Engine M189 FIP lines partial replacement

[lpeterssen]

Dear Friends

I am resurrecting an old w109-3.0 with a M189 engine with the latest 6 plunger Fuel Injection Pump.

Due to the effect of time and mices  I have some severely oxidized lines that will not withstand normal operation once the engine is back in shape.

Has anyone built by himself the fuel injection lines that come out of the mechanical FIP?

Which is the right diameter and the recommended alloy to do it.

I am also replacing many of the air lines for the air suspension, and I have been advised by a recognized community expert on air suspension to buy copper/nickel lines in 6mm OD.

Are the fuel lines in the same size?

Best regards
L.Peterssen

[Leester]

Its a longshot but you can try McMaster-Carr (www.mcmaster.com).  I have not attempted what you are trying to do.  I know there is a place, I think probably in Germany, that sells all this stuff but I can't find it.  Wish I could help you with the sizing but I have no M189 experience. Good luck.

[lpeterssen]

Many thanks Lester

What I am trying to do is just to build some of the M189 fuel injection lines coming from the mechanical fuel injection pump to the injectors.  Mine car has the later version 6 plunger FIP.  The shape of the Ines is not the same as in pagoda ww113-280SL since the engine is slightly tilt to one side and because of the valve cover shape.

Best regards
L.Peterssen

[rwmastel]

Does the shape, interior diameter (or volume) of the lines matter?  The volume put in by the pump will come out the other end of the line, right?  Does volume within the line affect pressure?  I'm not a fluid dynamics engineer.

[lpeterssen]

Dear Rwmastel

As Civil Engineer we have a course named Hydraulics, that covers this matter of the fluid dynamics.

Yes the inner diameter of any line conducting a fluid will affect the speed at which it flows. The higher the speed the greater the pressure losses in the way and therefore lesser the pressure of the fluid at the end of the pipe.

M189 engine, as is an older design will need a higher volume per injector.

Apparently M130 and M189 with 6 plunger Mechanical fuel injection pumps use the same line diameter. If that is true as M189 requires a larger gasoline volume per injector, you can guess that M189 injectors are designed to work at a lower pressure than 280SL.

The shape, bend and curves in the fuel lines after the FIP will affect the final pressure. More bends mean more localized pressure losses.

The only thing I need to confirm in my restoration project with this w109-M189 is which is the line diameter.

Any one with the info and suggestions for supplier of lines in rolls will be greatly appreciated.

Beat regards
L.Peterssen

[rwmastel]

Thanks for the brief education. It may not make sense to me, but I certainly yield to the educated.

[lpeterssen]

Maybe missed to tell that the speed of a fluid is dependent on the cross section of the line, the bigger the diameter of a line, the higher will be the area, and therefor a given flow in units like liters per second, will travel at lower speeds the higher the cross section.

Then as M189 and M130 engines with 6 plunger FIP appear to have same inner diameter on the lines going to injectors, as the flow in M189 should be higher as has more displacement and consumes much more gasoline, since is an older design, you can conclude that M189 injectors have a lower pressure set point for opening its inner valves that allow gasoline to be atomized on the intake manifold.

That all for today  folks.

L.Peterssen

[rwmastel]

Maybe missed to tell that the speed of a fluid is dependent on the cross section of the line, the bigger the diameter of a line, the higher will be the area, and therefor a given flow in units like liters per second, will travel at lower speeds the higher the cross section.

Yes, as it flows through the tube, that makes sense.  The river is wider at that point.  But, in my uneducated mind, what happens along the path wouldn't matter. Since the opening at the pump and the opening at the injector can't change without changing that equipment, I thought that those openings would be a constant in the equation.  The space or volume of the line in between openings would be a constant as well, if the tube walls are fixed and the fluid is not compressible.  One ml/sec of fuel in at X pressure would yield one ml/sec of fuel out at Y pressure.  That's assuming input and output diameters are different.  If same diameter, then X = Y.  That's my shade tree mechanic's science.  Help me understand why that's incorrect.  I do like to learn about physics and other sciences.  I can understand how bends in the line might create different diameters which would create different flow rates at points in the line, but I would think it's just the input and output rates that matter.

Apologies for hijacking the thread!   

[lpeterssen]

Dear rwmastel

Ok, let’s start from the beginning…..

What comes out of the FIP, is a certain volume per unit of time.  That is called “flow rate.” Let’s use a measure/unit for that as : liters per minute.

As you mention, explained by a simple mass balance…. What enters on one side of the fuel line comes out in exact measure on the output of that line.  Because there are no derivations or additional exits in between ….. law of mass conservation….

But there are other factors to consider in these matter of hydraulics, and that is pressure….

The pressure in civil engineering where you normally work only with water is often refered  or converted to Meters of water, because pressure gives you an idea of how high can travel water in a building and therefore  you take all the possible measures in the design of the pipeline so that water can reach the apartment that is on the 15 story (level). You play with pipe line diameters, reduce the amount of fittings to minimum, etc.

There are two types of pressure loses on a fluid traveling true a pipeline.  The pressure loses caused by friction of the fluid against the pipe walls (which is affected by distance and speed) , and the other type of pressure loses are called “focalized” or related to a fitting used on the pipeline.
There are tables that give you the pressure loss factor of each type of fitting, name them valves, 90 degree elbows, “T” connections etc.

So coming back to our case on gasoline traveling as a fluid through these pipelines from FIP to the injector, we have friction losses related to the length or distance traveled and diameter of the line, and localized pressure loses generated on each bend, or connection on the line.

The mechanical injectors should have a pressure range on which they can operate correctly.  I mean from 3 bar to 4 bar for example.do not recall or know that figure exactly.

The injectors that serve cylinder no.6 are the ones that are further away from the mechanical FIP.  Therefore  they will operate at the lowest pressure range of the injector working spectrum.

Pressure loses caused by friction in general are of lesser order of magnitude compared to localized pressure loss caused by accessories or bends in the line.

I hope that this lines help you understand a little more how hydraulics work.

Regards and Gute nacht
Leonardo Peterssen

[rwmastel]

But there are other factors to consider in these matter of hydraulics, and that is pressure….
....
So coming back to our case on gasoline traveling as a fluid through these pipelines from FIP to the injector, we have friction losses related to the length or distance traveled and diameter of the line, and localized pressure loses generated on each bend, or connection on the line.

OK, that makes sense.  I guess I just assumed (very bad practice!) that these losses would be so minimal compared to the pressure created by the pump that they could be discounted.

I hope that this lines help you understand a little more how hydraulics work.

Yes, very much so.  Thank you for taking the time!  Now, back to your parts search!!     I wish you well.

[Leester]

The source for materials to build the fuel lines that I referred to above is Cohline. The address below has hard fuel line in various diameters in steel and stainless. They also have the fittings needed. Again, sorry I can't help with the correct inside and outside diameter for the fuel line you will need but once you have established that, here's a source that hopefully meets your needs. Good luck.


 https://www.cohpro.com/wp-content/themes/cohprotheme/pdfs/CohlineAFHC2013-01.pdf

[lpeterssen]

Dear Leester

Thanks for the lead. That is what I needed

Best regards
L.peterssen

[Benz Dr.]

I would find a set of used ones.