Pagoda SL Group
W113 Pagoda SL Group => Electrical and Instruments => Topic started by: n/a on March 01, 2004, 12:32:20
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The beautiful weather here in Ohio this weekend lured me outside to pamper my 71 280sl. I had been waiting all winter to install a Pertronix electronic ignition to replace the points in the distributor. I also purchased the recommended ignition coil from Pertronix, the 40,000 volt, 3.0 ohm, high performance "Flame Thrower." The installation was amazingly simple. I could hardly hold back my excitement with anticipation of never having to mess with distributor points again.
The car started up fine and seemed to idle beautifully. However, when I reved the engine, to my horror, it sounded like the ending to a fireworks display on the Forth of July, kinda like someone was shootin' at me with a machine gun. I adjusted the ignition timing to 8 degrees ATDC as indicated in the Big Blue Service manual. Nothing helped.
The ignition on my car is a little different from earlier 113's. I have what is known as the "transistorized ignition," consisting of 2 series resistances ( a 0.4 ohm and a 0.6 ohm), a switchgear, and a Bosch blue colour coil. (See page 15-20 in the Big Blue Service Book). My distributor is the Bosch #0231 116 062. This distributor was not on the Pertronix on-line chart, but the sales person felt that the Pertronix 1863 was the one for me.
When I installed the Pertronix, I connected the black wire from the ignitor to the negative terminal on the new "flame thrower" coil, and the red wire to the positive terminal. I wired the positive terminal directly to the ignition switch wire, as recommended in the installation guide.
Anyone with experience in this area, please offer your thoughts!
Thanks,
Don
1971 280sl
"If you're not the lead dog, the view never changes."
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Don,
two WAGs:
On the 051 distributor, the bracket for the vacuum control rod has to be modified slightly to clear the Pertronix unit. Don't know if the 062 is the same, but maybe the vacuum control is hanging up on the unit?
Second, there is an rpm-controlled relay that affects ignition timing (vacuum advance/retard) on your car. If the Pertronix wiring eliminated the rpm signal to the relay, timing will be affected, although I'm not sure exactly which way.
Good luck!
George Davis
'69 280 SL Euro manual
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I have the Pertronix with the 062 distributor. Best I can recall, you have to attach the green wire (that once was connected to the transitor module) to the negative side of the coil to enable the RPM relay to pick-up the rpm signal.
Also, you likely know that you do not need the balast resistors with Pertronix. If you are running your power source through the resitors, that will be a problem.
Oh, one more thing...you will need a hotter coil than the standard coil. If you need a reference on the coil I have, let me know.
Best,
Tom
____________________________________
1971 280sl Tunis Beige Metallic
1971 280sl Tobacco Brown
1994 E320 Cabriolet, Smoke Silver
1999 E320 Wagon 4 matic, Brilliant Silver
____________________________________
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I have the 010 aluminum distributor with the Crane ignition system. Picking up on what the other guys said there should be a wire connecting pin 4 of the speed relay to pin one on the coil. I believe the wire is green/black in color. The speed relay receives rpm data from the coil and at 2400 rpms it energizes the two way valve which provides atmospheric pressure to the distributor which I think eliminates the retard. At 2200 rpms the speed relay removes power from the two way valve and vacuum is again applied to the distributor.
With the Crane unit pin one on the coil also gets an input from their ignition module and pin 15 on the coil gets an input from the .6 ohm resistor.
Jeff C.
1970 280SL 4-speed
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I saw the on-line information that Randy Durrance put together on the Pertronix. I had anticipated that I would need to modify the interior bracket. However, I discovered that this was not necessary for my distributor. I hadn't thought about the speed relay.
Thanks!
On the 051 distributor, the bracket for the vacuum control rod has to be modified slightly to clear the Pertronix unit. Don't know if the 062 is the same, but maybe the vacuum control is hanging up on the unit?
Second, there is an rpm-controlled relay that affects ignition timing (vacuum advance/retard) on your car. If the Pertronix wiring eliminated the rpm signal to the relay, timing will be affected, although I'm not sure exactly which way.
Good luck!
George Davis
'69 280 SL Euro manual
[/quote]
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Many thanks to Tom (and others!) who are helping with this issue.
I looked for info on the speed relay, and, sure enough, as Jeff described, on page 00-78/3 of the service manual it shows wire going from pin 4 on the speed relay to terminal 1 on the coil. I don't recall seeing that wiring for my car.
