71 250C advice

[1971 250C Rod]

I'll try posting to the vintage folks and see if I get a response...

Hi, I'm new to the mercedes forum. I am in the process of purchasing a 1971 250c with pretty extensive maintenance records and 2 prev owners. The car is pretty much in it's original state with exception of maintenance performed over the years (orig carbs were replaced with weber carbs in 94). The mileage is under 79K and interior and exterior are exceptional. Its a beaut and I am buying it with the expectation of maintenance and upkeep. Are there any words of wisdom/advice from 250C owners that I may leverage? I would like to know if there's anything outside of the common sense things like checking the oil, keeping the air filters clean, etc..to maintain on a daily/weekly/monthly basis to keep this car in great running condition. Also, how hard is it to get parts for these model cars? Is there a place I can get a service manual specific to this chassis (W114)

Thanks in advance,
-Rodolfo

[magnumrick]

Hi everyone, I am also new and also looking at a 250c as my first Mercedes and a daily driver to allow my gas pig F350 to rest. I would really prefer a stick shift and looked at a 71 euro car that had been converted. unfortunately it was a rust bucket. Does anyone know how difficult this would be and also what transmission and clutch parts would be required? Did any of the 114 cars come into the states stock with a floor shift? Would a 1972 250c with a 2.8 have all the mounting holes for the clutch pedal, clutch master, and slave? Thanks for any information. Richard

[Tristar1959]

I have a 70 250 with an M114 2.5L sohc and Webers, manual 4-spd, working on a 72 250C with a tired M130 2.8L sohc/auto (which I plan to put the 250's running gear into), a 73 280 M110 2.8L dohc Weber-carb'd/auto, and a 78 M280CE M110 2.8L injected dohc/auto - so have considered many of your points...
Re: Desirability. Lovely cars. If rusting out - RUN away. There are cleaner ones available. One local guy here selling a pretty clean 75 280C (US version - huge federal bumpers, slightly lower/wider grille, 2.8L M110 dohc/auto); "DaveStLouis" is looking at one in Mo...check his postings
The M110 dohc is the later engine (72 last sohc 2.8 M130, 73 first dohc 2.8 M110), but not sold stick in US; believe all US also carb'd until the W123 bodies (77-78). A Euro M110 is very likely high-compression (domed vs flat pistons) and will have to be fed high test. M130's are very simple and easy-to-care for engines, and lots of parts and junker spares still around.
Depends on how much mechanical work you can handle - but once they start to eat out, not worth the money to do extensive body work.
Check out systems stuff - central vacuum locking system (RH door/gas cap lid/trunk), electric windows, sunroof motor(if equipped), electric radio antenna, vacuum seatback locks (lock ON with motor running and doors closed) and especially the A/C and heating system (some vacuum and electro-mechanical switchovers - simpler than later W123 coupes, but can still be a headache)
Many folks have made auto/manual conversions of the 240 and 300 diesels -
And I used a '71 220D tranny and floorshift parts as a replacement in my '70 250, but it was already a column stick. The W114 (68-76) body pedals mount can handle the master clutch cylinder and pedal, and I believe all the 200, 220D, 240, and 300 mechanicals would be very similar, if not identical. Likely conversion sources in junkyards would be those models. There's actually an almost complete kit available on eBay parts this week; and Many Forum members should be able to source for you - ask the specific question.
Possible problem areas:
Flywheel: Benz engines of this era were generally balanced as a crank unit - balancer, crank, and flywheel. Some folks allege that, as long as you align the (faint) flywheel mark on the crank, you should be fine...as long as you're not racing, etc...more expertise available here on Forum, I'm sure. Don't forget pilot bearing whilst collecting clutch pieces-parts. M-B recommends ALWAYS using new flywheel-crank bolts (Stretch type torqued); and might as well use new throwout bearing and clutch disc, while you're in there.
Driveshaft:
Most different model variants use the same rear section between rear end and centermount; vary the front section depending on engine and tranny used. Although the pair are factory-balanced as a unit, most non-racers find or cut/weld/balance to make fit; but do try to preserve the disk alignment relationships of the old, just in case of harmonics, etc. You're also dealing with an (approx) 4-inch shorter wheelbase in the coupe, vs the equivalent sedans)
Miscellaneous: Collect all switches, such as neutral lockout and backup light wiring, etc.
Check/verify appropriate rear end ratios - should be fine; just be aware that some of the lower-powered versions (220's and 220D's and Hong Kong 240D's, for instance) have higher-ratio/lower-geared rear ends, which doesn't make for good mileage or interstate speeds (check/divide tooth counts stamped on bottom of chunk).
Keep us posted!

Rick,

Welcome to the forum. If you post your questions as a seperate topic, you'll get more responses-its also good 'net manners.

Rodolfo,

Parts are not at all difficult. Follow the link that says 'fastlane' at the top of this page and talk phil via. e-mail or phone-he's just top-notch and it supports this site. For some things (keys, interior parts, etc) you'll most likely go to the dealership, but for the majority fastlane quality is as good or better and WAY less expensive.

