Hi Barry--

The French origin 617 I have, comes with the 'normal' M type pump found on UK cars...

With regards the bearing failures, the 616/7 are not 'known' as having issues with the bottom-end at all that I know of.--But--Then again we dont have .951/2 Turbo motors here...

My explaination for bearing-failure would be that the nos. 1 rod bearing is the 'last one in the row' from an oil point of view, so over the years 'energetic start-ups from cold' could have the effect of more wear being apparent at the end of the chain of bearings.....

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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....

If the spring is already out, might as well set it to 27mm.

At the 21.0mm length, I have 15.0 psi of fuel pressure, so I don't think stretching the spring is prudent...Robert

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

There is that "I think" statement again.

Those of us that have actually tried it know differently. 15psi is only 1/2 of what it can be. No harm will be done and the engine will run normally. My 300D's spring has been streatched to 27mm and with 250miles on it, its running better every day.

Why am I the only one that is not allowed to express his professional opinion????

You contradict your previous posts where you recommend not modifying the spring until you verify pressures. In this case, my pressures are within the design specifications of 11psi to 19psi and to that end, it would not seem necessary to increase base pressure beyond that...Robert

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Is it possible that there are different versions of the IP relief spring????

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Its known there are two versions. The common serviceable and a somewhat rare sealed.

Key word there.

In your case it isn't worth the effort to stretch the spring unless you already have the spring out.

If there is a rod bearing failure on the four cylinder 616 engine it is almost always the number one rod bearing over here. There are far fewer 616 engines numerically than the 617 engines. Yet the predominance of failure percentagewise is much higher for our members and the 616 are not turbo over here.

If there was no pattern of the first rod being the primary failure in your country with no cigar hoses it would almost conclusivly prove the injection pumps are set up differently and the situation never can occur that increases the high frequency spikes with your pumps set up.

What would be really nice if rod bearing failure on the 616 was random over there when it occured. It would not even tend then to be conclusive proof yet pretty indicative. I wonder if you have any forum over there for users of the mv pump?

If so their archives would not miss discussion of the failure of the number one rod bearing in engines. Not from the perspective of cause. Just that it had occured.

The 617s have a much lesser rate over here but again it is usually the number one. The oil path to the number one on the 616 is certainly shorter than on the five cylinder. Of course my thoughts can be in total error. I suspect you are in a position to easily verify this one way or another.

If for example your independant mercedes or really older still practicing mercedes dealer mechanic people were to quote on failed 616 engines. It is usually not the number one rod bearing but seems random. We would really be able to get a handle on this.

I cannot post a clear warning at this stage as I truthfully have nothing to really back up my suspicions. Yes the original attempt of the cigar hose was to minumise the hammering. It must have been audiable. Somewhat like a water hammering I supose. But so fast it was a constant buzz or whatever.

The side effects I suspect or some of them occur when the cigar hose function is blocked by low fuel pressure in the injection pump base. Your mv pumps are probably calibrated with the pulses more in evidence so there are no problems possible of this nature.

The french car with the cigar hose and mv type pump only tends to increase my suspicions. There might be a problem if that pump was replaced with a used mv pump that had not been calibrated with a cigar hose.

Remember all this is just guess work. I have explained what injection pump effect when present could take the number one rod bearing in past posts. Part of my suspicions relies on mercedes not allowing an inadaquate oil feed problem to exist for the total length of production on these engines.

It could also as easily be something as simple as sludge buildup with age in the crank passages. Or exactly as you express. Also a common belief over here. I still keep an open mind believe it or not. Just like to turn over the ocassional stone from time to time for a look.

Well I have been watching my fuel pressure for awhile now and I noticed that it was not really as high as I wanted it. I first replaced the filter to see if there was a restriction there. The filter had ~7k miles on it and while black with junk was not a restriction at all. I stared thinking about the one way valves in the pump and decided to hone them like I had on my father's 300dt. It made no difference to the pressure. Hummmm. That is odd, I thought it would have some effect.

I am trying to figure out why I have a vibration issue, and it seemed to occur with the fuel pulsations. So I wanted to up my fuel pressure to be higher then the min. MB states in the FSM, to see if the vibrations would subside.

While pulling a head at the yard for the 300dt, I noticed the IP was in good shape. I pulled it and the guy at the counter said 25 bucks. I could not let it go at that price. Now I had a spare lift pump to look at without taking my car off the road. I pulled the pump and dismantled it.



The one way valves were pitted just like the ones on my other pump.



Now I also noticed that the metal surface where the plastic valve sits was pitted too.



Ah-hah I thought to myself this must be the reason I can't make higher pressure with my lift pump. So I made up a tool so that I could polish up the metal surface and keep it perfectly flat.



The tool fits into one of the lift pump fittings and is kept perpendicular to the metal face. After polishing for a bit I was able to make most of the pits disappear.



I also honed the plastic valve, and put the pump all back together.



It seems that the pump is double acting and self limiting at a pressure that acts against the spring and keeps the piston from returning.

After installing the pump I had pressure that had a low of 16psi and spiked to just over 30psi. Upon revving the engine, the pressure went up to 25psi and spiked into the 40's. I can see why Forced said he had 30psi at idle. With good one way valves the pressure from the pump is much greater. I wanted to see what the dead head pressure of the pump was and closed off the return line. The pressure pegged the gauge so there was more then 50psi. Looks like a healthy lift pump is capable of a lot of pressure and flow. It will be interesting to see how this effects how the engine runs. I hope it solves my vibration issue, but at a minimum it has given us more information about the pump and its abilities.

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1998 Mercedes E300TD

1983 Mercedes 240D Turbo, 131bar injectors, Cosworth intercooler and 63' Ford Falcon radiator, Ardic Parking heater, Headlight wipers, Best 38.6mpg.

1973 Saab 96 Rally Car, 1.8l V4 with all the race bits

A broad base of submitted information helps all that are interested. Some information will naturally fall by the wayside but the majority of it increases knowledge.

At a certain period in time anyone will know exactly what to do with their situation. Just by looking up some of the future posts on this thread.

Some of the major questions at present go unanswered at this time. That will not last forever. We certainly are on the verge of entering unknown territory to some extent. Or some are.

The pump find for twenty five dollars was nice as well. I did read about attempts you have made to lessen your vibration. Happening at two different engine speeds if I remember right might indicate a harmonic type problem. Really though it's one of those things that you have to hear yourself to take good guesses.

I am a believer that the pressure has to be high enough under all running conditions to keep the relief valve open. There have been efects reported if this is not so. Also the cigar hose should still be pliable.

Rough idle at llow pressures has been reported. Not one case of selective vibrations at certain rpms. But one must keep an open mind.

Are you sure your return line is clear? Those 16-30 pound swings should not be there I think. I might pull the return line and feed a new temporary line into a bucket and watch for the pressure swings . Something is causing them.