Now I'm really confused. I found the one that I thought was a free flowing damper just absorbing pulses. No restriction at all. Half of the casting is the same number, the other half is one number off. Soni don't know if they're intended to be different performing or if one is broken. I'm putting 300psi working pressure hose with protective braided covering and I really can't see any reason why I would want a restriction in the cooler. It's going to see full pressure from back feed into the filter housing anyway right? If the cooler is just a detour to then pass through the filter, the pressure will be equalized in the outer filter housing.

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WARNING!!! VINTAGE MERCEDES MAY MULTIPLY UNCONTROLABLY!!! I have tons of Sl/Slc parts w108 w111 w126 and more. E-mail me with needs
BirchsgarageMB@gmail.com

Ditch the damper; it is for noise attenuation only.
There is no need for it in your application.

What do you think about giving the internal bypass seat a little groove to always allow some oil flow? My fittings are a touch smaller than the smallest restriction in the factory stuff. I don't want it to have to cram the extra flow it would normally have through the 1.5bar spring constantly, but I was thinking that it's very possible it already does anyway over a certain rpm, so it might be pointless. This thing will live over 4000 rpm most of its life. When it's not idling.

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WARNING!!! VINTAGE MERCEDES MAY MULTIPLY UNCONTROLABLY!!! I have tons of Sl/Slc parts w108 w111 w126 and more. E-mail me with needs
BirchsgarageMB@gmail.com

Damn, a whole year later I'm finally getting back to this. The motor is mostly reassembled, I did decide to put two openings in the bypass valve that is supposed to open if there is more than 1.5 bar resistance going through the oil cooler. Since my fitting are just a hair more restrictive that the stock 4.5 fittings I figured I'd let a small amount bypass the valve and oil cooler to equal the factory oil cooler flow. Considering I've been essentially running no valve in the 4.5 block for 6 years and a very inconsequential oil cooler I don't think a small bypass will make too much difference. I just took a small cut in the valve seat on both sides. Can't wait to get it in the car. I got second in the drift competition series this summer, I was in the running for the championship so I didn't want to take the chance of this motor not working out or just working bugs out. So I'm getting it in for the last couple events before winter hopefully.

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WARNING!!! VINTAGE MERCEDES MAY MULTIPLY UNCONTROLABLY!!! I have tons of Sl/Slc parts w108 w111 w126 and more. E-mail me with needs
BirchsgarageMB@gmail.com

rwd:

PM sent

I don't know if I will ever find an oil cooler bypass valve for my 5.6 project unless I "borrow" the one from my 3.5 but I really don't want to cannibalize my 3.5. I thought of using a external thermostat of some kind. https://www.improvedracing.com/high-flow-engine-transmission-oil-cooler-thermostat.html None of the 4.5 blocks I obtained had one. Another item I cannot find is a correct 3.5 111 oil pan-the one piece finned item not the 2 piece with the sheet metal sump. The 107 sump is different and will not fit.

__________________
Tony H
W111 280SE 3.5 Coupe
Manual transmission

Past cars:
Porsche 914 2.0
'64 Jaguar XKE Roadster
'57 Oval Window VW
'71 Toyota Hilux Pickup Truck-Dad bought new
'73 Toyota Celica GT

Tony,
Do you have any diagrams, or pictures of the valve you are looking for?
It has been my understanding, perhaps entirely erroneous, that all iron blocks were equipped with a cooler bypass valve, even when a cooler was not installed.

You need to get it from a car with an oil cooler. All the early 450sl seem to have them. I have a couple that are going to be scrapped at some point. It's just a ***** to get out with the motor in the car.

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WARNING!!! VINTAGE MERCEDES MAY MULTIPLY UNCONTROLABLY!!! I have tons of Sl/Slc parts w108 w111 w126 and more. E-mail me with needs
BirchsgarageMB@gmail.com

Hope I'm not jacking your thread Jason. There is a plug in the cooler bypass valve port when the oil cooler is not present. I have already attached the diagram somewhere else in this thread but the detail does not show the bypass circuit. I thought I had a better one somewhere-I will look around.

__________________
Tony H
W111 280SE 3.5 Coupe
Manual transmission

Past cars:
Porsche 914 2.0
'64 Jaguar XKE Roadster
'57 Oval Window VW
'71 Toyota Hilux Pickup Truck-Dad bought new
'73 Toyota Celica GT

No, there's no plug in the bypass circuit when there is no cooler. That's where the oil flows. There's external plugs to keep the oil in. That threaded ring I showed is part of the bypass valve. I machined it to allow a small amount to always bypass the cooler which now allows for the same amount of flow as the factory oil cooler since my fittings are slightly smaller.

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WARNING!!! VINTAGE MERCEDES MAY MULTIPLY UNCONTROLABLY!!! I have tons of Sl/Slc parts w108 w111 w126 and more. E-mail me with needs
BirchsgarageMB@gmail.com

I pulled the bypass valve from my 3.5 engine. It is a spring, valve and seat. It operates on pressure not temperature to direct the oil to the cooler. Thinner hot oil is directed to the oil cooler. Not sophisticated but bullet proof. Given that I think I would rather use an external thermostat with a given set point for more precise control.
BTW I found a 3.5 pan. Came from Germany.
EDIT: sorry for the redundant info post. Reread the thread and realized you already hade the valve out. Getting it out with the front cover on is a little more challenging.

Attached Thumbnails

     

__________________
Tony H
W111 280SE 3.5 Coupe
Manual transmission

Past cars:
Porsche 914 2.0
'64 Jaguar XKE Roadster
'57 Oval Window VW
'71 Toyota Hilux Pickup Truck-Dad bought new
'73 Toyota Celica GT

I know this is an old thread, but I'm hoping to get some further info.

I'm in the process of prepping an M117.961 to go into an R107 Rallye tribute that i am building. Because I'm actually going to be using this car as an event car, (TSD and non-competitive road rallies) I've decided to add the oil cooler. I currently have everything I need EXCEPT for the oil cooler bypass valve. It's been a while since I went through the parts, but I managed to find all but one or two of the components that make up the bypass valve.

So here is the question:
Can anyone forsee any issues with just omitting the bypass valve and allowing the oil cooler to constantly remain active? Obviously, one effect would be that oil temp will take longer to get to normal operating temp, but aside from that, what other considerations would there be?

Thanks in advance for any info/insight.

In the 107 installation, as there is no thermostatic control of oil flow through the oil cooler, the bypass valve is the sole control of that flow. If you are not able to find all of the parts for the bypass valve, an external bridge connection which incorporates an orifice to bleed oil directly to the filter entry can serve to protect the cooler from overpressure.

So, translation: It's unadvisable to run a cooler without the bypass valve.

Understood. Thank you.

The cooler bypass valve will start to open at a pressure differential of ~1.5 bar (22psi). That is quite low compared to the filter bypass valve setting of 4 bar (60psi).
If you are able to source the closing ring for the cooler bypass valve, an orifice could be installed in it, which would avoid creating a bridge in the cooler hoses.