts is for, tamper proofing. If they have been disturbed the paint will crack.


No. The drip tube is a coarse adjustment/testing method. You can get it close, but it won't be exactly timed with the other ports.

Your local Diesel injecton shop should be able to repair your pump. I was quoted "a couple hundred" for running mine across their BOSCH test bench.

the injection pump calibration i beleive measures the amount of fuel injected per cycle measured over many cycles and set to the spec.you could theoretically measure this on the car by collecting the fuel and comparing each element having run the engine for the same duration each time.the other spec would be the vertical position and travel of the individual plungers coming to engine tdc.probably best measured with a dial indicator.the adjustment process here would be shimming under each plunger.considering the precision requirements of these measurements and adjustments a fairly reasonable fee charged by a expert fuel injection for this service would seem to make sense:)

It would if there was any structure to that paragraph! :dizzy2:

:D sorry for the train of thoughts composition.

Personally I don't see why you shouldn't be able to do it this way....

All the same parts (except for washers and seals) so nothing needs to be 'compensated for' or altered because of a change of part.

Do each one in turn, setting the engine position for exactly 1 drip per second on the element to be worked on, and after re-fitting set again to exactly 1 drip per second...No Problem!-
-OK, It aint gonna be as accurate as a Bench Test set up in accordance with the ISO Test-Plan, but better than pissing out valuable expensive fuel everywhere, and Infinitely Cheaper than a S/H Pump!!:eek:

Naysayers are often brainwashed by gloom and doom stories/myths told by Fat-Cat Injection-Shops and 'idiot' mechanics....who have their own adjendas-
-Why do you think the owners of such places all drive round in Jags!! (Because its a Rip-Off Trade, Has been for years!)

Unless you Try, You'll Never know!!--If I was in the same position, I would do exactly as you plan. I have often repaired items including FI systems/pumps etc, that I have been told was impossible without 'special-tools/knowledge' but with a bit of planning and lateral thinking has all worked out.....

If you have the time, parts/seals etc,-Go for it!!:D

you can get it within spec by hand. i have done it multiple times yes its not going to be friggen perfect but what do you expect from something thats free?

I say you do it and succeed.

Just because you did it does not mean you should have done it in the first place.

>>In other words: drip test to spec; pull #2; fix it; restore it; crank to 24d + offset where required. set element position to the measured drip rate;
ibid #3, #4, and finally, #1. Repeat as required to get uniform readings.

I heartily agree with Forced Induction's view that it's not really possible.

The reason is that in removing the element, you disturb 2 settings at the same time.

The phasing of the elements, which you are wanting to re-set is adjusted by the shims #62 - NOT by any rotation of the element.

The *relative* fuelling amounts delivered by the elements is set by rotating the outer of the element in the slack of the hold down forks.

In removing, working on and re-installing the elements, BOTH of these settings are disturbed.

So, to tune using the drip method, how could you be sure that the drip rate was being controlled by the phasing, or by the relative delivery amount?

Phrased another way, there is a very good reason why expensive machines are needed to set pumps up properly.

Good point. Thanks for adding a valuable input. I need to give the phase measurement & setting more thought.

Wow. Complete with typo. Sorry, michael cole. I'm embarassed to be a party to this.

>>I need to give the phase measurement & setting more thought.

I'm sorry if I've set the cat among the pigeons.

I think, but have no experience, that if there is no upper helix on the plungers and the rack can be held at a medium fuel setting that the phasing could, in principle be done via spill timing each element in turn. You would need a good stash of paired shims to use in the adjustment. It could be worse - on some pumps you need to change th roller in the cam follower to change the phasing!

To set the relative fuelling of each element, I imagine the closest you might get would be to keep the rack clamped at a medium fuel setting, refit the delivery valves and, with a swan neck on every element, crank the engine over with the swam neck pipes discharging into graduated containers. With either injectors or glow plugs removed, it would be OK to crank for, say, 30 seconds to collect a measurable volume. Then, adjust the rotation of each barrel to equalise the delivery.

It's not a quick procedure though - are there any shortcuts that I've missed?

So, perhaps ... and only perhaps ... one could use a set of drip tube adapters, make a short video of the spill cycling ... and review the video with a timecode editor to determine the uniformity of spill intervals ... and adjust from there.

My local Bosch dealer doesn't stock shims, but will acquire any range I need.
Motion Industries sells a similar shim product that I've used in the past for aligning tailstocks and fixtures ... although the shape would need to be trimmed.

I'm also thinking that doing this adjustment on a bench, where I can set it up with an low pressure electric fuel pump, adjustable pressure regulator, and catch tanks with good graduations might be easier. And allow me to set the exact input pressure of the fuel supply. As there must be some mechanical regulator inside the pump, this is a bit redundant; but at least assures that I'm not underunning the minimum input pressure, or losing pressure during the spill cycle.

After all, I'm attempting phase and relative volume alignment, rather than timing. So the engine just "gets in the way" more or less ...

>>So, perhaps ... and only perhaps ...

The use of a video camera to time the injection events is a really clever idea - it's something that we take for granted now, but when these pumps were new, cheap video technology simply wasn't available.

However, one thing that you'll definitely need to compensate for will be the variations in the speed of rotation of the crank and/or pump.

I can imagine that you'll want to time the injection events to be within 1 degree of crank angle of where they should be, which means 0.5 degrees at the pump - it's a tall order!

I was thinking of using a DC stepper motor to drive the pump, fixing the speed via proportion of some drive pulley arrangement. Steppers are cheap at surplus <$20 or so> and plentiful ...

