Benz-wise, the year 2022 will forever be the year of the 300 for yours truly. This year, I found and wrote up a W109 300SEL 3.5 saloon (utterly beautiful) and an ultra-rare mid-‘60s W112 300SE Coupé. Time to complete the 300 trifecta with the absolute star of the show, the “greatest sedan in the world” and arguably the most incredible Q-car ever made: the 6.3 litre 300SEL.
It’s a wonder that the 6.3 is only making its CC debut now, in a way. Sure, they’re pretty rare – only 6526 units made over five years – but they are beyond iconic and quite a few made their way across the Atlantic, so one would have thought one of these would have had its day on CC already by now. Not the case, no problem; Tokyo will provide.
Where to start on such a legend? First with the looks, perhaps. Let’s go full-on Biblical. In the beginning (a.k.a. 1959) was the Fintail. And the world thought it was good, but maybe could be even better. On the second day (1961), Paul Bracq penned the W111/112 two-doors, and the world said “Ooooh!”, and on the third day (1965) he designed the W108/109 saloon and the world went “Aaaah!” The definitive Mercedes-Benz shape was made.
Underneath, the W108/109 was also a direct descendent of the W111/112. The wheelbase remained identical – 2750mm for lower-spec W108s, an additional 100mm for higher-spec W108s and W109s, which were all longer “SELs,” unlike their W112 forbears. The swing axle rear end, a Mercedes mainstay since the late ‘20s, was kept on for one last go. W109s inherited the W112’s complex air suspension and its fuel-injected 3-litre straight-6, as well. The only significant change was the replacement of the Fintail’s rear drum brakes by discs.
The venerable M186 straight-6 had served Mercedes well, since its 1951 debut. It had powered the stately 300 “Adenauer” limos, the legendary 300SL, the elegant 300 S/Sc, the superlative W112s… It was never mated to the Pontons, which I feel is another point in its favour (I don’t like the Ponton). But by the mid-‘60s, the 3-litre’s time was running out. Mercedes were busy working on a pair of V8s, a 3.5 and a 4.5 litre with EFI, which not going to be ready for action before MY 1970. In the meantime, to take over luxury car duties, a 2.8 litre variant of the M108 straight-6 was devised, shared by the W108 and W109 (and the late model Pagodas) from late 1967 onward.
Mercedes-Benz 300SEL 6.3 German brochure excerpt, 1971
But the expected 3.5 and 4.5 litre engines were not the first V8s Mercedes ever made. In 1963 (I guess that would be the fourth day, which came before the third, but that’s just one of those quirks of scripture), M-B had shocked the world by launching the 600 (W100) limo, the sum total of all the technological sophistication that the company was able to muster into a single vehicle. And to give that behemoth sports car performance, Mercedes engineers created a 6333cc OHC V8 with an in-house mechanical fuel injection that churned out 250hp (DIN).
This M100 engine, as it became known, was mated to a Mercedes-made 4-speed automatic. There just wasn’t a manual gearbox around that could take on the job. But let’s return to the silly Biblical theme and get to day five, in 1966, when Mercedes-Benz test engineer Erich Waxenberger was berated by a journalist friend of his for building “granny cars and taxis.” That barb got under Waxenberger’s skin, so he procured a reject W109 body from Sindelfingen and shoehorned the 6.3 litre V8 in there, just to see if the result could be made to work coherently.
Famously, the prototype was made completely without knowledge or approval from the Daimler-Benz top brass. Waxenberger was a bit of a maverick, test-driving cars beyond their intended design briefs and relentless in his efforts to iron out defects as he found them. He was protected by M-B racing director Rudolf Uhlenhaut, who said of the engineer “I’m just glad to have somebody who can push our cars to the limit.”
One evening, Uhlenhaut heard the Waxenberger W109 burbling past his window. He immediately asked to be allowed to take a test drive, which Waxenberger managed to delay to the next day. A small team of mechanics and engineers worked through the night to gussy up the car and fine-tune it as much as possible. Uhlenhaut was very impressed with the results, soon taking the prototype on a long-distance European jaunt, just to gauge the car’s everyday usability, which seemed quite satisfactory. Once Uhlenhaut was on board, the notion of actually building that monster and selling it started to take root.
