W124 Conversion - Petrol to diesel

[joe_]

Hi There,
Has anybody had any experience of converting a 300TE w124 estate from Petrol to Diesel? I have a 91 J, with fuel injection / ignition faults which barely runs now and wondered about the feasilibility and costs of conversion to a diesel engine..Thanks
Joe

 

[jibcl500]

Wouldnt it be easier just to buy a 124 diesel.

jib

 

[roadhog]

I've been pondering about this as well for a while. I quite fancy a W124 Coupe with a multivalve diesel engine. Then slap on a turbo and run the thing on WVO. Motoring heaven!

I'm guessing you'd need to swap everything from fuel tank to wiring loom?
Park your car and a donor next to each other and keep swapping bits until it runs.

As for the cost, depends how much you pay for a donor car and how much work you're prepared to do yourself.

 

[Bolide]

In theory a petrol to diesel conversion is quite straightforward. But in practice I think you'll wish you never started

You'll need all the ancilliaries (starter, alternator, etc) to make the swop easy. You'll also need a donor from an estate so you get the self-levelling pump. You'll also need the binnacle for the tacho, speedo & glowplug warning light. You'll need to swop the diff or recalibrate the speedo if the final drive ratio is different

You'll need the glowplug relay & loom, the entire vacuum system for the Multivalve engine, the idle stabilisation ECU and loom and loom for the anti-jerk system

You'll need to establish the differences in the vacuum systems between the two cars - the diesel has no inlet manifold so has a vacuum pump

You'll need new engine mounts, probably gearbox mount and probably a different prop doughnut

Ideally you'll need the gearbox from the diesel as the gearing & torque convertor are likely to be different. The Multivalve box has a complex vacuum control system with restrictor valves & etc which is why the vacuum system is so important

The fuel tanks are different but you can interchange them with a bit of fiddling with connectors. You can lose the fuel pumps from the petrol car - the only fuel pump on a diesel is part of the IP

Throwing a turbo on a 606 engine won't get you anywhere - you'll need a new IP and control system to deliver the correct fuelling for the boost pressure. That's a whole different level of modification

Nick Froome
www.w124.co.uk

 

[steptoe]

How about the other way - a diesel to petrol

 

[Xtractorfan]

Really simple that one ..swap with joe