distributor help needed

[n/a]

Background:
About a week ago, after loosening the distributor clamp in order to set the ignition timing, the distributor drifted upwards.  As I was tinkering around trying to figure out why my Pertronix unit wasn't working, I noticed that the shaft to the rotor turned freely.  I thought I was in big trouble.  List member, NAJ, offered me hope and solice that I may only need to push the rotor shaft down whilst pushing the distributor down firmly against the clamp to fix the problem.  I breathed a deep sigh of relief as it seemed to go back down fine.  However, I still couldn't get the car to start.  I have spark (checks out with my timing light), and the engine will sputter and try to start, but conks out after a couple of seconds.  I suspected that the timing was way off.

Now for the interesting part:
I called Pertronix to verify that they sold me the correct unit.  They said that it was, in fact, the unit for my car.  They said that most complaints that they receive turn out to be low voltage issues.

The technician advised me to do a static timing in order to attempt to get the car running.  He advised me to take the following steps:
1. Set the engine to TDC
2. Remove the distributor cap and look for a notch in the distributor housing.  He told me that Bosch puts a notch to indicate where #1 cylinder should fire.
3. Set the center of the rotor to align with the notch.

Here's the problem:
After following steps 1 and 2 above, I saw that my rotor was facing 180 degrees away from the notch in the distributor housing.  I was excited to think that this might be the answer to the difficulties I have been having.  I loosened the distributor clamp and eased the distributor upwards until the rotor turned freely.  I pointed the rotor to the notch and worked the distributor back down.  I could hardly wait to jump in and start the car.  I was ready to start celebrating.  However, it cranked and cranked, but not even a sputter.

Here's the weird part:
So, I went back to square one.  Set the engine to TDC, and popped the distributor cap.  --->The rotor was, again, at 180 degrees away from the notch for #1 cylinder!  How can it be and what should I do?  I am totally stumped and open for comments, advise, and ridicule. :?:

Thanks,
Don
71 280sl   bosch dist. 116-062

[jeffc280sl]

I think we can help you on this.  The distributor is 180 degrees out of position.  The base of the distibutor shaft is keyed so that it will reinstall in the correct position.  If you force the distributor down with it 180 degrees off you can seat the key so the gear turns the distributor.  I suggest the following:  Crank the engine so that the rotor lines up 180 degrees off the notch in the distributor casing.  Loosen the allen bolt securing the distributor in place and gently lift the distributor up about 1/4 of an inch or until the rotor spins free.  Then line the rotor up with the notch on the distributor casing.  Then push the distributoe down and time the ignition.

When you disengaged the distributor you must have spun the shaft 180 degrees off where it should be aligned.  I hope this take care of you problem.

Jeff C.
1970 280SL 4-speed

[n/a]

Thanks, Jeff.  Like an idiot I forgot that TDC for #1 cylinder occurs twice for one complete revolution of the distributor rotor.  Correct?
Don

[George Davis]

Don,

correct.  You need #1 TDC on the firing stroke, which is identified by taking off the oil filler cap and looking at the two cam lobes for #1.  When it's on TDC firing stroke, both lobes will be pointing upwards, like a 'v'.

George Davis
'69 280 SL Euro manual

[ja17]

Hello Don,
I thought you might be interested in this post:

http://index.php?topic=739

To get the car running set the  "static timing" at TDC compression stroke(engine not running). The ignition should spark at number one spark plug. Snug up the distributor but leave it loose enough to turn by hand. Start the car and turn the distributor until the car runs and idles without stalling. Now finish timing with a timing light according to specs. Don't forget to push the distributor back down and tighten it after the timing is finished. If you do not have timing equipment, turn the distributor until the engine runs the smoothest. After test driving retard the timing (counterclockwise)if the car "pings" from pre-ignition under load. Always run High octane in these engines with standard compression. Eventually you may want to confirm you "timing by ear" with a timing light.Good luck, keep us informed!


Joe Alexander
Blacklick, Ohio

[Benz Dr.]

BTDT, but only one time ~)

Dan c

Daniel G Caron

[Cees Klumper]

For the foreigners, BTDT probably means "Been There, Done That" in other words, Dan made this error himself, but only once ;-)

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[Benz Dr.]

There isn't a mistake that I haven't made somewhere over the past 25 years. That's why I make the big bucks now ~)

 Always glad to help out but you need to apreciate the help. No one helped me along the way and that's why I made so many mistakes. I still do once in a while but almost never on things I'm familiar with.

One lesson though. Every time I try and save someone money it usually ends up costing me money or time. There's is a fine between ecomony and practicality. Be good to your mechcanic or parts guy. They can help you to help yourself.

regards,
Dan c
SL Barn



Daniel G Caron

[Cees Klumper]

There are several very knowledgeable forum members who donate a lot of their time to help us by sharing their knowledge; people like Joe Alexander and Dan Caron for example. I know their advice has enabled me to do practically all of my own maintenance and repairs. To me, this not only is part of the fun in owning a Pagoda, but it has saved me quite a bit of money along the way as well.

Dan makes his living maintaining, repairing and restoring classic Mercedes as well as selling the required parts. This means that the time he spends helping us, is not available for his business. I have bought parts from Dan in the past, and I hope you consider doing the same.

Cees Klumper in Amsterdam
'69 white 280 SL automatic