Production got under way in December 1967, but the 300SEL 6.3’s grand entrance only took place at the Geneva Motor Show in March 1968. Immediately, the new Benz’s price, displacement, performance and refinement placed it at the apex of the range, just under the plutocrat/rock star/head-of-state chariot that was the exclusive 600. It had nearly all the trappings of the Grosser, but half the ostentation. Hence the 300 number, one can only surmise.
The 300SEL 6.3 came fully-loaded: power brakes, steering and windows, leather or velour upholstery, genuine wood veneer, central locking, self-levelling air suspension, automatic gearbox… and a golf driver-shaped wooden gear selector, though that one might just be for this particular car. Ditto the steering wheel, of course. Period optional extras included power sunroof, radio with power antenna, A/C, radio-telephone, a luggage set and whatever shade of woodgrain one could want.
This is the ultimate incarnation of the classic autobahn cruiser, able to make five adults float above the asphalt at over 200kph in safety and comfort for hours – or whenever the 105-litre petrol tank starts showing signs of running dry.
When production was finally halted in September 1972, the 300SEL 6.3 had blown all expectations. As I said at the start of this post, only a little over 6500 units were made, which isn’t much compared to Cadillac or Lincoln. But compared to the Rolls-Royce Silver Shadow, which is arguably much closer to the Benz than anything Detroit had to offer, it’s a pretty great score. And it represents about a third of all W109s. Considering the minimal expense Daimler-Benz had to risk to design and produce the car, the 300SEL 6.3 was all gravy for Mercedes. The 300SEL 6.3 beats the Silver Shadow in nearly all respects, frankly — performance, handling, reliability, looks, sophistication. I’d say the only area where the Benz is bested by the Brits is, in my view, the Roller’s warmer cabin atmosphere and its sense of exclusivity. But not everyone wants do display their wealth so blatantly.
Fifty years on, the main challenge with these outstanding machines is being able to keep them on the road. All the components are extremely well made, but the complexity of the whole is pretty daunting. The air suspension, the mechanical fuel injection, certain weaknesses in the V8 (which can all be addressed, given enough time and money), the numerous electric and hydraulic peripherals and the ever-present threat of the tin worm all demand attention. It’s not easy to keep on top of everything, but I’m sure its highly rewarding. And since it’s a Benz, all the parts one might need are still available from the factory… for a price.
The W108/109 is probably the best-looking Benz ever made. This M100-powered variant is undoubtedly the fastest and most luxurious of the breed, so it’s a serious contender, at least in my book, to being the best Mercedes saloon ever made. They did try to recreate this superlative machine several times, such as with the 450SEL 6.9 or the Porsche-built W124 500E, but as far as I’m concerned, the original will always be unsurpassed.
Related post:
Vintage R&T Road Test: 1969 Mercedes 300SEL 6.3 – “Merely The Greatest Sedan In The World”, by PN
Amazing to find this beast lurking in Japan. I’m pretty sure that one spent several years in the US first. Beautiful find in the wild.
I always kept an eye out hoping to see one of these monsters on the streets of NYC when I lived there in the ’70s and ’80’s but alas, none appeared. Lots of exotics near East 34th street and many British super luxury cars in upper East Side neighborhoods, but no 6.3s anywhere.
Thank you for the back story of the 6.3. Skunk works creations are one of industry’s most interesting tales, if I can be allowed to use the Wikipedia definition of skunk works as “… widely used in business, engineering, and technical fields to describe a group within an organization given a high degree of autonomy and unhampered by bureaucracy, with the task of working on advanced or secret projects… “
Apparently, Lockheed Martin has registered “Skunk Works” as a trademark, although they freely acknowledge that the term was borrowed from Al Capp’s comic strip Li’l Abner.
In Li’l Abner, the “Skonk Works” was a shack housing an illegal still for making moonshine (“Kickapoo Joy Juice,” which later lent its name to an actual soft drink). The name was suggested by a Lockheed engineer named Irv Culver, who was a Li’l Abner fan.
That’s interesting. Back around 2000, I read the Book “Skunk Works: A Personal Memoir of My Years at Lockheed” by former Lockheed employee Ben Rich.
It’s a great book, and I remember talking about it with my father. He told me that in the ’60s he worked at a pharmaceutical company’s machine shop, and his group called themselves the Skunk Works because they’d build a lot of specialized equipment on demand. He said the term was very widely used then (I’d never heard of the term before then)… probably borrowed from Lockheed but eventually becoming generic. I wonder when Lockheed became possessive over the name?
