A forum friend very early in this did mention a constant pressure fuel supply. At the time it did catch my attention. Perhaps useful at some point if the pressure could be remotley varied or controlled. These were my thoughts only a week or so ago.

Interesting that you should see no cigar hoses on your cars. If the same lift pump basically is used on our respective pumps. I wonder what or how your pumps are dealing with this pulse? Unmodulated the pulse must be at least from 0 to 30 psi or more every cycle. Perhaps the lower pressure number is higher because of the actual operating conditions. . Unfortunatly the constant pressure supply in the light of the little learned so far is not practical for our pumps over here unless they were re calibrated for it in my opinion.
Why you do not have a cigar hose could be benificial to know. And what they are actually doing instead. If the difference was properly considered it might give clues to further possible enhancements. On both sides of the pond.

Their still exists a possible silver lining a little later. I feel that once a good operating pressure has been obtained by many some elevation of it may be benificial again within reason. The timing issue will raise its head on diesel fuel I am pretty sure otherwise. Think 20-22 pounds under load operating fuel pressure for now. This is basically the upper end recommended limit it seems. Mercedes probably did not set that high a pressure during production. Now age and use may have further taken it's toll as well.

The proper timing correction at certain pressures can be done with the pizzo electric timing gear. Once we obtain the figures anyone can copy them if we get into this area.

I do not really trust timing these engines only by ear. The absolute last thing I want to see is someone damaging their engine.

Strange how things are slowly shifting to not examining the running loaded fuel pressure may damage your engine.

Right now I am just posting a lot to try making people think and contribute. I am a bit of a slow learner sometimes and can miss things. Tenacity is perhaps one of my stronger traits though. Dog with a bone may have nothing on me.

All I set out to do really a year or so ago was find the missing milage component so obviously missing especially on many 240ds. For the common good. In a way that task has been pretty well acomplished in my mind at least. . . All my observations till this came along did not really fit.

What was pretty iritating is it was only an engine and a pretty simple design at that. Yet in a way the thing was defeating me yet at the same time there existed quite a few solid clues.

Now where does this go from here in my opinion? For me much of the preliminary things have been considered and absorbed. My imagination or whatever will watch what others post. Something will come up or provide something to consider. It is almost inevatable as this is still almost a brand new area for consideration. It may not be over by a long shot. In fact this may just be the basic beginning.

I still think if the milli volt method had proved tractable and I had the faith to believe the numbers it was producing. . This problem would have become history much earlier. I still would like to see a dynmaic spread of the timing on the 616 and 617 engines. There may be room there to further improve efficiency.

As I also stated I believe but might be wrong of course. The number one rod problem would have been solved if a lubrication issue in my opinion a long, long time ago. There by now would have been at a minumin a modification for rebuilders to preform during their rework of the engines. These engines produce a superb high volume of oil pressure remember.

The ideal of the higher failure rate on the four cylinder versus the five cylinder engines way back when I questioned this caught my attention. I basically considered them the same engine. So why was the 616 failing at a higher percentage? Sure it was pulling the same load with less that may have increased bearing loading. Enough difference to destroy that rugged bearing I thought not. This basic simular engine pulls trucks.

I now believe it is because of the unbalanced lower quantity power strokes per revolution compared to the 617. It will never be proven but I will not run the risk.

Yellit ( Kevin) out pounding the road with little fuel pressure had to be stressing the number one bearing compared to the others from what I can grasp so far. It could be no other way if the number one injection pump element is the high pressure loader in the cycle.


As stated many times before I can and will be wrong from time to time. That is the price of trying to understand and change things. I am totally receptive to ideals. Lets get some more fuel pressure gauges installed out there to help this along. There is no doubt about it's worth in at least my mind. Milage will vary.