distributor/timing question

[Joe]

I decided to set my timing this evening. The car is a 1965 230SL, euro type. According to the BBB, the timing should be set at 30 degrees BTDC at 4500 RPM with the vacuum line disconnected.
I was able to set it on 30, but wanted to set it on 34 to compensate for being 6000 feet above mean sea level. This is what a local trusted mechanic recommended.
Trouble is, the distributor is turned all the way ccw, and the vacuum advance device is actually touching the head, at 30 degrees. To get more than 30, I need to turn the distributor further ccw, which is not possible.
Figuring I needed to shift the distributor a gear, I removed it, only to find a slotted part in the bottom, allowing only one position.
The distributor is an 046. It has a fine adjustment device on the bottom, and I turned that all the way, too, in order to get the full 30 degrees. Can't adjust it any further.
Can someone advise me on how to get another 4 degrees advance? Most of my driving that will not be at 6000 feet will be at higher elevations rather than lower, so I want all the advance I can get.
Hope this makes sense.
Joe

[ja17]

Hello Joe,
You will need to re-set the distributor from scratch. Set the engine at TDC compression stroke #1 cylinder. Remove the oil filler cap and make sure the front two cam lobes are pointing upwards (10 o'clock and two o' clock over the first cylinder). The crankshaft pointer should be set on Zero. Remove the distributor cap and ditributor.  That slotted gear below the distributor can be removed or repositioned. First there should be a small spring on the top of the gear, (look with a flashlight). Remove the spring then take a large slotted screwdriver and turn the gear clockwise, it will rise and fall back into place at a 40 degree different position each time. Notice the top slot of this gear is offset very slightly. The distributor is meant to engage the gear only one way.

Download Attachment: offset  slot.jpg
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Do not force it on 180 degrees off! The distributor orientation for all except the later replacement aluminum units should have the vacume cell at about two o'clock and the condensor at about 9 o'clock. Looking down on it facing forward. Turn the distributor drive gear in 40 degree incraments until this correct orientation is achieved. The rotor should now be pointing to the slash on the distributor rim (designation for # one cylinder spark plug wire). Dont't forget the little spring and always push downward on the distributor when locking the distibutor down. Otherwise the little spring will push the distributor upward and disengage it. Take a look at this photo of the gear and the little spring(often missing!)
Download Attachment: Distributor drive gear.jpg
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Also see the slight off-set of the slot in the top of the distributor gear (photo).

When the distributor is oriented correctly you should have plenty of room for adjustment. If you need more details or photos let us know. Good Luck!



Joe Alexander
Blacklick, Ohio

[Joe]

Thanks, Joe, for the details. My condenser was at six o'clock, so two gear changes fixes it. I have the distributer out now, deciding to clean it up and repaint it while it is out for the gear change. The thing works ok, as evidenced by the dwell shifting only two degrees (40 to 38) when reving the engine, and the timing marks staying stable above about 3000 rpm, but I thought it might be a good idea to explore the innards and see if some preventative maintenance might be called for. I've found some rust and dryness in the area where the springs are located, and will see what I can do about that without removing that portion. The two plates at the top, onto which the points mount, do not slide against each other easily, so I'll clean that out with carb cleaner and then spray some silicon in there. I didn't want to remove the ball bearing device that holds the two plates together. Any advice on this cleaning/lubing process is appreciated.
Also, the shaft of the distributor body has a groove on it. Is there supposed to be an o-ring in that groove?
Joe

[ja17]

Hello Joe,
Sounds like your making good progress. Your early distributor should be lubed at the felt and the little capsule on the side during regular lubrication service. Applying a bit of grease on the distributor cam will also keep the contacts gaped correctly longer. The "sliding plates are very basic. The ball bearing simply holds them close together. Disassembly is not very complex. The centifical advance springs and weights are below these plates. You may want to inspect these, but you are probably ok with the dwell specs that you recorded. To remove the distributor shaft the pin must be driven out of the cog on the bottom of the distributor. Keep track of the spacers and insulator rings for re-assembly later if you go that far. One critical area to deal with is the terminal stud where the coil wire and condenser terminate on the distributor. This 7mm bolt must be insulated as it passes through the distributor housing. If the original insulator rings are bad or missing a rubber o-ring works fine. The two fiber insulating washers should always go back in place. Make sure the forked terminal on the ignition points does not touch the breaker plate or any other metal or the ignition is grounded out, (no spark). Carry on!


Joe Alexander
Blacklick, Ohio

[Joe]

Well, thanks again, Joe.
Actually, it is all back together now, and running fine. I did take the distributor apart as far as I could without removing the pin in the bottom. I cleaned up the considerable gunk in the body with carb cleaner, and reassembled the clean parts with lube. I can't tell any difference in performance, but the distributor sure looks better. It was very rusty, like most of the parts under the hood. At some point, I'd like to clean it all up and dress it up with new cad.
Thanks for the advice.
PS. Please see other new note under "fuel guage question"!
Joe

[jeffc280sl]

I would like to thank Joe Alexander for his contributions to this group.  I have been installing the Crane ignition unit in my 1970 280SL.  I took the distributor out and took it apart to clean it.  I did not realize that the bottom fitting was offset.  It is very hard to notice.  Anyway I reassembled the distributor and installed the bottom fitting by reinserting the locking pin.  I tried to reinstall the distributor and could not get it to seat properly.  After reading Joe's post I realized that the bottom fitting was reinstalled 180 degrees from where it should be.  The distriobutor would not line up with the bottom gear fitting.  Needelss to say I punched the pin out, turned the fitting 180 degrees and was in great shape. One must read Joe's posts very carefully.  There are years and years of lessons learned and knowledge to be had.  Take the time to read and digest what he has to say and you will solve your problem.

Thanks Joe!!

Jeff

[Cees Klumper]

Jeff - a few of us are in the process of sorting and archiving all of the old Yahoo! posts and the posts on this site into Word documents, as the basis for our W113 Ownership, Maintenance and Repairs ('Tech') Manual. What I was planning to do is accumulating ALL of Joe Alexander's posts into a separate document that, with his permission of course, could be made available to the members until the Tech manual is ready. Because as you say, there's a huge amount of knowledge and experience within those posts.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[ja17]

Hello Jeff,
I'm glad the information is helping out. The nice thing is there is always something new to learn even for myself!

Joe Alexander
Blacklick, Ohio