M272 Balance Shaft issues exist outside the published range

Premature failure of the Balance shaft on the Mercedes M272 engine is a known problem.   Apparently the balance shafts were too soft and so they wear out quickly.   This was the subject of a class action lawsuit in the United States.   Over there, the shafts in affected cars were replaced by the dealer out of warranty.     This wasn’t the case here in Australia, although it is possible that a handful were done for good customers.     There is a service bulletin published by Mercedes-Benz that outlines the repair and the engines numbers affected by the soft M272 balance shaft.   Generally those engine numbers correspond to 2005 to early 2007 production.

About 5 years ago,  I was in the market for an E350 Wagon for my wife.   We wanted an occasional 7 seater that wasn’t an SUV.   Based on the service bulletin, we purchased a 2007 rather than the 2005 we were looking at.   The car we eventually purchased was well outside the known range of bad M272 balance shaft issues.

About a year ago, we started getting codes from the car indicating the the timing was off in one bank.    Based on the knowledge that the car was outside the affected range, we started looking at other sources for the problem.   First, I tried changing the magnetic adjusters.   These are a known problem also and an easy fix.    After a while, the light came on again, so next I tried the sensors.   This didn’t have much of an impact.    I took the car in to be looked at, and it was suggested that the broken intake manifold flaps may be to blame, so I had those fixed too.    Again, same problem.

From there I was becoming more and more convinced that despite being outside the published range, I had a bad M272 balance shaft.   I took the car to another shop who had done hundreds of these repairs to check.   they took off the cam covers and were able to spot the worn balance shaft.     The quote to fix is $6,000 which is in line with other good independent shops in the area.   This includes 24 hours of labour and taking the engine out completely.

As can be seen above, the part is quite innocuous, but a lot of the engine must come apart to change it.    As well as what is pictured above, normally the head gaskets, timing chain and sometimes sprockets are changed.

I suspect the M272 balance shafts are harder after the known range, but still fail.   Our car now has almost 180,000km on the clock.   It had about 170,000km when these symptoms started occurring.  I suspect these issues could also affect the M273 V8.   Those engines do not have a balance shaft, but they do have an idler sprocket there.   That sproken was also known to be soft in the early engines.

I have been thinking long and hard if I will fix the issue.   I have decided to fix it.   Used car prices have gone so high since COVID that the car is worth more than what we paid for it 5 years ago.   Buying a different S211 would also have the balance shaft risk, plus not have the work I’ve done on this car recently such as rebuilt front end, intake manifold, rear air springs etc.   With used car prices the way they are, a S212 wagon is still more expensive than we would want to spend.

It will likely get booked in for the job in the first half of 2022.   While the update 211 is a good car,  there are a number of design flaws.    Obviously there is the balance shaft issue.   There is also the plastic intake manifold flaps, other plastic parts in the engine that don’t last very long, and rear air springs with a short service life.

2021 Fleet Update

With the year coming to a close it felt like a good idea to do a 2021 fleet update.   A bit of a summary of any issues I had with each car, how much I used it and any future plans.    I don’t own a modern car, so these cars not only get used as a hobby, but as everyday transport – regardless of weather or traffic.   My wife does own a 2007 car, but I only use that car when the whole family is going somewhere.   The cars are listed in the order of how much I used them this year.

Highlights and lowlights:

The highlights this year are the 60th anniversary of the E-type celebration, and some of the extended drives I did while I was between jobs earlier in the year. There was also Youngtimer Sacco day and the 107 Bridge drive.   The lowlight of course was crashing my 250SE Cabriolet into a Kangaroo, although that was later tempered with how well it was repaired.   It was also a shame that so many events were cancelled this year due to COVID-19.    I’m also happy with the purchase of the AMG wheels for my 450SLC and 560SEC.   Overall I drove the cars 18,500km this year, quite high for me.

Fleet Changes:

I purchased the 1979 280SE, which will replace the 1986 300SE.   I also purchased the 1987 420SEL parts car, and have started dismantling it.   I didn’t sell any cars this year, but the 300SE will be for sale soon.

1987 Mercedes-Benz 560SEL

The 560SEL is  a fairly recent purchase (March 2020) and I managed to use it a lot.   As a one owner car that was well looked after, it had the foundation to be really nice and I’ve now done a lot of the things I need to do to get it up to the level I wanted.    You really wouldn’t know it has 336,000KM on the clock.  Despite no major issues, I ended up spending a fair bit on this car, but I expect it should be a lot less next year.

