Vince.... I take it then you disagree with the MB executives & engine engineering directors, the MB service executives, etc. that are quoted in Engelen's book.
BTW, I found the correct translation for "gefressen" as refered to in the cylinder wear problem ... it's in my BBB with German Text describing the pictures of different degrees of cylinder wear.... with the English terms for each level of wear listed below this.... the English word for engine cylinder "gefressen".. past tense of "fressen" is "Seized"... so the "grosse Fressen" refers to the engine seizing problem in cylinders 1 & 2 predominantly.
Yes... I am an engineer.. mechanical... and have spent a large part of my career fighting the fundamentals... differential CTE's, heat transfer rates & capacities, thermal gradiant induced high localized stresses... cyclic fatigue fractures, tribological wear mechanism's... you get the picture... I'm relatively well versed in these issues as they relate to fundamental root causes of wear & failures in metals and ceramics.
I'm not an automobile engine engineer... but I have worked with some that joined our company from r&d at Ford and while I worked in Germany and England, a couple that had worked at MB's engine division in r&d. I didn't learn any particulars about their research at that time (I wasn't interested, nor were they), but they all said that compared to the methods and approach we used in r&d that Ford and MB were still in the dark ages. In essense, I was convinced that the approaches used thru the 80's in the automobile industries r&d divisions left a lot to be desired. For example, while we were researching the sensitivities of compound interactive variable tolerances on the systems, using multivariate statistical methods and upwards of 300 - 400 asm's or sub-asm's for each of several variants, Ford and MB were using numbers in the 10's to 20's and thereabouts.... and which largely relied on grossly empirical results. While our modeling efforts were advanced and had evolved with more and more knowledge over time, the automobile's mechanical modeling in r&d were not nearly as sophisticated... and more often than not the models didn't match the empirical results in triboly or even fracture locations.
I'm not surprised therefore that in the late 50's and early 60's the methods were far more empirical and even less sophisticated than they were in the 80's. Hence, I'm also not surprised that for example, the engineering team didn't know they'ed need 7-main bearings for the M129's higher stroke engine to prevent excessive loads on the 4 main's used in the M127.... before the tests showed them the failures occurring in dramatic fashion. Now, to be fair, there may have been some good engineers that screamed to their superiors that the mains would fail with 4 main-bearings... but the fact that they didn't start testing with a 7 main bearing engine in the 1st place, and that the product (M127) was delayed as a result, only indicates either the engineer's at the working level didn't know, or that the approach used was purely empirical.... 'try it and see what happens.
Empirical evaluations in development are the name of the game... so I'm not saying it's a bad aproach... and has to be used ultimately in any event to verify whatever engineering sub tests or calculations indicate. But some things are just fundamental.... surface stress to surface failure at temperature and pressures (load) based on surface finish and viscosities of lubricants under loads and temperatures. If you're going in the direction of increasing HP, by increasing displacement or increasing compression, you're in effect required to increase the forces acting thru the piston to the crack shaft and on the mains. Maybe it's just me, but it seems rather a fundamental of engine mechanics that the r&d team would have known how close to bounderies of metal surface fatigue they were before they even contemplated increasing stroke on the 2.2L engine. Or maybe they did, but then why force a delay in the program by waiting for life reliability testing elapsed time to show that?
And, btw, you can't possibly drive like the Germans did going from Santa Cruz to SF no matter how hard you think you were pushing it. I lived and drove in Germany when I was unaware of the possibility of death or maiming myself... i.e. fearless (16 - 19) and risk prone... though to be honest, I didn't see it as a 'risk' at the time. I've driven & lived in the bay area since I was 20... Santa Cruz being a frequented haven in spring and summer from SJ and SF/Oakland environments. For one thing, you weren't passing on blind curves and blind hills winding out to 6k rpm on every acceleration either. For another, the SL's and other high speed vehicles in German drove the straightaway's on the Autobahn's full near throttle between gassing up... if they had to let up on the throttle it was because the curve they were going into was a tad to sharp for the speed... otherwise, if they had to pull off the throttle because somebody was in front of them going slower horns would be blaring, fists shaking, and high beams blinking, while they rode your rear bumper with an inch clearance. In short, the discipline of driving in Germany at that time was such that if you were in a slower car than the one coming up behind you, then you were obliged to move over before the upcoming car behind you was forced to pull off the throttle... much less have to brake. This was common curtosy, since every driver, in slow cars or not, wanted to eventually be driving a faster one and have the slower car's pull over for them when they were able to achieve that level of car in their life-time. Sitting back driving relatively slower in the fast lane just wasn't done... anymore than stopping in the middle of the freeway.
