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Advice on Five Gear 280SE

Started by RustInPeace, 25 January 2012, 11:08 AM

RustInPeace

hallo 116'ers

Introduction
-----------------
I'm a newbie in the forum and crazy about oldtimer Mercedes. Been driving W123s for the last 16 years and finally got the W116 fever! Last winter I wrecked my beautiful signal red 230E 5-gear after flying off the edge of an ice covered embankment into the side of a railway. Three hours after getting released from hospital I was in a barn looking at another W123 230E 5-gear that had been neglected for the last 14 years (mouse nest in air filter, condoms in ashtrays, earth and corn cobs in trunk..). Long one short, after much welding/spannering the car is fixed, loved, and driven each day, the M102 motor totally solid and gives a decent 10-11 l/100km. Once got 8.5 l/ but then the alarm clock woke me up when I got to where I was going. Silberdistel paint still looks decent too.

Help|Advice Needed
------------------------------
Now I've been looking for a W116 in less of a hurry and would really appreciate some input and help.

I found a tidy '76 450SE nearby, but I'm a bit spooked by the fuel consumption for using it every day (which is my intention). The other good option is a silver green '73 280SE 5-gear with almost no extras (no sunroof, no headrests, no back seatbelts). This car is from southern France with fantastic original paint almost totally rust free! Moreover it's a good price (1500Euro) as it was not registered here in Germany and not offered for sale on the internet (farmer living in pampa, needs space for oldtimer tractors etc.).

Some concrete questions:
* Is the 5-gear manual good to drive? I never liked automatic and have had good experience with M102 motors with both 4 and 5 gear GETRAC gearboxes. The 5th really makes a huge difference in noise and consumption. Is this the same for the M110 motor? I never saw a 5 gear 280SE, how rare are they? Is this a good thing?
* Is there any big disadvantage to D-Jet? Is it worth (i.e. easy) to change to K-Jet? I only had K-Jet till now.
* What are the major rust weak points? Different from W123?

Better go before the post gets too long.
Greetings from Mercedes-Land,
JC


Great party. Even if I find my trousers I think I'll stay..
W123 280E 5-speed
* der Rolls-Royce ist DER Mercedes unter den Autos *

Casey

D-Jet gets worse fuel economy than K-Jet, I guess emissions are worse too.  I'd *really* love to find a 5-speed manual transmission to buy...if you don't like it you could always sell it to me. ;)

I think the only downside to the 5-speed is that they don't last as long as the 4-speeds.

adamb

Nice to see German members!  ;)

I once owned a 1973 280SE auto in left hand drive form. The early 280SE is a great car. It's not particularly economical - expect 12-16 l/100km typically depending on how heavy your right foot is and how hilly it is. Forget about conversions to K-jet - just buy a a 1976 car or newer. D-jet is not hard to work on though parts are more scarce. W116 rusts everywhere so check carefully. Good luck - I'd buy it for 1500 euros!


Big_Richard

#3
.

jbrasile

JC,

5 speed 116's are extremely rare. A 280SE with a 5 speed should be a great car to drive and enjoy, offering decent fuel consumption and great performance. The 5 speed box transforms these cars especially on the highway. Yes D-Jet is less fuel efficient than K-Jet but finding a K-Jet 5 speed car would be almost impossible. I beg to differ from MT, in my opinion a D-Jet 280SE CAN be setup properly as long as you get yourself educated enough to work on the injection system yourself or coach your mechanic on how to tune and adjust everything. Yes parts are quite scarce but injectors can still be had new or rebuild. ECU's are NLA and so are manifold pressure sensors.

Engine harnesses tend to go bad in these cars after so many years so check connectors and wire insulation for cracks and damage. One of the most important things when buying a D-Jet equipped car is to replace ALL engine fuel hoses, many cars have caught fire due to negligence in this department so be safe and don't postpone it.

Having said all that for 1500 euros you just can't go wrong...

A 450 is a totally different animal but if fuel consumption is a concern be prepared for some hefty gas bills... we are talking 12 or so l/100km on the open road, around 20-25 in heavy city  traffic with the a/c on.

116's just drive different from 123's, they are heavier, more luxurious inside and give you that presence that only an S-Class can. These cars a very nimble and you may even notice that the suspension is a little harder/rougher than the 123's you had in the past, that's just the way they are. Once you get addicted however it will be hard to like anything else...

