MERCEDES 280SL
The 250SL was in a sense an interim model: In late 1967, Mercedes switched from the M129 six to the bigger M130, also used in the latest W108/W109 sedans. The new engine retained the M129’s stroke, but had re-spaced bore centers, allowing the bore to be expanded from 82 to 86.5 mm (3.23 to 3.41 inches) for a total displacement of 2,778 cc (170 cu. in.). Adding this engine to the roadster created the third and final iteration of the W113 platform: the Mercedes-Benz 280SL roadster.
On U.S. cars, the Mercedes 280SL’s M130 engine was basically the same as the one in the 280SE models, with 160 PS (118 kW) and 177 lb-ft (240 N-m) of torque (DIN; 180 bhp and 193 lb-ft SAE gross). European cars had a hotter camshaft, giving 170 PS (125 kW; 195 bhp SAE). While the M130 was more powerful than the M129, some testers and owners complained that it was still susceptible to plug-fouling in traffic. (author photo)
The new engine’s additional power and torque were blunted somewhat by the W113’s steadily increasing weight, which now approached 3,200 lb (1,450 kg) with automatic and power steering, but the 280SL was nonetheless the quickest W113. With 23% more torque than the original 230SL, an automatic 280SL was now capable of 0-60 mph (0-97 km/h) times in the mid-9s, although top speed was little changed, limited mainly by gearing. The ZF five-speed was still nominally available, but not common. It disappeared from U.S. options lists in 1970, although it was catalogued in Germany to the end of production.
Depending on your point of view, the 280SL felt either more mature or a trifle lazier than the early 230SL. The suspension was also noticeably softer (thanks in part to the adoption of rubber suspension bushings to reduce the need for chassis lubrication), although by this point nobody except the occasional errant journalist expected the W113 to drive like a Corvette. The engine was less eager to rev as well, although with an extra half-liter of displacement, there was also less need to.
One might have expected that by 1969 the W113 would be in its declining years, especially considering that the exterior styling had changed almost not at all in more than five years, but based on the sales figures, the SL had found its niche. 1969 production topped 8,000 units — not a lot in absolute terms, but more than double the total 1955–1963 production of both the 300SL coupe and roadster.
While the European Mercedes 280SL retained the previous 3.92 axle (with 3.69 or 4.08 ratios optional), U.S. cars initially had the 4.08 axle as standard, perhaps as a concession to low American speed limits. With either four-speed transmission, that meant about 4,000 rpm at 70 mph (113 km/h) in high, a figure more befitting a Triumph Spitfire than an $8,000 luxury touring car. Late U.S. cars belatedly reverted to the 3.92 ratio. (author photo)
One reason for the 280SL’s continued strong sales was that by the late sixties affluent American buyers were discovering Mercedes in growing numbers. In 1964, toward the end of Daimler-Benz’s distribution relationship with Studebaker, Mercedes sold around 11,000 cars in the U.S.; by 1970, Mercedes-Benz of North America was approaching the 30,000-a-year mark. The 280SL represented a relatively small fraction of that total, but was something an intrepid dealer could sell to a customer who already had a Mercedes 300SEL or wanted to show up their golf partner’s 280SEL 3.5 coupe. Such buyers appreciated the W113’s build quality and durability, and were not troubled by its high maintenance costs or other minor foibles.
QUEST FOR POWER
Despite the Mercedes W113’s growing popularity, there was obvious room for improvement. The M130 engine still didn’t have an abundance of torque and was not especially quiet when pushed. In a drag race, the 280SL wasn’t far behind comparably priced American personal luxury coupes like the Cadillac Eldorado or Lincoln Mark III, but extracting such performance required more screaming 6,500 rpm manual upshifts than the average Mercedes owner was likely to tolerate. The automatic transmission, now ordered by more than 60% of customers, was short on finesse, considering the SL’s price and clientele, and still didn’t start in first, an irritation Mercedes had already addressed on the sedans. There was also a growing threat from BMW, whose new six-cylinder 2800CS coupe was aimed at the same market as the Mercedes 280SL.
