250 SL Reputation

[Bianchito]

Hi,

Im the new owner of a 1968 250 Sl, that Im still havent received.(shipping process)

When i told this to the members of my classic car club, all they could ssay was  that it was the most problematic version of the three engines (compared to the 230SL and 280SL).

Could you guys let me know which is the your experience and if this is true to some point, and which are the main difference with the 230 and 280??

Thanks!!

[Douglas]

Here's a good synopsis of the differences and some of the problem areas:

http://silverstarrestorations.com/113SL.htm

I don't believe it's fair to say the 250 SL is the most problematic, so don't worry! I would judge the particular car on its own merits.

Good luck & please let us know how the car turns out.

Douglas Kim
New York
USA

[glennard]

The differences in engine design are minor compared to the differences caused by the differences in differencial maintenance.  Change oil and filter religiously, keep rpm down(below 4000), keep FI system in tune, keep valves adjusted correctly, etc.  5000 hours on the engine should be attainable.  D'land Pagoda113s uber alles!

[thelews]

quote:Originally posted by glennard

Change oil and filter religiously, keep rpm down(below 4000), keep FI system in tune, keep valves adjusted correctly, etc.  5000 hours on the engine should be attainable.  D'land Pagoda113s uber alles!

I think Vince, the previous owner of my car would disagree with you on the RPM comment.  His experience is that these cars like to be driven and driven strong.  He says his, now my, 250 SL ran best at about 4500 rpm doing 85 or so MPH.  He once drove 375 miles in 4 hours in this car.   At 117K the engine was rebuilt and they were hard pressed to decide to go to the first oversize, everything looked so good.  Also, the 250 SL has three more main bearings (7) than the 230 SL.  Babying these engines (driving, not maintaining) is not good.  They were designed for the autobahn.

John
1967 Early 250 SL Red/Caviar, Manual

[Joe]

What difference does it make that an engine has five rather than three main bearings unless you really stress it?
Joe

[glennard]

First- Number of bearings-early straight sixes had four mains( one at each end and two dividing the six pistions into groups of two).  Later ones had seven mains- a main between each cylinder and and the ends.
Second- Imagine a crank with ONE main and six cylinders.  Have to be a BIG main and a sturdy crank!  Each additional Main lowers the load on each bearing.

Next rpm.  Don't know the exact math on rpm vs load(i. e. life), but it is not proportional.  Probably, square or cube.  One of you academic types can answer(I've forgotten).   Running at 4000 rpm or 80 mph is about all we Americans can do, IF we can find an open highway.  Most driving in Boston is 0-15 mph!   But, an occasionsal venture into 5000 rpm territory - OK.   7000 rpm?  why? how? when?   How many hours will it last at 7000 rpm vs. 3500 rpm?   You'll get there twice as fast, but only 1/5 or 1/10 as many times.  Your choice.

So, rev it up to 7000 and listen to the timing chain, chain guides, camshaft, valves, rocker arms, rings, etc. SING big time.  Metric, Gernod, here it comes.

[JPMOSE]

I think your club members should stick with what they know (which obviously isn't Mercedes).  The 250SL probably has less problems than late 280SLs (USA Versions) that were equipped with emission controls.  But that isn't a slam against late 280SLs...it is just my personal observation  The 250 engine is strong...and I agree with Vince.....I have driven mine at 105 mph and it purrs.  My 1968 250SL has been nothing but a dream since I initially found a problem with a return line (a steel ball was placed in it when the injection pump was rebuilt...why I will never know).  It always starts instantly when cold or hot.  I sometimes wish I had a 1967, as I think the earlier details are prettier but this is minor.  

I would would be pleased with any Pagoda as long as it has been maintained and is free of corrosion!

Best Regards,

J. P. Mose
1968 250SL
1987 560SL

[glennard]

Driving 375 miles in 4 hours(all + or-) in 4th (or 5th) is in the 4000 rpm ballpark.  Try driving it at 7000 rpm in 2nd or 3rd for a 1000 hours and see how long it lasts!!!

[thelews]

quote:Originally posted by glennard

Driving 375 miles in 4 hours(all + or-) in 4th (or 5th) is in the 4000 rpm ballpark.  Try driving it at 7000 rpm in 2nd or 3rd for a 1000 hours and see how long it lasts!!!

