Correct, but on the other hand they are working on the future.
Our knowledge let's say 10 years earlier and we could probably do something in terms of emission reduction...
There are very few people who are able to understand the old stuff (and they disappear more and more). The kids have no interest.
When looking for a VTG boost controller I met a young guy working in Bosch training centre and I expected some progress but he does not even have a car!!
When he asked me how in general a turbo works with his hands deep in this pockets, thanks bye bye.

Tom

I am ordering elements from two China manufacturers this week. I am curious to see how they compare to each other.

I went to order the $12.50, 8mm elements and they were out of stock and were not planning on making any more soon. I did not check the $64.80, 8mm for stock.
Due to the rare nature of the 8mm elements, I will be modifying 10mm elements as they are plentiful.

One company has 10mm elements for $13.50ea and the other @ 11.85ea, with $50.00 shipping for each company.

I now have a sample 10mm element that I will take to the grinder today to physically show them what I want to do.

I figure I have another 6 hours of figuring before I will have the specks to have the barrels and plungers modified. My output target @ 85% rack travel is 90cc per 1000 strokes.

I will also be able to cut down the cam a bunch which will help with higher RPM operation.

I'll be interested to see what you come up with. My biggest worry with China vs. Bosch elements is metallurgy, although fit & finish is also important.

Please keep us posted on what your ideas about cam profiles/heights are. I'd worry about blindly messing with the injection duration. There are a lot of variables in this. Really getting the big elements to run right will probably have something to do with a customized timing advance device.

As for you guys (tomnik and OM616) talking about how nobody knows anything anymore... I agree people want quick, thoughtless money. A shop wants to do something they have done 1000 times before, they want to know their profit margin ahead of time. Its near impossible to get anything "custom" done for a reasonable amount of money, and most of the "custom" guys are B.S. anyway.

I don't agree that mechanical governors are the way to go, but until I've acquired some hardware to play with, my hands are tied on that one. I'm hoping to have something rudimentary by the end of the summer.

Electronics could make MW pump tuning a heck of a lot less expensive, more precise, and yield better running engines.

__________________
99 E300 Turbodiesel 100k

Since it appears that the 8mm elements are not consistently available, I am making calculations for the more common 10mm ones.

I agree that in order for the 10mm elements to work properly the entire system must be set up for them as the system is currently set up for the 5.5mm elements.

Simple volumetric calculations show that I only need .050 inches of plunger lift past fill port closure to get the max delivery quantity I am looking for, (90cc per 1000 strokes), @ 75 to 80% of useable rack travel.

I do not see any reason for the plunger to travel any further than is necessary to insure that the desired fuel quantity can be delivered, and as such, I will be re-grinding the cam to reduce the total plunger travel to that which is needed while retaining the deceleration geometry of the lobe. This will reduce loads on the cam, reduce turbulence in the IP fuel cavity, allow increased time that the fill port is open which will help barrel refilling, and allow for an increased RPM limit.

I am also going to have some nozzles extrude honed to open up the dia significantly in an effort to allow an increased volume of fuel to pass through as tight of a gap as possible. With the larger dia the pintle will not have to lift as much to pass a given volume of fuel over a given period of time. This combined with the pop pressure set to 200 bar should produce a very fine fuel fog. I think it is critical that because the fuel will be delivered over such a short period of time that it should be delivered as burnable as possible. Some initial tests I have done and have seen of increased fuel volume or same volume delivered in a reduced time have shown that the initial spray pattern is made up of a fine mist, but quickly turns into a stream when the pinte lifts too much.

I have made a couple different Prechambers and I want to eliminate the ball all together in the next generation. If I can get a fine fog out of the nozzles, I don't think I will need the ball to brake up the fuel stream, but that is for a different thread.

I only mention it because as with the delivery time being reduced so reduced is the amount of time that is allotted for the pressures to equalize after ignition of the fuel. The stock Prechambers breath very slowly and because the 5.5mm elements take so long to deliver the fuel in any quantity, there is time for the pressures to come close to equal, but this is only in the very concretive stock fueling quantity and slow speed.

Also it is my thinking the timing advance needs to go away. I do not see any need for it with the 10mm elements.

The only thing that I am still kicking around are the Delivery Valves. I will want to either change the springs, or the valves and springs, to work with the 200 bar pop pressure. They are easily changed so I am not overly concerned about them at the present.

I have quotes for 10mm elements from 2 different China companies, both sell them for about $13.00 ea, the third charge about $70.00ea, so I am going to try the least expensive options first. I will order 5 from each company for a total of 10 elements.

I was going to order them last week, but money was tighter than I wanted so they are on hold for a week or so.

Any updates?

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87 w124 om603

Well I ordered 10mm elements from two different manufacturers, 10 elements total. They should be here by the end of the month or early next month.

I have spent some time at the grind shop talking with them about the best way to set up the plungers in the grinder. It turns out that I have the same grinder that they would recommend using, so I may vary well be able to grind them myself once the process figured out.

They will be grinding the cam though as they have a CNC grinder that will be able to maintain the lobe profile geometry only with a reduced lift radius.

