Looking at a '72 280SE 4.5

[Bengoshi2000]

I've been car shopping here lately for a newer model car to use as a daily (or semi daily) driver and I just keep getting sucked in by older Benz. I assume everyone here understands this sickness...

So I've found a '72 280SE 4.5 locally that cosmetically, is about a 7 or 8 out of 10 (exterior and interior). Evidently it was in storage for the better part of two decades and the current owner has been bringing it back up to, and has allegedly achieved, daily driver condition. Before I do anything I'll get the records for the work that's been done. He's been very straightforward that he has no maintenance records prior to storage.

I don't know anything about these cars, specifically any trouble spots I should inspect IF I decide to go take a look at it. So I'm here asking for advice.

The overall question I have is the relative dependability of 280SE's and more importantly, parts availability.

What say ye?

[cleeves]

Originally Posted by Bengoshi2000

I've been car shopping here lately for a newer model car to use as a daily (or semi daily) driver and I just keep getting sucked in by older Benz. I assume everyone here understands this sickness...

So I've found a '72 280SE 4.5 locally that cosmetically, is about a 7 or 8 out of 10 (exterior and interior). Evidently it was in storage for the better part of two decades and the current owner has been bringing it back up to, and has allegedly achieved, daily driver condition. Before I do anything I'll get the records for the work that's been done. He's been very straightforward that he has no maintenance records prior to storage.

I don't know anything about these cars, specifically any trouble spots I should inspect IF I decide to go take a look at it. So I'm here asking for advice.

The overall question I have is the relative dependability of 280SE's and more importantly, parts availability.

What say ye?

I would suggest converting the fuel injection system to a megasquirt so you get better mileage. One of the injection systems from those days has the injectors "on" all the time rather than spritzing at just the right point in the cycle. This is really primitive, and not too hard to overcome. For a daily driver, it might be worth it to your pocket (and would also be better for the planet).

Check over every piece of rubber underneath it - a lot may need to be replaced.

It is getting harder to find parts, but if you insist on riding in style every day, it's hard to beat such a machine.

-Henry

[cth350]

the things to look for are rust, suspension "short cuts" and scary FI/ignition repairs.

Rust, under the car matters, since this is a unibody car. You might easily find it with the car on a lift. You might find evidence of it by finding evidence of body repair with bondo on the lower few inches of the car (the rockers under the door, the lower parts of the trunk, especially the part at the nose that holds up the bumper). I got a good laugh at car that somebody fixed up the rockers using pop rivets rather than welding the parts back in. You want to see welded seams and clear delineation of the floor, inner and outer rockers.

On the suspension, there are dozens of spots to be greased. Find them make sure there is evidence that it was done. Not just to make sure it's good, but to make sure the guy getting the car running knew enough to do it. There are some key rubber bushing in the rear that just get tired with age. The keep the rear attached to the car, and even when old are usually safe, but when they are new and if they are the correct factory parts, the handling of the car should be surperb. Look for receipts and talk to the guy about it. Many folks go with the "ain't broke, don't fix it rule". Others go for the "make it ride right" way of doing things.

With the wheels off the ground, there are simple things to check to ensure the steering and suspension is tight. This car has vintage 50s technology (king pins rather than ball joints) in the steering. A good mechanic who's touched older cars should hopefully know what's up. A visual inspection of all the bits should reveal that all the parts are in place (little things, like the steering damper and stabilizers that can be removed and not put back matter).

Somebody suggested swapping out the factory EFI system, which is delicate, for a more modern system. If the seller has done that, it's fine, if he did it well and documented what he did. If he didn't do that, make sure he put the old system back so it looks right and doesn't have a dozen splices in the wiring and slipshod parts held down with zip ties. Note that doing it right is expensive these days. The correct ignition system has a little silver box and a pair of balast resistors and a blue coil. If all the parts are correct and the distributor is in good working order and the hoses are new, you should be able to hook up a meter and read precisely the right dwell. Hook up a tail pipe sniffer and see the correct level of CO% at the right idle speed and as you push it through different RPM ranges, you should see the right timing. All of that means attention was paid to the details to get it right.

