M103 Best Motor Ever
 

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.

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

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. :D 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. :D

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.

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!

Love 'em.

Ignore Croc Rock

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

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.

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.

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! :eek: BMW...eh, whatever. :D

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. :eek:

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!

My. that's hard to believe
 

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.

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

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.

I agree
 

I have a W123 with AC running 134. It pulls hard, and the cooling is a joke. Now our 95 Town Car Lincoln is on 134 since new, 200,000 miles and only occasionally have I had to add a bit of freon. And it will freeze your bottom. I'll keep my fingers crossed on that town Car. But my W124 will have R12, maybe duracool, or no AC, but no 134. But my W124 with a 5 speed is an awesome driver. I think that starting pretty easy in second gear, it will do 0 to 60 in about 6 seconds, and will reach just about 80 mph at redline. It is a flyer! I got that great engine from John Hef. Thanks John!

[QUOTE=amg280;2227281] 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. QUOTE]


I've owned a number of manual transmission Benz cars, in fact my first Benz was a manual (59 190SL in 1974).

Without exception, I've found the shifter to be way to insulated and vague.

It's not that I do not like manuals, I currently have 4, it's that the later MB automatics are so nice, that I prefer my Benz cars to have automatics.

Jim

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

Mine is smooth as silk and from 60 mph on up is very quick.

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...

I almost bought a 400E, but the seller decided not to sell. :o

Eventually I'll have one. :D

The tightness in the engine bay was one of the main reasons I went back to looking at M103 cars....

There is a reason the 400E gets virtually identical fuel mileage. They are the same car. Beyond driving style, the most important factors in fuel consumption are weight and aerodynamics.

Although, I'm fond of my 5 speed 300E and have lots of time in the drivers seat, I don't consider the M103 the Masterpiece engine of all time. It rates reasonably high, but there are lots of modern engines, even some of US design and manufacture that are masterpieces IMHO.

You are comparing Oranges to Apples with those two a/c's. The MB is a converted system originally designed for R12. The Town Car has an a/c that was DESIGNED for use with R134a. 134 requires more condensor area to make up for the use of a less effective refrigerant.

Since this is a thread about the M103.....does the timing chain on a M103 ever need to be replaced or dealt with? I remember reading that since its such a short traveled/simple setup that the chances of failure are nearly 0. Is this the case?

Purchased my coupe with 75k on it, with full records, from the original owner. Has ~220k now. Timing chain never replaced, and I have it serviced religiously by Enrique at Mr. M.B. Motors. If it needed a chain, he would have told me.

That is probably the main reason I have cars with an OM617, an M110, and an M103. The only V-8 equipped Mercedes I got were for bought just for stripping. Even for that purpose the engine bay was too tight. I don't want it unless I can work on.

Awesome. Mine only has 139k....so it has a looong way to go yet.

Same here. I'd never want a V8 that I had to maintain to daily driver status....as a project/fun car maybe, but they are indeed a pain to work on.

All but one vehicle in my entire family have inline engines! Once my sister's minivan bites the dust (probably not too far off).....we'll peer pressure her into a 240d or 190e or something. :D That thing is a PAIN to work on.

The M103 has very little strain on the chain AND has a ratcheting tensioner. My car just hit 310,000 miles with the original chain.

That said, FREQUENT oil changes, which my car has experienced will add greatly to timing chain life. Lack of frequent changes allows tiny particulate to circulate with the oil that adds significant timing chain wear.

How frequent? I change it every 4k with synthetic Rotella Diesel oil. 5w40....and I use the genuine German filters (Mann or Bosch) Is that a good enough interval?

Don't know about Rotella Diesel oil, but the interval is fine.

I have my oil changed every 3750 miles, (plus or minus a hundred or so), with Pennzoil 20-50. That is an even multiple of 15K/30k/60k which are more extensive services. Makes the math easier. I made up a spreadsheet after the maintenance book "expired" with mileage service is due, what type of service, and space to fill in the date of service and any other things that were "fixed" or replaced. I just keep it in the map pocket of the driver's door with the owner's manual and registration in that cheesy clear plastic pouch.

Unless you do a considerable number of short hops, a 4K oil change interval should work well. Using Rotella in one of these engines is not a bad plan either. Flat tappet cam engines need ZDDP additive for cam and lifter life. Todays passenger car oils don't have it due to the vast majority of cars having roller cam followers these days.

Thanks to the latest emissions pressure on diesel engine oil, the ZDDP content in the the diesel oils such as Rotella has decreased. Since, however, this is a sliding follower system, the amount of ZDDP in the latest Rotella should be adequate.

The vast majority of the miles on my 300E have been with Chevron Delo, the Chevron equivalent of Rotella. I personally would NOT run any of the newer passenger car oils in the M103, especially in the super lightweights that so many modern engines successfully use.

I've wondered about this . Why is this so? Are they that bad, or is the parts support bad, or is MB that good?

They're a dime a dozen in the San Francisco Bay Area. But maybe because there's no snow, no salt etc. I wonder if they rust quickly and get junked?

Good to know. I will continue my synthetic diesel oil....it seems to like it, and it lowered consumption dramatically. I did run 0w40 Mobil 1 in it for about 3k....and it went through it rapidly....like 800 miles to the quart....I put a stop to that real quick! :eek: It goes about 1300-1500 miles now between needing topping off. I am using a synthetic due to the cold climate here, otherwise I'd probably run a dino oil like regular rotella or delo.

