Mercedes-Benz Forum banner

21 - 31 of 31 Posts

·
Registered
1973 450 SL
Joined
·
2,062 Posts
I do have that rubberized trigger points plug mounted on the bracket near the water neck. Recommend not putting a tool on it because the plug inside the rubber cover is made of Bakelite. Just grab the plug and wiggle it off with a rocking motion.
 

·
Registered
1973 450SL, (Previous 2008 ML350,2002 E320 Wagon, 2000 SLK230)
Joined
·
51 Posts
Discussion Starter #22
OK - so I did it. Thank you for the tips and tricks, as it made the procedure seem much easier, and yes it was. Removed the connector, then the grease caked distributor (5mm Hex nut), then started the cleaning process. Degreased the distributor, removed the trigger points (oil was on the inside of the housing) and the lower ones had oil between the contacts - when open and closed you could see liquid separating between them. I thoroughly cleaned the trigger points, distributor body, interior where the trigger points insert. I thought I'd do a little twist when I reinserted the distributor, I reinstalled the points.

With no experience with points, I inserted them, the capacitor was disconnected and cut off, but with posts I read previously stating they didn't need a condenser (and wiring to the condenser, terminal connector, and wire to the connecting block cut) you can guess what happened next - no start. I then thought I'd reinstall the Pertronix, and lets follow the trail - the screw for the coil base fumbled and fell into the trigger point chamber - time to go to bed.

Today, refreshed and several youTube vids under my belt, I started again. Began by removing again (I'm getting more and more comfortable doing this), removing the condenser, connecting point, and repairing and resoldering along with a new wire (the original one was damaged from heat ). Using my newly bought feeler gauge, adjusted the opening to .018, cleaned the oxidized terminals on the rubber connector, dropped in, ensured the marks all lined up, and turned the key - success with points. Fired up and At this point I'm calling it a night, but some great lessons, as well as confidence builders - thanks to all that have helped me to this point.

Tomorrow if the weather is decent I plan on attempting the starting, timing, driving, and adjusting phase. I'll let you know how it comes out.
 

·
Registered
1973 450SL, (Previous 2008 ML350,2002 E320 Wagon, 2000 SLK230)
Joined
·
51 Posts
Discussion Starter #23
New day, and here we go. Set up timing light and it shows as 30BTDC. First try at 5 ATDC and runs poorly, sputters consistently through acceleration. 5BTDC and better, but still sputtering. Then 10, 15, 17, 20 - this was where it was actually running best weirdly (this is with the points). at the higher numbers, especially beyond 10BTDC, acceleration was smooth, consistent, with occasional sputtering. My only other thought at this point once the car cools down is place the pertronix back in, and see if I get similar or identical results.

My two theories and let me know if I may have something. WIth over 43 years of different ownership, mechanics, etc if at some point a mechanic removed the distributor and when reinserted had it one tooth off could this be why I'm having to set to "funky" settings in order to get this running well. My second, especially if the Pertronix is inserted and I'm getting similar results, will be to extract the distributor once again to see if oil is getting onto the trigger points (as indicated earlier where you could see the oil when opening contacts - it was actually only one of the lower ones the last time I had it out). If so, I would say it may be time for a distributor rebuild (Cardone) to replace those seals/gaskets so oil stops penetrating the inside chamber coating the trigger points.

Please let me know if I'm all wet on both theories, but it almost seems like progress was finally being made.
 

·
Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
Joined
·
10,459 Posts
Those are very odd numbers. You may have to go back to square one.

Set the passenger cam on the TDC marks (you have to remove valve cover) At this point, the balancer should be close to TDC. Note how far from TDC it is. That is a measure of chain stretch/sprocket wear. Rotate engine and set balancer to TDC. Then re-insert and turn distributor so that the rotor points to the mark on the casing at about 1 oclock. This is the proper starting point for timing.

Now close everything back up and reset the timing. Start with 5BTDC with vacuum attached.

If you keep the points, gap of 0.014 is closer to correct.
 

