Author Topic: Electronic Ignition Choices? (Read 27262 times)

Douglas · « **on:** March 13, 2004, 23:57:11 »

I am about to make the leap to an electronic ignition & am wondering what the preferred setup is. Is there a concensus? Is the preferred place for installation under the battery? Petronix? Cranes?

Douglas Kim
New York, NY
280 SL #018260

Cees Klumper · « **Reply #1 on:** March 14, 2004, 00:43:22 »

I would go with Newtronic. Made in the UK I believe, inexpensive, very reliable and none of the problems that have been reported from time to time with the Pertronix. Also, I was able to install it myself with only one small instruction sheet. I have the installation manual put together by John Hassel for the Crane XR700 and it's 27 pages! So I can recommend Newtronic. It's available in the Netherlands through. among others, Sparcon: info@sparcon.nl and eds.classic@worldonline.nl

Cees Klumper in Amsterdam
'69 white 280 SL automatic

Douglas · « **Reply #2 on:** March 14, 2004, 02:03:26 »

Cees, I went to their site & downloaded the pdf list of applications. They don't indicate a W 113 application. Do you have the model #? Also, where did you physically install it? Underneath the battery? Finally, did you have to buy a different coil?

Douglas Kim
New York, NY
280 SL #018260

JamesL · « **Reply #3 on:** March 14, 2004, 02:28:03 »

Douglas

For what it's worth...I just had one fitted by the main Pagoda man in London. He's fitted over 100. I didn't get a choice, but he's fitted Crane

It's sitting, (your) drivers side, on top of the wheel arch, just before the "drop off" into the engine bay itself. Cabled all nice and neatly. Will send a pic if you want

Naj ✝︎ · « **Reply #4 on:** March 14, 2004, 03:44:07 »

Douglas,
For me Crane seems to be working better than Pertronix.
With Pertronix, you don't have that additional box to worry about.
Mounting the Crane box under the battery tray hides it out of the way nicely. There is an led to set static timing and if you fit it facing the fan, you can still use it effectively if you have to remove the distributor in future.
Dont forget to oil the felt under the rotor and the little oil 'capsule' on the side of the disrtibutor body occassionally.
If you ignore this, you will be looking for a new distributor in future!!
naj

65 230SL
68 280SL

Douglas · « **Reply #5 on:** March 14, 2004, 07:18:37 »

Thank you everyone for the advice. Please keep it coming as I'd like to hear as many different perspectives on this as I can.

Also, pix would be wonderful. My interest is performance, reliability and discrete installation.

Douglas Kim
New York, NY
280 SL #018260

jeffc280sl · « **Reply #6 on:** March 14, 2004, 10:04:02 »

Doug,

I have a 1970 280SL with the crane unit. The most difficult part of the installation is the optical trigger. I had to file part of the mounting plate to make sure the plate advanced and retarded without coming in contact with the trigger. The trigger and disk needed to be installed almost as one because I could not fit the disk inplace after the trigger was fitted. I mounted the box under the battery. You need to remove the distributor and then mockup the wiring using your battery. You can do very fine alignment of the trigger in the mockup using the LED on the box. I think you want the LED to fire on the leading edge of the slit in the disk. Once installed it works flawlessly. I have some pics. Send me your email address at lax882@aol.com and I'll send them to you. Can't seem to post pics on this site.

Jeff C.
1970 280SL 4-speed

Cees Klumper · « **Reply #7 on:** March 14, 2004, 10:10:57 »

I bought my unit through AI Motors in The Netherlands (no website, but their contact info is on our vendor database - they are specialised in new and used classic Mercedes parts and also do maintenance). It is correct for my car. I did not have to get a different coil. You could send an email to Sparcon and ask them on the M130 engine specifics. But, again, AI Motors definitely have the correct unit.
I mounted the aluminum box on the same bracket that some of the relays are on, closer to the brake booster than to the distributor. I don't care much about original appearance under the hood, I prefer easy access and visibility of essential components. But I reckon the box could be mounted underneath the battery tray very easily - it's pretty small and very sturdy - seems perfectly weather-proof.
The fitting on the plate inside the distributor took some handi-craft: I had to drill + tap-thread a hole to mount it. Then you have to make sure the wire for the (I believe) optical pickup is routed such that the vacuum advance movement is obstruction-free (but that's the same with all makes no?).

