Only the 606a got larger elements. only 6mm though, not really worth the effort with 7 and 7.5mm available for the same cost.

What else will that plate tell me? Do you know if the cam is different in the 3.0L 603.96x and the 3.5L 603.97x?

__________________

Gone to the dark side

- Jeff

The cam has to be the same. The elements are the same for 3.0 and 3.5l.
The differences are adjustment. Besides different features at the back of the governor also emission regulation need different settings and there are many of them.

The type plate does not tell much more really interesting. There is an explanation somewhere in the forum.

Tom

Missing why the cam has to be the same. Not meaning to sound clever, quite the opposite really, but my thought is that the 3.5L has 1/6 more displacement, and is a lower RPM engine. Seems that the same elements needing to inject 1/6 more fuel in the same rotation would need to use more of the elements' stroke volume in the same degrees of rotation. Tuning could deliver more volume but wouldn't it also change the end of injection if the injection rate wasn't also increased (more aggressive cam profile)? This can also reduce emissions, another goal of the 3.5L. Is there a parts breakdown of the different pumps in the EPC or is this a Bosch-only database?

__________________

Gone to the dark side

- Jeff

Bosch information only, but I don't have access at the moment.
As soon as the program is up again I will show you that elements and cam are the same.
The 3.5l has nearly the same hp with larger displacement so there is not significant more fuel. As you mentioned the rpm are lower this is also an indication that only adjustments are different.
I will also try to find the adjustment instruction.

Tom

Some years ago, I did some tuning on my CAT engine, with a lot of injection shop help, and one improvement was a different IP with a more aggressive cam = higher injection rate, which was developed for lower emissions. Am I clueless for thinking that Bosch/M-B did the same for the same result?

I understand that same hp = same flow, just at lower RPM so probably same lift and definately the same 5.5mm elements. Timing device is the same too, so I'm also wondering if the timing is the same in the cam grind.

__________________

Gone to the dark side

- Jeff

Just got a quote from a different source. 8mm (MW) Barrel and Plunger assemblies for $12.50 ea. I have asked them to quote some 10mm ones. (Edit): $13.50 ea for the 10mm.

This is from a different manufacturer that the gentleman over at STD purchased his from, (from my understanding).

I plan on ordering some 8mm elements from both vendors, test them head to head and see how they compare.

If the $12.50 ones check out, it would cut the cost to build a hot MW dramatically, as I am most likely going to have them modified along with the cam, and the costs add up.

On another note I am considering rebuilding my engine dyno for performance testing. The biggest hurdle is finding a CHEEP engine that is not shot to use as a test bed.

With a working dyno, all my pumps would be performance tested on the dyno before approval for shipment.

I had a chance to work with an M pump yesterday and I am not impressed with the design, it is definitely designed to be slammed together on an assembly line. I can see having to grind every roller to get the start of delivery deviation as close as I want it to be.

As a result, I am not going to be working with any M pumps. It sounds like Tomnik's guy is the best option, (at this point), to have am M pump modified. I am going to focus on the MW pumps.

I have received prices from three different, (China), manufacturers and will be ordering sample 8mm MW barrel and plungers, (elements), from each one to compare quality.

I have a line on a Bosch 8mm element, but even at a discounted price it is still up there. I may get one to compare the others to but that will be determined by my funds at the time.

To everyone with an M pump that contacted me, I do appreciate the opportunity, but at this time, I am not comfortable enough with them to play engineer with someone else’s M pump.

As for the MW pumps; I think they are a much better design. Plus, I think they will take a lot more abuse, (higher pop pressures and larger elements).

I have two local shops that can handle the plunger, barrel, and cam mods, so I am hoping that when I have the changes figured out, it should come together quick.

My 616 pump has one element that puts out more fuel when cold than hot, so I will do that pump first. Plus it is easer to get in the governor for tuning. I have a VNT to hang on the exhaust at the same time, so that will add some additional variables, but nothing unmanageable, IMO.

Proper planning prevents piss pore performance.

Cool, a hot mw!

My words!
There are different rollers available from Bosch to adjust the pre-lift, but the cam has to be out to change them. If your measurements and notes are not good you might do the cam disassembling more than 2 times...
Start of delivery is set by fixing the counterweights at a certain position on the cam (before that the pre lift adjustment has to be correct).

Tom

Yes, one is limited to the availability of roller sizes. If you need a roller that is between a size step, you will have to decide which way to push the timing, (the roller on the tall half will advance the start of injection on that element, and the roller on the short side will retard the start of injection on that element). I guess it comes down to how precise one wants the setup to be.