Shop manuals are here:
http://mb.braingears.com/

You can also buy them in CD version from mercedes (i think they are only 20 bucks now), and perhaps as well from mercedes classic (see the mercedes benz official website)

I think the biggest problem with the 114 cars are the dreaded tin worm...you might want to get it under-sprayed and kept away for the winter if they salt the roads.

cheers,
dan r.

[1971 250C Rod]

What a great forum! I am impressed with the caliber of information and the helpfulness of this bunch..I have a private email that I need to respond to as well that offers much help.

Thanks to everyone,
-Rodolfo

[250C/8 + 230SL]

I am new to 250C ownership myself, a 1972 model. I can't offer much advice. However, I can say go for it, though. The 250C is so surprisingly fun to drive. In some ways it's actually more fun to zoom around in than the 230SL manual I have. Maybe I am nuts for saying that, but it is quickly becoming my favorite ride.

BTW, I searched for a rustfree pre-73 model. It took a while to find one really rustfree. Good luck.

[Tristar1959]

Speaking as a W111, W114 and W123 coupe lover, as well as being very fond of the way my 250/8 drove and handled

BUT

someone whose real hankering is for (other than a 540K cabriolet) a W113 250SL...(but would settle for a 230 or 280)...

That's quite a statement!

Well, at least it'll make all us 250C/280C drivers perhaps appreciate them a mite more...

Stan

[250C/8 + 230SL]

I just had no idea the 250C would be so fun.
It's a nice ride for the money. A really nice rustfree SoCal car for less than the cost of (a replacement grill and euro headlights) for a w113. Dollar for dollar the w114 coupe returns more fun enjoyment; there's something very satisfying about a reliable, stylish and fun ride for little beans.

[meltedpanda]

Check out my saga for useful info on the 114/ 115
I also have a partscar if you need anything PM meif you do
Good luck


1971 220

[Tristar1959]

I am of the opinion that your candidate 72 250C would very cheerfully accept any and almost all stick parts from the rustbucket 71 Euro sedan, but the 71 SEDAN may be a 2.5L sohc M114 engine, while the 72 is most likely the original 2.8L sohc M130 engine. The old numbering system fell apart with the 250C, which shared the sedans' "250" nomenclature in the body shell (even my 73 M110 twincam badged 280 is a "250/8" body on the plate) but (IN THE US) always had the 2.8L sohc M130 engine from the bigger-bodied cars. Apparently they didn't want to confuse things with the 280S and 280SE's, which were the W108 older-style larger bodies...
When they went to the M110 twincam 2.8L six, they adopted the "280C" badge, as with the sedans.
Just to cornfuse further - there were EURO 250C's (carb'd 2.5L) with sticks and automatics, as well as EURO 250CE's with electronic fuel injection; probably also 280C's; and possibly early M110 280CE's...

BACK TO THE POINT:
When I rebuilt my M114.920 2.5L six, I converted the cam gear, rails, chain, and crank gear from the single-chain to the M130's double chain - direct conversion/fit. Another bud of mine opines that the flywheel MAY be identical, and you could ask that specific question in a new thread - "what conversion flywheels/clutches would fit my _____ engine?"
HOWEVER....
These are balanced as a unit, SO - find and scribe/punch/mark BOTH the auto's flexplate/crank relationship, AND also mark it at TDC; do the same for the stick flywheel/crank relationship. This allows you to cross-correlate the (new) flywheel to the old crank's TDC position. The original marks may be painted or very faint scribes or both, in the hollow where the torque convertor hub or pilot bearings go...and they may not necessarily be at the same place, with respect to TDC (but hopefully are).
THEN, you can take the flywheel to a GOOD machine shop and have it balanced to match the old flexplate/starter ring (you're asking them to match the corresponding IMbalances drilled out/welded on to balance the original crank.)

The one trouble spot I would forecast might be the driveshaft front section length - ask someone the specific question in a new thread - "Can I use W114 250C auto driveshaft with a 250/8 sedan manual? If not, what would work, without cutting/welding/rebalancing?"

You can also search the threads or seek help from oldtimers or moderators far more experienced in this forum - try "conversion" as a likely first shot...

The other W114 candidate cars for almost everything, including mounting flange, tranny mount, clutch linkages, shifter parts, etc would be 220's(4cyl gas), 220D's(4 cyl diesel), 230's(6cyl gas) (actually an older engine design than the newer 220's), 240D's (4cyl diesel) and 300D's (5 cyl diesel), as well as 250's(6-cyl gas). For the flywheel, though, I'd suspect the closer, the better - either a manual 2.8L or 2.5L SIX, but perhaps a 230 2.3L - but it had different bearings and might balance differently...although all have the same firing order.

Candidate donor originally-manual engines will carry the "10" designation in their engine numbers and chassis numbers...as in a 114920 10 123456
or VIN 114060 10 123456; autos a corresponding "12" (in LH drive cars).