Cees Klumper in Amsterdam
'69 white 280 SL automatic

n/a · « **Reply #8 on:** March 14, 2004, 15:51:49 »

Mounting the control unit for the electronic ignition under the battery involves the risk that battery acid will damage the unit; if a short is created there would also be a risk of fire. Joe's instructions also detail how to mount the unit on the inner fender well. They are long, but they are meticulously detailed and very clear. They would have been shorter, I think, had Joe not been determined to write instructions ANYONE could use (as Patrick O'Brian wrote.."adapted to the meanest level of intelligence"

). The anecdotal reports are that everyone who has tried the Crane unit has been quite happy, the Pertronix less so. The other one I am not familiar with. I got the CRane unit for about $85 from Jeg's in Ohio.

Bill Rader · « **Reply #9 on:** March 14, 2004, 16:04:01 »

Hi Douglas,
I have a Crane unit in my 250sl.It was easy to install and has worked perfectly for over 2 yrs.
Bill Rader
'68 250SL

hands_aus · « **Reply #10 on:** March 15, 2004, 04:42:34 »

Hey Doug,
I have recently installed a Pertronix unit in my 1967, 250SL.
After setting the timing to the BBB specifications, the car is running great.
There is no additional "external unit" to be mounted anywhere. The whole process leaves the insides of the engine bay as tidy as it was initially.
A small bracket inside the distributor needed to be 'sized' to allow the magnetic collar to spin freely.

I bought the unit online from www.carshopinc.com for USD $74.95 plus freight.

Bob (Brisbane,Australia)
early 250 SL, RHD

Douglas · « **Reply #11 on:** March 15, 2004, 09:43:46 »

Bob,

I like the idea of not having a box to hide. Did you change your coil as well?

Douglas Kim
New York, NY
280 SL #018260

hughet · « **Reply #12 on:** March 15, 2004, 12:27:43 »

I put an Allison xr700 in my 65 230SL 14 years ago and it has run great ever since. As I remember, it took about 15 minutes to take the points out and install the kit. It has an amplifier that I attached to the inside fender next to the battery. The unit was a little tight in the distributor because the distributor is small but it fits OK. I can not remember where I bought it but the unit says it is manufactured by Allison Electronics in Brea CA. It cost less than $100 at the time.

Tom Hughes
St Louis, MO

Cees Klumper · « **Reply #13 on:** March 15, 2004, 14:19:32 »

Allison is now Crane I believe.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

n/a · « **Reply #14 on:** March 15, 2004, 14:50:48 »

Hi Douglas,
I chose pertronix because it was the favorite of the late Randy Durrance, an expert on older MB's. I also sought to avoid an external box and tampering with the distributor. It seems that some people have had great success with pertronix, and others have not. I'm afraid I fall into the second category. After what seemed to be a wonderfully easy installation, I've been met with failure.

The most frustrating thing is that I really cannot figure out why the pertronix is not working. I followed the instructions and even used the recommended pertronix coil. The first time I started the car, it started and idled fine, but backfired violently on accelleration. Subsequently, I've tried everything, but cannot get the car to start.

I'll be taking a closer look at the Crane.

Regards,
Don

Klaus · « **Reply #15 on:** March 15, 2004, 15:31:01 »

Douglas,
its an interesting subject...because there must be something that many Pertronix installers first do wrong, without knowing.
I had Pertronix installed by Wolfgang's last June just before driving out to Ohio for the Tech Meet at Joe Alexander's. Wolfgang has done many Pertronix installations, and hardly any Crane, he said. When I picked up the car, I simply drove home, which is part load. Next time I used the car, I drove to Ohio. On the highway, at more than part load, or uphill, I had what has correctly been described in this thread as the "fireworks". I nudged the car to Ohio (at part load, you could do 80mph, no problem, just no fast acceleration). In Ohio, Joe Alexander looked at it, dismantled it, couldn't find anything wrong with it (only changed the spark plugs), put it back in - and since then it works perfectly, no more fireworks, fast start after weeks in the garage, etc.
Probably something gets stuck in some installations and interferes with advance/retard. Or its just Joe's magic hands...