Variations are possible of course, but the more deviations from the book you find, the more worried you should be. Also, the fewer variations you find, the more green will be slipping through your fingers.

-CTH

[rumb]

Maintenance parts are easy enough to come by. Trim parts not so much.

[Graham]

That car has the Bosch Djetronic electronic fuel injection system. Commonly called a Djet. It is a simple system and works very well when properly set up. There is a lot of support for the Djets available on-line including original shop manuals. I would avoid the Megasquirt - You tend to be on your own trying to get those systems tuned and working.

Post 1975 Benzes used the Kjet system which is a mechanical fuel injection system but perhaps not as easy to get working well, when things go wrong??

There are several key fuel injection parts:
- The ECU
- MPS (Manifold Pressure Sensor)
- Pulse generator (aka Trigger Points) located below the usual points in the distributor
- Throttle Position switch.
- air and coolant sensors.
- 8 injectors plus a cold start injector
- Djet specific fuel pump
- Fuel pressure regulator
I have a 72 350SL with same engine. At 165k miles runs well and still has all original parts and engine.

Replacement parts are either not available or very expensive. Used parts are not hard to find and existing can be repaired.

Ignition system is straight forward. Points plus transistorized switchgear. Points or points+swichgear are sometimes replaced by a low cost Pertronix Ignitor. No more points to wear or set! Otherwise no issues with ignition.

Compared with modern cars, these V-8s are not fuel efficient! about 14mpg would be good! They do use regular gas.

Much as I love my Djet, I would not recommend one as a daily driver! You might be better to find a good W123 or W116 diesel . The 280SE 4.5 could make a great hobby/collector car.

[Tony H]

There are many "self tuning" EFI's on the market like Holley and Edelbrock, etc. You could even use your original fuel injectors but there are many easily available, high impedance fuel injectors that will fit in the D-jet heads. Just don't buy the China knock-offs. Some early Mustang injectors will fit if you change the pintle caps. You would need to fabricate fuel rails. You might as well go to a distributor less ignition while you are at it.

[Graham]

Bengoshi said: "So I've found a '72 280SE 4.5 locally that cosmetically, is about a 7 or 8 out of 10 (exterior and interior). Evidently it was in storage for the better part of two decades and the current owner has been bringing it back up to, and has allegedly achieved, daily driver condition."

Sounds like he has found a good car that someone has already sorted. After storage, the fuel delivery system is usually what needs attention. Hopefully it still has original or an equivalent fuel pump. The Djet IS a reliable injection system. Can't see why this thread is suggesting changing that on a car that buyer/seller say is in daily driver condition.

Several owners who tried to convert to things like MS never got them working. Most disappeared without reporting their experience! One on another forum, at least came back, described the problems he had and has since converted everything back to Djet. MS is perhaps an interesting hobby - if you want one

Bengoshi, if you are interested in learning more about the 4.5L Djet, it is an M117. Engine and other system covered in this link:Model 107 Maintenance Manual Index. M117 4.5 & Misc Information
have useful info. '72 R/C107 and W108 Djets have same engine and other similarities.

[Idle]

Check out parts prices on Evil Bay since this seems to be about the only place to find then on a steady basis.

Some of the parts are quite pricy. Such as the thermotime switch or the trigger points. I think the trigger points can be reworked but the thermotime switch is not an easy thing to repair if can even be done.

The MAP sensor is also an expensive item. Check to see if it is holding vacuum.

And the heater and A/C need to be in working order. Check that the heater is not bypassed as pulling that heater case out is a massive job.

[tbogert]

Originally Posted by Bengoshi2000

I've been car shopping here lately for a newer model car to use as a daily (or semi daily) driver and I just keep getting sucked in by older Benz. I assume everyone here understands this sickness...

So I've found a '72 280SE 4.5 locally that cosmetically, is about a 7 or 8 out of 10 (exterior and interior). Evidently it was in storage for the better part of two decades and the current owner has been bringing it back up to, and has allegedly achieved, daily driver condition. Before I do anything I'll get the records for the work that's been done. He's been very straightforward that he has no maintenance records prior to storage.

I don't know anything about these cars, specifically any trouble spots I should inspect IF I decide to go take a look at it. So I'm here asking for advice.