Tom,
Please describe in more detail what you are saying about a green wire that was once connected a "transitor module." What is the transistor module that you are referring to. I think you are onto my problem. I need to find that wire.
Thanks,
Don
quote:
Originally posted by Tom
I have the Pertronix with the 062 distributor. Best I can recall, you have to attach the green wire (that once was connected to the transitor module) to the negative side of the coil to enable the RPM relay to pick-up the rpm signal.
Also, you likely know that you do not need the balast resistors with Pertronix. If you are running your power source through the resitors, that will be a problem.
Oh, one more thing...you will need a hotter coil than the standard coil. If you need a reference on the coil I have, let me know.
Best,
Tom
____________________________________
1971 280sl Tunis Beige Metallic
1971 280sl Tobacco Brown
1994 E320 Cabriolet, Smoke Silver
1999 E320 Wagon 4 matic, Brilliant Silver
____________________________________
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Tom,
One more thing. What specs did you use for the ignition timing? According to the way I interpret the chart for 1970 and 71 280sl, it should be set at 8 degrees ATDC (to the left of the zero when viewing the car from the front) at 800 rpm (idle speed).
I did purchase the high performance coil recommended by Pertronix.
Thanks again,
Don
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Don,
This is from memory, but the wiring harness has several connections to a bakelite electrical terminal block that is located in close proximity to the transistorized unit, which is attached to the underneath of the battery tray.
Note the green wire in the attached pictures of that same bakelite terminal block as well as the green wire coming from the harness.
For ignition timing, focus on setting the timing at appx 30 degrees BTDC at 3000 rpm, with the car warm, vacuum line attached to the distributor vacuum box, and the rpm feed (green wire) attached to the negative terminal of the coil. You will note that if the RPM relay is picking up the rpm feed that the two way switch will kick in at about 2400 rpm and release the retard and advance your timing. If you don't see a sudden advance in timing around 2400 rpm, something is not working correctly. Of course, in setting timing, ensure your linkages are adjusted, fresh plugs, etc. before setting timing. Timing at idle should be at about 0-5 degrees before TDC once the timing at 3000 rpm is set correctly.
Best,
Tom
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____________________________________
1971 280sl Tunis Beige Metallic
1971 280sl Tobacco Brown
1994 E320 Cabriolet, Smoke Silver
1999 E320 Wagon 4 matic, Brilliant Silver
____________________________________
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Thanks Tom. It looks like this is the terminal where the condenser wire attaches. Sound right?
Really appreciate the help.
Best regards,
Don
This is from memory, but the wiring harness has several connections to a bakelite electrical terminal block that is located in close proximity to the transistorized unit, which is attached to the underneath of the battery tray.
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Tom,
The Pertronix part they sent me was 1863. Is this the same part number that you have for your 062 distributor?
I would like to be certain that I am working with the correct unit for my car. Also, have you ever measured the dwell after installing the pertronix. I believe it should be 29-31 degrees.
Thanks,
Don
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Don,
Don't recall the model number of Pertronix that I have. Is this on the Ignitor? I will check tomorrow.
My dwell is 38 degrees and never changes.
My Pertronix was installed by Randy Durrance at the same time he re-built my distributor, and I recall he had to grind down the bracket to get it to fit the distributor.
Did you re-install the small screw on the side of the distributor that use to hold the condenser? If you did, remove it, as without the space taken by the condenser bracket, the screw will make contact with movement inside the distributor and possibly damage the springs.
Don't give up on the Pertronix unit-it works great once you get it right.
Best,
Tom
____________________________________
1971 280sl Tunis Beige Metallic
1971 280sl Tobacco Brown
1994 E320 Cabriolet, Smoke Silver
1999 E320 Wagon 4 matic, Brilliant Silver
____________________________________
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Not quite. The car has to be in gear and at road speed before it will switch over at 2400 RPM. So many people make that mistake and think the distributor switch gear isn't working. I believe there's also an oil temp and coolant temp input that can affect the switch over. A simple test is to undo the plug on the two way valve and drive the car and see how it runs ( which won't be impressive)and then plug it back in and compare. It should pull well up to higher RPM 's in all gears.
