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  #16  
Old 03-17-2011, 12:06 PM
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Quote:
Originally Posted by Graham View Post
Your points are enclosed and I don't think you can get at them without destroying the covers. Those points never burn out - they just sometimes get an oil coating. Don't use any kind of abrasive on them. At most, if you can get at the contacts, slide something like a thin piece of a business card back & forth a few times and see if it picks up any grease or oil. If you can't get at them, try spraying them thoroughly with some electrical contact cleaner in hope that this will remove any oil.

Regarding testing the trigger points. What actually wears on these points, is the fibre rubbing block that contacts the cams. In one of the earlier links I gave you, I may have provided the distance between the rubbing blocks for my two sets. If I recall correctly, one set was worn more than the other.

To test the points, I set them up in a vice. I connected an ohmmeter between the centre connector pin and each of the other pins in turn. For each pair, I rotated the distributor (using the rotor) and noted the angle that that pair of points stayed closed. From the design, you can see that this angle should be roughly 100deg. I had one set of points that were bad in that they stayed closed for almost 180deg. This caused the ecu to inject fuel incorrectly and I had a very rich mixture. The points can't really be adjusted. Some (including me) have tried bending the mounting bracket but it would be much better to try an get one of the new repair kits when they become available. But only if tests show you need them.

I am running on my spare used set and have a brand new set still in the box!

Regarding lubrication, the felt pads on trigger and regular points are just lubed once in a while. The distributor itself has a hollow double concentric shaft. There is a small felt plug near the top (under the rotor) You are supposed to add a drop of oil once in a while. I seem to recall that not all cars have that felt plug, but my '72 SL does.
Graham: Thanks so much for your precise information. I'll report back as soon as I have better data for my trigger points.
Martin

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  #17  
Old 03-17-2011, 12:40 PM
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A dollar bill is the ideal cleaning tool for the points or so Frank Mallory believed. -CTH
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  #18  
Old 03-18-2011, 10:34 AM
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Originally Posted by JPMOSE View Post
The trigger points (pulse generator) are NLA at the dealer. However, Bosch is issuing a repair kit, starting this month!

Follow the Bosch link in the site below and there are a lot of Vintage Bosch goodies in it's news letter and website:

http://forum.w116.org/mechanicals/news-from-bosch-automotive-tradition-centre-re-d-jetronic/
Wow! This sounds promising. See how expensive the repair kit is. But at least a serious option if the old part fails.
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  #19  
Old 03-18-2011, 10:38 AM
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Originally Posted by bwostosh View Post
"Maybe it would be a good idea to pick up certain parts that you might need in the future."

I've been pulling and stashing these parts for 15 years, some think it is a little wacko to be doing this instead of a normal hobby. Fooled them, this hobby will be a service to the Benz community someday. What does golfing contribute?

I was priced out of the old BMW R69S motorcycle market and learned from that. Loved that bike, couldn't afford the parts.
Brian: If you love what you are doing then you are doing an awesome job.
There will be a time when your storage will become very valuable.
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  #20  
Old 03-18-2011, 03:07 PM
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I have no idea what the repair kit cost...if you find out, let me know. I would just like to buy one as a spare. The D-Jetronic parts (along with all MB vintage parts) are getting so high, I'm surprised they have many customers! lol
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1970 280SE 3.5 Cabrio
1987 560SL
1990 560SEL
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  #21  
Old 03-20-2011, 12:43 PM
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Originally Posted by cth350 View Post
A dollar bill is the ideal cleaning tool for the points or so Frank Mallory believed. -CTH
A well spent dollar... hopefully.
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  #22  
Old 03-24-2011, 07:47 AM
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update: I have put the parts of my distributor back together.The job is not complicated.
I have used synthetic ATF (a left over) to lubricate the cam spindle and I put new Bosch grease on the felts. It went well. I also put sealant on the vacuum actuator and the trigger point drawer before closing with some hope that water can be kept out.. I have not touched the trigger points at all
I was testing the trigger points and this is a question for Graham:
I found that 3 of the points stayed close for 120 degrees (and open for 240 degrees) and one point was closed for 160 degrees (open for 200 degrees).
Graham or others please weigh in here.
I am about to put the distributor back into the car.
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  #23  
Old 03-24-2011, 10:58 AM
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I just replaced the vacuum diaphram on the distributor (same as yours for the W111) due to a slight leak. Dealer list was around $190....luckily I was able to obtain it for $127. Still! I think they are around $35 on a late model MB!
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1970 280SE 3.5 Cabrio
1987 560SL
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  #24  
Old 03-24-2011, 12:16 PM
Brian Ostosh
 
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Martin and all,
Another post told of 110 degrees is correct, 120 deg. says rubbing block wear.

Bend to adjust?
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  #25  
Old 03-24-2011, 02:52 PM
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Originally Posted by bwostosh View Post
Martin and all,
Another post told of 110 degrees is correct, 120 deg. says rubbing block wear.

