My garage is being built this summer, which means then it's time to rebuild the series 3.

I want to "restomod", I'm going to be looking at upgrading it to meet modern driving without losing it's feel and charm. Nothing from the outside will be changed, I'd like to go back to the original colour, which was yellow. The interior will remain unchanged except a bit of sound deadening, some plushness on the seats but it will be used on my farm still so will need to be able to take a little punishment.

Underneath however, I want to have things a bit silly. I'm thinking of going for an OM606 engine, not in any great tune but the sound is just phenomenal and I'm very quickly gaining appreciation for the sound of big diesels. So OM606 running standalone management, coupled to an R380 and LT230 with the 2wd kit installed. HD half shafts to take the power. I'm not after silly power, just drivability and reliability.

I was toying with putting one in the P38 but I can't seem to get around the BECM issue.

Is anyone on here running one in a series 3? I have seen a short snippet on YouTube of one, just looking to pick brains.

I know of 4 cyl Merc conversions, but they are the older engine and very slow. I'm very familiar with the OM 603 and have a lot of respect for it, a fantasticlly well engineered engine. I think you will have several problems even if you can get the adaptors:
1 the 6 cylinder Mercs are big long engines, the 603 takes the whole bonnet lenth of an e-class with no space to spare, I'm sure the 606 is the same.
2 They have no bottom end torque, none, not a jot. That's why the G-Wagons with them are so pants off road. Rev them hard and they fly, but forget 4WD going slow.
3 They are heavy, not a show stopper but I've driven E-Class for around 100k miles and the front springs work hard.
4 The turbo could end up where the brake servo and steering column should be, they were optimised for LHD.
(It makes me smile - in a "Don't mention the war" kind of way. My other car is a Merc and its clear they did the least possible to make it RHD, the arm rest is still on the LH seat, the bonnet release is in the pas footwell.)

rob1miles said:

I know of 4 cyl Merc conversions, but they are the older engine and very slow. I'm very familiar with the OM 603 and have a lot of respect for it, a fantasticlly well engineered engine. I think you will have several problems even if you can get the adaptors:
1 the 6 cylinder Mercs are big long engines, the 603 takes the whole bonnet lenth of an e-class with no space to spare, I'm sure the 606 is the same.
2 They have no bottom end torque, none, not a jot. That's why the G-Wagons with them are so pants off road. Rev them hard and they fly, but forget 4WD going slow.
3 They are heavy, not a show stopper but I've driven E-Class for around 100k miles and the front springs work hard.
4 The turbo could end up where the brake servo and steering column should be, they were optimised for LHD.
(It makes me smile - in a "Don't mention the war" kind of way. My other car is a Merc and its clear they did the least possible to make it RHD, the arm rest is still on the LH seat, the bonnet release is in the pas footwell.)

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That's a good point about the low down torque, just looking at it's power curve, it doesn't do much til about 3000rpm! I didn't think about that, it would have to used as more of a road vehicle than an off roader in that case.
With regards to length, I was thinking of cheating slightly and look at fitting a stage 1 front end. I know it's sacrilege but It wouldn't upset me

Hmmmm, yeah, it's not really suitable! back to a lexus 1uzfe v8 idea then shed loads of low down torque and v8 sound.....

I thought you said nothing on the outside will be changed, moving the front end out is a major change and stops it being a proper series 3.

Col

Just to expand on the "no low down torque" issue. I used to drive the OM603 (in a 124) which is around 100 bhp and also no torque below 3000. Wonderful engine for motorway cruising but had to be on auto box. But low down torque was so poor with the 4 speed auto box there were trerrible gaps. A long hill would require planning. The worst was the hill on the M40 coming from Oxford. If I hit the bottom I at 70 I could make the top at 65. If I got held up and hit the bottom at 60 or less I would be down to 35 before I could kick it down to 1st and use 5000 plus revs to get back up to speed. My series has a Perkins 4203. 63 hp but max torque at around 1800 rpm and max revs 3200, its geared for 3000 at 60 and is really nice to drive in the series.

The OM unit in my mates 240d couldn't pull yer díck straight..

That being said, at 345k it's done well

I'm partial to the original 2.25 engine myself, that or a 2.6 IOE 6 pot!!