I have done some preliminary calculations that get me in the ball park so to speak regarding total delivery quantity and corresponding required stroke. After seeing unmodified 10mm elements run in a 617, I am confident that I can get the results I am looking for, but the proof is in the pudding.

I am trying to figure out the best way to eliminate, or lock, the timing advance mechanism with it in the engine. I have not seen one, any ideas?

I still have to look at some things, but it might be necessary to make it work backwards, as a timing retard instead of advance because of the incredibly short delivery duration.

I can imagine that statement will raise some questions, but it would be very helpful if thoughts were focused on locking the timing device or making it work backwards regardless what one thinks about the idea. The discussion as to the merits of this modification will be discussed later when the time comes as it is a theory subject that will take on a life of its own.

My goal is to keep on point. I hate threads that separate progressive logical thought into chunks, because of tangential sections, or argument of a parallel aspect, that is best placed in a different portion of the thread.

Don't get me wrong, feel free to post, just please try to be mindful of whether the post coincides with the current subject, or if it would be better to hold off until the time if right.

If in doubt, do not hesitate to PM me your thoughts.

I never had a timing device in my hands but I think you could fix the moving part just with a bore and screw for a first test.

Could you please explain how you intend to grind the cam?
You know that the plunger speed is designed for low speed during filling the element then increased speed during injection and decreased speed closed to the TDC all in relation to the fuel supply bore of the barrel.

Next: grinding the plunger? Reducing effective stroke also means taking care of the location of the bore plus adapting this range to the speed/stroke range (cam profile). Are you planning to relocate the supply bore in the barrels?

Tom

Yes that is correct. Because the 10mm plungers have such an incredible volume displacement per increment of plunger lift compared to the 5.5mm ones, and the comparatively minimal amount of fuel that is required, (even at full power), for my application, the actual required productive plunger lift, (after fill port closure to the point where the helical groove is uncovered ending injection), will be less than .075 inches, closer to .050 inches (aprox 1.9mm / 1.2mm).

If the start of injection, (fill port closure), is at .118 inches, (3mm), of lift, the combined total required lift, (not taking into account the deceleration ramp), would be .193 inches, (4.9mm).

I do not see any benefit in continuing to lift the plunger, pushing fuel out of the barrel, only to have to suck it right back in, creating all kinds of turbulence in the IP in the process and reducing high speed barrel VE.

One way to visualize what I am going to do is to imagine removing the portion of the acceleration lift ramp, between the end of injection, (at full power), to where the deceleration ramp starts, resulting in the deceleration ramp starting at .193 inches, (4.9mm), of accelerated lift. This will allow additional time for the fill port to be open, and, since only the quantity of delivered fuel, (plus any leakage), needs to be replaced, the high speed barrel VE should be improved and turbulence in the IP reduced.

Now because the acceleration ramp is so short, the plunger will not be going as fast as if it were lifted to the full stroke, so I may look at altering the deceleration ramp to reduce additional unnecessary plunger lift, but the 10mm plunger has more mass, so the stock 5.5mm deceleration curve might be good. I have not gotten that far yet. I have designed and developed valve train camshafts in the past, but the geometry of the IP cam is unique. Ill have to through it in the computer and see what it looks like.


No. I am going to alter the Plunger Helix Angle, leaving the fill port alone. The new angle will reduce the max displaced stroke distance, and spread the fueling out over the entire rack travel range.

Regarding injection timing;

I think I am going to have to grind an angle on the top of the plunger to progressively delay the start of injection as the delivered fuel quantity is increased with rack travel. (I know that is not written well)

Because the injection pulse width is going to be so short, I think the injection timing will have to be adjusted to match the quantity of fuel delivered to achieve the desired pressure curves at different engine loads.

I have found that my 616NA and 617 turbo want as much advance on the bottom end as I can give them, but, as the bottom end torque increases, the top end power suffers because of the additional advance from the advance mechanism, the pressure curve is too high too soon. So I have to back off the timing on the bottom so the engine will start easily and run freely at full power.

5.5mm elements take so long to deliver the fuel at full power that the pressure curve can be relatively optimized with a lot of advance, but with the 10mm elements, 100% of the full power fuel would be injected in less than, (guestimateing here), 10 crankshaft degrees as apposed to 25+ crankshaft degrees with the 5.5mm elements.

Still have a lot of thinking to do, but I want to have the low power, (low delivered quantity), timing around 25/28 degrees BTDC, but at full power, I can see delaying the start of injection to around <15 degrees BTDC.

It should be noted that I am modifying the Prechambers as well, and that the above injection timing guestimets take into account the observed altered Prechamber affects.

The only way I can think to vary the start of injection timing proportionately with the delivered fuel quantity is to grind the top of the plunger, and have the helix angle correspond to end the injection at the desired quantity respectively.

big task of grinding the cam an plunger helix.
But if you have the possibilities and enough "test plungers and cams" why not.