  • KM Driven: 5,200
  • Spend level: High
  • Availability: Excellent
  • Highlight: How well this car drives now I have re-instated the self-leveling rear suspension.   Youngtimer Sacco day.
  • Lowlight: Front suspension rebuild was more expensive than I was hoping.   The sway bar mounts required the fuse box and brake booster to be removed.  Took a couple of goes to get the alignment right.
  • Work this year:  I had the B pillar trim and sagging seat fixed, as well as the front suspension rebuilt, new brake hoses and oil level sender.  I also changed the wheels out for a refurbished set.
  • Plan for 2022:  After doing a lot in 2020 and 2021, just routine maintenance.    I’ll see if I can hit 340,000.

Fleet Update

1987 Mercedes-Benz 560SEC

I’ve now owned this car for three years and it’s getting better and better with more use.   This year, I did a fair few things to this car, but they were mostly upgrades rather than mechanical work.   I’m really happy with the Cocomats, stainless steel exhaust and the AMG wheels.   It may not be next year, but at some point I plan to fix the rust under the rear window and fit an upgraded A/C condenser.   I’m glad I bought a 560SEC when I did as prices have started to climb.

  • KM Driven: 4,300
  • Spend level: High
  • Availability: V. Good.  Was out of commission for about a month while I waited to do brake hoses.   The car had a spongy pedal.
  • Highlight:  Some of the longer drives I did and how well the AMG Aero I wheels came out after refinishing.
  • Lowlight: None.
  • Work this year: After driving the car on a hot day and experiencing a very spongy pedal, I had all the brake hoses changed.   I fixed the in-dash outside temperature display, purchased, refinished and fitted the AMG Aero I wheels and had a new stainless steel exhaust system installed.  The A/C was also recharged.  There is a minor leak from the compressor.   The A/C is really cold when freshly recharged on this car.  For some reason it is much better than the 560SEL.
  • Plan for 2022: Oil level sender is leaking.

Fleet Update

1986 Mercedes-Benz 300SE

I originally purchased the 300SE as a daily driver.   These days, with my children a bit older so they don’t require fitted child seats, and regular working from home, I don’t have the same need for a daily driver as I once did.   The 300SE went on club rego and still got used when I needed to run errands or take the children to and from daycare and school.   Now owning the 560SEL, I found I didn’t drive it as much as last year.   I also had the strange issue of the oil pump catastrophically failing.  I was lucky I noticed the low oil pressure and was able to troubleshoot this and have the pump replaced before any damage to the engine.   This car will be for sale early in the new year with an asking price of $11,000.

  • KM Driven: 2,500
  • Spend level: Medium
  • Availability:  Good.  Was unavailable for about a month while I waited to have the oil pump replaced.
  • Highlight:  Its a great car to drive around town.   Its far more nimble than the V8 models.  I also really like the Signal Red.
  • Lowlight:  The failure of the oil pump.
  • Work this year: Replaced the oil pump, changed the brake hoses and bled the brakes.  I also changed the fuel pump, adjusted the self-leveling rear suspension and changed the passengers window regulator.    The car now has a USB port in the dash too.
  • Plan for 2022:  Sell the car.    I’ll miss the car, but I’ve got two other W126 models and have never owned a W116.

Fleet Update

1977 Mercedes-Benz 450SLC

I ended up doing a lot of work to the 450SLC, most of it not planned.   I discovered rust in two places that I addressed – on the passengers floor from the A/C condenser and under the rear screen.   The floor I tackled myself, but the rear screen needed a fair amount of work to be done.    Due to COVID, the car sat without a rear screen for months, meaning that I probably only had access to it for about half the year.    The driving experience had become progressively worse over the last couple of years, so this year I had the subframe mounts changed.

  • KM Driven: 2,200
  • Spend level: Very High
  • Availability:  Poor.  I wasn’t able to use it for extended periods of time and it wasn’t running or handling well for much of that.
  • Highlight:  The MBCNSW 107 drive over the bridge.   We had 47 cars, which which was pretty cool.
  • Lowlight:  Finding rust under the rear screen and having to spend a lot of money to get it right.   I am very happy with the outcome.
  • Work this year: Replaced fuel accumulator, drive shaft flex discs and centre support, installed a new foglight lens, replaced the rear screen, fixed the rust and had that part of the car repainted, purchased AMG ‘Penta’ wheels and tyres, fixed the A/C rust, replaced subframe mounts, fixed sticking odometer, new plugs  three new suppressors.
  • Plan for 2022: I am planning to drive this car to the Mercedes-Benz clubs national rally in Adelaide, April 2022.   At some point, I would like to install a Nardi steering wheel and a set of cocomats. I’ve also got a noise from one of the rear wheels I need to sort out.   I think it is caused by a lug bolt touching the parking brake spring.