[250C/8 + 230SL]

F/u webers:

JAM engineering called me back and say their Weber kit for this car is a bolt on kit and jetted right for it, and quite easily done. Anyone with the experience of doing this, perhaos with their kit?

[1971 250C Rod]

Well, I bought the 71 250C and drove her home this afternoon. She drives great, but a little sensitive on the throttle? I also noticed some warm air blowing from the vents in the floorboard area ( I haven't read the manual to figure out all the controls yet), but I'm hoping its just an adjustment on one of the dashboard heater/ac/defrost knobs? I enjoyed driving this baby more than my decked out Acura MDX. Back to basics, windows down, wind blowing and AM radio playing some tunes...made me feel like I went back in time 35 years! there were at least 5 people made comments about the car. I can see learning all there is about this model and keeping it for quite awhile. I will definitely stay in touch in this forum, since there are so many other MB afficionados out here.

Regards,
-Rodolfo

[t walgamuth]

the fsm describes the flywheel as being balanced with the crank, in actual practice many folks have found that they are not.

to be safe i would check them for being neutrally balanced. this is simple. take your automatic fw and check it and then check the stick flywheel and if they both check out as neutral (i bet a beer they do) you are all set.

if the automatic off your engine is not neutrally balanced then the above described method can be used to match it to the new one. if the new one is not (but your original one is) then it can be made neutrally balanced on its own and then installed.

good luck. the solex carbs were always a lot of trouble. if you convert to the webers with the jam kit you will probably find happiness.

if you find a car with the four barrel i once converted a bmw bavaria 3 liter to use a quadrajet with a euro spec manifold so i could perhaps help out a bit if you wanted to do that. it was a lot of work but once sorted out that beemer would really scream from 3k to 6.5k rpm.

good luck with your new purchase. the coupes are lovely looking cars.

tom w

[Tristar1959]

Rodolfo,

Glad you got it - I think you'll truly love that car, and it sounds like a great buy.

Your linkage may be too "tight" - you want just a little free play either in the idler plate (down on lower front R side of engine) and/or at the linkages/levers on the carbs themselves, so that they don't open the throttle plates immediately, but only after taking up just a little slack - the adjustable throttle stops should set the "rest" position, not the linkage. This also makes them less sensitive to small engine movements and the +/- G forces involved in normal starting and stopping...
You may also want to check spring pressure, acting back against your foot - if too weak, won't "fight" you enough - also being "over-responsive".

Balancing carbs may also be in order - using the plastic "cup" adapter that rests over the tops and upon the bottom plate, with hole in top on which one can rest a good ol'-fashioned UNISYN-type adjustable venturi plate vacuum ball tube guage.

Remember the old dictum about dual carbs...one's always rich, the other lean...


Re: WEBERS
I don't remember who my kits were from, twenty years ago, but I had minor problems with the ball-and-socket adjustable linkages, as well as minor probs with the feed and return lines - but all within adaptability quotients of any normal shade-tree mechanic...
Once initially set up and balanced, they have remained responsive and trouble-free ever since.

[Tristar1959]

I always found the easiest way to use the heater controls is to use the little diagram for "DEF" - top two/usually blue levers to L (verify) directs the blown heater air UP to DEFrost; two lower/red levers to the outside (wide end of the little triangles = MORE red (hotter))(verify). When you want the air down (footwells; well, you need the opposite of DEF, right? - e.g., tops more or all the way R (you can mix, ratio in middle somewhere. As driven home, your slide levers should have been blues Right (air down), R & L reds outboard (hot) or mid (warm). The side nozzles are just that - some can be adjusted with a clamshell open/closed, any rotated to direct the slats/airflow toward vent window and sides, to help defrost/defog side windows.

Middle lever in grille only opens/closes flap for center air/A-C vent - does not directly control temps or activation of either A-C or heat.

Middle or upper R knob (sometimes blue tapered "swirl" center, sometimes numbered) controls fan motor speed by selecting a pathway through a resistor bridge network up inside the air plenum - knob location varies by some models/years; CCW Off; CW on through three speeds, usually Off, Hi, Med, Lo.

White Dot center knob is usually rear pax overhead light switch - has nothing to do with heat/A-C...

Green knob with tapered "swirl" sets A-C temperature - and drives/sets a complex temp tube/electrical/vacuum control. Usually all way CCW/L is A-C Off, at which point the vacuum controls allow vacuum solenoids to move the central and door flaps to have the plenum blower fan's air come through the R & L heater elements. To R/CW/ON (range or 1-2-3 by knob) makes the vacuum flaps and controls gate the air through the A-C evaporator and up/out the center vents rather than through the heater cores and available to footwells or sidevents or defroster vents, also controlling the A-C compressor's clutch activation in accordance with the temp tube/diaphragm's cold-to-cool setting, via electrical make-break contacts.

Hope it's all working well for you. If not, give a holler - have rebuilt a couple of these systems - there's hard and easier ways to do most things. The most fun is probably replacing the blower fan motor, which requires pulling out the ENTIRE heater/A-C box to get at it... May you never have to do that!