I don't agree with you regarding the timing.
Imagine the inner cylinder pressure curve of just cranking without injection.
Starting from BDC (valves are closed) the pressure rises and peaks at TDC.
After TDC the pressure decreases. Simple pump following the sinus of the crank.
The compression means energy into the machine.
Now injection is added:
The later you inject (of course always before TDC) the better, the higher the compression temperature is therefore better start of burning.
The start of burning has a fuel specific delay in such a way that the peak of pressure (now an addition of pure compression and burning) is at or short after TDC. In any case not before TDC because this increases the energy you have to put in. This will be the case when timing is too early. The engine is not willing to rev up easily and is nailing. Combustion pressure is against the upwards movement of the piston and injection starts at a point where compression/temperature is still low.
The retard edge of the plungers is just a way to correct the too wide range (in sense of crank rotation) of injection to avoid too late end of injection at load.
With larger elements the duration of injection is, let's assume 50%.
Imagine to shift this range in such a way that you inject as late as possible without getting black smoke or other negative things like bad starting.

Extremely speaking: With larger elements your end of injection might be before TDC, meaning your pressure curve has its majority before TDC, the engine will not run. Ideally you inject just before TDC (pilot "light" the fire) and main inject into the pilot "fire" while the piston moves down keeping a constant pressure (pressure rises because of thermal energy vs. pressure decrease because of mechanical expansion).
Now with your extreme short injection it gets hard to burn well. You might distinguish the fire or get incomplete combustion.
This is the reason why today they have multiple injection with a desired duration of injection while the piston moves down.

Tom

The pressure peek sweet spot directly correlates with the length of the stroke and connecting rod length along with the piston dia. Additionally as you mentioned, the length of time it takes to burn the fuel, and area that the combustion radiation has to travel, (and decay), also needs to be considered. Plus, the quality of the injection and combustion chamber shape and environment, (temtretures/pressures), have influence also.

To help with the injection quality, I am going to open up the injector nozzles in an effort to maintain as tight of a gap between the pintle and the seat during injection, while allowing a high volume of fuel to be delivered is a shorter period of time. Also, I am going to set the pop pressure to 200Bar. The goal being a very very fine injection that is ready for combustion without additional atomization efforts. Whether this can be accomplished with the "vintage" parts is yet to be determined.

My understanding is that there are two phases to combustion pressure. First is the actual combustion, where the fuel is converted and expands into a super heated gases, at the same time, the radiation from the combustion it self heats the surrounding gasses causing them to expand as well. This is one reason why the Prechamber design is not as efficient, as the area of the cylinder combustion chamber is isolated from most, if not all of, the combustion radiation, resulting in a cooling of the Prechamber gasses as the heat is absorbed by the cylinder gasses in an attempt to equalize the over all gas temperature.

Thermally isolating the combustion areas from the surrounding metal would have a big effect on the pressure curve as well. The next batch of Prechambers will be coated with a thermal reflectant.

This subject is very theoretical. Personally, I have gotten the best results from testing the different settings and to see what the engine its self wants. I have an engine dyno, but not an engine to run on it.

As I said, I still have a lot of thinking, and math, to do before I start grinding the plungers. I may be trying to get too greedy, wanting the best bottom end and top end as possible. Electronics are the ticket for that!!

I think it would also be a good idea to get a cam from the 10mm element IP to see if there is anyting that can be learned from it.

Unless they are the same?

I just sold the 300D that was my guni pig, so the development projects are essentially over until I find another one.

I was at the gas station and a guy asked what year it was. When he saw it was a 4-speed he offered me $4000.00 for it. I said 4500.00 and it is yours, thinking he was BSing, but he said done!. We went to the bank, I signed the title, pulled the plate, and away he went.

Now I just have the 240D that is getting a VNT before any IP work. The good news is my mortgage company is happy.

How about experimenting on the 240D pump....?

Apart from the VNT, what else have or are you doing to the 616?

__________________
http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

You live in Michigan. "Your" mortgage company will be happy when they forclose, get .30 on the dollar, and invest it overseas.

__________________

Gone to the dark side

- Jeff

Quote:

Originally Posted by Alastair How about experimenting on the 240D pump....?

That one was in line once I had everything figured out on the 617, but since the 617 is now gone, things will be progressing slower and more cautiously. My 616 IP has a week element, so I intend to address it with the modded 10mm elements.


I have turned up the IP and advanced timing.

I installed a stiffer spring in the lift pump and I am running @ 30 PSI.


Made an in-line thermostat housing that uses Small Block Chevy thermostats so I can run a 160 degree thermostat as well as pick one up at any drug store.

I had a M90 blower on it for about 1000 miles,(running 6 lbs), but it was so obnoxishley noisy I removed it and made an resonant chamber intake with a long air intake snorkel to the Air Filter, (improved torque).

Cherry bombs in place of mufflers, 300D aluminum fan and fan clutch.

I have a 2056 (liberty) turbo and air to water IC to put on it.

I want to advance the cam some.

Custom Prechambers are also on the list.

I am making adaptors that will allow me to use standard 300D pence glow plugs in place of the loop plugs.