The overall question I have is the relative dependability of 280SE's and more importantly, parts availability.

What say ye?

hi, Bengoshi i see you're in NC. i live in CLT and daily (as in it's my only car) my 72 4.5. mine is almost factory-stock, and i do a lot of the work myself. for what i can't do, i use charlotte star services here in charlotte (after making the rounds with other shops). there are a few local resources i've found for parts, specialty service, etc. (one guy in burnsville, nc has two massive metal buildings filled with parts he's amassed over the years). lmk if you want to meet up or chat and i'll share whatever i've got that's helpful. this is my second daily-driven 4.5, so i'm a willing participant to the experience.

[Idle]

A word on the throttle position sensor.....

These do go bad. But they can usually be rebuilt. For those reading here and trying to deal with the same decisions as the original poster the info on rebuilding these, or even for current owners, is worth knowing.

The main thing to know is they can be popped apart and the interior metal runners made accessible. There they will either be dirty, which is what you hope the problem will be, or they will be worn through, which is what you don't want to see.

If they just need to be cleaned start with some electronic cleaner and then try to polish the runners with the same cloth you would use to police jewelry. Then put the thing back together, which is easy, and you are good to go.

If the runners are worn through a pit of foil tape over the worn spot will get you by until you can find another TPS.

I have opened these up and found them to be defective right from the factory. And yet they were still working after 40 years. So they are hard to mess up while being assembled. Just a bit of care is all it takes.

[Idle]

And.....

I remember when the D-Jet came out. It was implied that you needed a massive amount of special tools and Phd level skill to even start to repair it.

But I had an Opel with the system that no one could get right. So I dived in and found......

If you have a Ohmmeter and know how to run a continuity test you could fix anything in the system. It is just a carburetor reduced to its' different components and spread around the engine area. And everything is electrical and not mechanical. There are mechanical parts that fail, too, but they are a small part of the system and even easier to test.

And repair is easy. You find the bad part, toss it and replace it with a new one.

All it takes is time and a tiny slot screwdriver to release the plugs.

[cleeves]

Originally Posted by Graham

Bengoshi said: "So I've found a '72 280SE 4.5 locally that cosmetically, is about a 7 or 8 out of 10 (exterior and interior). Evidently it was in storage for the better part of two decades and the current owner has been bringing it back up to, and has allegedly achieved, daily driver condition."

Sounds like he has found a good car that someone has already sorted. After storage, the fuel delivery system is usually what needs attention. Hopefully it still has original or an equivalent fuel pump. The Djet IS a reliable injection system. Can't see why this thread is suggesting changing that on a car that buyer/seller say is in daily driver condition.

Several owners who tried to convert to things like MS never got them working. Most disappeared without reporting their experience! One on another forum, at least came back, described the problems he had and has since converted everything back to Djet. MS is perhaps an interesting hobby - if you want one

Bengoshi, if you are interested in learning more about the 4.5L Djet, it is an M117. Engine and other system covered in this link:Model 107 Maintenance Manual Index. M117 4.5 & Misc Information
have useful info. '72 R/C107 and W108 Djets have same engine and other similarities.

This is an interesting observation. I guess I had not explored the idea of it enough myself to realize this many people had difficulty.

I remember in my BMW 635 days that quite a few folks got MS systems running well on those cars with turbos, and my reading on those projects had me thinking it was very doable. Perhaps it is more challenging with the M117.

Without MS, I would have a hard time justifying one of these machines as a daily driver. The fuel inefficiency would really be an issue for me ... it's like driving 4 modern cars all at the same time to wherever you want to go. (12mpg * 4 = 48). I could maybe justify 18 mpg .... but less than 15, yikes!

-Henry

[cleeves]

I have wanted a W108 since I was probably 16 years old. I'm 31 now - can't imagine anything better still.

Norma Bates (from the Bates Motel TV show) ... the "IT" person of W108 sophistication ...

https://www.gettyimages.co.nz/detail/news-photo/the-deal-episode-305-pictured-vera-farmiga-as-norma-bates-news-photo/469180548

Someday, I will have one as a weekend car ...

-H