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6.9 K-jetronic rough and high idle cold start

Started by Jan S, 10 June 2021, 05:36 PM

daantjie

I did some digging and looked at the hose on the 126.  Part number is 1160900882.  Looks a bit different and maybe length will not work but might be worth a gamble?
Google the part number and then pics come up.
Daniel
1977 450 SEL 6.9 - Astralsilber

daantjie

Daniel
1977 450 SEL 6.9 - Astralsilber

Jan S

Thanks a lot, daantjie - fantastic effort!

I've spend a few hours googling tonight. There's a ton of breather hoses out there in all shapes and forms ... but not the "100".

The challenge is none of them have the inner diameter listed online. And I have some space constraints due to fuel lines.

I have looked at the 126-hose. If the inner diameters are ok I might be able to use parts of it inclusive hose connectors. But hose has to be cut. See pics and illustration.

I will call MB tomorrow and check if they can give me the specs of the 126-hose.

I also need a 3-way hose splitter. Found a brass splitter that should work. An alternative might be the hose splitter from the 126-hose.

To be continued ...
1975-mod W116 450 SE with 6.9 engine

Jan S

... no information from MB regarding the hose specs (e.g. inner diameter).

Working on several options ...
1975-mod W116 450 SE with 6.9 engine

daantjie

I wonder why the 126 hose has these ribs on it, maybe as insulation from touching the hot engine?
Daniel
1977 450 SEL 6.9 - Astralsilber

goldacre

Ummm, thinking reinforcement ribs to stop it being sucked inwards restricting vacuum? And as a contact reinforcement?

G
12/1979 450 SEL 148K on clock (museum piece)
12/1986 Lotus Esprit Turbo 87K on clock 'Darling, look what Q has brought for us, isn't it nice' :)

raueda1

The conditions under the hood are bad enough as it is, that's why all these parts eventually turn hard and brittle.  I'd therefore stay away from brass fittings to the extent possible.  Brass contains copper which promotes thermooxidative degradation of most plastics and elastomers unless specially formulated (which this stuff most certainly is not).  Cheers,
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

Jan S

Thanks, raueda1 - I didn't think of that.

One solution I'm following right now is to use a hose splitter made of nylon plastic. The temp range is up to 135 deg C (275 deg F).

Is that sufficient, what do you think?
1975-mod W116 450 SE with 6.9 engine

Jan S

Quote from: raueda1 on 09 March 2022, 04:42 PMThe conditions under the hood are bad enough as it is, that's why all these parts eventually turn hard and brittle.  I'd therefore stay away from brass fittings to the extent possible.  Brass contains copper which promotes thermooxidative degradation of most plastics and elastomers unless specially formulated (which this stuff most certainly is not).  Cheers,

I found a 3-way hose splitter made of stainless steel. Should be fine?
1975-mod W116 450 SE with 6.9 engine

daantjie

Does anybody know exactly the function of this assembly?  To me it looks like it is a vent of sorts?  On the 126 it connects to a vent tube for the injectors. Hmm...
We need Aaron to school us here methinks 8)
Daniel
1977 450 SEL 6.9 - Astralsilber

Jan S

daantjie,

yes that is also my understanding - a venting system. A small amount of gas from the combustion process "leaks" through the piston rings (more if the engine is worn out). It's also called "blow-by".

Many many years ago I had a Ford Zephyr 6 1964. On this engine these gases were released directly to atmosphere, through a cap on the valve cover (if I remember correctly).

A more environmentally friendly solution is to lead these gases back to the combustion chamber through the air intake.   
1975-mod W116 450 SE with 6.9 engine

ptashek

Would an off-shelf fuel hose with a brass 3-way splitter not do the job? It looks like the hose is over-engineered for no good reason at all.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

Jan S

Yes, the current solution is an off-shelf straight silicone hose that can be bend (to some degree) under the FD + a stainless steel 3-way splitter + 2 x 90 deg hose bend + 2 x aluminum hose connectors.

The silicone hose can stand 185 deg C (365 deg F)

The one challenge I have is the reduction at idling house from 22mm to 5/8"mm with approx 22 deg bend (the inlet part of the hose). But I'm getting there .....
1975-mod W116 450 SE with 6.9 engine

johnnyw116

would an hose adaptor solve the reduction of the hose ?
something like this :  https://www.ebay.co.uk/itm/122049247077
JohnnyW116

raueda1

Quote from: Jan S on 09 March 2022, 05:48 PMThanks, raueda1 - I didn't think of that.

One solution I'm following right now is to use a hose splitter made of nylon plastic. The temp range is up to 135 deg C (275 deg F).

Is that sufficient, what do you think?

Stainless and nylon are fine.  Just nothing with copper.
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0