250C/280C/240D daily driver...
 

Good morning,

I've been checking out this board and others for a while. It's time to dump my old POS BMW, which has becone a money pit even by money pits' standards! I'm seriously considering an old Benz.

I may have a chance of aquiring a 240D with a manual tranny. This seems to be the choice for a baby Benz in terms of reliability and longevity. It is really clean and low miles. I'll know more later.

Next up are 250/280Cs. Here are a few questions:

Firstly, what are your opinions on buying from a dealer, provided the cars have records, etc... Here are two--

http://www3.sympatico.ca/cw.classics/cars4.htm

This looks like a beautiful car in a really cool color, but it is in Ottowa.

http://adcache.collectorcartraderonline.com/10/0/2/37388302.htm

This is alot closer and still a cool color.

I was into 2002s for a while, so I know about rust issues. Where are the usual culprits on these cars. Rockers? Floors? Firewall?...

How about carbs? Did they come with Solex or Zenith carbs? I read that you can put a Weber 32/36 on these and still keep the stock air filter. Will they take a 38/38?

Any other major things to check out?

Also, if I don't get the 240, is there anyone either in Ottowa or downstate NY that can give the above cars a once over for me before I make the trek myself?

Thanks,

Peter

P.S. I may also have a line on a free, but slightly rusty 300CD.

Peter,
The '70s 240/250/280 cars can be fine daily drivers if you can avoid driving a nice one on snowy salty roads. These cars often rust through the firewall then water leaks in to rust the floors. Also the usual rust around the headlights, wheel openings and rockers.

I think the single cam 250 sixes with the twin Zenith carbs are a better choice for DIY. The twin-cam 280 sixes with the 4V Solex carb are more complicated and some suffered from excess camshaft/lifter wear and thermal-reactor woes. There's a couple of outfits marketing carb replacements, though if the example you try runs satisfactory, you can probably keep the original carbs working OK. With automatic trans and no overdrive gear, don't expect great fuel mileage with the gas engines. Some 250s were imported with manual gearboxes before 1971. I'd look for one of those. The coupes are the collectibles in this series of cars.

The 220D/240D were the only '70s Mercedes, sold here, with a manual shift. They're slow so avoid the automatics in this model
Old diesels with high mileage may suffer from cold starting problems. Try to start any diesel you're considering while its still cold. For winters in your area, you'd probably need to use an engine block heater on one anyway.

Maybe you can find a good 250C for nice days and get that free, rusty 300CD for snow days.

Happy Motoring, Mark

Thermal reactors?
 

As in emissions crap? If there is alot of emissions crap, can it be yanked out.

As far as carbs, if I can put on a Weber, I will. I've had experience with them and I have heard of alot of problems with Solexes.

"The 220D/240D were the only '70s Mercedes, sold here, with a manual shift. They're slow..." Boy is that an understatement! I want a 240 only if it has a manual tranny. I've also been reading up on the diesels so I'm pretty familiar with the issues of cold-weather starting. (It was -5F this morning!)

Peter

Peter,
The nice thing about the W114/115 is that it rides so well. Also, the glow plugs and controller can be upgraded with an inexpensive kit made by Bosch. I installed it without much trouble and have never had a hard start since.

However, if any diesel you are looking at has been sitting, rather than being driven, I would walk away. I have spent over $4k on repairs related to improper storage. e.g. rubber rot, fuel tarnish, stuck rings...

You might look into a W123 diesel--bullet proof.
Edit: rust is everywhere on my W115, especially rockers and floor. K&K manufacturing sells replacements at good prices, put $$$ to install.

Cheers, Andrew Seidel.

Peter,
Some of the mid '70s 280 twin-cam engines had thermal reactors (a sort of converter) bolted to the head, in place of the exhaust manifold. They kind of look like a pair of large coffee cans. The heat they generate may cause damage to the head over time. The reactors may crack and leak exhaust and good replacements may be hard to find. Getting
rid of the reactors involves finding a conventional exhaust manifold and matching exhaust system parts for replacement. I think the 280 after '75 had the thermal reactors.

Some '68 and '69 carbureted sixes had smog pumps.
'70 to 72 250 just used a series of temperature and RPM regulated vacuum valves that controlled ignition timing to reduce emmissions.
I think the 280 4V Solexes are a bigger headache than the twin 2V Zeniths on the 250. The Weber replacement I've seen for the Solex involves replacing the 4V wth a 2V and adapter.
'72 and later cars had lowered compression to
used unleaded regular gas. Earlier, higher compression engines may have slightly better performance and fuel mileage. Condition of the automatic trans has a big effect here too.
Some later Mercedes automatics used a torque converter instead of a fluid coupling. I Don't know if or when this applied to the 280.

I mentioned cold starting diesels because a well worn diesel with low compression may be impossible to start cold, even on a warm day.
If you go to look at one thats already been warmed up, it may start up just fine until it cools off. A friend had a high mileage 240D that eventually would only crank start in warm weather and as it got worse then would only push start. Finally it had to be push started even after the engine warmed up!

Happy Hunting, Mark