My first step was setting the correct advance curve for my engine.   Luckily the workshop manual has all the specifications I needed.    The first specification covered the static timing value for the ‘047’ distributor my car was equipped with.

This distributor was shared with the 250SE saloon and coupe, as well as the 250SL and some versions of the 230SL.      Next the manual also covered the advance curve.     The ‘047’ and ‘051’ distributors are a little different in this regard.   While they have a normal advance curve, they use a vacuum retard curve.   As far as I can tell, this was not emissions related, just a quirk of these engines.    It’s quite odd, as the curve for related engines like the 250S is totally different and does not use this vacuum retard.

I used the centre of the curve for my initial setting, adding 5 degrees for the static timing value.    Setting the vacuum retard was a little more tricky, as the add actually doesn’t really allow it, but there are settings you can use to ‘fool’ the system into doing retard, not advance.    The 123 ignition company provides such an example on their website, which I used.

The car started up fairly well, although idled quite high.    I took the car for the first test drive since fitting the new distributor.    The test drive showed a lot of promise.    I had none of the missing, stalling or stuttering that I had experienced before.    On the other hand, the car was pinging quite a lot under load.   I tried a few minor adjustments to see if that would help.   I used the app to set up the advance curve to be the bottom of the curve rather than the centre.   It helped a bit, but the car still pinged.

A couple of days later when I had more time, I started by checking the timing with a timing light against the values in the distributor.  To make sure I was checking static timing, I zeroed out the advance values in the app below 3,000RPM. Immediately the error was apparent.   I really should have checked this first.   I had assumed my static timing was at TDC, but actually I was between 15 and 20 degrees BTDC.  No wonder the car pinged.   I loosened and rotated the distributor until it was at 5 degrees BTDC, per the factory setting.    A byproduct of this was the idle went down a bit too.

Based on this, I then set the advance curve per the centre of the curve on the page.     I took the car on another test drive.    This time, the pinging was gone.    Since this test drive was at 10pm, and it was only 15C out, I left the settings where they are.   In the future, I will take the car for a longer drive on a hot day, and experiment with advancing the timing a bit, for example to the top of the curve.

During these test drives, I was able to have the 123 ignition app up on my phone to see what the distributor was doing.    It’s quite useful!

The other positive thing was that the car ran well on this test drive.  Again, no missing, stalling or stuttering.   While the problem was intermittent, it would have normally manifested itself in the two drives I have done so far.   Things look extremely promising.

The car is having a power steering leak fixed next week, so after that I will be able to take it for a longer test drive, and further adjust the settings on the 123 ignition distributor.    So far, the 123 ignition has exceeded my expectations.    I also need to mount the coil properly and tidy up the leads.    Separately,  I found out that the residue around #5 spark plug is likely just grease coming out of a fitting on the side of the head.     Based on that, and since the car is running well, I have not changed the spark plugs so far.   My next step is really to put some more miles on the car and make sure the problem really is gone.

The post W111 123 ignition – part 2 appeared first on Classic Jalopy.

I spoke to the local agent for 123 ignition, and based on that discussion, I checked the distributor in the car.  My car being an early 250SE (10/65) has ‘0 231 116 047’.   This lined up with the technical data book, indicating the distributor is likely original.

The ‘047’ distributor lined up with the Mercedes-6-R-V distributor.   This distributor was also used on late 230SLs.   The Mercedes-6-R-V had a curve (D) to replace this.    I was also advised to buy a new coil, and I went with a Beru blue coil.    The requirements were that it didn’t use a ballast resistor and was at least 3 Ohms.    Since I was trying to rule out the ignition system, I also ordered a new set of Beru leads.

The next day the local agent for 123 ignition contacted me to inform me that he didn’t actually have the Mercedes-6-R-V in stock, but he would be happy to upgrade me to the Tune+-6-R-V-M at no extra charge.    The tune plus does not come with set curves, but instead is fully programmable via a bluetooth app.    The app also lets you set a pin and use it as a immobilizer too. This was a very kind offer, and I was very happy to try the programmable distributor.

Last week I started to install the 123 ignition distributor.   I reviewed the manual, and also watched the video from 123 ignition.  It seemed fairly straightforward.

The first step was to set the car to TDC.  I took the lazy approach and used a remote starter switch to turn the engine on the starter.   Next, I removed the cap and ignition leads from the car.   I was able to confirm that I was at TDC but also checking the rotor was pointing to the marking for #1 on the distributor.

It was a simple task to remove the old distributor.  I also removed the ballast resistor (not needed with the 123 ignition).   I couldn’t get the old coil out of the bracket, as the screws were rounded off, so for now I just put the new coil next to the old one.    The new distributor seemed to slide in quite easily.

The next part of the installation is to time the distributor.     The distributor has three wires coming from it.    There is a red wire, that goes on the positive side of the coil, along with the switched power from the car.    The blue wires is a ground and the black one goes on the negative terminal of the coil.    These wires do not come with ring terminals, which you need to fit yourself.   To do the timing, you only connect the red and blue wires.

The procedure is that you first turn on the key, and then turn the body of the distributor anti-clockwise until the green light comes on.   I did this, but I was a bit perplexed as the green light only came on when the rotor arm wasn’t quite lined up with #1 on the cap.   After trying a few times, I wasn’t able to get it to line up perfectly.    I decided to get it as close as I could and try it.   To try it, I tightened up the distributor, fitted the cap, fitted the leads, and fitted the back wire.

I tried starting the car, and it wouldn’t run.   By this time it was about 11pm, and I was a bit frustrated so I went home.

Over the weekend, I found a lot of people on the W113 pagoda forum had fitted 123 ignition distributors to the pagodas.   These were primarily people who owned US model 280SLs with the emissions system that retards the ignition.

Today I went back to the car for a fresh look.   I wanted to start from scratch, so I attached my remote starter switch and took off the distributor cap to find TDC.   I was able to use the scale on the crank pully and looking at the cam through the oil cap to find TDC.    In doing so, I noticed something important.   When turning over the engine, the rotor arm was hardly moving.   Obviously the car isn’t going to run when the rotor arm does not move.

This prompted me to think of something I had read on the pagoda forum.     Some members had reported that the clamp that tightens the distributor fouls on the distributor body, and stops it properly engaging the engine.   To solve, a few posters simply turned the clamp over, so it faced down.

The picture above shows the camp before I turned it over.    The portion where the screw goes into the camp is what fouls on the distributor.    With the clamp inverted, the distributor went in properly and I was able to set the position correctly so the rotor arm was pointing to #1.

The green light indicated that the distributor was in the correct position.

I tightened up the distributor, fitted the cap, leads and the black line.   This time, the car fired up properly and seemed to run quite well, albeit with a very high idle.   That was expected, as I had not yet connected the vacuum line.   The ‘047’ distributor uses a vacuum retard.   The factory vacuum line screws in, but I was able to extend and adapt the vacuum line with some joiners from the 420SEL parts car.

With the vacuum line connected, the idle settled down, although it was still a little high.

When fitting the leads, I noticed that there was some residue under the spark plug for #5.   Perhaps some leakage.  Once I get everything working properly here, I will change the plugs too, but I want to focus on one thing at a time.

From there I focused on tidying up the wiring and leads, so I could take the car for a test drive and play with the tunable ignition curves.   The 123 ignition app is quite good and shows various stats that you can monitor while the engine is running.

Tomorrow I will take the car for a test drive and see how it goes.

Update 6/10/23:  Link to part two.

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