Tks,

Joe

Big_Richard

#5
.

pompy

Yup, inevitably, you'll have less head-aches with K-jet than d-jet.

Type17

I'd still go for the D-Jet car though, as it's a great price if the body is good, it has a rare, more economical gearbox and it's a nice colour (I think it is, but I'm biased  ;) ) - you can enjoy it, and if the engine/fuel injection gives too much trouble, it can be changed from a rusty K-Jet 280SE donor car.
'76 350SE in Silver-Green

Casey

Quote from: jbrasile on 25 January 2012, 11:38 PM
A 450 is a totally different animal but if fuel consumption is a concern be prepared for some hefty gas bills... we are talking 12 or so l/100km on the open road, around 20-25 in heavy city  traffic with the a/c on.

I'm not sure how that translates to mpg, but the difference between my 1974 D-Jet 450 and 1977 K-Jet 450 is probably around about 50% better mileage in the K-Jet.  Neither one is very nice on the wallet when used as a daily driver.  The D-Jet is in my opinion more enjoyable engine to drive around and has a nicer sound to it, though.

RustInPeace

Many thanks for such a great response. I hope I haven't started a religious war with D- vs K-Jet!

Setting up the K-Jets was not so difficult -I'm an engineer by profession, but for me the D-Jet is unknown territory. Have to admit I heard *horror* stories about the 250 with carburetor! My father-in-law had one of these in the 70s and even then was difficult to find someone who could keep it setup. That problem despite that he is living in Stuttgart where all this Mercedes stuff is coming from! Some folks reckon the D- has advantages with less moving parts that get worn or stick. Electrical components and wiring is not resistant to aging either: I just got a blown Blinker relais last week and could not get a direkt replacement. Mercedes oldtimer has it's own special pin arrangement. In the end I popped that badboy and replaced a Condensor, two Diodes and the IC - now all is good again :)  What's worrying it that you can drive without the blinkers, but if the ignition does something like this then I have to explain to my wife why she can now tow me home and no, I need her car for a little while, and yes, the children can walk a bit more..

@Raptelan that's interesting stuff about your D- and K-Jet direct comparison. I know that someone nearby in Munich who converted his 350SE using an accidented car. The new motor and systems had less than 100,000km on them! If I get a chance I will get some feedback on his experiences. In theory the conversion might not so painful, as the K has little connection to the loom but is pressure/temperature controlled. Especially if the whole car with motor accessories is available.

@jbrasile about the fire issue: A guy from our workshop had an engine fire from his 280 W123. That thing had a carb and he was saying that it's not unknown to have the fire department called with these cars! I had some trouble also with my ECU some years back and almost died at the price of a replacement. Ebay wasn't so big then! Thank you also for your impressions about the driving feel (fahrgefühl?). Another one from our workshop has a W126 380SEL and it drives like you say. Massive bonnet, *very* smooth and quiet motor, instant gas response and suspension gives a gliding feeling. He's getting from 11.5 to 13l/100km on landroad, about 15 or so around town. That's great, but it just isn't a 116 though!

About fuel consumption. I live out in flat country, *real* flat, and drive 80-110km/h on open roads.There is practically no town driving for me. If I got 13l/100km on that landroad I'd be more than happy!  Another option is not to sell my W123 but register it for winter months only, something quite common here. Not many want to take their perfekt W108 Heckflosse for  -15C salt baths and rocking it back and forwards with the automatic to get off the side of the road!

The main point I am looking at with the 116 is how good the bodywork is from the 280 and 450 that I found, as I had a bit of an overdose with hours of welding the W123! You can get repair plates for all the problem areas of the 123 because there were so many produced. I don't yet know if these are so (cheaply) available for the 116. I am using Mike Sanders body sealer always, this is *the* favorite oldtimer anti-rust here. It creeps slowly into every rusty corner in hot summers and is like solid turkey fat in the winter cold, mmm. My workshop friend used Fluid Film on his '67 T-Bird, but that stuff kinda stinks out the cabin (everyone is telling him this but he is not listening any more)   ;D

Both 280 and 450 have strong points. I really appreciate the opinions of those in the forum for helping here. Maybe next week I testdrive the 450, at the moment it's snowing here and I don't want to plant another road carrot like last winter. The 280 gearbox is still attractive: A M102 motor with Getrac|Zeppelin gearbox is not supposed to last as long as the 4 gear but I didn't manage to make it kaput yet. This is my second one, the last one was pulled out of the railway side last year with 265,000 km gearbox still working perfekt. With luck, the 5 gear would reduce the noise, 'buzz' and fuel from the double cam six on longer travels like it does on the 102 motor. The rarity thing would make a replacement almost impossible, so it would be worthwhile rebuilding in the event of an..

