Mercedes 250SE Coupe ('65) - Engine choice

[maros733]

Dear ecomodders,

I have a chance to buy a nice Mercedes 250SE Coupe (W111 platform). Car is in the middle of restoration, but it is missing engine and transmission. I was thinking of diesel conversion with modern engine and 6-speed manual gearbox and use it as highway cruiser for long trips. Unfourtunately (or luckily?) this car has no electronics, CAN bus or ABS sensors, which is normally necessary to fire up modern ECU operated engine. There are other problems too, like connecting it with mechanical speedo and rev counter. What should I do? Is there any crate diesel manufacturer with engine and transmission that would fit? Or should I buy used donor vehicle (like older 1.9TDI VW Passat) and transplant all the electrics if possible? Or it is just not possible? Car itself is quite light, about 1200kg without engine, but can support heavy one.

- My budget is about 22 000€, including work (I want it to be build by professionals, which means about 20€/hour of labour)
- Displacement should not be over 2.5L, 1.9L would be nice
- I want to get reasonable mileage (about 5-6 L/100km or less)
- Parts and service available in Europe

Thanks for any advice.

[RandomFact314]

The diesel engines they used to put in Mercs were bulletproof. I would go with one of them. Even if the MPG isn't amazing you will be saving the money in not having to repair it ever, haha. I would get one of those good engines and then just work on driving more efficiently, get a vacuum gauge to help you out

[tjts1]

Modern high compression spark ignition engine + LPG.

[maros733]

Thanks for responses. Unfourtunatelly, original engine was ruined and it is not suitable for restoration. I am considering older (mid 90s) MB engines too, just because of mentioned longevity and low running costs in long term. Also modern spark ingniton + LPG was considered, but my problems persist. What specific engine to use and how to bypass the problems with missing electronics, have anyone tried? How costly it can be? I was thinking of engines commonly used in kit cars (so electronics should not be problem), but they are far too overpowered and thus they will not last long.

[pete c]

OM617, 5 cylinder TD from old benz. Should be an easy fit and with 6 speed and proper gearing should easily exceed 30 mpg. It will give excellent performance and last pretty much forever.

It is IMHO, the best damn engine ever made. Why use anything else?

Newer TDs give better performance and slightly better mileage, but, they are junk compared to the OM617.

[maros733]

I know that OM617 is a solid choice, but I am not sure about matching it with 6-speed gearbox. Has anyone done it? What gearbox is be the best match with minimum alternations?

[pete c]

i know it has been connected to W56 5 speed toyota tranny. Not sure about 6 speeds. I suspect there is someone out there that has done it.