The Mercedes 280SL’s interior was mostly the same as the late 250SL’s, differing from the early 230SL mainly in minor details. Most were safety-related, but there were also improved seats and better lighting for minor controls. The W113 had decent but not outstanding heating and ventilation for the era, but there was no provision for factory air conditioning (although a Frigi-King or other hang-on unit could be added beneath the dash), a shortcoming addressed on the R107. (author photo)
In the summer of 1967, Erich Waxenberger tested at the Nürburgring a W113 test mule into which he’d stuffed the big M100 V-8 from the Mercedes 600 and 300SEL 6.3 sedans. The 6,332 cc (386 cu. in.) V-8, which had 250 PS (184 kW; 300 bhp SAE gross) and 370 lb-ft (502 N-m; 435 lb-ft SAE) of torque, made the SL a real hot rod, but jamming the enormous M100 into the W113’s engine bay wasn’t easy, and the V8’s substantial extra weight spoiled the roadster’s handling. The project was subsequently abandoned and the test mule scrapped.
The following year, Daimler-Benz engineers explored a more radical idea: creating several W113 prototypes powered by the M50F, a three-rotor Wankel rotary engine with 203 PS (149 kW). Since the W113 was nearing the end of its production life, there was little chance of a rotary W113 being offered for sale, but the M50F was seriously considered for the W113’s planned successor, which was designed with provision for the rotary engine.
A V-8 W113 would have been possible had Daimler-Benz been so inclined. In the fall of 1969, the S-Class sedans and 280SE coupe and cabriolet had received the new M116 engine, a 3,499 cc (214 cu. in.) SOHC V-8 with 200 PS DIN (147 kW; 230 bhp SAE gross) and 211 lb-ft (286 N-m; 231 lb-ft SAE) of torque The M116 was more compact and considerably lighter than the M100 — in fact, the smaller V8 was only a little heavier than the M130 six — so installing it in the W113 to create a “280SL 3.5” would probably not have been a difficult exercise.
It takes a sharp eye to distinguish the various iterations of the Mercedes W113 series. Late U.S. 250SLs and all U.S.-spec 280SLs had side marker lights and other lighting changes to comply with federal safety regulations, but otherwise, a late 280SL looks much like a 230SL. This 1970 has the standard steel wheels, but attractive Fuchs alloy wheels became available in 1969. (author photo)
Had the “Pagoda” line continued for a few more years, we assume Daimler-Benz would have offered such a car, which might well have been the most desirable W113. However, by the time such a car would have been ready, the W113’s successor, the R107 roadster, was very close to production, rendering the older car redundant.
W113 production ended in March 1971, although the 280SL remained on sale for the rest of the model year — mainly in the U.S., where the new R107 350SL was not introduced until August. Total W113 production was a respectable 48,912 units, including 19,831 230SLs, 5,196 250SLs and 23,885 280SLs. The six-cylinder Jaguar E-type still outsold the Mercedes, but the W113 figures weren’t bad at all considering the Mercedes-Benz cars’ much higher prices. The W113 also outsold the 190SL and 300SL combined, and was probably more profitable than either.
Aaron,
Thanks for the mention as a source. Glad I could assist! As a former owner of a 190 Heckflosse, I really enjoyed the write-up!
Keep up the excellent work!
EB
Thanks for another good read.
In the second paragraph of the 250SL section is this line:
“…combined the 82mm (3.23-inch) stroke of the 230SL’s six with a longer 78.8mm (3.10-inch) stroke for a total displacement of 2,496 cc (152 cu. in.).”
You’ve got two numbers listed as the stroke. Am I correct in guessing the 82mm number is the bore of the engine?
Oops! Yes, that should have been "the 82mm (3.23-inch) bore."
Thanks for the correction — I’ve amended the text.
Thorough and judicious as always, you capture perfectly the virtues and drawbacks of the113 with a fine sense of historical context and the competition.
I may be wrong, but I believe the dark blue 230SL you show has replacement US headlight frames from a 280, with the much larger orange turn signal lens, instead of the narrow orange strip at the bottom–a not uncommon thing to see, as are replacement tail lights with orange blinkers, instead of the full red lenses. Not nit-picking here–in the eternal restorers’ debate between aesthetics and accuracy, I am an aesthete. I have a 67 pseudo-250SL: originally a 230 (as VIN indicates), but a replacement block from previous owner from a 250SE. He also put on a 250SL trunk badge, which is one of many hard-to-find-so-absurdly-expensive parts for 113’s. I’ve further mucked it up for purists by installing European headlight units on an originally US car, but they express the clean original Bracq design much better to my mind.