I know some use heavy stuff like 20w50.....but that stuff must be like glue in the cold....can't be good for the engine. 15w40 dino oil barely comes out of the bottle at 10F....

I'm in the "high desert" of Southern California, (elevations around 2,500 to 2,800 feet). Pretty warm around here most of the year. Does get chilly in winter, but not so bad. When I go to work on winter morning, my main concern is ice on the road. It rarely gets into the high 20s around here, even during the dead of night. So, 20w50 works fine for us.

I use 10-30 in my wagon (due to rebuild) and 20-50 in my 260E as it is burning a little.

I gotta say that the top end rebuild on my wagon was just awesome. Plenty of space to work with and it was very straightforward!

On the BMWs, I own three with the single cam I6 (weirdo turbo ones but basically the same)...

Motor is half a liter more in displacement on most (some were 733i, less cubes)
Far more advanced port fuel injection (Ljet were early, Motronic late)
Easier to rebuild front end (struts), similar rear
Single row chain on the M30s (small six had belts)
Four speed trans w/ lock up

HVAC is terrible on them. You think the MBs are bad... LOL Tiny condensers, tiny aux fans, etc. Separate temp wheels from pushbutton unit equates to more crap to buy. PLUS vac pods UNDER HOOD AND INCABIN. Heater cores always fail.

Lots of electrical crap can keep you stranded. Main relay, fuel pump relay, on board computer, fuse boxes melt down, etc.

ZF's 4HP22 will burn up the forward clutch pack unless the trans has been remanufactured properly. $2-3500 price tag most owners face... just junk it instead. This was super common... even worse if you have other aforementioned issues.

Starter R&R will make you punch a baby.



That's at least for the E23 7-series. Great when new, but get terrible quick.

I have to agree it IS a fun motor...
 

Normally I love driving my '78 280 coupe, but today I was driving home from work in Kerrville to San Antonioin the 300 - just felt like letting it wind up thinking about this thread and remembering my 5spd 2.6 in Germany, I dropped it into 3rd and ran it back up to 5th not shifting till the redline each time.

Once I got to 120 I backed down to 90 or so and just enjoyed letting it rev a bit in 4th.

Effortless from 80-105 -- much smoother than the 2.6 motor and more power than the M110 even though I STILL feel better driving the old coupe :)

Hey - it was Father's Day with no traffic and I felt like risking it for a change. Just wanted to share my fun for the day.


John in San Antonio

no, I live in the High Desert....5200 ft....not 2800, that's baby stuff....doesn't have anything to do with anything as far as how a car runs....

In Southern California, the "high desert" is commonly used to designate the Antelope Valley part of the Mojave Desert extension of the Sonora Desert, as opposed to the "low desert" which refers to the Coachella Valley, (Palm Springs and environs). It's just a local designation that has nothing to do with absolute elevations, and when when colloquially stated, people who live for any amount of time in Southern California know of which area is being referred.

The Coachella Valley is pretty much near or at mean sea level while the Antelope Valley is between 2,300 and 3,500 feet. Hence, the "high desert" and "low desert" nomenclature.

However, you miss the point. Being in the 90's and sometimes in the low 100's most of the time, I can run 20-50 all year long without designational effects on my diesel engine.

I enjoy the performance of the M103 very much in my 300SE, however, the whole belt tensioner, water pump access is a horrible design at best.

That is all relative though, each engine will have its item that is hard to replace or reach compared to another. I think the water pump is a minor issue, with the right tools its not too bad. The belt tensioner design is fine IMHO....


Mine goes to the dealer tomorrow for valve stem seal replacement. That should stop the oil consumption and spark plug fouling. :D

Don't make a huge bet on the valve seals being a cure all.

Yes the belt tensioner and water pump are a pain, but these engines have many other, more important redeeming qualities. I don't consider the M103 to be the end all masterpiece, but it is a very good engine.

Ethanol and the M103
 

I filled up with a blend of premium and 10% Ethanol yesterday and I got to wondering if M103 digests Ethanol blends well and if so, to what degree?

Anyone have thoughts or comments from experience?

I'm sure that 10% Ethanol is digested just fine. The question surrounds what materials it attacks on the way to the stomach.

Why not? :eek: I sure hope it at least really reduces oil use....so long as it stops fouling plugs I'll be happy. Currently about 2 plugs get fouled after about 1000 miles of driving....the others look fine. The valve seals are original at 140k....so they're probably stone hard. Hopefully it improves things!

I agree w/ Larry. The seals won't help like you think, you need to yank the head. BTDT.

I was once told the valve guides on the M103 are very soft causing them to wear quick.

You think the guides would already be really worn with only 140k on it? I read on here that the guides usually last till around 200k ish before needing replacement. :o I guess I'll have to hope the seals help, I have no $$ to be pulling the head.....I still need to fix my SD! :eek:

You fail to recall it's not only mileage that wears a motor, but HOURS.

The seals are easy, you should have done them yourself. I did mine in a few hours, waste of time but I did them.

Fix one to have a 100% vehicle then you can afford to have the downtime with another... versus having two 50% vehicles.