According to the USPTO TESS database, Lockheed Martin first filed around 1980, claiming they had first used the term in commerce in June 1943. They filed an additional flurry of registrations (trademark registrations are by class) around 1999–2000, five years or so after Ben Rich’s book.
Fascinating – thanks for looking that up.
A lovely car! And, finally – a Mercedes with the kind of power that American luxury car buyers wanted. But at a really stiff price.
I will echo RLPlaut – I had never known how these came about and the story is really interesting.
If I made money from crypto mining next year, I would get one as my daily commuter vehicle. BTW, in New York area, Benz G Wagon is the crypto king pin wagon.
The gear selector and steering wheel are not original. Mercedes had no intention to turn these into pimp mobiles 😉
I am still a bit surprised at the 6.3’s performance stats, given its 250 PS/300 (gross) hp rating. 0-60 times of between 6.3 and 6.9 seconds are very quick, given its 4000 lb weight, as is its 1/4 mile time of 14.2 – 14.9 seconds. I do wonder if MB sandbagged the hp rating some, especially since it’s such a convenient round number of 250/300.
These were not uncommon in the LA area back in the day. I do wonder if some folks added the “6.3” to their 300 SELs, or swapped that badge for the 3.5 and 4.5 badges.
I found a fairly ratty one at the curb in San Mateo about ten years ago, but for some odd reason, I never got around to writing it up.
What’s that under the car, an anti-theft thing?
Is it one of those lots where the car can be “elevated”, so another could be parked under it?
Its a parking lock. You drive over it, it pops up, and it won’t go down till you pay the parking fee. Here is a picture of an empty 3 stall one from Google.
I have seen the elevated parking things, single ones mostly in private residences. Including one in Hiroshima that was used to park a car in the driveway, then elevate it so other cars could access a larger parking area behind the house while still being able to park in the driveway.
I believe it’s a parking meter enforcement device. Pay up or you can’t drive away. Japan has a very low crime rate compared to the US–or just about any country.
The little “pug faced” ride, parked next to the “Benz” is kind a neat.
There just wasn’t a manual gearbox around that could take on the job.
Actually at least one was built with a ZF 5-speed manual, and that’s also the transmission that was used in the AMG racing version, which made much more power from its 6.8 L engine.
But there was no reason to offer that to the public, as the 4-speed automatic was very efficient and did not not hamper performance, as 4th gear was not an overdrive gear, so its four gears were essentially comparable to those in a 4 speed manual. And the fluid coupling was more efficient than a torque converter.
Clients in this price class were quite happy not to have to shift. Frankly, a manual transmission with an engine like this, with its massive low end torque and quite modest power peak rpm (4,400), a manual is really not an asset. You could just use 2nd and 4th and be done with it. Why bother?
There’s an interesting comparison with the March 1963 Motor Trend test of the 1963 Pontiac Grand Prix with the Tri-Power 421, which Roger Huntington estimated was making about 320 net horsepower (gross rating was 370 hp and 460 lb-ft of torque). It had a curb weight of 4,190 lb.
That car, which had the close-ratio four-speed and 3.42 axle, produced the following times:
0-30: 3.0 sec
0-60: 6.6 sec
1/4 mile: 15.1 sec @ 94 mph
The Road & Track test of the 1969 300 SEL 6.3, which had a curb weight of 4,010 lb and a 2.85 axle, did the following:
0-30: 2.9 sec
0-60: 6.9 sec
1/4 mile: 15.1 sec @ 90 mph.
Even with its tall axle ratio, the Mercedes had much higher numerical gearing in first and second (11.34:1 and 7.00:1 versus 7.52:1 and 5.61:1) and slightly higher numerical gearing in third (4.50:1 versus 4.34:1). I don’t have tire diameters at hand, but I’m guessing an FR70VR14 is not too far off an 8.00×14 bias ply in terms of diameter, at least not enough to alter the Mercedes automatic’s overall advantage. The Mercedes 4-speed automatic was designed to minimize power consumption, although it was obviously still going to use more power than a four-speed manual.
Despite the identical quarter mile ETs, the 4 mph difference in trap speed despite a 180 lb weight penalty means the 421 was producing more horsepower. Lighter weight and shorter gearing allowed the Mercedes to stay even on time, but not in speed.