Market values for the 250SL (real, not pseudo, like mine) remain oddly less than one would think, given their short production run, and what at least some consider its combination of superior power to the 230 and lighter weight and less squishy suspension than the 280. The latter seems to have been modified with more of an eye to the US market, particularly in the increasing prevalence of automatics over manual gearboxes. With the 107 firmly aimed at American tastes, the manual all but vanished from US-spec models, and Mercedes certainly cashed in. There’s an interesting (arguably saddening) history to be written about the evolution of Mercedes in response to the US market, from the 70s to the present, as they’ve recalculated designs according to customer tastes, changing technology, and (perhaps most dramatically) the rise of Lexus in the 90s.
For all the drawbacks of the long throws, the engine noise from gearing ratios at high speed, and so forth–about which you’re spot-on–the manual in my 113 is so much fun to drive, and the exhaust note is wonderful (the sound of engineering, not “sound engineers” fiddling with the muffler or (laughably, to me) electronic tweaks to the stereo system, as in some new sports cars. The 113 as a whole can be a money-pit far beyond the 107, given the complexity of welded body work around the grill, hood, and fenders (none bolted on, as with 107’s); aluminum hood, trunk lid, doors, and use of metal instead of plastic in so many places (grill screen, dash, door sills, and on and on); complex, difficult-to-fit wood and other trim on the dash; literally countless grease fittings (and I do mean “literally” in the dictionary sense; even experts on SL forums seem to discover new ones); and antiquated rust-proofing on a body that seems designed to collect water rather than drain it in certain spots. The mechanical fuel injection needs adjustment beyond the skills of all but specialists, including MB dealers, and front-end body work is both expensive and, unless very well executed, will give itself away immediately in panel gaps around that lovely hood design. A 107 is a much saner and cheaper collector choice. But with a fairly well-sorted solid “driver,” by no means fully restored, I’ve never regretted getting my 113, which feels like a machine, not an appliance, yet is utterly easy to drive and rides better than many cars designed decades later. And the shape and proportions are to my eye almost perfect; next to it, the far-more-modern 107 sacrifices character for sleekness. In Dallas, I get happy waves from people who would never notice a 107 (which are all over the place) or a late-model SL that cost 5x what mine did to buy.
Apologies for self-indulgent response. And thanks again for your work!
Thanks, Rick! I think you’re right about the lights and have amended the caption. I was so distracted dealing with the paste-up (typing HTML img tags by hand — don’t ask) that I missed that.
I would be very curious to know how many European W113s of each generation had automatic. Based on the comparative U.S. and rest-of-world production figures and the various estimates I’ve seen for the percentage of cars with automatic, it can’t have only been American buyers opting for it. Still, the fact that the U.S. R107 was offered only with automatic is noteworthy.
For better or worse, the R107 is still too ubiquitous to really stand out. In this part of Los Angeles, it’s hard to go outside without seeing one and the longevity of the design means that it registers as an older car rather than an Old Car. (The C107 is considerably less common.)
On the fuel injection system, I suppose it’s only fair to point out that most mechanical injection systems of that time were similarly intolerant of shade-tree mechanics. On Triumph’s 2.5 PI engine, for instance, the factory service manual included stern warnings not to even try adjusting or resetting the metering unit’s diaphragm springs, which required very fine tolerances.
One would assume that since the R107 was offered only with automatic in the U.S., a majority of American W113 owners had ordered automatic. But there’s another wrinkle, which Road & Track mentioned in their first road test of the R107. Smog-certifying both manual and automatic R107’s for the U.S. would have been that much more expensive. Road & Track gave a figure (which I no longer remember) for the percentage of W113’s sold with automatic in the U.S. and said Daimler-Benz “had to go with the majority.”
As an indication of one demographic to which the W113 appealed, I read an article around the time the BMW 325 Cabriolet was introduced. The writer said that until the advent of the 325 Cabriolet, the W113 was really the only game in town for doctors’ wives.
To my eye the boxy look is fine on M-B sedans but not on the R107. The W113 is so much more graceful.