... and a DC pulse controller that I happen to have laying around. Also considered using a <spare> Megasquirt controller and degree wheel
as the "sync" generator. MS can readily be offset "tuned" to within 30? uSec of accuracy on a pulse trigger, from memory - using its ignition circuit as a driver.

Thinking of pressing an IP coupling bushing into <an appropriate> puiley bore. Have lots of BMW & Montero pulleys and Ford wheels from previous EFi projects.

The controller -- perhaps -- might strobe a 12V support flash, simplifying "freezing" the images and rate change computations, at least at slow speeds.

At WFO pump speeds ... < where 4 pulses per rev * 2600rpm = 10Kpulses per minute == 173hz == too high for a strobe?> ...
... it just gets more and more complicated. Pump oiling? Even 30fps will be bandwidth limited to about 1,000 rpm pump speed.

If a pump alignment can be had for 2-3 hrs service <or about $200US> ...

You'll need a lot more than a $20 stepper motor to turn the pump at 1000rpm. Those $100,000 Bosch test benches use a 220/440V power source for a reason.

<If you dislike flames; hit the next button at the flame markers! I, for one, have had it with this noise.>

And "the reason" is .... what? I suspect you might know.

"The reason" is probably because their 'industrial rail' power is 3-phase <in the U.S.>, and the semi-ancient control toplogy is switch-based DC solenoid "ladder logic" <partly because this was before ubiquitous, cheap switched-mode power supplies, and allowed easy localization> ... which was most commonly available when these machines were last re-designed, circa 1980.

Don't see what voltage ratings have to do with the subject at hand. Feel free to explain, if you think it has something "220/44V" implies something about the capacity of the drive system. Show me a hospital, and I'll show you 1/20th HP multi-phase <freq-drive, more correctly> 20K rpm motors.

To the point:

I expect, from a quick back of the napkin calc, that pumping + friction will consume around .1-> .2HP at a VE of 25%, which should be about average. Diesels are probably better than this at idle, but this one <mine> is worn. And after all, my "ideal" test in bench/drip mode, not operating valves <injectors>. I used a simple static-fric-coef of .1, , saving myself the added work of torsional dynamic guess-timation, if that means anything to you.

If not, feel free to look it up.

I can buy a 1/3HP, 3450 rpm open 56 frame motor, excess from obso'd dishwashers, sump pumps, and the like ... all day long ... for about $12. own at least two. See emerson.com if you need more explanation as to how cheaply these are manufactured these days. I won't waste my time.

Which, at 3:1 reduction, should easily power a test mode pump to about 1,100 rpm, assuming can splash lube it effectively. Albeit fixed speed.

Hence -- a small perske, salvaged from an industrial router. $20. Call me cheap, today. I can wait. I know of 2 I can have for the price of a pair of 6205s. Not worth the labor to fix, over the counter.

Your guess-timate of "$100,000 Bosch test machine" is merely a claim, not a validating feature. Some of us have participated in the design, test, and manufacture of similarly complex<and WAY more expensive> equipment for many years. That experience, in part, is what drew us to 'old school' diesels ... in the first place.

There are others, with different, but equally valid experience levels and bases. I, for one, appreciate when they weigh in with things I would "typically overthink".

It p|ss|s me off, frankly, when you post condescending one liner retorts, with apparently little provocation. And no content of any value.

<flame on>
What's your point? Are you going to participate in this discussion? Or just continue to weigh in with "smarty one liners" <and that's as nicely as I can put it>, and useless, unsupported factoid banter?

I actually still believe that you may be capable of adding some desirable thinking & content ... you seem bright and experience enough that my expectations are quite high ... should you be able to lose the <readily apparent> assumption that everyone else here is a dolt.

Give me a break. I already know you're in love with the bosch test stand from your last N posts, wherein you repeat, like some sort of mantra "its so-o-o-o- expensive! it must be better!"

Got milk?
<flame off>

>>as the "sync" generator

Ah!, clearly you're on the case there!

Two thoughts spring to mind;

1) Although you aren't driving injection events, just spill events, you might get smooter rotation if there is some extra added rotational inertia at the pump drive.

2) Driving forwards, you would be trying to see the end of spill - perhaps it might be easier to see if you ran the pump backwards, and looked for the start of spill with the video camera. I haven't thought too hard about what sort of errors that might introduce, but as everything is running at light load, I shouldn't have imagined the errors will be too great.

Your pump needs to be 5hp or better.

I have asked around on the arduino forums, about measuring pressure and quantity with out much response. I think this is where things start to get expensive.

>>Your pump needs to be 5hp or better.

Which part of the setup needs 5hp?

I'm probably missing something, but;

For phasing, even the delivery valves won't be causing any pessure to be built, and so the IP becomes little more than a shaft in bearings.

For equalising the delivery quantities, you wouldn't necessarily need to be building full injection pressure - each element pumping into a check valve something like that on the IP return (set at something like 50 psi?), and then delivering into a measuring tube or vessel would be enough to provide a basic check of the volume.

I think the rig might be seriously cumbersome to use, but, I'm beginning to think it might just be able to work.

It's an interesting thing to try to do - I wish the OP good luck.

He is likely talking about the motor to drive the pump.

Either way, I pity the fool who thinks they can do better than a $100,000 tool.
http://i201.photobucket.com/albums/a...ityTheFool.jpghttp://www.ljdiesel.com/testbnch.jpg

Sorry motor. I dont agree with FI however, that system is pretty generalized. Making a specialized one *HAS* to be cheaper.

hes no worse off than he was before then correct? if he messes it up then he has to take it out anyways. It may not be correct but it works and thats what matters.