Fleet Update

1965 Mercedes-Benz 250SE Cabriolet

The main occurrence this year was the crash.   I was also chasing some rough running issues.  I really enjoy driving this car and am glad I was able to have it repaired so well.

  • KM Driven: 2,100
  • Spend level: Medium
  • Availability:  Poor:  Was off the road for months due to the ‘Roo incident.
  • Highlight:  Having the car fixed after the ‘Roo incident better than ever.
  • Lowlight:  Hitting the ‘Roo.
  • Work this year: Repairing the car after the ‘Roo.    I also fitted a new battery,  had rear seatbelts installed and addressed some running issues.
  • Plan for 2022:  Nothing major, drive the car.   Apparently the Mercedes Club are planning a Paul Bracq day next year.  I’m still getting some strange issues with the radio I need to sort out.

Fleet Update

1965 Jaguar E-Type

I was able to take the E-Type on a few really good extended drives, where its in its element.   One of them went down to Oberon and then back up to Bathurst.   The other was also to Bathurst, but with the Jaguar Drivers club for the 60 years of the E-Type celebration.   The car was also featured in the November edition of the JDCA Jaguar Driver magazine.   I really enjoy driving the E-Type but its not the sort of car you use for errands, so it does slightly lower mileage than some of the other cars.   For all the stories about classic Jaguar reliability – I find it to be a very reliable car.

  • KM Driven: 1,300
  • Spend level: Low
  • Availability:  Good.   Just a minor electrical problem in one of the tail lights.
  • Highlight:  60 years of the Jaguar E-Type celebration.
  • Lowlight:  None.
  • Work this year:  Preparing the car for the 60th anniversary drive by fixing a minor electrical problem.
  • Plan for 2022: None, just drive the car.

Fleet Update

1970 Citroen DS21

I only used the DS a couple of times this year.   There were a series of minor issues that kept me from using it and COVID lockdowns exacerbated the time taken to get them fixed.   I started out with a very leaky hydraulic pump that was sent off for a rebuild.   There were a few issues getting it fitted, as at first it wouldn’t prime.   Once that got sorted out, I had two further problems.   One of them sounded like an engine knock.  Turned out it was just a broken air cleaner bracket.   engine vibrations were causing it to tap against the exhaust manifold.   I also had increasingly poor running.   This was caused by one of the idle jets working its way out of the carburetor.   Finally, I had a bad LHM leak from the brake accumulator.     The good news is that none of this was particularly expensive.

  • KM Driven: 900
  • Spend level: Low
  • Availability:  Terrible.  A series of small issues have kept me from using the car much.
  • Highlight:  None really.   The one decent drive I had the car kept stalling as the idle jet had fallen out.
  • Lowlight:  Not being able to use the car much.
  • Work this year: Rebuilt Hydraulic pump, broken air cleaner bracket, carburettor idle jet and leaking brake accumulator.
  • Plan for 2022: Drive the car more.  At some point it will need a clutch, but not immediately.

Fleet Update

2021 Fleet Update Summary

It was a an odd year in that I got to use the cars a lot in the first six months, due to being between jobs.   In the second half of the year we had lockdown for about four months and I had a new job that kept me very busy.   For most of the year, the fleet didn’t change much other than a parts car, but I was able to do some nice upgrades on a few cars, and managed to crash and repair my 250SE.   I’ve also started a change with the introduction of the 280SE.

MBCNSW late December 2021 night drive through Picton

Last night was the final night drive (and last official drive overall) for the Mercedes Club in 2021.    Since the lockdown was lifted, we’ve really struggled with the weather for these night drives.  Finally, the weather held up and we had a great turn out of 17 cars on the night.   It started out hot and humid but cooled off and proved to be a great night for the open topped cars.   I had originally planned to bring my 250SE, but hadn’t had a chance to get the club registration signed off in time.    Given the route we took, I’m glad I took the 560SEC as I’m not quite sure the 250SE could have kept up with the pace set by the AMG cars.

Picton

The route had us start in Camden, drive down near Thirlmere and then take Picton road to join the M1 near Wollongong before heading up to meet at Heathcote McDonalds.   We end a lot of the night drives at McDonalds as they are open 24 hours, have clean toilets and allow people to buy a drink or snack.    Even better, one of the people on the route was a local who helped us vary the route a bit around Camden on some better driving roads.    We also took a short detour to Bald head lookout before the final meeting point.

Some people peeled off before the Picton road section and headed back to Sydney via the M31.   This worked quite well as it allowed them to come for a shorter drive and the main group to do the full route.

Picton

As usual, we had a good variety of cars.  This included four 107s, three 124s, two 126s, a 108 for the classics.  For the moderns, we had an S class V12 as well as some other AMG cars including two C63s, a CLS and a CLA45S.

