M103 Best Motor Ever - PeachParts Mercedes-Benz Forum

Michael K · #1 06-18-2009, 12:52 AM

So this is not really a tech help thread but I just had to give a shout out to the M103, especially when driven by a manual transmission. The M103 has really seduced me. Let me say that I actually have three mercedes, two more modern chassis and motors than the the R107 with the M103, and I love the oldest the best. The more modern motors are technically better. I'm comparing the last of the true small mercedes motors from my two other cars, the M111 and M104, and they are smoother, quieter, have duel cams, are electrically managed, produce more power at a lower engine speed, give off less emissions, and are more fuel efficient. But they don't make my heart go pitter patter like the M103 does. Daily life with the M103 euro spec is like living with a Ferrari compared to the more modern engines from the nineties (note that the really modern from 1998 and beyond have a facsimile recreation of that classic sexiness, but it is so transparently manufactured). The M103 likes to rev. It's nothing to tool along with the engine going four or five thousand RMP. That's where its happy. The power, flexibility, and speed that it drives through the power band between two thousand and six thousand RMP something special. You really have to tune into its ability to dart up and down through its power to appreciate its nature. Hooked up through a slow, but seriously solid and smooth mercedes getrag manual transmission, and I don't think there is anything better.

#2 06-18-2009, 04:01 AM

Yes, I have an 88 300E with a manual transmission and it's a jewel.

I think though that your SL is an M104 twin cam engine, not a M103 single cam, but I might be wrong.

I reread your post and it sounds like your SL is a Euro car which I suppose is an M103. Sorry for doubting you.

I have spent almost 300,000 miles in the drivers seat of my manual transmission M103 car and I share your love for this drivetrain.

JimFreeh · #3 06-18-2009, 07:20 AM

Different striokes for different folks I guess.

I wasn't that impressed with the M103/ 5 speed manual in my W124.
Nice, but not one of the better manual transmission setups I've owned.

The M103 is a very nice engine, when it's good. But when it's bad, it's very, very bad....

How many head gaskets have you been through?
Ever change a water pump on a M103?

If you like the M103, try the M104.

I did.

Jim

#4 06-18-2009, 08:54 AM

You have a point about service difficulties with this engine, but it does have excellent long term reliability and rebuilds very well.

I have heard the complaint about the transmission before, but I have never personally found this to be valid. Maybe that's because I've driven so much and almost every single mile in a manual transmission vehicle of some sort, so I just naturally deal with whatever shifter traits are present and simply enjoy the fact that I'm not having to drive something with an automatic transmission.

I've never known of any head gasket maladies with the M103. I did the head on mine some time ago, but it was due to corrosion due to the previous owner not changing anti freeze. Most any aluminum head engine is prone to head gasket problem if it overheats. Changing the head on the car was no problem though. Very straight forward, unlike the water pump as you point out.

pawoSD · #5 06-18-2009, 12:00 PM

I am a M103 fan too....the sound when they rev up into the 4-5k range is awesome.

I think I actually prefer it to the sound of a V8....it sounds so smooth and refined!

Mine has not had any head gasket issues....we'll see how long it goes. Big deal if it needs a headgasket every 120k.....most people need a new CAR by then.

DslBnz · #6 06-18-2009, 12:11 PM

The M103 300SE I drove for some time had no problem exceeding it's indicated redline, and was making the best power (AFAICT) at 5.5K - whenever I decided to shift (I never found the redline limiter). Once accidentally hit ~ 8K revs at WOT in 2nd (It races up there and never bogs). No problem, and the car had never run better afterward.

Top speed = whenever you decide to lift your right foot.

Happiest in the 6 - 7K range, IMHO. For sustained cruising I would never exceed 6.2K.

At least it's still in the family. And will always be. Personally logged over 15K miles like that.

volosong · #7 06-18-2009, 12:13 PM

Ditto head gasket problems. With almost 220k miles on my M103 coupe, head gasket has been fine. However, you do have to replace the valve guide seals about every 75 or 80k miles.

The only thing that would make my car the "perfect" car is replacing the auto transmission with a manual...but the wife said she would leave me if I spent the money to do that. Though decision!

DslBnz · #8 06-18-2009, 12:15 PM

Love 'em.

Ignore Croc Rock

http://www.youtube.com/watch?v=LJE9Mxt25zU

pawoSD · #9 06-18-2009, 12:46 PM

Quote:

Originally Posted by DslBnz

Love 'em.