Dan c
Daniel G Caron
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With a timing light, with my head under the hood and the car *in park*, I can actually observe my retard going away and advance kicking in at 2400 rpm. The car (at least my car) does not have to be in gear and on the road. And I have an automatic, which could make a difference.
Otherwise, how would one set the timing other than at idle? Also, the book gives a spec for timing at 3000 rpm and doesn't indicate in the book that it has to be done on a dyno or at speed.
Best,
Tom
____________________________________
1971 280sl Tunis Beige Metallic
1971 280sl Tobacco Brown
1994 E320 Cabriolet, Smoke Silver
1999 E320 Wagon 4 matic, Brilliant Silver
____________________________________
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Hi Tom (and others with Pertronics)
There have been some comments that there is a misfire (flat spot??) around 4000/4500 rpm with the Pertronix system installed. I certainly had quite a bit of trouble with my original unit, which was then replaced but it is still there but to a lesser degree.
Anybody else notice this?? :(
naj
65 230SL
68 280SL
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Naj,
I have not noted the flat spot you mentioned. I think the Pertronix works pretty well, and I actually had a Crane system in that I switched out for the Pertronix. Crane worked well, but I just wanted to tinker (running out of projects) so I put the Pertronix in.
Best,
Tom
____________________________________
1971 280sl Tunis Beige Metallic
1971 280sl Tobacco Brown
1994 E320 Cabriolet, Smoke Silver
1999 E320 Wagon 4 matic, Brilliant Silver
____________________________________
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Hey Tom,
Any time you feel the urge to tinker, and you'd like to visit Cleveland--be my guest. I got this benzino in the garage that just loves to be tinkered with. ;)
Crane worked well, but I just wanted to tinker (running out of projects) so I put the Pertronix in.
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I'm going to look at this again but I was under the impression that an oil pressure switch on the auto trans needs to be on for the switch gear to work. Normally I put a test light on the switch over valve and tape it to the windshield. I've not been able to make them switch anyother way other than during driving.
You could be right though.
Dan c
Daniel G Caron
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Hey Tom or anybody with the knowledge,
With the Pertronix unit, is it important to have the correct Dwell angle?
I ask because I have just installed a Pertronix unit (1864LA for 051 distributor) in my car BUT the Dwell angle shows at 33.5 degrees not 38 degrees as per specs.
I am having trouble getting the timing correct in my 250 SL, is it possible that is the cause?
Bob (Brisbane,Australia)
early 250 SL, RHD
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Bob,
You cannot adjust the dwell angle in an electronic system. The processor does that??
Should be able to time correctly though.I had to file a notch in the mounting plate (where there is a little bent over tang - on the lower plate to keep upper plate in place) to get the sensor to mount properly.
I believe the 1864LA is the correct mounting plate for the 051.
Please let me know if you get smooth operation thru the rev range once the timing is correctly set.
naj
65 230SL
68 280SL
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Bob,
Puzzling to me why you can't get 38 degrees dwell-should get that out of the box.
Dan, I have another 71 280sl that is an automatic and fairly original. I will put a timing light on it as well and see if I get the same advance at 2400 rpm as I do on my driver.
Best,
Tom
____________________________________
1971 280sl Tunis Beige Metallic
1971 280sl Tobacco Brown
1994 E320 Cabriolet, Smoke Silver
1999 E320 Wagon 4 matic, Brilliant Silver
____________________________________
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I have an electronic ignition unit made in the UK (by Newtronic) that has performed flawlessly from the get-go. No flat spots etc. I must say I have not measured the dwell angle, but here's the point: on my unit, there is an optical pick-up that is triggered by a plastic disc that is rotating in the distributor (slips onto the shaft) and it has six slits in it. I have always assumed that the width of these slits determines the dwell angle (that is, I have also assumed that dwell angle means the length of time / number of degrees that the signal is transmitted). Point being that the dwell angle, if I am correct, on my unit is 'mechanical' rather than 'electronic/programmed'. Am I wrong? And do Pertronix units work differently?
Cees Klumper in Amsterdam
'69 white 280 SL automatic
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Naj,
Given that there is no adjustment for dwell on the 1864la unit, I figured it should be set for the correct dwell angle of 38 degrees.
I will keep you informed of my progress.
Tom, I thought it should be 38 degrees out of the Box too.
Pertronix do not recommend removing the resistors on all systems. They say to keep it if it is in the circuit all the time like for my 250SL. This is different from the 280SL with two resistors.