PictonIt was a really great drive to end the year on, and most people seemed to enjoy it.   I’m looking forward to the 2022 night drives.  There are still a bunch of drives we planned for 2021 but could not do because of lockdown.

560SEL refurbished Gullideckel wheels

My 1987 560SEL is in very nice cosmetic condition for its age and mileage.   The only thing that really let it down was the condition of the alloy wheels.    It was clear that they had been cleaned with harsh wheel cleaners many times over the years.   The paint was badly discolored.     I had some spare Gullideckel wheels that I could have sent away to be refurbished.   However, I also had a lovely set of refurbished alloy wheels on my 450SLC that were correct for the SEL.    That got me thinking that it might be better to get a different set of wheels for the SLC and put those refurbished Gullideckel wheels on the SEL.

The reason why I had the Gullideckel wheels on my 450SLC goes back to late 2018 when I purchased my 560SEC.   At the time, it came with a set of Simmons wheels.   They are a high quality Australian made wheel that are very popular on Fords.   I didn’t think they looked right on the SEC.    At the time, I was able to buy a lovely set of refurbished Gullideckel wheels from MB Spares and Service.   I originally planned to put them on the SEC, but in the end I decided to put the 8 hole replica wheels on the SEC and put the Gullideckel on the SLC.   The 8 holes rubbed slighly on the SLC and didn’t look quite right.

Based on all this, I purchased the Penta wheels for the 450SLC which I am very happy with.   I originally planned to wait a year or so to put the refurbished Gullideckel wheels on the 560SEL.  That was because the ratty wheels had good Michelin tyres from 2016 and the refurbished wheels had cheap tyres I didn’t like the feel of.   Two things changed that.   Firstly, a Black Friday sale for 50% off Pirelli tyres.   Secondly, I noticed that one of the Michelins had worn down on one of the edges from the alignment being slightly out.

I had recently had the front suspension rebuilt on my 560SEL.   My mechanic took it to be aligned, but I don’t think the alignment shop used the right specs as the handling was downright scary after the change.  I really noticed that driving in the wet for the Youngtimer Sacco Day.    I took the car back, and it took my Mechanic a few goes back to the alignment shop for them to get it right.   At the same time they wanted the castor bushings changed, which were slightly worn, but not that bad.    At least now I had a good alignment to start with for my fresh tyres.

The Black Friday sale meant that the tyres were only $270 fitted.   A great deal that also included some fuel discount cards.   I also kept the Goodride tyres, as they have tread left and I should be able to get $100-$200 for those.  They are currently for sale!

To take advantage of the deal, I fitted the nice wheels to the car a couple of days before.   While I was at it, I cleaned the wheel wells like I have for the SEC and SLC.    They were just as dirty and grimy as those cars.   I had the new tyres fitted the other day and the look of the car is transformed.   Its also much nicer to drive as well.

Gullideckel

A nice set of wheels really make the car.   The Gullideckel were always an attractive style of wheel.   In my opinion, much more so than the previous set of available alloys.    The change also allows me to use the old wheels as spares in the various cars.   Three of the four Michelins are in good shape and from 2016.   This gives me a spare in the SEL, SEC and SLC.   The spares in all of those cars were well over 10 years old and not something to be relied on for long trips.   This was especially important for the 450SLC, as I plan to drive it to Adelaide in 2022 for the Mercedes Benz Clubs national rally.   I may even take a second spare in the boot.

Troubleshooting 280SE running issues

One of the things I noticed right away when I got my new 280SE was that it wasn’t running well.    It was very hard to start and keep running.   Eventually, if I warmed it up a bit it would idle, but giving it much throttle would have it stutter and die.   I was able to get it off the tow truck and into the warehouse, but not easily.

Getting it to run properly is my first priority as it will also confirm that the drivetrain is good.   My first attempt was to check the spark plugs.   I thought that perhaps they may have been all fouled up from getting on and off the tow truck and at the auction site.   The nice thing about the M110 is that they are so easy and accessible.  Given that, it made sense just to change them.   This would allow me to see if it made any difference and check the condition of the existing plugs.

To more easily get at the plugs I removed the air cleaner assembly.  I was very happy to see a near new Mann filter inside. The breather hose was also nice and supple.  Another sign that the car has been properly taken care of.   I changed out all the plugs and they looked pretty good.   This ruled out fouled plugs or the car running really really rich.

280SE running issuesI took the car for another drive around my warehouse unit carpark.   There really wasn’t any change.    It felt like the car was not getting enough fuel.   I noticed the gauge was sitting between 1/4 and empty.   Old car gauges are not always the most accurate.   I thought the easiest thing to do would be to make sure there was actually fuel in the tank.   Perhaps my 280SE running issues was simply a lack of fuel?