Ignore Croc Rock

http://www.youtube.com/watch?v=LJE9Mxt25zU

Yeah! Listen to it roar! Amazing how high they can rev with no issues. I haven't had the guts to go much over 6k rpm....thats plenty! Coming from the land of the 617 diesel where I rarely go much over 3500-4000rpm....(and am usually at less)....6k is scary!

lkchris · #10 06-18-2009, 12:19 PM

IMHO the M103 doesn't hold a candle to the BMW six (chain drive, i.e. 33 or 35 and not 25 or 28) of the same timeframe.

The BMW engine is better all around mechanically, and more importantly BMW had the guts to go with L-Jetronic rather than K-Jetronic.

Now the cars these engines were installed in is no contest. Not that many '80s BMWs around, are there?

I've always wondered what the 70-75 mph engine rpms are with an M103 with standard trans. Any less than the 3500 with the auto? The manual big six BMW was about 2800 IIRC.

Finally, "best ever" stuff is almost always wishful thinking, and it is for sure in this example. Mercedes invented the automobile and has been ahead ever since. (Not so much with engines, however, as theirs remained rather "trucklike" until BMW and others showed the way and with the introductions of the M112/113 engines.)

Nevertheless, it's irrational to think a company like Mercedes doesn't make improvements with each subsequent generation of engines, transmissions, and bodies. One glaringly obvious example not that many years apart is the driving feel of a V6 W210 with the 5-speed auto--it's supurb compared to the racket and thrashing of the M103/4-speed auto combination.

Having owned W123, W124, W210, and now W211 I can for sure state that each generation was better and there's not a single solitary thing about a W124 that's better than the same thing on a W211.

Don't get me wrong--if all you can afford is a W124 you're for sure doing the very best you can and you have a car that's lots better than lots of newer cars ... except for newer Mercedes. W124 deserve to be kept in like-new condition and I hope this is happening.

pawoSD · #11 06-18-2009, 12:44 PM

Quote:

Originally Posted by lkchris

IMHO the M103 doesn't hold a candle to the BMW six (chain drive, i.e. 33 or 35 and not 25 or 28) of the same timeframe.

The BMW engine is better all around mechanically, and more importantly BMW had the guts to go with L-Jetronic rather than K-Jetronic.

Now the cars these engines were installed in is no contest. Not that many '80s BMWs around, are there?

I've always wondered what the 70-75 mph engine rpms are with an M103 with standard trans. Any less than the 3500 with the auto? The manual big six BMW was about 2800 IIRC.

Finally, "best ever" stuff is almost always wishful thinking, and it is for sure in this example. Mercedes invented the automobile and has been ahead ever since. (Not so much with engines, however, as theirs remained rather "trucklike" until BMW and others showed the way and with the introductions of the M112/113 engines.)

Nevertheless, it's irrational to think a company like Mercedes doesn't make improvements with each subsequent generation of engines, transmissions, and bodies. One glaringly obvious example not that many years apart is the driving feel of a V6 W210 with the 5-speed auto--it's supurb compared to the racket and thrashing of the M103/4-speed auto combination.

Having owned W123, W124, W210, and now W211 I can for sure state that each generation was better and there's not a single solitary thing about a W124 that's better than the same thing on a W211.

Don't get me wrong--if all you can afford is a W124 you're for sure doing the very best you can and you have a car that's lots better than lots of newer cars ... except for newer Mercedes. W124 deserve to be kept in like-new condition and I hope this is happening.

My W124 300E runs about 3100rpm at 77mph.....very quiet and fast. And the pickup it has from 75 to 125 is amazing. It can clear that very quickly!

BMW...eh, whatever.

Racket and thrashing? I think the M103 + auto is a very very smooth combination, a little sluggish off the line, but still very smooth. Compared to a 617 auto drivetrain its waaaay different.

And, I hardly ever see an old BMW around here, when I do, its pretty much a rusted out shell with a seat and an engine attached to it.

JimFreeh · #12 06-18-2009, 01:59 PM

Quote:

Originally Posted by pawoSD

My W124 300E runs about 3100rpm at 77mph.....very quiet and fast. And the pickup it has from 75 to 125 is amazing.

Ever driven a 400E?
It'll run away from a M103.
And gets about the same highway mileage as the M103.

Loved my 400E, but boy that engine is tight in a W124....

By the way, I am fond of inline sixes......

Jim

Chowbow · #13 06-18-2009, 02:44 PM

Gotta agree with lkchris a bit. I think the M103 is a great engine, but I'm much more fond of some BMW engines. I personally really like the M50/52 engines. Long lasting and a decent amount of power and really smooth, and sounds great to boot. The power delivery is very linear and predictable, and just a blast to drive. I'm also driving an N54 motor in a newer E90 BMW and while the power is awesome, I'm just not confident that the engine and turbos will last like the E36/M52 combos have done so in the past. Time will tell...