W108 280S Engine/Trans Swap with 1978 W123 280CE M110 Compatibility

[julz_w108]

Hi all,

I am pretty new to this forum, but have found it invaluable in my quest to learning more about parts an compatibility. So that you to all who contribute.

Particularly this thread: http://www.peachparts.com/shopforum/vintage-mercedes-forum/243327-108-series-280s-engine-replacing-options.html

So I am just about to acquire my first vintage Merc, a grandad spec 1969 W108 280S. She's a beauty, however... The original engine has seized and will need replacing.

Reading the thread above, it appears that an engine and trans swap from a W126 1980 280S is the most ideal path to go. However, I am finding it hard to source at the moment. There has been a W123 280CE 1978 pop up that will part out the engine, trans and front brakes.

I just wondered if I would hit any forseeable roadblocks in using the engine and trans from this model for my 280S?

Thanks in advance,
Julz

[cth350]

There's a parts 280S on Facebook in NJ.
Basically Any benz straight 6 will fit, but anything more modern that the original requires additional work.

The M110 engine you mentioned has a weak carb (the Solex 4A1) and requires both drive shaft & exhaust changes. The fuel injected M110 needs the same, but the carb is supplanted by FI hardware to plumb in.

The M103 motor is bullet proof, but now you have drive shaft, exhaust & major wire harness isses.

A note on the automatic trans...
The 280S has an "old style" drive shaft; the connection for it to the trans is pretty much the same on all the straight-6 cars from before 1968 or so. The /8 cars in 1968 introduced a new drive shaft connection style and the 280SE adopted it somewhere around 1969, but the 280S didn't.

About the exhaust...
You'll discover that the header pipes on the the 280S are the same for all the benz cars with zeniths. The rest of the exhaust system follows the same bend patterns as the other straight 6 W108 cars and the straight 6 W109 cars can be cut down if that's all you find, should you need one.

-CTH