I bought 25 litres of fuel and the car started running better.  It took a bit of time before this happened.  It was also able to cold start far more easily.  There could of course be other issues, but there were two possible issues I could do some simple tests to rule out.   Firstly, that the fuel strainer or swirl pot at the bottom of the tank was clogged.   If this was the case, raising the fuel level made it easier for the pump to suck more fuel and hence allow the car to run better.   Alternatively, the fuel in the tank was so old or contaminated that putting in 25 litres of fresh fuel allowed the car to run much better.

The test for both of these would be to drain the tank, and inspect the strainer.    Before I did this, I thought it was probably worth trying to look into the tank to see its general condition.   I borrowed a 48mm hex socket from a friend to remove the tank sender.   This would allow to have a bit of a look inside the tank and also see how dirty the sender unit was.   If the tank and sender unit was obviously filthy, then it would make sense to remove the entire tank and have it cleaned.   Some information on the internet says you can get the sender out with a pipe wrench or similar.  I found I could not get a good grip on it.   The right 48mm socket had it out in seconds.

The good news is that the tank looked very good.   Unlike the flat tank of the W111, the W116 tank is much taller, so it is harder to see into it from the sender hole.   You can’t see the swirl pot for example.   From what I could see, there was no reason to remove the tank.   The sender unit was quite clean, and there was minimal debris coming out of it.

280SE running issues
My next step will be to drain the fuel, inspect the strainer and change the filter.    Even if this does not fix the problem, they are service items and it makes sense to be able to rule them out before starting to look at the fuel injection and the engine itself.   I am hopeful that it is one of these things that is causing my 280SE running issues.   If not, I’ll move on to things like fuel pressure tests.

I would like to get this sorted out by mid January so I can sell the 300SE and have a bit of time to drive this car before I hopefully sell it to buy the 450SE.

Machines and Macchiatos December 2021

Machines and Macchiatos is another local cars and coffee event I’ve been meaning to check out.   I finally made it today, at their new location in Belrose.   This location is very convenient to for me.   Its on the second sunday of the month from 7am to 9am.   Between the St Ives event, Eastern Suburbs and this event I could be going to an event almost every Sunday.    Turnout was quite good, although a lot smaller than the St Ives event.   I’m not sure if this is normal, as the weather had been wet all week and looked quite iffy in the morning.   In any case, the Machines and Macchiatos show has a small fee to attend, which goes to Charity.

I had originally planned to take the Citroen DS to this event, or if not that, my Jaguar.   In the end I took my 560SEC.   I had a very busy week at work so didn’t have time to have the rebuilt brake accumulator fitted.   With the iffy weather, I also decided to leave the E-Type at home.  It was the first event with the new AMG Aero I wheels, which look great – even if a bit muddy from the rain.

Machines and MacciatosThe Mercedes Club had an official event within an event at the show, so there was a nice lineup of Mercedes cars.   I wasn’t part of this as I wasn’t originally planning on bringing a Mercedes, or even 100% sure I would come.   It was good to see some of the members and their cars at the event.     Probably the most common cars there were American cars – in particular Mustangs.   There were also a few nice full size American luxury cars like an Imperial and a Lincoln Continental.  I must be odd as I was more excited about seeing an original condition Landcrab than the McLaren that was on display.

This is a pretty good event.  I was home by 9am and it was easy to get in and out.   I would certainly attend again if i’m free on a Sunday morning.

MBCNSW early December 2021 night drive to Bilpin

Last night was the first of two planned December night drives with the Mercedes Club.   This was now the 3rd time we’ve run the drive to Bilpin.   We did the route in May 2021 and November 2020.  The drive is pretty simple.   We meet at Windsor McDonalds and drive up to the Apple Pie Cottage at Bilpin.   The Apple Pie Cottage is run by a club member who puts on coffees, apple pie and this time Pizza as well.   Not only that but he is quite the comedian.

Apple Pie CottageWe’ve had some really wet and wild weather in Sydney of late and last night did not disappoint.    It was absolutely bucketing down.   Not surprisingly, the almost 20 registrations whittled down to about half that number.

What was surprising was the number of classics in attendance far outnumbered the modern cars.

Apple pie cottageIn attendance we had two W116 cars – an anthracite 450SE and an astral silver 450SEL; three W126 cars, My signal red 300SE, a smoke silver 420SEL and a lapis blue 380SEC; and two W124 cars, a white E280 and a diamond blue 230E.  The W116 is starting to build in popularity again and its nice to see them regularly at club events.    For the moderns, there was a W211 E55, an E400 cabriolet and a CLA45S.

