Timing marks?

[dseretakis]

Got my 71 280SL started yesterday after replacing ignition components (wires, distibutor cap, rotor, points, condenser and spark plugs) but car runs poorly.  I was thinking about checking timing but I don't see any marks on the crankshaft pulley!  Anyway, other issues include dwell angle changing on its own.  First it read 35 then progressively increased to 44 without adjusting the points.  I also noticed that distributor advance was not hooked up to vacuum, but when I hooked it up it ran even more poorly.  Any suggestions?
Dimitri
71 280SL

[ted280sl]

Dimitri,
  The timing mark on the crankshaft can fill in with dirt and grease. I suggest you crwl under the car and clean the crankshaft pulley. Hopefully you will find the timing mark. I am not an expert on distributors but, I suggest getting the timing right then hooking up the vaccuum advance. This may alleviate your dwell angle from changing. My distrutor self destructed a few years back and it cost me $300 to replace it. I believe it is always good to know the range of damage you may be dealing with.
Regards,
Ted 1969 280SL

[Raymond]

Dimitri,  There are lots of reasons why our cars can run poorly.  More often than not, it is a mixture or linkage problem.  

For timing, use a 27mm socket on the bolt on the front of the crank to turn the engine manually.  When you get the crank balancer cleaned off and can see the marks, paint a white line on the zero line, it will help immensely when setting the timing.  If you do a search on this site, there are some great threads about timing and fuel.  Real experts have written out thorough explanations of setting the timing, dwell, linkage and mixture.  It's a re-iterative process that just takes time.

As to the dwell changing, it could be your meter or connection.  If not, it could be that you didn't have the points as tighened down as you thought, or possibly the pad wore down quickly.  I am distinctly unimpressed with the quality of point sets that Daimler is foisting upon us these days.

Ray
'68 280SL 4-spd Coupe

[tuultyme]

Since you have a 71 which has the early pollution components;  some of these components may not be working correctly.  The speed relay causes the engine timing to speed up over 2200 RPM's by opening up the vacuum; thus advancing the distributor timing.  I sent my malfunctioning speed relay to Beckmann Technologies, NC, which solved a lot of my running problems.

Bruce; 268Blaugrun(green) 1970 280SL; IL

[hands_aus]

Test the distributor springs by rotating the rotor to the right and then let it go. It should spring back to its normal position.
Apply a couple of drops of oil to the wick in the centre of the distributor shaft and also to the outside 'OEL' point.
If the shaft and weights are not lubricated you can have a devils trouble getting consistent idle rpms.

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[dseretakis]

Ok, so I rotated the distributor shaft by grasping the rotor, turning and releasing.  It sprung back as it is supposed to except that I turned too far to the right and the shaft and rotor all rotated to a new position.  The car will no longer start.  I'm not sure how to fix this problem.  Any suggestions?
Dimitri
71 280SL

[rwmastel]

I'm no distributor specialist by far, but isn't the distributor shaft "hard connected" to the engine by a gear?  You should not be able to turn it by hand, right?  Maybe your rotor turned on the shaft.  Just guessing.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[hands_aus]

quote:Originally posted by dseretakis

Ok, so I rotated the distributor shaft by grasping the rotor, turning and releasing.  It sprung back as it is supposed to except that I turned too far to the right and the shaft and rotor all rotated to a new position.  The car will no longer start.  I'm not sure how to fix this problem.  Any suggestions?
Dimitri
71 280SL

Rodd is correct about not being able to manually rotate the shaft.

Given the amount of new components, is it likely that the distributor was removed from the car and not re-installed correctly?

Check inside the rotor where it sits on the shaft to see if the locating tab is still in place. It should be there.

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[Naj ✝︎]

Its also possible the distributor clamp is not properly tightened and the body has moved up (see if there is a gap between distributor and  clamp) and disengaged from the drive dog.If so, you could try turning the rotor and pushing the distributor body down at the same time until it re-engages.
Have you found the timing marks yet?
You'll need those now to correctly retime the distributor.

naj


68 280SL