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.

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Michael

1988 300 SL (5 Speed)
1994 E320 Wagon
1997 C230

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.

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

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles

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.

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.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

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.

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1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)

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!

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-Steven

---
1959 190b, totalled
1968 220D, sold
1969 230/8, sold
1980 240D manual, gave away at 300k (stupid me)
1985 190D 2.2 manual, gave away to a youngster
1989 300CE, sold when I retired - major regrets

Love 'em.

Ignore Croc Rock

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

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1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)

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.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

I actually did the opposite. I had an 86 300E with a 5 speed. I found the manual in that to be the clunkiest, rubberized shifter I have ever driven. I found a wrecked 300E and put an auto in it. Im sure mine was pretty wore, but still.

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93 300D 2.5 Turbo, Black/Palomino 273K
09 E350 Black/Black 41K

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.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

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!

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Hard to think that someone would dump a five speed out of an 300E. I totally love driving mine, though I do limit my shifting a bit by starting in 2nd usually on flat and downgrade roads. Second gear performance is awesome. The rest of the gears are all very good. I find it a delight to drive - AC is still on R12 and I don't want to change to R134 so I find it a bit warm and have it garaged until cooler weather arrives. Mine is a 130,000 mile W124 with a low mileage 89 M103 I installed last summer. I find it a driving combination that is hard to beat and really enjoyable all around. Mine was a very sloppy shifter, but when I installed the 89 engine I also replaced the bushings in the shift levers and it shifts like new.

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

I would think the A/C would perform better re-charged with R12 than it would being converted to R134....

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

The 124 cars originally on R12 are some of the WORST candidates out there for 134 conversion. There's just not enough reserve condensor capacity.

R12 is coming down in price and plentiful any way.