Don, there is a Freqently Asked Questions page on the Pertronix site worth reading.
It tells you how to work out if your voltage and resistance are correct. Yours should be spot on with the new coil.
My understanding is that the MB electronic unit REDUCES the current through the Points which extends their life.
So I have another question,
Does the Pertronix unit REPLACE the MB electronic unit in the 280 SLs OR does the MB unit provide other features too?
Maybe Don can remove/disconnect the MB electronic unit.
Bob (Brisbane,Australia)
early 250 SL, RHD
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Bob,
The Pertronix unit obsoletes the transistorized ignition module that is under your battery tray. You can remove it if you like.
Best,
Tom
____________________________________
1971 280sl Tunis Beige Metallic
1971 280sl Tobacco Brown
1994 E320 Cabriolet, Smoke Silver
1999 E320 Wagon 4 matic, Brilliant Silver
____________________________________
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Thanks to everyone who tried to help with the Pertronix setup on my 71 280sl. However, it seems that the results have gone from bad to worse. The initial symptoms were that the car started and idled fine, but backfired violently when the engine was reved. Later on, it started idling very rough, and it was difficult to keep it from stalling out. Now, I can't get it to start up at all. I am getting some spark (according to my timing light). However, it cranks and cranks, with an intermittent putter. Plugs become wet with petrol. I needed to recharge the battery 3 times due to energy loss from cranking.
I don't know if the source of the problems is related to the tinkering around, a faulty Pertronix unit, or an incorrect Pertronix unit. As mentioned before, my Bosch distributor 062 is not listed on the Pertronix on-line list. The sales person recommended Pertronix part #1863 for my car. I also installed the recommended Pertronix high performance coil. I wired the coil directly from the ignition switch, as recommended in the literature. I by-passed the MB "transistorized" ignition parts.
At this point, I'm pretty close to giving up with Pertronix. I'll check their on-line FAQS to see if I can learn anything new. I plan on calling Pertronix to see if I can try another unit, since I have heard reports of faulty units.
If none of this works, I guess I'm left with exploring Crane or going back to (aaargh) those mechanical points.
Best regards,
Don
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I also just installed the electronic unit in a 64’ 230sl with the later 250 motor in it for a friend of mine. It was a little tricky at first but I found the problem and now it runs GREAT!!! When I first installed the small little ring on the distributor shaft I did not notice that it was hitting the small bracket for the vacuum advance. This interference was very minimal and only caused the ring to sit slightly higher on the shaft. The car would run like this but I could not get the timing straight. It would pop and miss differently each time I ran the motor. After grinding the little bracket on the vacuum advance and getting the ring to fit properly the motor ran like a champ. I did however have to make a large adjustment to the ignition timing but that was it. This is a great little unit and a wonderful upgrade on our ignition systems. (No flat spots in the RPM curve and much better throttle response.)
I don’t know if this is going to help you but it dose sound like your symptoms are the same.
Jerry P.
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I really don't want to throw in the towel (or I guess the shop rag) on this one just yet. Can Tom, and others, who have installed the Pertronix, tell me exactly how they did the wiring? Did you run a wire from the negative terminal on the coil to ground? Any ground wiring that needs to be done to the distributor?
The tech support guy at Pertronix told me that almost all complaints they receive are related to voltage issues. One problem that I have is that the wiring on my car is a bit weird because of the transistorized MB ignition. I'm not 100 percent sure about proper wiring. I am bypassing all resistors.
Can anyone offer suggestions about getting the timing closer to spec by just cranking the engine? I can't get it started to properly do the timing. I've been tinkering around with the timing and I fear that it is now way off.
Thanks,
Don
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Dwell angle is the amount in degrees that the points are closed. As the shaft turns the points are closed until the cam opens the points. Once the points close again the coil builds up a charge ( coil saturation ) until the points open again and the coil releases the high tension voltage to that part of the system ( cap, rotor, wires, spark plugs)
If you have points you have a dwell angle. Electronic systems do this , well...... electronicly and so there is no dwell angle but rather a point of fire that lets the coil build up a charge in the same way as a points coil system. This is a very similar idea to dwell angle done by points except this is done by induction pick up or some other means and is basically service free.
( I bet no one can make sense of this)
Dan c
SL Barn
Daniel G Caron
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Dan,
I think I actually did follow your line of explanation regarding dwell!