Klaus
1969 280 SL

hands_aus · « **Reply #16 on:** March 16, 2004, 04:33:18 »

Hey Doug,

Before buying my electronic points system, I too read the Randy Durrance article about ignition systems. He did say that he preferred the Pertronix unit.

I have a file called Ignition Systems 101. It was from Randy Durrances' web site.
It is a basic ignition system primer, in that it explains for the the beginner (like me) about ADVANCE , RETARD, DWELL, etc.
If you would like a copy I could email it to you direct. It is a small WORD document of 42KB.

Have a look at the site below (The article was contributed by Randy Durrance) to see what is involved with the installation of the Pertronix unit. It is for a Ponton car but the mechanics of installation are the same.

http://www.mbzponton.org/valueadded/maintenance/ignitionpert/ignitionpert.htm

I used the existing red top coil and 0.9 ohm resistor and I added new Bosch W7DC spark plugs.

Remember my car is different to yours, 250 SL --- 280 SL. It has the resistor in circuit all the time.

The car starts easily, hot or cold.

Initially I had the problem of the car running rough and back firing, but after adjusting the timing to BBB spec and then adjusting the AIR/FUEL mixture the car is running great.
Let me say, I have not taken the car for a long drive yet only short bursts on the local freeway around town (100KMph/60mph max).

Please keep us informed of your choice.

Bob (Brisbane,Australia)
early 250 SL, RHD

hands_aus · « **Reply #17 on:** March 16, 2004, 04:46:18 »

Don

Test to see if you have a spark, even at cranking speed.

If yes, the Pertronix unit is working. Then it must be something else that won't allow the car to start.

Bob (Brisbane,Australia)
early 250 SL, RHD

n/a · « **Reply #18 on:** March 16, 2004, 10:29:25 »

Hi Bob,
Yes, I agree that what you are saying makes perfect sense. I, most likely, need to get the ignition timing set correctly.
I think what I will do is go back to basics and re-install my old system in order to get the car started and timed correctly. Then, try to figure out why the pertronix isn't working.
What still has me scratching my head, is, why the bloody pertronix turned my car into a fireworks finale when I increased the rpms. Since then, my problems have been compounded by my fiddling around with the timing.
Best regards,
Don

quote:
Originally posted by hands_aus

Don

Test to see if you have a spark, even at cranking speed.

If yes, the Pertronix unit is working. Then it must be something else that won't allow the car to start.

Bob (Brisbane,Australia)
early 250 SL, RHD

gwuisman · « **Reply #19 on:** March 17, 2004, 13:47:21 »

Bob a.o.

I did some research on the way magnetic and optical systems work. Perhaps this will help to understand why some people are happy with Pertronic and others not.

The backfire problems can be caused by inbalance of the distributor axle. This phenomena is the result of normal use. Older modern cars - which have a magnetic system as standard - suffer the same problem. Most distributors of our cars will have disbalanced axles because of their age. The more revs the stronger the inbalance. A balanced axle makes the magnetic feeld work in a equal way in relation to the system switches. When the distance between the magnet and the switches differs because of the inbalance of the distributor axle the switches will work earlier or later. This results in dynamic angles and wrong timings in relation to the level of revs. So in some situations the engine runs fine at iddle but not when reving, in other casesb it has problems right from cranking. In this theory - which seems quite realistic - a flawless working Pertronix is possible and indicates the good condition of the distributor. The working of optical systems does not depend on the condition of the distributor axle. Their weakness is the problem of burning through of the electronic part when the contact is on without a running engine.

Gerard Wuisman

Cees Klumper · « **Reply #20 on:** March 17, 2004, 14:50:48 »

On the basis of Gerard Wuisman's last post - if you have / start developing these erratic symptoms with your Pertronix unit and it's due to the distributor shaft being out of balance then I would suggest this is because of normal wear in the two (bronze?) bushings that the shaft runs in, inside the distributor.