So... when's the last time you sat on the throttle at over 6k rpm for 2 hours at a stretch without letting up more than 500 rpm on rare occasions?
I'll go with documented evidence in the book which is consistant with my experiences driving in Germany at the time.
By the way... I did say already in one of my posts on this thread that the US market wanted acceleration at low speeds... so torque was the US market quest. Europe wanted high speeds and acceleration at high speeds... i.e. from 80 - 120 mph in a blink of an eye... not speed off the mark. While the US muscle cars were laying screaching rubber off the mark, thru each of 3 gears (read high torque), the Europeans were watching the results at Lemans 24 hr indurance races for which car's had the best longevity at high speeds. The US's stock car racing at the time was as you must certainly know, not the mark of endurance at high speeds... 100 mile races were even then in the rarified stratus of stock car racing with the US muscle car's oval track racing circuits.
One of the statements in the book quoted from an MB official at the time was that the holy grail was that in the early '60's the everyday driver could buy a car that would go 200km/hr ... and many European automanufacturers had achieved this milestone 2 years before MB's 230SL hit the market. There was immense concern by the board of directors that the 230SL wouldn't achieve the 200 km/hr or more top speed. They barely hit it in fact... and breathed a great sigh of relief since with that 200 km/hr moniker they could stick with the 'sports' car image they'd left behind with the 300SL.... and that image meant sales.
So I beg to differ with your opinion that MB was after torque.... they were after a 200 km/hr engine... and high speed acceleration... not torque... they needed torque improvements, to be sure, but that was not their primary endeavor in the engine division nor for the SL series. It was only
after the 230SL that they they wanted to increase the torque (from the auto mag's testers comments related to slow time off the mark).... but they were still after horsepower as primary. The US Daimler Benz of North American's heads came to Stuttgart during the 250SL engine development... and they and the VP for MB sales said they didn't need to push the 250SL any faster to market, nor accelerate the 2.8L engine's development since sales in the US were accelerating at an accelerating rate already. In fact, their biggest concern, and that of the board was that the rumor of the 250SL being an imminant introduction (1 year before it was announced) would shut down the sales of the 230SL in US and Europe... in anticipation of the 250SL coming to market. A great effort was put in place by MB to quash all such rumors and they put tight security on the development work going on with the M129 engine.... even though that engine was introduced already by then on the W108.
By the way, do you mind my questioning your source information from MB and documents pertaining thereto?
Also, btw, I've at various times on this site, stated that I'd purchased my 250SL in '84 and drove it a couple years before letting it sit for the next 15. ... and that the reason I stopped driving it was that it was weak in one of the cylinders, and smoking oil at an increasing rate of consumption. That was at 106k original miles on the engine. It had had always had a little lower compression in that cylinder and a little smoke & spark plug fouling faster in that cylinder than the others even when I bought it, but it got progressively worse. I purchased the car with 103k miles on the engine. The diagnosis when the head was removed --- to determine the extent of the problem... was that the cylinder was worn and compression ring fractured.... so I decided to have the engine rebuilt (long block) by Metric Motors in LA.
Was I surprised that the engine needed work on the cylinders and head at 100k miles? Not at all, and not in the least. Would I have been surprised if the engine siezed & needed to be replaced (beyond reboring) at 50k km's (~30k miles)
? you betcha!... and especially if I'd paid what the then going rate was for an SL at the time.
Finally, relative to Engelen's book... His research and documentation is well regarded from what I've read.... and there's been no smear campaign by MB to discredit his book or information... though the books been out since 1990. The book is fundamentally a documented history of the developments & changes in the SL series vehicles from the 300's, 190's thru the 280sl's, both from the perspective of decisions made by upper management and the board, as well as technical details involved in these cars and their effect on their successors. I've seen no claims or remarks of a negative or positive nature in the book so far that isn't supported by quotes from MB and documents from the time from MB or the automotive test results by both MB and the automobile magazines. keep in mind that if the author's work was to have a credible basis, he had to remain objective in his reporting... otherwise nobody'd have paid any attention to it if it were highly biased to one side or the other... therefore, I believe Engelen's done a credible job of reporting on the negative issues that occurred within MB and the SL's as well as the accolaids they won and the accomplishments made.