The separate emissions certification cost is a major reason why we no longer get a lot of cars with manual transmission even if they’re sold that way in other markets — or if we do, the manual actually costs more than the automatic. (That said, it’s interesting to note that some Japanese cars have been sold here with manual transmissions that weren’t offered in the home market.) In any case, the newer three-speed torque converter transmission was probably better suited to U.S. driving styles anyway, particularly with a V-8 engine.
I have a feeling the R107 was intended to look more “masculine.” I don’t recall offhand if the designers specifically said that (although they were certainly conscious that it was bigger and bulkier than the W113), but it would make sense from the results. I don’t know how the demographics of the R107 differed from those of the W113 overall, but at least in L.A., it seems the R107 had a fairly unisex appeal.
I think perceptions of the R107 end up being skewed somewhat by the model’s longevity. Its lifespan overlapped several generations of Mercedes-Benz sedans, each of which became progressively sleeker while the roadster stayed (at least visually) the same. Not that the R107 isn’t objectively bulkier and less graceful than the W113, but having viewed it against cars of the late ’80s as well as the ’70s, the effect is exaggerated.
This was a fascinating and quite comprehensive read. At the last Frankfurt Auto Show and more recently the Essen Techno Classica there were many W113s present. It is apparent their values are increasing, unlike the not particularly liked successor. A number of specialists here in Germany have taken to building cars that retain the 230-280SL styling but with modern Mercedes-Benz engines and transmissions. At an impressive price, of course!
i learned to drive on my dad’s ’71 280sl. only negatives were the automatic, 4.08 rear end (felt bad taking her on the interstate), heavy a/c that was never used, and the points constantly frying up.
love to do a resto-mod if the car would still sound the same. amazing exhaust note. perfect car for going to the golf course.
Thank you for this article. As I’ve only just discovered this website, I am very impressed with the thoroughness and depth that make this article a true gem. Very inspiring.
My grandmother bought a ’72 250C brand new, she kept it for 25 years, and I drove it a lot over that time. The comments on the Mercedes automatic transmission are so spot-on. If you drove it with just the right amount of partial throttle it shifted almost smoothly, anything else and it was jerking and slamming gears. Boy, I miss that car.
Did any of the early 1964 230 SL come with dual carbs instead of Bosch fuel injection.
Not from the factory, but since there were dual-carburetor versions of the 220 and 250 engines in the sedans, it seems entirely possible that someone might have done a swap for some reason.
Owner of 1970 250C …..motor swapped on 76′ to a 280 S/A…..yes yes stamped on the head is S/A ….definitely not a 8 ….block says 130 923 12 001641 …does anyone know this model ? Closest I could come was a 280S a/c or the 280 S/8
The Triumph Stag was aimed at more or less the same market segment as the W113 and R107. Unfortunately for the Stag, it was developed and introduced at a time of extreme dysfunction at British Leyland. It quickly acquired (and never really lost) a reputation for poor build quality and engine problems.
Thanks for that fine article. I recently purchased a 1963 MB 230SL
standard transmission. The car seems to be treated poorly at sometime during it’s past. The steering wheel cracked, the top of the ashtray is missing, but it is a fun car to drive, I am slowly bringing it back to good form. BTW, any idea where I can get a top to the ashtray? I fear that I might have to get it fabricated.
I’m afraid I can’t help with parts or repairs, sorry!
The Stag was a later car than the W113, and was an occasional 4 seater. Its main competitor , on the UK market a least , was the Reliant Scimitar GTC
All true. On the other hand, the W113 was one of the key inspirations for the Stag (whose development was quite protracted) and Triumph explicitly hoped to make the Stag that kind of car. Obviously, the Mercedes was a lot more expensive (and the R107 350SL was even more so), and Triumph didn’t have that kind of cachet, but that’s the sort of buyer they wanted to court.
Of course, it didn’t turn out that way, but massive disparities between intention and outcome are a central theme of the Stag story…!
Rather intrigued by the 115-134 hp 2.2-litre output of the M127 engine in the Mercedes-Benz W127 prototype, both it not being produced with neither it or the Mercedes-Benz W121 featuring a coupe bodystyle were missed opportunities.
Quite perplexed by the outputs of the M180 6-cylinder engine as find it difficult seeing capable of putting out 110 hp whereas the M127 was comfortably able to exceed those figures, also interested to know the M180 family’s relation to the larger M186 family.
