Mercedes-Benz USA's Classic Center 
The Mercedes-Benz W108 and W109 vehicles equipped with the 4.5L SOHC cast-iron block m117 V8 were produced, starting in early 1971, with the 280SE 4.5. The 4.5 engine was released by MB initially for the North American market, to get around the tougher emissions standards without killing the engine output and performance of the 3.5L engine. The m117 4.5 is very similar to the 4.5, with a 30mm taller stroke. The heads were also given larger combustion chambers, lowering compression to 8.8:1 or 8.0:1, depending on engine variation and production date. Power was 230HP or 200HP, depending on compression. The D-Jet EFI system was tuned further for the 4.5, with a specific ECU that gave a 10% full-throttle enrichment. This (along with a taller rear-end gear) allowed the 4.5 to have similar efficiency to the 3.5, yet more power on full throttle.
Note: I have a whole section dedicated to 4.5 m117 performance tuning (coming soon!)
The 108 and 109 Chassis Mercedes Benz vehicles with the 4.5L m117 V8 engine are still, to this date, sought after by many people who owned one of these in the early 70's (or who had a family member or friend with one of these wehicles). Also, many people who live in Europe are buying rust-free examples from the USA and shipping them back to Europe. The 4.5 wasn't actually offered in Europe at the time, and it has perhaps a stronger following than the 3.5 in Europe.
The 280SE 4.5 |
- D-Jetronic Fuel-injected SOHC 4.5L V8. Vented front disc brakes, rear disc brakes. Later models had a compression "Nerf" to conform to tougher emissions standards. This is true across the whole 4.5 series. |
The 280SEL 4.5 |
- D-Jetronic Fuel-injected SOHC 4.5L V8. Vented front disc brakes, rear disc brakes. 4 inches more legroom (and 4" longer wheelbase) than the SE model. |
The 300SEL 3.5 |
- D-Jetronic Fuel-injected SOHC 4.5L V8. Vented front disc brakes, rear disc brakes. Same wheelbase as the 280SEL 4.5, but with air-suspension. |