Rebuilding the distributor is actually a fun job. I did several during the past months, using Bosch rebuild kits I got from Dan Caron (BenzBarn / Dr Benz, see vendor database) for around $50 a piece that he puts together specifically for these distributors. The kit incudes all the wear and tear parts, including the bushings. So if you feel up to it, I suggest you get a rebuild kit from him. This rebuilding is of course also useful for distributors that have not been modified to electronic ignition.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

n/a · « **Reply #21 on:** March 18, 2004, 10:04:19 »

Gerard,

Thanks for your post. I think you may have the answer. After reading "Ignition Systems 101" that Bob Smith gratiously sent me, my next step was, in fact, to test the condition of my distributor. According to this terrific paper, authored by the late Randy Durrance, the method for checking distributor wear is to measure the difference in dwell angle between idle and 3000 rpm. If the dwell angle changes by more than 3 degrees, the bushings are probably worn.
I plan on performing this test tomorrow morning, but I suspect I already know the answer.

Now, if I only knew the correct hook-up for my Sears dwell meter for the MB transistorized ignition. The BBB describes the hook-up for a Sun Tester or a Bosch Tester. My tester has a green wire and a black wire. The wiring on my system is a little different from the normal set up. My system includes 2 resisters and a switch box, in addition to the coil.

Cees, does the distributor rebuild kit come with instructions? Do you have some tips to help with ease of installation? I am encouraged by your comment that this will be fun. I sure could use a little fun with this project.

Thanks,
Don
Cleveland, OH

quote:
Originally posted by gwuisman

Bob a.o.

I did some research on the way magnetic and optical systems work. Perhaps this will help to understand why some people are happy with Pertronic and others not.

The backfire problems can be caused by inbalance of the distributor axle. This phenomena is the result of normal use. Older modern cars - which have a magnetic system as standard - suffer the same problem. Most distributors of our cars will have disbalanced axles because of their age. The more revs the stronger the inbalance. A balanced axle makes the magnetic feeld work in a equal way in relation to the system switches. When the distance between the magnet and the switches differs because of the inbalance of the distributor axle the switches will work earlier or later. This results in dynamic angles and wrong timings in relation to the level of revs. So in some situations the engine runs fine at iddle but not when reving, in other casesb it has problems right from cranking. In this theory - which seems quite realistic - a flawless working Pertronix is possible and indicates the good condition of the distributor. The working of optical systems does not depend on the condition of the distributor axle. Their weakness is the problem of burning through of the electronic part when the contact is on without a running engine.

Gerard Wuisman

Cees Klumper · « **Reply #22 on:** March 18, 2004, 14:11:52 »

Hi Don - no, my kits did not come with instructions and, actually, I could not find an explosion drawing of the distributor anywhere. Almost all the steps are intuitive - once you disassemble the unit, you will see what new parts come in the place of the old parts. One of the steps is to remove as the excess (up and down) play of the shaft and for that there are multiple shims included. In my case I did not need to replace the bushings and I don't know how involved this is. They appear to be a press-fit so this may require a hydraulic press and reaming afterwards, I don't know. If so, I am sure you can have this done. Perhaps Dan (or someone else who is familiar with this procedure) can comment.
I have about 4 more of these distributors lying around waiting for me to rebuild them. What I can do is take photos and prepare a 'how-to' on the steps that I know, when I get around to doing these four. This may not be in the next two or three months however.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

George Davis · « **Reply #23 on:** March 18, 2004, 19:28:31 »

A word of caution on distributor rebuilding: excess play or wobble may not be worn bushings, but may be due to wear between the upper cam section of the shaft and the lower section of the shaft. A rebuild kit won't help you with that. I sent my distributor to Dan (Benz Dr.) and that's what he said about it - perfect bushings, but worn upper shaft. Although I much prefer to do things myself, I'm glad I sent it to Dan because I don't have a nice collection of parts distributors as Cees does!

Vive le points!

George Davis
'69 280 SL Euro manual

hands_aus · « **Reply #24 on:** March 19, 2004, 01:31:09 »

Hey Guys,

I think Joe Alexander started a thread a few months ago about distributors. It had pictures showing them dismantled.

Bob (Brisbane,Australia)
early 250 SL, RHD

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Author Topic: Electronic Ignition Choices? (Read 27262 times)

Douglas

Douglas

Douglas

jeffc280sl

n/a

Bill Rader

Douglas

hughet

n/a

Klaus

n/a

n/a

George Davis