·
Registered
1973 450 SL
Joined
·
2,062 Posts
Since you are comfortable pulling the distributor, there is an O-ring on the stem that might need replacement. If you find limited range of ignition advance during your next test, the mechanical advance might need to be cleaned and re-lubricated - moot point if you decide to send it off to Cardone for a rebuild; they will do all that for you.
 

·
Registered
'72 450SL, 107.044-12-000422
Joined
·
262 Posts
The mark on the distributor Graham is referring to is an etched mark on the lip. It represents where the rotor should be pointing with the crank at TDC. Simple test of your “one tooth off theory” would be to position the crank at TDC (with the right extension, you can get a 27mm socket on the crank bolt and turn it from underneath) then check that the rotor lines up with the etched mark.

If the oil on the trigger points persists, I don’t believe there is a fix other than distributor rebuild. I could be wrong but I don’t believe there is a seal there to prevent oil migration-rather there are grooves machined in the shaft that are supposed to divert oil back down.

As far as the ignition points- I would ditch them for the pertronix since you already have it. Takes one more variable out.


Sent from my iPhone using Tapatalk
 

·
Registered
'72 450SL, 107.044-12-000422
Joined
·
262 Posts
Since you are comfortable pulling the distributor, there is an O-ring on the stem that might need replacement. If you find limited range of ignition advance during your next test, the mechanical advance might need to be cleaned and re-lubricated - moot point if you decide to send it off to Cardone for a rebuild; they will do all that for you.
Brad, does the shaft O-ring do anything to prevent oil on the trigger points? I didn’t think so but could be misremembering.

If so, I have a spare sitting on my workbench.

Mgambuzza, if you want to pm your address, I’ll mail it to you.


Sent from my iPhone using Tapatalk
 

·
Registered
'72 450SL, 107.044-12-000422
Joined
·
262 Posts
One more thought:

You probably already know this, but timing should be set with engine up to operating temp and idle speed close to specs 700-800 at idle).


Sent from my iPhone using Tapatalk
 

·
Registered
1973 450 SL
Joined
·
2,062 Posts
Brad, does the shaft O-ring do anything to prevent oil on the trigger points? I didn’t think so but could be misremembering.
That's funny, your post about the oil return helix cut into the shaft made me doubt my suggestion about the O-ring. I'm not sure which of these is important to keep oil out of the trigger points.
 

·
Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
Joined
·
10,459 Posts
Simple test of your “one tooth off theory” would be to position the crank at TDC (with the right extension, you can get a 27mm socket on the crank bolt and turn it from underneath) then check that the rotor lines up with the etched mark.
I have tried to do that, but short of removing the fan and maybe radiator, I could not get at the crank bolt. There are obstructions! Besides, it is very easy to rotate the engine using the PS pulley nut. I think 7/8" or equivalent metric fits. Just pull up on under side of belts while rotating to maximize tension. Works perfectly.
mgambuzza must be rotating engine? How are you doing it mgm?

If the oil on the trigger points persists, I don’t believe there is a fix other than distributor rebuild. I could be wrong but I don’t believe there is a seal there to prevent oil migration-rather there are grooves machined in the shaft that are
I am sure you have seen the thread in EGv107 that covers this. Pictures from about #8 on. When distributor develops axial slack, then perhaps more oil finds it way up the shaft. Worn bearings wouldn't help the "screw pump". There is a fibre washer at top end of the main shaft inside the cams, but doubt it does too much in way of sealing. Don't know if there ever was one at bottom.
Not sure which 0-ring Cush referred to? Only one that I see, is on outside of casing at bottom, but that wouldn't stop oil reaching trigger points.
 

·
Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
Joined
·
10,459 Posts
One more thought:

You probably already know this, but timing should be set with engine up to operating temp and idle speed close to specs 700-800 at idle).
True, but need to get it running first :) So set it at 5BTDC at idle, run until engine warms up. Then recheck at idle and at 1500 and 3000rpm.
 
21 - 31 of 31 Posts
Top