The issue was pretty plainly torque, and in particular the shape of the torque curve. Torque output with normally aspirated engines is directly related to displacement. Many of the changes that will provide more horsepower from a given displacement either won’t produce a commensurate increase in torque. Some will actually hurt torque output or at least alter the torque curve in undesirable ways. The M127’s torque peak was 4,500 rpm, which was quite high for the time and forced some awkward compromises in gearing to compensate. In the heavier sedans and coupes, that would have been even worse.
It’s easy to lose sight of that issue when one becomes accustomed to modern engines, which are vastly more flexible. With modern engines, especially with forced induction, the torque peak doesn’t tell you much about the shape of the curve, whereas with early sixties technology, a torque peak above 4,000 rpm was likely to mean a very peaky, high-strung engine.
Can understand as way variations on the M180 were still used to some extent instead of the M127, just brings up the question of whether even further could have been extracted from the M180.
Like the idea of the Mercedes 190SL W121 receiving an 110 hp M180 or 115-134 hp M127 in W127 prototype form as a German equivalent to the Big Healey, which also switched from 4-cylinder to 6-cylinder engines.
Despite the potential compromises in refinement and tractability, is it known how much more power was capable of being extracted from the 105 hp 1.9-2.0 M121 4-cylinder engine or what it would have likely entailed?
I don’t have any details regarding what Nallinger tried in getting more power from the M121, but in that era, the steps involved in getting more power out of a given engine of given duration were generally straightforward: bigger ports, bigger valves, greater valve lift, longer duration, more carburetion. Not all of those are necessarily practical; for example, existing cylinder head design may impose limits on port size and shape, or oil system design may be inadequate for sustained high-rpm use. This makes your question more complicated than it might appear because some modifications may have required extensive and expensive design changes, such as new cylinder heads, for very modest improvements in power and significant cost to low-speed response.
The Big Healey is potentially a misleading comparison because the switch from the big four to the six was initially a matter of production economy rather than a product planning decision; the initial 100-6 lost some ground in performance. (It’s also significant there that the 2.6-liter C-series six was actually about 21 cc smaller than the big four!)
Read the M121 later M115 4-cylinder and the M180 family up to the M110 6-cylinder were related to each other (along with the dieselized 4/5-cylinder units), given the M121 and M180 engines shared history (and other related derivatives) it is strange the 6-cylinder was not capable of reaching 3-litres+.
In theory an 1897cc/1988cc 4-cylinder M121/M115 of similar spec to the 134 hp 2196cc M123 or 168 hp 2778cc M130 have a potential output of 115-116 hp (1897cc) and 120-121 hp (1988cc) for an alternate 190SL W121. Meanwhile using the much later 182 hp 2749cc M110 Twin-Cam as a rough guide equates to a potential 1988cc 4-cylinder output of 132 hp.
Brought up the Big Healey comparison because it immediately comes to mind even if the background for it differed from the W121 and W127 prototype.
I can’t claim to be sufficiently familiar with the fine details of Mercedes engines to tell you how closely their four- and six-cylinder engines of this vintage relate to one another. However, comparing specific outputs the way you’re doing is potentially misleading. A six-cylinder engine has a number of intrinsic advantages, including in breathing, and if the engines are part of the same family, the six will also have greater displacement and thus more torque. Even for engines of identical displacement, the four will need significantly bigger valves to match the total valve area of the six, which the standard port design might not easily accommodate, and would need greater valve lift and longer duration to compensate, hurting low-end response.
My suspicion — which again I’m not familiar enough with the engine development saga to confirm — is that porting ended up being a limiting factor for the M121. Small ports have advantages; they tend to give better low-end torque because you have greater intake velocity at low rpm, and they allow the head to be physically smaller. They obviously become a bottleneck when it comes to extracting more power, but if you have a closely related small-displacement six, that may not seem like a significant problem. However, if you want to get more power out of the four, the port design may leave you boxed in, wrestling with questions like whether it’s worth the cost to completely redesign the head for a gain of a few horsepower.
As for the displacement, I don’t think that one should assume an engine not being expanded beyond a particular threshold meant that it wasn’t capable of being expanded that far. The 2.8-liter threshold was a pretty hard limit in terms of taxation in some markets, like France, and Mercedes-Benz wasn’t yet centering the U.S. market in their product planning decisions. They may well have said, “We’ve already got a 3-liter engine for the few applications that need it,” and left it at that.