Starting Problems:The Key is Key

[sjiatrou]

I had been experiencing some starting problems similar to those described in the Technical Manual: I would turn the key and the fuel pump would come on, etc. but when I tried to crank the starter...nothing. No click, no hum and no dimming of lights whatsoever.  I tried all the tricks listed in the manual and still had the problem. It was intermittent for a while and then it became permanent. I had this problem earlier in the year and had the ignition switch changed so I was quite upset to see the problem reemerge.  I was relying on a Thermo switch-battery jumper to start the car (so I know the starter was fine) until I could find the time to really dig into everything to find the problem.  Then I had an idea, maybe it was the key itself. I have been using a new, non-MB key for years and had stashed away the original keys.  But I figured I give it a try. I got out the original key and vrooom, she fired right up.  I had two original keys so I did several A, B, C tests and the starter engages without a pause with both original keys but doesn't do a thing (original symptoms) when I  tried the non-MB key.  The newer keys are almost imperceptibly shorter than the original and apparently after a while they no longer properly engage the switch.

I apologize for the long narrative but I'm thrilled to have found such a simple answer to the problem and thought I'd share the lesson.  If you try to crank the starter but get absolutely no response (but you are confident that your starter and connections are fine) try the original key.

Thanks for listening.

Steve

Steve

[scoot]

That's the strangest thing I've ever heard.  I'm glad you posted it, I would never have thought to try that.

[bpossel]

Steve, thanks for posting this!

Looks like a good one to add to the Starter trouble-shooting area of the Tech Manual.
Do you want to add, or should I?  Let me know.
Thanks, Bob 

[66andBlue]

...  The newer keys are almost imperceptibly shorter than the original and apparently after a while they no longer properly engage the switch. ...

Hi Steve,
it is nice that you could trace the problem to the new keys and thanks for letting us know.
What I am wondering is whether the length of your new keys is really the problem.  As I understand it the key itself doesn't turn the switch it is the tumbler that fits into slot in the center of the switch housing (shown in panel A of the attached picture).  Could it be that your new key will not allow full rotation of the tumbler to allow engagement of the contacts needed to complete the starter circuit?

Perhaps Al Lieffring can enlighten us more since he has repaired his 230SL ignition lock.
See "reply #34" in : http://www.sl113.org/forums/index.php?topic=5639.msg36413

[sjiatrou]

I agree, anything's possible. Admittedly my experiments were not well controlled but the results were certainly satisfying.  I jumped on the key-length issue because it was the only discernable difference I could see in the keys.  What's interesting is that the newer key worked just fine for several months, if not a year or so. Perhaps something slips out of alignment over time and a simple tightening of a screw will bring things back into alignment.  I too hate leaving the problem unanswered and relying on anecdotal vice solid empirical data but I'll have to defer further investigation until I can pull the switch.  Hopefully Al has the answers! 

Thanks for the pictures, those are very helpful.

For Bob: I'll try to add the information to the Tech Manual.

[sjiatrou]

I added some info to the starting problems section of the tech manual in the "car does not start" section under Electrical Systems/Ingition System/Ignition Switch:

http://www.sl113.org/wiki/pmwiki.php?n=Electrical.IgnitionSwitch

[al_lieffring]

Alfred sent me a message off forum asking if I had any insights and or photos of how the early ignition lock and switch works.

First of all it sounds to me like the using of a different key to make the starter engage is just buying some time. I don't think that you have realy fixed anything. I would think it is more likely the electrical switch in the photos Alfred has posted.

When I went to start up my car after it had been sitting for 25 years, I had the same symptoms, The key would turn on the ignition and the fuel pump, but the starter motor would only engage by turning the key with excessive force.

I found out that there is nothing in the key tumblers or locking bolt that will prevent the key from turning from the run to start position, The stop is inside the electrical switch assembly, with the switch removed from the lock the key will turn past the point where the starter would engage. The switch containes a mechanical lock out that prevents the starter from engaging a second time unliss the ignition is turned to the off position. It is usuall a failure of this lock out that prevents the switch from engaging the starter.

The tell tale sign that the key tumbler is about to fail is a crack becomes visible below the key, on the side of the tumbler where the flat side of the key goes into the slot.

The single sided key is a completly different lock assembly than the one used in the later 250 and the 280's. The 230 and 280 locks are not interchangeable the /8 steering coulmn has a different configuration for the collapsable steering hub.
The tumbler for the double sided key can be removed and replaced, but the lock assemby with a single sided key was designed as a sealed assembly. The chrome bezel is atached to the housing by two steel pins that are driven into the housing, and are almost impossible to remove.