The drive up to the apple pie cottage at Bilpin was a bit slower than usual given the conditions.   Most of the cars have no driver aids of any kind.    Sadly we lost the E280 and the 420SEL.  The E280 had a flat bettery at McDonalds and the 420SEL had the low coolant light come on.   Better to be safe than sorry and overheat the aluminium V8.

It is great to see the classics out in conditions like this.   They are meant to be driven and enjoyed and this drive certainly allowed that.

Apple pie cottageI took my 300SE on this drive.   This was because its good in the wet and I wanted to get one last club drive in before I sell it.   Even in the 300SE I lost traction on a roundabout on the way to the meeting point.

After a feast of pizza and apple pie, we proceeded back to Sydney.   There was an unmarked speed camera hiding in one of the zones where the speed limit drops from 80 to 60.   The tolerances have been recently reduced in NSW, so I hope nobody was pinged by the camera for doing 65km/h.   I didn’t get home until 1;30am, but the drive was well worth it.

I didn’t take any photos at the Apple pie cottage as its too dark for them to come out properly.   The final night drive of 2021 is the week before Christmas, starting in Camden.

IMG_6256

The R16 resistor on the Australian W126

The second generation W126 controls ignition timing from the EZL.   In most countries, Mercedes-Benz provided a knob to adjust the timing based on the petrol that was available in your area.   This knob is present on my UK delivery 560SEC.   I immediately turned the knob up to 98 octane petrol, as that is what I use in the car.   In markets like Australia and the USA, they did not provide this knob.  Instead, they provided a fixed resistor for that market.   That allowed them to optimize for the petrol available in that market and focus emissions testing on that.   That resistor is known as the R16 resistor, from the wiring diagram.

There are countless threads on the various Mercedes forums like BenzWorld and PeachParts about this resistor and various attempts at changing it.   Most of these attempts are for the W124 and nearly all of them concern the USA version.   This made me think about what this might mean for the Australian version.   The Australian version has slightly more power than the USA version.   However, it has no EGR, no smog pump, and a far less restrictive exhaust system.    The other difference is that the USA version is set up for 95 Octane petrol and the Australian version for 91.  For more details on all these differences, please see this article.

Its not possible to use 91 Octane petrol in a W126 in Australia anymore because it has been contaminated with Ethanol.   Real petrol is only available in 95 and 98 Octane.   That made me think it would probably make sense to optimise the 560SEL for 95 petrol since that is what I use.   Based on that, I started my research.   Most of this data comes from the 1987 technical data book.  The values here are focused on the V8s, but the M103 is very similar.  This was a project I did during the COVID19 lockdowns earlier this year.

The first thing was to map the values of the switch provided in most cars to the fixed resistance values found in Australian, USA and Japanese cars.   In these tables, the S position corresponds to premium petrol and N regular petrol.

ResistanceMarketECEKATRUFOctane
InfiniteS198
240022
1300N3
750USA, J4S95
47055
220AUS6N91
077

As these versions are all catalyst cars, we can see that the USA and Japanese versions correspond to the premium (95) position, and the Australian version to the regular (91) version.    The ECE version is set up for 98 if on premium, which is what I use on my car.

From there, we can then look at what these settings actually do to ignition timing.

Timing Degrees before TBCIdle (without vacuum)Idle3500 RPM (without vacuum)3500 RPM
RUF (S)8-1210-1826-3041-45
RUF (N)2-614-1820-2441-45
KAT/CH (S)3-710-1420-2441-45
KAT/CH (N)(-3)-110-1418-2240-44
ECE (1)8-1214-1822-2641-45
ECE (4)2-614-1816-2041-45
AUS (220)(-3)-110-1418-2240-44
J (750)3-710-1424-2840-44
USA (750)3-710-1424-2840-44

In the table above, we can see that the main difference is that the timing without vacuum is lower.   I’m not really sure what impact this has in the real world.     The other thing we see is that the same switch position can lead to different timing maps depending on the version of the car.   To see what this meant, I cross referenced the EZL part numbers for these versions.   These are the numbers for the M117.968.

MarketPart number(s)
USA/AUS004 545 53 32
004 545 55 32
RUF004 545 34 32
KAT/CH004 545 34 32
ECE004 545 00 32

The main outcome of this was that the USA and Australian versions seemed to use the same EZL.   This meant that in theory, I should be able to replace my 220 Ohm R16 resistor for the 750 Ohm R16 resistor.    I tried to buy one new, but like a lot of W126 parts, they are now NLA.    In the end I found one on USA eBay to try.

