W124 engine replacement?

[ms500]

I have a 300TE-24v with the M104 engine, and after living with it for a while I kind of wish I had gone for a 300TE with the M103.

Don't get me wrong, it is a nice car with decent performance, although there are some engine characteristics I dislike; such as the lack of power below 3000 revs which makes it sluggish around town (I get left behind by Micras!), the loudness of it which makes it feel unrefined, the size of the block makes it awkward to work on, and the sheer weight of the engine causing alarming understeer.

So my question is, If I could source a complete 3-litre M103 engine, would it be possible to swap it into my W124? I presume it would drop right in since the M103 was originally offered in the W124, with about a day's labour at a good garage?

 

[Dieselman]

Sell the car and buy another, preferrably a 300 diesel or 320 petrol as they offer more torque for wafting.

You should obtain a higher price for the 300-24 than a 300-12, so could simply trade and spend less.

 

[gt-83]

i asked this question a few weeks ago....but the other way round, because somebody offered me a 104 to replace my dead 103.....didnt do it on the advice of other members......my car is now scrapped

i have to agree with you on the difference in engines......my coupe is a lovely old thing.....but give me my old 103 engine any day!!!

 

[ms500]

Sell the car and buy another, preferrably a 300 diesel or 320 petrol as they offer more torque for wafting.

You should obtain a higher price for the 300-24 than a 300-12, so could simply trade and spend less.

The rest of the car is great; it has loads of equipment, leather seats, and all the electrics work fine. The bodywork is good with only isolated patches of rust.

I see your point, but good W124s are not easy to come by. I love the car, I would just prefer the M103 engine.

 

[kth286]

It is not a straight swap at all as the electronics are different in quite a major way.

The engines are the same block but with different head ie twin cam 24 valves, with variable cam timing and all the associated wiring etc that goes with that configeration.

 

[ms500]

It is not a straight swap at all as the electronics are different in quite a major way.

The engines are the same block but with different head ie twin cam 24 valves, with variable cam timing and all the associated wiring etc that goes with that configeration.

If I changed the engine electrics, could I just change the head on the engine and 'turn it into' an M103 then?

 

[Ade B]

Something is not right if you are getting left behind by Micras...

Granted the 24v engine develops peak torque over 4k rpm but its hardly sluggish... silly point but perhaps you simply need to push the accelerator further as the first quarter on mine doesn't produce a great deal of effect.. Is the gearbox hooking up properly, I drove a couple of C124s with horrendous gearbox flare between changes when looking for mine.

Regarding the noise, personally I love it - pootles around serenely most of the time and lets you know its there when you ask it.

As for weight, I can't imagine there is a significant difference between the M103 and M104.. I have not yet managed to provoke understeer in the CE, perhaps I'm getting old...

If you want to get rid, I might be interested.


Ade

 

[ms500]

Something is not right if you are getting left behind by Micras...

Only for a few seconds, once the car is moving it flies past them.

Granted the 24v engine develops peak torque over 4k rpm but its hardly sluggish... silly point but perhaps you simply need to push the accelerator further as the first quarter on mine doesn't produce a great deal of effect..

Possibly; the pedal seems quite stiff on mine, perhaps resulting in me not pressing it as much. I wouldn't describe it as a slow car, it's really quick on the motorway and great for 70-100 acceleration when overtaking, it just seems to take a while to get moving.

Is the gearbox hooking up properly, I drove a couple of C124s with horrendous gearbox flare between changes when looking for mine.

This may be something I could look at, gearchanges are pretty quick and smooth, although kickdown is a little jerky.

Regarding the noise, personally I love it - pootles around serenely most of the time and lets you know its there when you ask it.

It does sound great when you accelerate up to around 4000rpm, but on the motorway and generally around town it just sounds like a droning noise.

I do have a corrosion hole in the rear exhaust silencer which is due to be replaced soon, though I doubt that would make much of a difference.

If you want to get rid, I might be interested.

Ade

I may consider it if I manage to find a nice M103 300TE.

 

[Ade B]

It does sound great when you accelerate up to around 4000rpm, but on the motorway and generally around town it just sounds like a droning noise.

Something not right there.. around town I can't hear the engine and on the motorway the loudest noise is tyre roar and a bit of wind noise.

I'd suspect the corrosion is causing more noise than you think. Might be worth looking at engine mounts and also checking there are no bits of exhaust rattling..

Whilst mine rasps a bit when you leather it over 5k rpm, at all other times it is smooth and very quiet (AC compressor aside )

Ade

 

[Ian B Walker]

Deffo something wrong with your 300-24. Mine uses the "Scorched Earth Policy" whenever I take it out. . Weight for weight both engines are about the same however as has been previously posted the electrics would take some sorting out. Given your concern I would have someone look at it with an unbiased eye. Preferably someone who has a similar car.

 

[Uberwagon]

Fit a M119 engine.

Dave!

 

[kth286]

ms500

You could check that the cam advance mechanism has not been disconnected in front top of engine.

 

[ms500]

ms500

You could check that the cam advance mechanism has not been disconnected in front top of engine.

It's booked into Mercedes tomorrow to have a new gearbox sump fitted, I'll get them to have a look at a few other things too.