In addition to being limited to the roller size steps, the rollers are expensive and one would have a lot of money invested in inventory in order to have the range of sizes that could be needed when moding an M pump with different elements.

Too much of a PIA IMO.

I am also not a fan of the Bosch method to determine the start of delivery.

I set an 616 MW pump up in my rotary table and, using the Bosch method determined the start of injection on the #1 element, and set a marker on 0 degrees. I then rotated the table and determined the start of injection on the other elements and noted the degree reading. Now it should be noted that this is a used pump, but there was a three degree spread, (from highest to lowest), and that is at the pump. That would be twice that at the crank.

To be sure I was doing it correctly, I reviewed the Bosch service manual and an International Harvester service manual for an MW pump, and repeated the process. I compared the two, (Bosch method), readings and they were within 2min of the first reading.

Then I tried it my way. I measured the #1 plunger height, (3mm lift if I remember right, would need to reference the service manual to refresh my memory), and set a marker on 0 degrees. I then rotated the rotary table, and stopped at every 90 degree mark, (I have a certified table with a 10 sec vernier, and a certified .0005 inch dial indicator). I noted the plunger height of each element. I then disassembled the pump and measured the distance from the top of the barrel to the top of the fill port.

I then compared the two measurements for each element. I found that the 90 degree plunger height deviations corresponded with the observed (Bosch method) trends.

I then reassembled the pump using the fill port height of each element as the plunger lift speck and shimmed each barrel to achieve each speck at their respective 90 degree increment. I made custom shims to set each barrel with in .0005 of the fill port height that was measured earlier.

I then did the Bosch method and noted readings within 2min of each 90 degree mark.

I took the pump to a Bosch shop, (my bench is not ready yet), and they balanced the fuel output. I put it on my friends 240D about a month ago now, (his pump was ruined by water in the fuel), and he said that it has never run so smooth.

I like using actual measurements instead of cresting fuel, what a stinking mess. When I installed the pump I set the timing via the plunger height instead of the drip method. I think that is how the VE pumps are timed as well.

Now I am sure I am going to get some flak for this, then again the earth was once the center of the universe and flat too.

physically correct is only the drip method. They pump fuel into the gallery with removed DV and rotate the cam until the flow stops.
Measuring the plunger height is more clean and obvious but I would prefer the flow method.
On the other hand I have talked to several Bosch shops and they usually don't use different rollers. "Are yours damaged? Or why do you need them?" This was their reply when I asked for rollers of a certain diameter.
It is simply too expensive to set up the pump precisely and the huge tolerances that Bosch allows for individual start of delivery supports them.

Exactly for this reason it is important to find the right partner or just do it on your own.

Tom

Just so I completely understand, are you saying that; ("It is simply too expensive to set up the pump precisely and the huge tolerances that Bosch allows for individual start of delivery supports them"), however you have found a partner who will, "set up the pump precisely", without being "too expensive"?

I only ask because my understanding of your goal is to build as precise and highest quality of a pump as possible, but the first statement states that anything better that OEM tolerances with an M pump is cost prohibitive.

Cost is the first thing that I thought about when I looked at moding an M pump. There is no way anyone would pay what I would have to get to cover my time and parts to get the M pump up to my tolerances; (Fill port closure plunger height +-.0005 inch @ degreed location +- 10sec), I haven’t worked out my delivery quantity tolerance yet as I haven’t completed my bench yet. I am working on the data collection system now.

I don’t mean to bust your chops, but I have told a few people that your goal was perfection, as is mine. I just want to be sure I know where of I speak.

Dave

... too expensive (and not precise enough for me) to find a Bosch shop.
Less expensive (not cheap yet) would be a guy that has a bunch of rollers and the skills and experience to take off the cam only once (maybe twice) and all the necessary tooling but not at the labour cost of a Bosch shop. On top this guy has to identify himself with the project and not just waiting for the weekend or end of the day.
Most shops are looking for max profit instead of doing something interesting.
I spoke with many shops, some people showed interest but not their bosses.
I still don't make any compromise in quality (this is why things take so long) but I also don't pay any price.
Look for a bench guy that kind of depends on you in some way and you will get what you want at reasonable cost.
I also tried to get in Mercedes or Bosch development/training centre but they play computer and lost the relation to the basics. Same with universities etc.

Tom

It is a shame that there is so little interest these days in how things became what they are today. I am convinced that if all the information that was used to get to the moon was lost and they had to start over from scratch, that they could not do it today.