Part NumberResistance
000 540 22 81220 Ohms
000 540 23 81470 Ohms
000 540 24 81750 Ohms
000 540 25 811300 Ohms
000 540 26 812400 Ohms

R16 resistorI drove the car around after the swap and I really couldn’t tell any difference.   A better test would be to do a back to back run up a long freeway onramp to see if I felt any difference at higher rev ranges.   By modern standards, a 560SEL is not a particularly powerful car.  It is powerful enough that it is hard to use the higher rev ranges safely on most roads.

I’m not sure of the end outcome of this.   Best case, I have optimized the car for 95 octane petrol.   Worst case, I’ve not really made any difference.

Evaluating my 1979 280SE

I took the risky move of buying my 1979 280SE sight unseen.   This isn’t something I particularly recommend, but you can get a good sense of a car by looking at detailed photos very carefully.     The thing that attracted me to this car was the condition of the body and interior.  I assumed a couple of mechanical issues in my buy price.    I figure you can always sell a car with a great interior and paintwork.   This is especially the case with a W116, as the model is known as rust prone, a trait it shares with the 107 and /8 models.   As I outlined previously, this car is planned to be an interim car, until the 450SE I hope to buy comes on the market.

1979 280SE

The car arrived this week, and while it had the couple of mechanical issues I expected, I was relived that the interior and body were pretty much as expected.   I was also pleasantly surprised with signs and evidence that the car has been well looked after by its previous owner.   Things like near new brake hoses, recently rebuilt front calipers, a new new Mann air filter, near new fuel pump and filter, diff mount and reconditioned radiator.   The warm up regulator also looked quite clean, so possibly removed and rebuilt at some point.   Plus things like he vacuum lines were all the correct colours and still in excellent condition.   Really the only thing I can see wrong with the interior is the rear parcel shelf.

I put the car up on the hoist and really could not see any rust at all.   Common places like the bottom of the doors, sills, floors etc all seem to be good.   There is some delamination in the rear screen, but the seal is new so that looks like any issues have been addressed.   The seal for the front screen is a bit old and should be done at some point.

1979 280SEThe biggest mechanical issue I noticed was the car was running terribly.   It was almost impossible to start, and ran poorly.   Once it warmed up, it would eventually idle.   It didn’t want to rev when driving.    This will be my most important thing to fix.

The second most severe is the exhaust system.   It has issues in three places.   The rear muffler is a stainless steel system that was installed many years ago.   The rest of the system is original and pretty ragged.   The RHD 280SE has a major weakness in the exhaust system.   On the LHD models, and on the W126, the twin exhaust manifolds join up to dual pipes.   On the RHD car, they join directly below the manifolds into a Y piece and go down as a single pipe before they split again before the centre box.   The M110 head is quite long so over time as it heats and cools, it expands and contracts and cracks the Y piece at the join.    This is an issue with my car.   I also have a couple of small holes in the pipes before the centre box and where the old pipes join up to the new rear stainless section.

I have not yet decided what to do about this.   The best fix would be a new stainless system from the manifolds back.   This would go to dual pipes like the LHD cars and eliminate the Y piece.   It will not be cheap and I may end up loosing money on the car.  It’s generally my preference to do things properly though.

1979 280SE

Next, the steering coupling is worn out.   This is much easier to get to on the six than the v8 cars.   I had this replaced on my 450SLC a couple of years back.   On the SLC the steering box comes out, as there is less room.   It also needs a new height control rod and shift bushings.

There are also a couple of issues I won’t be looking to address.   The A/C is not working and neither is the rear window on the drivers side.

As well as the material condition of my 1979 280SE there is also the service history.   The car comes with quite a lot of it.   The car was first owned by the Consul Commercial of Greece, based in Sydney.   After a couple of years, it was sold to another gentleman, based in Sydney’s Northern Beaches.    After that, it went to a long term owner in Melbourne who owned it from the mid 80s to around 2000.    I have all the stamps in the original log book for the first 200,000km and every receipt (including for wiper blades) for the long term Melbourne owner.   Also with the service history is the data card, original becker manuals and more.

Overall I think this 1979 280SE is a good car that has been looked after.

My 1979 280SE project and my quest for the perfect W116

I’ve been thinking about selling my 1986 300SE for a few months and replacing it with something different.   I bought that car five years ago when I needed to be able to drive it every day to drop my daughter off at daycare then to the park and ride to get to work.     I no longer work in the office every day, so the need to have a full registered car for this purpose is gone.