PS, @Type17: I'm biased too: I'm driving a code 881 Silberdistel which was an, um..acquired taste!


W123 280E 5-speed
* der Rolls-Royce ist DER Mercedes unter den Autos *

oscar

JC, man, sorry to hear about your accident that would've been scary.

On the d-jet v k-jet options, I've always been biased to d-jet but only because it was in my first w116. I can't really add much weight to the arguments and I never really pay attention to fuel economy because I'm always planting the accelerator to hear the exhaust 8) I will say though that I reckon a 5spd manual d-jet 280 would be a lot of fun to drive. 

Anyhow, with an engineering background and if you do go d-jet, you'll benefit by going through this next site.  I stumbled across it years ago and it's been a wealth of information for d-jet theory.  Particularly this next page which has the technical journal articles from the late 60s, in German too. http://members.rennlist.com/pbanders/djetfund.htm
But check out his main site and all the other links under the "D-Jetronic" title http://members.rennlist.com/pbanders/  Although Porsche based it covers in depth all the generic parts that make up a d-jet system, an invaluable resource.

1973 350SE, my first & fave

carl888

As a counterpoint to the above comments re: D + K jet, I dislike K and love D!

With K jet, it's a very very difficult system get running correctly.  A K jet car will invariably run, maybe badly, but sorting out the issues can be a nightmare.  It is tricky to diagnose, you need specialist test equipment, preferably a K jet bench and a gas analyser that will read values on the fly.  I have two K jet cars, both took over two years each of fiddling to sort.  The second one, the previous owner spent $11,000 (Yes, really) trying to get running right and ended up selling the car in frustration as it never ran right. 

K jet problems start with the fact that it runs a low pressure, meaning any issues with the injectors will manifest themselves quickly.  Additionally, being mechanical, any wear, faults or mis adjustment means it is impossible to maintain the correct AFR over the operating range of the engine.  This is the biggest issue I have found with K jet so far. 

D jet is easy, once its set up.  My D jet 280 took just a day to check pressures, peripheral components like the auxilliary air valve, points, timing, injectors, mixture, cold start etc.  And it works really well.  Snappy throttle response and good low down torque.  Parts can be expensive, like the injector points but they have a long service life so I don't see it as a problem.

There is little difference in fuel consumption between my W116 280 SE D jet and W126 280 SE K Jet

Good luck with the car, I'd be happy with a 5 speed anything irrespective of the induction system.

Regards,

Carl.


Big_Richard

#12
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oscar

Just wait till I start on the beauty of Solex 4A1 8)  Hmm, probably be defeated before I begun.
1973 350SE, my first & fave

koan

Not sure I agree with you Carl on D vs K jet.

The way I see it is K is a simple mechanical system, warmup reg can be a bit of a problem but easily fixed by a competent DIYer or professionally rebuilt. Injectors are dirt cheap but last forever anyway. Fuel distributors are and expensive item but just seem to keep going. Fuel pump/ fuel filter /accumulator down the back can be a problem but again easily replaced but at some expense.

(K-jet runs higher pressures than D-jet)

Now D-Jet, an early analog electronic injection system, injectors, manifold pressure transducer and fuel pump all expensive if still available, fuel pump can be rebuilt unlike K-Jet unit. Distributor trigger points can be a problem.

If both systems are well maintained with the required money spent there's not much to pick between them. D-Jet is getting harder to source parts for (Bosch tradition appear to be making some trigger points again) though.

I like K-Jet just because of its mechanical elegance.

D-Jet has on advantage, if anyone was thinking of ditching the analog electronic box and going the MeagSquirt route it's possible to use existing injectors and temp sensors, and adding a throttle position pot is easy.

koan
Boogity, Boogity, Boogity, Amen!