Don,
Let me try this with a focus on the coil, which of course has two terminals, one positive and one negative. Under the Pertronix system, two wires connect to the positive coil terminal and two connect to the negative terminal. The first two wires (red and black) come from the Pertronix Ignitor unit contained within the distributor housing-red to positive terminal and black to the negative terminal of the coil
The third wire is the hot wire with switched power that was once the lead wire to the first ballast resistor. This should be attached to the postive terminal of the coil.
So now you have two wires connected to the postive terminal and one wire connected to the negative terminal of the coil. Once these three wires are connected, your system should work.
The fourth wire that is not connected is the RPM feed. The RPM relay that feeds the 2 way valve with an RPM reading to turn your vacuum on and off needs the wire to feed the RPMs. The wire that does this emerges from the wiring harness that runs along the fender. The wire emerges from the larger sheathing as a smaller sheathing with two wires. I am now questioning my original indication that it was the green wire and will need to verify this and get back to you.
However, I left that 4th wire unattached for months until I figured it out and the car ran fine. It just runs better and allows you to set your timing and get the proper overall ignition advance curve. So work with the three wires until I can figure out the 4th wire and report back.
Best,
Tom
____________________________________
1971 280sl Tunis Beige Metallic
1971 280sl Tobacco Brown
1994 E320 Cabriolet, Smoke Silver
1999 E320 Wagon 4 matic, Brilliant Silver
____________________________________
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Hey Dan,
That makes a lot of sense to me. (ex electrician)
On my 250 SL the Magnets in the Pertronix rotating collar allow approximately 38 degrees equivalent Dwell angle. I believe this is right on spec.
Don,
The ground wire to the negative side of the coil should not be there.
On my 250 SL there is no speed relay and no 4th wire.
Just the switched positive wire plus the red wire of the Pertronix unit go to +ve terminal of the coil, then the Black wire from the Pertronix unit goes to the -ve terminal of the coil.
There is a small ground wire inside the distributor that goes under the screw that holds the little bracket that I had to modify so that the magnetic collar could rotate freely and holds the base plate in position to the vacuum rod. (I remember you saying that you did not need to modify that bracket).
I am not sure if that ground connection does anything now that the Pertronix unit is installed still it won't hurt to have it in place.
You are not far off now.
Bob (Brisbane,Australia)
early 250 SL, RHD
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Brisbane Bob,
Should the red wire not be on the switch side of the ballast resistor - giving it full 12 volts?
naj
65 230SL
68 280SL
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OK Dan - that's what I had always assumed. Still, your explanation of the dwell (duration of impulse) being determined electronically makes a lot of sense also. Maybe the only way to find out for sure is by asking one of the manufacturers of these electronic units or reading up on the subject somewhere. Electronic ignition ins-and-outs may be a good topic for a Pagoda World article actually.
Cees Klumper in Amsterdam
'69 white 280 SL automatic
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Hey Naj,
I checked my set up and you are right, I do have the red wire of the Pertronix unit connected to the switch side of the ballast resistor, so yes it does get 12 Volts.
Bob (Brisbane,Australia)
early 250 SL, RHD
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Being at wits end, I decided to pull the pertronix and re-install my old system. The car started right up and idled fine with my old points ignition! I set the timing with my strobe and adjusted the idle.
So, I guess that narrows my problem to pertronix. But, how and why is still a mystery.
Don
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Hi Don
I came to this thread very late and ended up here accidently looking for info on pertronix for my 3.5 108 BUT, having read all the details on your problem and some of the other comments on the thread, I am thinking they simply suggested the wrong kit!
Elsewhere on the thread folks refer to the 1864LA unit as correct for a 280SL - now even though your distributor isn't listed, I would think that getting the 1864LA - which is different than the one they supplied you - was worth a try. Did the dealer suggest the one you fitted because it matched your distributor number, or they just took a guess.
I don't know if this is worth a try, but good luck in solving the problem anyway.
Regards
Richard
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hi don just some info, your ign. system is the one put on the `107chassis starting in 1972. it was on my 450sl & others i worked on. i think you have the wrong kit.
vincediver
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Not sure what this was...was not posted by me. I was "retired" in mid 2007.
I erased the message...it was in HTML code and was full of dead links.
Richard M, Feb 29, 2008