Last year I dropped it back to club rego.  While it got used a lot, it was always second preference to the 560SEL and SEC.   Club rego lets me drive on 60 days a year.  Between the four ‘modern’ cars I own, I have 300 days I can use.  It also gives me a bit of flexibility if one or two of them are off the road while I repair something.     Right now, I classify the W126s and the 450SLC as ‘modern’.    They all run a bit better with more regular use too.

I had a few candidates in mind.   I wanted something that I could move to from the 300SE without a massive outlay.    A W108 or early XJ12 are cars I would love to own, but are significantly more valuable for the condition I would want.   That got me thinking of a W116.   Prices are similar to the W126 for the most part.   This would allow me to move to a nicer car with more history for a reasonable amount more than I could sell the 300SE for.    Its a model I have always admired, but never owned even though I have driven a few.

Going with a W116 would allow me to build a more balanced Mercedes collection of a S Class coupe and saloon from the 70s and 80s, plus the 250SE.    In time, I could add a 60s Saloon too.   The 450SLC isn’t technically an S-Class, but it filled that niche in the line up.   Given both of my remaining W126s were the same colour, I also though it would be fun to find a car in the same colour as my 450SLC.    Of course most people would think buying sets of twin cars is madness – but these people would think owning 7 cars is madness anyway.

This narrowed it down to a W116 in 906 Grey Blue.   To continue the theme it really had to be a 450.  This would give me a pair of 450s and a pair of 560s.   My preference is for a short wheelbase car.  That narrowed it to a 450SE.

There are a few reasons for this.   I find the short wheelbase cars nicer to drive unless you regularly transport adults in the back.   They are more nimble, easier to park and look more balanced.  I already own a LWB car in my 560SEL, and the W116 was the only S Class the larger of the two standard V8s came to Australia in a SWB.   In the W108/W109 the biggest engine available in Australia was the 3.5 for the SWB.   For the W126 we got the 380SE and 420SE for a couple of years only and never the 500 or 560.   Even the W140 and W220, the 500 was LWB only.   It wasn’t until the W221 that this omission was rectified.

My preference for year was 78 then 79.   While the D-Jet cars (73-75) are more powerful and responsive, they are harder to find in nice shape and more maintenance intensive.   In 78/79 there is the nicer interior with the dash wood and much nicer carpet.    For 78 there is the pinstripe Becker Mexico if the car is still so equipped.   This is a much nicer looking radio than the more modern Mexico found the 79 and 80 cars.   I am looking for a nice original car, so my preference would be that it still have the original radio.   76 and 77 were less attractive to me, as they had the detuned engine of the later cars, but without the interior improvements of the 78 and 79 cars.   80 was out, as 906 Grey Blue was gone, replaced with 930 Silver Blue.

Through word of mouth, I have heard of a car that may be coming up for sale next year.   It is the exact car I am looking for.   A 1978 450SE in good original condition, and in Silver Blue.   Even better, it has the painted hubcaps rather than alloys.   Through a friend of the owner, I’ll have first chance to buy it once the owner decides to sell it and comes up with their asking price.

The smart move would be to hold tight until that car is ready for sale.   However, I figured the 300SE is running really well now, with everything working properly.   Maybe its better to sell it for a good price before some other repair comes up – e.g. a leak in the A/C.   Instead of taking the easy and sensible route, I’ve gone with the more interesting but harder work route buying an interim car.   The 300SE will be for sale in the new year.

My interim car is closer to my ideal spec than the 300SE is.   Its a 1979 280SE.   Its a short wheelbase W116 in the right colour, with a nice condition interior and great paint.   It doesn’t look quite as nice as the 78 car, but its still very nice.   The idea is to fix a couple of small mechanical issues and drive it for 4-6 months, selling it to buy the 450SE.   Ideally I at least break even on the 280SE.   It also means that if the 450SE doesn’t come onto the market as soon as expected, I can continue to drive the 280SE.

1979 280SE project

As can be seen in the picture above, the paint and exterior condition of the car is really nice.   It has parchment MB-Tex which is also in great condition, and an original Becker radio.    The Wood trim is in perfect condition – I don’t think I’ve ever seen one this nice outside of show winners.

It does need a couple of mechanical things fixed up, which I will cover in a separate post.   I suspect my 1979 280SE project is going to keep me busy.    Once I sell it, I’m going to miss my 1986 300SE.   It’s been a great car for five years and 15,000km.   The signal red colour is really striking and different from most second generation W126 models.

The funny thing is that when I was buying the 300SE, I almost bought a 1978 450SE.   It wasn’t Grey Blue, it was Ikon Gold, a superb colour.   I was actually looking for a W116 at the time.   The gold car had a perfect interior and a lot of recent mechanical work, but bad paint.   However, just before I bought it, it suffered a catastrophic engine issue,  so the seller and I agreed not to go ahead.