I'm not sure what the rpm he sustained was, but that drive would have averaged over 90 mph.  The car is a four speed.  I'm not sure who you're addressing the 7k comments to...if me, I was just suggesting that consistently under 4K is a little too tame and these cars like to put out a bit, not be flogged at redline.

John
1967 Early 250 SL Red/Caviar, Manual

[rwmastel]

quote:Originally posted by thelews

.... I was just suggesting that consistently under 4K is a little too tame and these cars like to put out a bit, not be flogged at redline.

I would agree to keep it under 4,000 RPM until you and your mechanic are well acquainted with the current condition of the engine.  There is no point in pulling the car off the transport and racing it around town at 5,500 RPM on the first drive!  Unless you personally know the person you bought it from, you'll need to check engine compression, timing chain slack (crank shaft position v. cam shaft position), crank bearing condition, presence of ALL oil filter seals, and much more.

Regarding the 250 SL "reputation", I think most people here would agree that they are fine cars with sturdy mechanial systems.  No worries from the engineering stand point, just from a maintenance stand point from previous owners.

Rodd
Pagoda Technical Manual
please contibute: http://www.sl113.org/wiki/pmwiki.php
1966 230SL
2006 C230 Sport Sedan

[thelews]

quote:Originally posted by rwmastel
I would agree to keep it under 4,000 RPM until you and your mechanic are well acquainted with the current condition of the engine.

I do know the condition of the engine, have spoken at length with the previous owner and this car has documentation of every part and service that has been replaced/fixed/performed since 1971.  It's quite remarkable!  That said, I always drive my cars respectfully even though I drive them spiritedly as conditions allow.  I don't beat on them.  I'm not sure how that impression came to persist in this thread.

John
1967 Early 250 SL Red/Caviar, Manual

[rwmastel]

John,

That's good that you know your engine, but I meant that comment for Bianchito and his newly acquired (shipping in progress) 250 SL.  Since he does not even have his car "in hand", so to speak, I didn't want him to have the impression that he should drive it hard the first day he has it.  He should learn about his new purchase before running it hard.

And yes, I have no idea where Glennard got his 7,000 RPM idea as that figure was not mentioned prior to him posting it.

Rodd
Pagoda Technical Manual
please contibute: http://www.sl113.org/wiki/pmwiki.php
1966 230SL
2006 C230 Sport Sedan

[ja17]

Hello Bianchito,
I cannot really say I have ever noticed the 250SL engine to be any weaker than the rest. The block itself is probably a little stronger in 250SL since  there is  more space between cylinders. The head gaskets seem to like this. The 250SL engine should run a little cooler and is less complex having no ignition emission relays etc. Using a 250SL head on a 230SL is actually a popular performance upgrade!

All the 250SLs had the oil cooler, It was optional on the 230SL and standard on the 280SL. This M129 engine was used for couple of years in the 250SE sedans before the 250SL came out.
The pistons are virtually the same design as the other W113 engines.  The crankshaft and the connecting rods were redesigned and most likely improved in the 280SL engine. However, even the 280SL had one or two improved cranksahft and block designs. Keep your oil changes regular.

Joe Alexander
Blacklick, Ohio

[glennard]

Guys, There are various levels of 'stuff' on the site.  Somebody apparently has a 3 or 5 main bearing Pagoda engine.  Bob Possel got kicked out of a 280 at PUB2005 because he wouldn't rev it up.  The same guy urged me to peg it to prove the 280 had more pep than a 230(mine-the 280 was about the same).  I stopped at about 6500.   Others think the bumperettes make the engine perform better.  

    Some stuff is a matter of taste.  Other things are fact like frequent oil/filter changes and avoiding excessively high rpm extend engine life.  
   There's a reward for the 3 main bearing Pagoda engine.  Maybe Walt's diesel.

[Benz Dr.]

Anyone who thinks that there's something wrong with a 250 just doesn't know engines. The 250 is an improvement over an already great design. All three cars perform about the same with the 280 being a bit faster.
 I can say that I've driven some really fast 230's and some 280's that were dogs. Who cares, anyway?

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061