Hello all, new to this forum. Busy with full mechanical re-build of a 66 W108 250S. Great hobby car, as it is an early W108 so mechanically like a Fintail and as such you can do most work on it yourself. However it still has that class and "jewel like" quiality Mercedes cars are famous for! Recently de-rusted my exhaust manifolds in some fermented Molasses. Yes, if you've never tried this, you won't believe how well it works! They are now painted with high heat paint and look good. The only cloud on the horizon is these strange "valves" in the manifolds. Very little mention of them in the books I have. They seem to provide some warming of the inlet manifold, probably in very cold Wx conditions, at start up, then open when the engine gets warm? The point is I'm very keen to restore this car as original as possible, so would like to restore this system. However, the spindles the "butterfly" like valves sit on are frozen solid in the manifolds. some gentle persuasion with heat and copper mallet has not worked. Don't want to damage /crack the manifolds! Luckily they are frozen in the open position. So my question is:
What is their function exactly?
Wil the car be effected when they don't work? (I've come across cars in South Africa, which seem to be unaffected by them not working?)
Can you get spare parts to re-build them?

Any views/experiences will be appreciated. Will try post some photos when I can sort out how to!

I have no idea about the valves but did you say you derusted in fermented molasses? I am from a small town in NE Texas where we drank a lot of fermented things but this is the first I have heard of this.

Yep! Didn't believe it till I tried it. It's a sweet deal price wise, never would have thought, but the proof of the pudding was in the eating thereof!!

When it ferments it forms acetic acid. This works on the oxygen in the rust, and turns the rust to jelly. It will get to rust in places you can't reach.

You need to fully submerge the part in a piece of wire or hook. Leave for 3-4 days. A good scrub with a wire brush whilst you hose the part off with water and the metal comes up like new! It will still have scars/pockmarks from the rust, but the rust is gone. Paint or oil it quickly, because the metal is so clean it will flash rust when it dries off.

After that you can distill the molasses and enjoy a long cool Rum'nCoke whilst you admire your shiny car parts !

Those flaps are "heat risers" here in the US. They should be open when the engine compartment is cold and thanks to a spring on the outside of the manifold, shift to the closed position.

Frozen flaps open isn't good, because they will get your carbs toasty warm. You'd rather have them frozen shut if possible. The parts are replaceable through Rusty or the Classic center. Then there's machine time.

- Two bushings
- Thick pin
- Plate
- Two screws
- Spring
- Spring stops (1 or 2, I forget)

Basically you cut the pin out, press out the bushes, install new parts.

If you're not in snow country, just weld the holes shut and don't look back.

-CTH

__________________
- cth350@gmail.com
http://www.111lakeside.com/

You can get some good information from the Ponton group. Those cars use similar systems.

Mercedes-Benz Pontons (1953-1962) © www.mbzponton.org

Mercedes-Benz Ponton Workshop © www.mbzponton.org

__________________
Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

Thanks very much for answers/replies!

One thing confirmed, I will have to cut them out, even if I was going to re-build them, I think the ones in there, are un-recoverable. They are in the open (I mean not restricting the exhaust position), so that's good. If the new parts are going to be very pricey, I will decide on cutting them away. Here in Australia, it gets cold in places, but not that cold!

By open do you mean bypassing the fins on the underside of the intake manifold or diverting the hot exhaust gases to the underside fins of the intake manifold. A picture would help.

__________________
Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

inside in manifold there are vacum during engine running, this vacum evaporate fuel, this means part of fuel convert to gas, this phisical process take energy, to shake the molecules, and this is the reason inlet manifold gets very cold during idling, so warming it will help to vaporize fuel in mixture. springs are not springs, they are bimetallic (thermal sensor) and actuator to opens butterfly.

hope this helps

__________________
Alex Rozzi
1967 250 SE
Buenos Aires, Argentina

Very interesting about the idling Alex. I've decided to re-build the valve system. In for a Penny in for a POUND$$$$$$$$ (as it's a Merc!!). Good and bad news, all the parts Bi metallic springs, bushes, etc are all cheap/affordable...BAD news, the valve spindals are $$$$$$$$$ !! Anyone have some old exhaust manifolds you could cut the spindals out of? I'm in Australia so cutting them out would cost lots less in postal fees!

in my 230S i tried to free up the heat raisers and eventually got them operating .After a winter of perfect operation they got stuck in the open position.Then the car would simply not shut down ,shuddering for a long time as if overheated . i welded shut the raisers and never had a problem . Alaska