The book is highly technical.. not written in an historical "novel" style, and for most readers would be too technical in nature to hold interest for very long... so it's intersperced with pictures and short captions to solve that problem.... along with relatively larger type font and highly calendered paper.
The item that started this was a suggestion to use Enelen's book for dates and chassis numbers that identified what changes were made to each model. There are over 10 pages of this detail listed... almost all of them on the 230SL's changes. I had previously surmised and conjectured about why the 250SL was so quickly replaced by the 280SL and ventured that the reason was related to the US DOT regulations changes that required smog and other HP robbing conditions so that they 250SL's HP was replaced by the 280's to continue to reap the rewards being had in the US market.
Klaus then quoted loosely from Engelen's book on a section that desribed a wear-out failure problem with the M127, 129, & 130 engines and used this quote to describe it as the reason for the replacement of the 250SL by the 280SL. Naj then requouted from Klause's quote and inserted the words "[of the 250SL]" to more directly state that the engine problem was a 250SL engine problem. I've read Englelen's book extensively since then and found not only was Klause's quoted statement taken out of context in refering to the 250SL being replaced by the 280SL, but that naj reinterpreted Klause's quoted statement even more wrongly as applying specifically to the 250SL's engine.
Since those posts, I've reported on other aspects of the engine wear problem from my reading of the book thus far from the 220SL (there was one, you know... just not brought to production) to thru the 280SL.... and to summarize once again ... it was an inherent issue with the entire series... becoming worse with each increase in Horsepower, requiring increasingly more and costlier changes to mitigate and move the problem out in time.... and ultimately compromising the SL's potential Horsepower which could have been achieved had the "Zylinderverzug" problem not been so dramatic.
I've also clearly stated that this was probably not as big a problem with the US market for the car due to slower speeds (speed limits) and the American attention therefore to "off the line" time.... i.e. torque intensive attention. The US paid attention to Max speed in the literature, but not as a practical matter, as in fact they couldn't use it anyway outside of as a flat out race car... who was going to use it to go 125 mph other than maybe 1x for 1/2 mile just to check it out once. In contrast, the high speed autobahns and German/European driving culture in post-war Europe on Germany's no speed limit Autobahn's and to a very large extent their Highways (Bundesbahn's) made for extensive use of high speed driving in the 160-180 km/hr range a common occurrance for the higher end, high priced cars. Like I said, I drove my Volvo B1600 Sport 4 speed stick at full throttle (~110 mph) most of the time on the autobahn and near that on the highway's, though more curves and traffic that I couldn't pass due to directly oncoming traffic slowed me down a little. I've probably driven in excess of 100mph up to 125 or so for an extended 5-10 miles (ha) maybe 20 times in the past 30 years in the US. On each occasion I've either been back to German to visit or work or live, I've driven at that speed for an hour our more at least 2x per week while there..... even with speed limits now on much of the autobahn system... as long as the traffic would allow it, I was able to drive at those speeds without too much consideration for somebody arbitrarily pulling out in front of me with little or no warning from the right hand lanes. Traffic on the autobahn's and their relative lack of having been widened extensively in the recent past has dramatically reduced average speeds and especially the free driving 100 mph + speeds... not to mention the more extensive use of speed limits now. Gasoline consumption increases with increasing speeds as well, and with more and more taxes in Europe on their Gasoline, this has also decreased speeds in general.
The reason that the Zylinderverug "fressen" problem is thematic thruout the SL series development and version to version in Englelen's book is simply that it was the limiting condition for the time-lines for introduction of each model and the limiting factor in HP and performance and not simply solved without going to great expense in MB's factories... which they didn't (obviously) chose to do. The problem was never solved... and at best pushed out in time (use)... mitigated, but not fixed. Do you want to know why MB lists Oil mfg'ers and Oil grades from each in the owner's manual? Because MB ran tests on them to find out which ones mitigated the 'fressen' problem and which made it worse!... that was one of the executive boards command decisions... spend the money and evaluate oil mfg'ers and grades.... among other command decisions to find ways to mitigate the problem.
It's not my intent to be derogatory about our beloved SL's... rather simply to provide some of the information all the SL owners would perhaps like to know more about.... and had Engelen's book been translated and published in English in the early '90's the items he's brought to the light of day would be well known by the US SL owners public by now.
Longtooth
67 250SL US #113-043-10-002163
'02 SL500 Sport