I took pieces from a 230sl lock, a 67- 108 sedan lock and one of several electrical switches i had and made one complete woking unit out of it, Sorry i didn't take pics, and I'm sure I pitched out the pieces i didn't use so i can't make photos now. sorry.

Just as an experiment, I took one of the /8 style plug in style switches just to see if it would fit the early lock housing and work. And yes it does, I then soldered the plug into the harness, and now have a working radio accessory position on the key switch.

 

[66andBlue]

... I found out that there is nothing in the key tumblers or locking bolt that will prevent the key from turning from the run to start position, The stop is inside the electrical switch assembly, with the switch removed from the lock the key will turn past the point where the starter would engage. The switch containes a mechanical lock out that prevents the starter from engaging a second time unliss the ignition is turned to the off position. It is usuall a failure of this lock out that prevents the switch from engaging the starter. ...

Hi Al,
thanks for this valuable information. 
I'll add it to the Tech Manual.

[sjiatrou]

Al:
Great info.  Concur, I didn't really fix the problem but for now I've stopped the bleeding and I'm waiting for a scab to form.  As long as the old key continues to work I see no reason to open the patient. I'm not applying any turning pressure to get it to engage, just an easy twist.  I've copied your notes and if it fails again I'll go in for more permanent corrective action.

Thanks again,

[66andBlue]

Steve & Al,
I was digging a bit into the German web site (Pagodentreff.de) and found a few posts with pictures that might be useful for our discussion here.
Several mentioned that one should not use a key chain with weighty items because the constant downward pressure is not healthy for the tumbler pins.
One poster ("Matti") was showing three locks made by the Neiman Company for the W111, 230SL and "slash 8" cars. Another poster mentioned that the lock from a 220SEb might fit "with a bit of modification".
Also "D.Hahn" posted a few pictures showing more of the innards of a 230SL lock.  I hope these gentlemen don't mind  reposting their pictures here.

[Naj ✝︎]

Off topic (again  )

Anybody know where to buy reasonably priced key blanks for the 230 SL?

naj

[al_lieffring]

Alfred

Thanx for finding these photos.

In the top photo the lock labeled as "NEIMAN 95" was not the original equipment lock, but a replacement part made to fit two applications, the 111 coupe (not sure about the fin tail) and the 108 sedans that used the early single sided key.

Compared to the 113's "NEIMAN 120 the external configuration is very similar to the 95 without the additional bosses where the sedan/coupe lock bolted to the dash board cross member.

When I first got my 230 (in 1976) there was the crack in the tumbler I had mentioned earlier, it eventually fell apart when I pulled out the key. Tiny springs, pins and the broken tumbler bits went flying every direction. I had no tools with me and finially got the car started by reinserting the two broken pieces of the tumbler and the key back into the lock and was able to start the car one more time and get home.

I had parted out a 250s sedan and used the Neiman 95 lock from it to get my Pagoda running again and drove it that way for years. I edited a photo to show the depth the lock inserts into the clamp on a pagoda's steering column, The 95 lock will fit into the Sl's clamping ring, but its locking bolt will not extend deep enough to reach the steering shaft. It will operate the ignition and starter and from the oustide have the same appearance, but it will not lock the column when the key is removed,

Al

[66andBlue]

Naj,
have you tried the "Key Men"? http://key-men.com/shopping/show_cat.php?catid=Mercedes.

Al,
do you know whether Neiman was the OEM for Mercedes or did they make only replacement parts?
The discussion on the German web site centered mostly whether a tumbler (with or without the "collar" where the tumbler fits in) from a W111 would fit into the 230SL housing and it appeared that the one from the 220SEb might work.

[al_lieffring]

Alfred
I posted my reply berore it was finished.
I havn't tried to post photos since the forum change-over to the new site and wasn't sure how it worked.

Yes, if you can figure out a way to get the pinned-into-place chrome bezel off, the single-sided key & lock tumbler from a 111 coupe / sedan, or 108 sedan will fit into a 230SL's lock assembly.
The lock I am currently using has a key and tumbler from a "95" installed into a "120" housing. Neiman was the OEM supplier, but to reduce parts inventory several similar locks were combined into one assembly. So the lock you find in one of these cars may have a slightly different appearance.

Al