Bend to adjust?
Brian....I can try and 'adjust' the trigger point in order to match the 110 degrees
especially the one trigger point that is showing 160 degrees.
The only problem is that it is hard to do in reality because I need to remove the tray for every attempt for adjustment meaning bending the existing point.
Also I guess i need to destroy the plastic caps covering the trigger points in my unit. What do you think?
Is it worth the hassle? I mean does something not work in the current condition with the 120/240 and 160/200 condition?
If I have no choice I'll do it.
Martin
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  #26  
Old 03-24-2011, 11:31 PM
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Originally Posted by werminghausen View Post
Brian....I can try and 'adjust' the trigger point in order to match the 110 degrees
especially the one trigger point that is showing 160 degrees.
The only problem is that it is hard to do in reality because I need to remove the tray for every attempt for adjustment meaning bending the existing point.
Also I guess i need to destroy the plastic caps covering the trigger points in my unit. What do you think?
Is it worth the hassle? I mean does something not work in the current condition with the 120/240 and 160/200 condition?
If I have no choice I'll do it.
Martin
I would only bend the points if you have experienced a problem - In my case I had a very rich mixture. One set of points was staying open for almost 180deg and I suspect the injectors fired when they should not have. A new good set of points cured the problem and putting the old set back in, even after trying to bend them, caused the problem to return after a short time.

There are no right and wrong angles published that I know of. But I do have a new set of points and a spare distributor that I could use to measure these. If I don't forget (likely!), I will do a test when I get back home in mid April

I don't really know how having worn rubbing blocks affects the data to the ecu. I have read that the trigger points initiate injection and that engine load as measured by MPS determines how much fuel should be injected. But this is also a function of engine speed. Engine speed is determined by measuring the time between pulses from the trigger points. So, it is easy to see that worn trigger points could cause incorrect speed measurement.

Bosch apparently designed the points to last for 100,000 miles. But that presumably assumes proper lubrication intervals.
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  #27  
Old 03-27-2011, 06:47 AM
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Thanks to Graham and Brian

update triggerpoints:

I just wanted to tell you that I tried hard yesterday to make the old trigger points work. I measured again the existing dwell angles more precisely with a tool and found: 140 - 170/180 degrees (never measure dwell andgle with your thumb!). I did a search on the web to get single points but with no success. Barri was emailing me that old VW type3, Volvos 144 E? and Porsche 4 cylinders had the very same points...just one set for 4 cylinders which I could try to get and use. No success here so far over the internet.

In my despair I was taking the 4 point assemblies off, and was bending the upper plates where the small contact is located to a more upward position in order to compensate the wear of the rubbing blocks. It is nuisance and difficult to predict what the bend does in terms of dwell angle but after hours I had them all at 110/250 confirmed original set point)
Well the downside is that the upper contact point is now shifted in an angle (some maybe 20+ degrees as the arm is very short) caused by the bend and I had to grind the edges of the contact point slightly ...just so it didn't look too odd.
I have no clue what the metal composition of the contact is and if this was a good idea. I guess it was rather not but my only choice. I didn't bend or touch the stronger ground plates...so I could just put new points in if I can get them anywhere for a decent price.
After hours (it is an insane process) I had all points at 110/250 +/- 5 degrees.
I am still looking to get 4 new points.
Any suggestions where I can get them? Mercedes, VW, Porsche?
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  #28  
Old 03-27-2011, 10:50 AM
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Quote:
Originally Posted by werminghausen View Post
I have no clue what the metal composition of the contact is and if this was a good idea. I guess it was rather not but my only choice. I didn't bend or touch the stronger ground plates...so I could just put new points in if I can get them anywhere for a decent price.
After hours (it is an insane process) I had all points at 110/250 +/- 5 degrees.
I am still looking to get 4 new points.
Any suggestions where I can get them? Mercedes, VW, Porsche?
Your best bet may be to find one or two used sets of complete trigger points and if they too are worn, and try and salvage the points that have the least wear to make one good set. I have seen them being sold for $35.00/set on the forums but haven't looked recently (eBay sellers usually want too much)

BTW, in looking through some old pics, I found this one. Is this where you bent the points? Shouldn't have needed much of a bend to make up for the rubbing block wear?
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  #29  
Old 03-27-2011, 11:47 AM
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Quote:
Originally Posted by Graham View Post
Your best bet may be to find one or two used sets of complete trigger points and if they too are worn, and try and salvage the points that have the least wear to make one good set. I have seen them being sold for $35.00/set on the forums but haven't looked recently (eBay sellers usually want too much)

BTW, in looking through some old pics, I found this one. Is this where you bent the points? Shouldn't have needed much of a bend to make up for the rubbing block wear?
Graham:

I didn't bend the basis (which is the thick metal bracket that is not moving)
Instead I have bent the moving part which is a thinner metal arm with a rivet to the rubbing block. I bent this part upward in order to compensate the wear.
Although it might be better to bend the thick metal arm I did bend the movable part because I want the option to install new points. Martin
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  #30  
Old 04-01-2011, 11:23 AM
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Graham: I was ordering now trigger point which were offered for a VW type 3 which contain 2 single points for the VW 4 cylinder D-jet. I'll take the 2 single points out and install in my distributor and will replace the 2 point which I had to bend very much in order to achieve the 110 degree dwell angle. I am still looking for the other 2 points.

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