If Huntington’s estimate of the 421’s net horsepower was reasonably accurate, I would guess the Mercedes engine was off by about 30 to 40 horsepower, in addition to the greater power consumption of the automatic. (I recall a Car and Driver article from the period that I think claimed the four-speed automatic used only 7 hp, although I’d have to go digging in my notes to verify that.)
At a very rough estimate, I’m thinking something in the realm of 275 net horsepower.
Ah, I found the reference I was remembering: Karl Ludvigsen, “Mercedes Builds a Brain Box,” Car and Driver Dec. 1961. Mercedes-Benz said it weighed 130 lb dry, 30 lb more than the four-speed manual, and consumed only 8 hp.
Ack, this was supposed to be in reply to your above comment — I don’t know if WordPress screwed up or I did.
Thanks. That sounds more like it.
Another point of comparison: I was just scanning an R&T test of the 1969 Corvette with the 435 hp 427 (w/ aluminum heads). It had a 4.11:1 rear axle. Weight: 3262 lbs. They called it a “More of a race car than a road car”
0-60: 6.1
1/4 mile: 14.3 @98 mph
But its acceleration stats weren’t exactly all that wild, considering that the 6.3 did the 0-60 as quick as 6.3 seconds in other hands. And its factory 0-100 kmh time was given as 6.6 sec.
The quarter mile trap speeds, rather than the 0-60 times, are probably most revealing of actual developed power. There are a number of ways to get a good 0-60 mph (or 0-100 km/h) times (light weight, high torque, short gearing, good launch characteristics), but trap speed comes down largely to horsepower.
With the big-engine Corvette, comparing the trap speed to its 0-60 times (which aren’t that impressive) suggests that it really was making boatloads of power and torque that it had trouble putting to the ground effectively. The Mercedes clearly wasn’t as outright powerful, but it was making pretty efficient use of all of its actual output.
wow. Absolutely wow! That seems to be one very clean car and is stunning in that blue. Although my MB was nothing close to this one, I had a 1969 280 sedan in this same color combo and it was a nice clean car. It had a 4 speed manual and A/C, but that was it. It was a very fun car to drive. However, this car makes the baby one I had look like a dirty dog along the curb!
I’m more of a Cadillac guy, so when I think of luxury it’s normally big Cadillac’s from the 70’s and 80’s. Not so much any more today with the “sport” side of Cadillac going after the wrong brands (IMO). I do feel the MB still has some very nice luxury models still today, but they are being drown out by the nasty boxes they call SUV’s and cars like this 6.3 take me back to that time where true luxury was a beautiful sedan like this and those big Cadillac’s I mention above.
Thanks for yet one more great story with fantastic pics.
I had 2 clients who owned multiple M-B cars with the 6.3 M100 motor.
Client number one was local to me and owned a 300sel for each of the years they were sold in America. One of them was fitted with a raise & fall division window, something I’ve never seen again. This guy was quite wealthy, as his grandfather had founded a flooring company that had only 1 contract; the company renovated all the flooring for the Pentagon in Arlington, VA. and due to the building’s size, it was a never ending process.
The car with the division window required the front seats to be repositioned a couple of inches forward, making the distance between the steering wheel and my client’s grand circumference too small for him to drive the car as he became older and larger. So every few months I would come over and drive the car to keep it in excellent condition. He told me the car was on the showroom floor at the local M-B dealer in Bethesda, MD, and they figured with all the high end and diplomatic buyers, it would sell quickly. It didn’t, and after being available for over a year, my client was able to purchase it well below manufacturer’s cost. It also didn’t hurt that my client also owned several Rolls-Royce and Bentley cars, bought new at the same dealership.
My other client with multiple M100 engined cars lived in the middle east. His incredible car collection was well over 500 vehicles, including 18 [yes, eighteen] M-B 600 cars, in all wheelbases, some with division, some without. One is a landaulet over the back seat. I was able to both drive that car, and ride in the open back with the top down. The convertible section was only over the back seat area [not convertible to the division window area], and surprisingly there was almost no wind at 80kph. I’m attaching a pair of photos showing a few of his M-B 600 cars. An interesting note concerning the factory A/C in that car; There was a switch that when the landaulet top was retracted, turned off the A/C for the back section, as the folded top blocked the A/C vents.
And of course he had several 300sel 6.3 cars, at least 2 of them were extended wheelbase cars with division window. In the mid 1980s my client found and purchased a non-running 600 limousine, and it was missing the entire fuel injection system. [it’s different from the 300sel 6.3], so his very gifted chief mechanic converted the engine to a carbureted version!
