Converting a 500sec to diesel?

[heywood970]

Is it possible to transplant a merc diesel into a 500sec?

I really love these cars but can not affort the petrol

I want to use it as my daily transport and I travel 60 miles every day and more at hte weekends.

Will any of these work with the auto box or will any other engine work.

Really appreciate any advice.

Model Years Chassis # Engine #
300D Turbo  87  124.133  603.960 
300TD Turbo  87  124.193  603.960 
300SDL  86-87  126.125  603.961 
350SD  91  126.134  603.970 
350SDL  90-91  126.135  603.970 

 

[heywood970]

anyone any ideas??

:? :?

 

[dave elcome]

anyone any ideas??

Yeah..............Don't do it!!

 

[Andy]

I echo those sentiments

 

[heywood970]

Guys.

Which is better.

Be able to drive a car that I truly love, although in "bastardised" form or have to drive a Nissan or something efficient.

I budget ?3,000 for the conversion, and will save that in 1 year in fuel.

If I garage the car it will depreciate anyway.

If I remove engine and box and replace with a diesel engine and box it should be straightforward to reverse in 3 or 4 years I hope.

Soon it will qualify for reduced insurance, but it will still be ?2,500 p.a.

Geneuinely, I think I have ot do this, and any ideas or suggestions would be welcome.

 

[nasher]

Wouldn't an LPG conversion be a better idea? It would be cheaper to convert, cheaper to refuel and you wouldn't loose much of the performance.

 

[dieselman]

I think this sounds like an excellent idea!

You want to discount any of the motors that are normally aspirated, and also discount any 3.5 litre TDs as these have weak conrods.
If possible go for a later style 3litre six cylinder with alluminium head or a 2.9L 5 cylinder direct injection. The direct engines are a bit noisier but more fuel efficient.
If you opt for an engine out of a van or G wagen it will be de-tuned.

You might have enough space to be able to fit someting really interesting under the bonnet, like a truck engine! Talk about torque.

You will probably be able to use the original autobox and in fact will need the strength and higher gearing that is provides. When I read a report of the new 4.0 litre on test in'98, it was mated to a S class V12 autobox as it was the only box MB had that was strong enough to take the torque.

 

[heywood970]

have pictures of a diesel in an sec if anyone wants a look

cant seem to load them [/img]

 

[cal300SD]

W126 Diesel Conversion UK

8) Obviously this is posted a year later, but I am new to the site and also new to Mercedes ownership. Like the originator of this thread, I wanted all the benefits of a great W126 car with some reasonable long distance economy. After sampling a 350 and 300 Turbo version in Europe and USA, I wanted similar here in UK but alas they are not sold here. SO next best thing is to make one from Mercedes bits and I have (or am in the process) of doing just that. I have a man who has done more than 100 of similar such conversions since early 90's. In my case I am starting with a late 88, 420SE with a duff motor and good (excellent) body, interior, all else working as it should for its meager 62k miles. We are simply bolting in a 300D from an E class using completely standard parts and methods. Whether I turbo it or not remains to be decided, however, modern variable geometry vane technology, ai-to-air intercoolers should enable the installation of a reliable and improved performance upgarde without buring the motor's internals. We think we can get a good 165bhp and near 250-290ftlbs of torque across a good low to high rpm range. With the V8 ratios and higher diff, it should pull like a train and cruise all day at between 80-100 and still do 29-32mpg. I also get full use of my boot (trunk) as well as spare wheel. All up the car, conversion and turbo will cost me less than 3k pounds taxed and new tyres on the road. Now that's a bargain.

 

[TimN]

Have a look on ebay. I think you will find an old dog currently bidding at £200 with a 300 5 cylinder in it.

 

[jaques2k]

I also would say: don´t do it!! But if you really want, over here I´ve seen such a conversion, and the guy who owns the car says it runs excellent (though it´s "a bit" lazy). He has run the car for several years and has a 300 diesel engine with autobox in it. I don´t know anything else about the car or how he did it, sorry.

 

[DavidBlake]

See the club magazine Oct 2003 issue. Dave Prowse converted a 500SEC to LPG. And it worked well for many years. (still does) This will maintain the character and refinement of the car and is a much better bet than a diesel conversion.