I am currently looking at a couple of 280SE (w108) 1971 models for restoration. My plan is to keep the cosmetics and exterior completely standard, but I am considering replacing the engine with a newer type as fuel in our country is becoming increasingly expensive, so I need some advice and guidelines. My plan was to fit a 2.8 Straight 6 with modern transmission (as used in the C280 or the W124 280E) to the car. This should give better consumption and emission levels. I got the idea from the â€śour SLâ€ť website. On there they have W113 280 Sls, completely rebuild and with modern engine, transmission and ABS brakes. Is there any one that has tried this or do you think it is a waste of time?
It's lot easier than these others realise. In fact all you need is a engine hoiust and some time. You need a donor car so a written off W124 is a good start.
Remove the old merc engine and trans. Keep the drive shaft and shift linkage .
overhaul the front end because after 37 years it wll be worn. keep the standard brakes and steering bercause if they are good enough for a 6.3 liter V8 they are good enough for your six.
Drop the engine into place . you will need to fabricate two new engine mount arms to locate the engine in the wider space.
the trans nmount should bolt up. the drive shaft is a similar design but it's possible to use the W124 friont shaft in the rear W108 shaft.
Get the original radiator overhualed and get the top and bottom hose connections modified to fit at the same time.
Undo the wiring harness from the W124 and note the connections for the starter ,alternator and so on. you casn wire the stock W108 into this loom and ECU.
These are the basics ,you will find a lot of design similarities between the two different models and you notice that most things interchange. Good luck!.
BTW,heres a link to a good read about dropping a 560 into a W123. Same basic process.
Retro Rides - 1984 Mercedes 230E 5.5 V8