This client loved M-B vehicles and had a very large collection of them, most of the cars being rare examples. M-B liked my client too, so much that they built a 3 level parking garage and service facility to house and maintain a fleet of hundreds of late-model M-B cars that were used by my client’s guests!
Wonder if your client #2 is Saudi Royal Family. Are those 13 W100 Mercedes 600 are in running conditions? Frankly this is probably the largest collection of Mercedes 600 in the world.
Tygerleo,
Nope, not the Saudi Royals, I don’t think the Saudi Royal Family antique car collections come close to this one. As per promises made 40 years ago, I won’t disclose the location or owner. Almost no one knows about the collection, and all the people who work on the collection are pledged to secrecy. On one of my visits there, I was a guest at a “National Car Club of _____” dinner event, and not one mention of the collection by all who attended.
As far as I know, I’m the only person given permission to photograph the collection. Over 3 long days I went thru a hundred [or more] rolls of 35mm film in doing so. Many of the post WW2 cars were presented to the collection owner when new, and they’ve never been used.
I had proposed that in having the photos, it would aid me in making sure I sent the correct spare parts, and I was also able to obtain most of the VINs. Before I began providing the parts they needed, they said the wrong parts were sent by the previous sellers. The primary reason this happened was they were providing incorrect car info. For example, they needed body/trim parts for a 1956 Imperial, but they said the car was a 1957 Imperial. Except for the basic mechanical parts, nothing interchanges between the 2 years.
A few stand-out examples:
1957 Chevy Belair convertible, factory A/C and fuel Injection [the only one built with both options], and when I looked at the car it had about 1,400 miles showing on the odometer. My notes suggested the top has never been opened.
A set of 4 matching black Cadillac Fleetwood 60s sedans, with sequential serial numbers, all with “delivery mileage”.
1958 Buick Limited 4-door hardtop station wagon. The Fisher Body plate on the firewall is marked “Body style_____” [no number stamped], and “Body number____1”. I assume back in 1958 when you have enough money, GM would build you the car you want. He wanted a Limited wagon, and he got one.
“National Car Club of _____”
Brunei?
I can’t divulge the location, even the country. I made a promise in 1987 to keep the location and owner info to myself. I wish I could, as I’ve had several car magazines want to publish the story and photos.
I was so impressed by these cars after reading a test in Road Test Magazine in the late 1960’s. ( I was in the eighth grade and not really a potential, buyer.) Even though they were kind of plain compared to the ’69 Riviera and the ’69 Toronado that were also featured in the issue. I seriously kept an eye out for at least a V8 model later in the 1990s. Then I considered a 6.9 model. I discovered that a Northstar Cadiilac STS could match the performance with a much newer and hopefully more reliable car. I wanted a 450 SEL for years but gave up on finding a nice example. The 6.3 and it’s lesser [powered variants are just such tasteful and elegant cars. Peak Mercedes?
The ultimate GT car, bulkier cars with more geegaws could be had from Cadillac and Lincoln, slightly better performance could be got from Ford in 71 but that was really only a race car and only 300 made, not a comfortable fast tourer MB at its best.
My friend’s dad has a clean but deflated and non operative 6.9 in his car collection. Word was he bought it for $1 from an acquaintance’s estate. Pretty wild stuff.
I wonder if you’ll come across a 300SL over there? In my mind that’s the 300 that matters.
Back in 1980 a so-called “exotic car dealer” near me had one of these available for $10,000. It was in remarkable condition, showing about 40,000 miles.
But as fate would have it my Audrey Hepburn clone girlfriend at the time didn’t like the gold color and being the practical type pointed out that $10,000 would almost buy 2 Toyota Corollas.
Trying to make her happy, or keep her happy, or just keep her quiet I passed on the Benz.
Here’s an interesting comparison table from AMS 6/1968, whose performance results were no less spectacular than the American tests.
Ack, the image didn’t attach.
I have always struggled to reconcile the 6.3’s performance stats with its hp and weight. It seems to defy the laws of physics. Either Mercedes really under-rated this engine, or? Do you have any explanation?
In principle, the DIN standard for calculating engine output is a strict about underrating as overrating — it allows plus or minus 5 percent — but 100 mph in 17.3 seconds in a 3,800-pound car with an automatic transmission and a 2.85 axle ratio sure sounds a lot more like 300 net hp than 250.