Author Topic: Spark Plug Wires  (Read 3461 times)

MikeSimon

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Spark Plug Wires
« on: December 08, 2022, 20:52:14 »
here is something I discussed with a fellow member during breakfast today and I want to run this by the community for some comments.
I own my car since 1982 and have not done anything to it in that area. I want to believe that it is mostly original but this seems not possible.
The car was built in November of 1970 and is a German spec car.

The spark plug wires at the distributor cap have 3 horizontal and 3 straight ends.
The horizontal ones are Beru and the straight ones are Bosch.
The Bosch ones have a part number. The spark plug ends are all Beru caps.
I have a spare set of wires and a cap with all 6 horizontal plugs by Bosch. No ID number.
1970/71 280SL Automatic
Sandy Beige
Parchment Leather
Power Steering
Automatic
Hardtop
Heated Tinted Rear Window
German specs
3rd owner

MikeSimon

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Re: Spark Plug Wires
« Reply #1 on: December 08, 2022, 21:29:12 »
More pics
1970/71 280SL Automatic
Sandy Beige
Parchment Leather
Power Steering
Automatic
Hardtop
Heated Tinted Rear Window
German specs
3rd owner

MikeSimon

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Re: Spark Plug Wires
« Reply #2 on: December 08, 2022, 21:32:55 »
More pics
1970/71 280SL Automatic
Sandy Beige
Parchment Leather
Power Steering
Automatic
Hardtop
Heated Tinted Rear Window
German specs
3rd owner

MikeSimon

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Re: Spark Plug Wires
« Reply #3 on: December 08, 2022, 23:13:26 »
Pics
1970/71 280SL Automatic
Sandy Beige
Parchment Leather
Power Steering
Automatic
Hardtop
Heated Tinted Rear Window
German specs
3rd owner

MikeSimon

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Re: Spark Plug Wires
« Reply #4 on: December 08, 2022, 23:14:28 »
Pics
1970/71 280SL Automatic
Sandy Beige
Parchment Leather
Power Steering
Automatic
Hardtop
Heated Tinted Rear Window
German specs
3rd owner

lreppond

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Re: Spark Plug Wires
« Reply #5 on: December 08, 2022, 23:48:29 »
I have a November 1970 build car as well (-022320). My dad got it new March 1971.  It was a US car. It came with all Beru horizontals.  None were Bosch.  I believe the horizontals were used to accommodate the suppression plastic cover used because of the transistorized ignition.  The wires were routed under the FI tubing. 
~Len

1971 280 SL
576G red/251 Beige
4 speed manual
Family owned since new (father —> son)

rwmastel

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Re: Spark Plug Wires
« Reply #6 on: December 09, 2022, 05:21:20 »
You didn't ask a question.   ;D
Rodd

Did you search the forum before asking?
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MikeSimon

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Re: Spark Plug Wires
« Reply #7 on: December 09, 2022, 13:07:15 »
I have a November 1970 build car as well (-022320). My dad got it new March 1971.  It was a US car. It came with all Beru horizontals.  None were Bosch.  I believe the horizontals were used to accommodate the suppression plastic cover used because of the transistorized ignition.  The wires were routed under the FI tubing.
My car is -22774, so rather close. But it is a German spec car. I think all US cars had horizontal plugs because of the ignition (?) I really wonder why someone would change 3 plugs, especially as the harness seems totally undisturbed, still has the sleeve around it. I wonder whether the horizontal Bosch plugs are from a different, later model.
1970/71 280SL Automatic
Sandy Beige
Parchment Leather
Power Steering
Automatic
Hardtop
Heated Tinted Rear Window
German specs
3rd owner

mdsalemi

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Re: Spark Plug Wires
« Reply #8 on: December 09, 2022, 15:08:31 »
...I wonder whether....

Don't we all?

I have a working theory on many such questions. Remember, the oldest of these cars will be 60 this coming year, and the newest of them will 52. Unless you personally bought your car new from a dealer, and stored it away in a bubble, well, anything is possible in such decades of time.

For the first few years of these [new] cars lives, they were most likely maintained and serviced by an authorized dealership. They only used--so we think--MB branded parts in their supply chain. But what about dealerships in distant locations? Maybe one in The Philippines, Central or South America, or Africa or someplace that may not have had a ready supply chain of factory parts? OK, just interjecting the possibilities.

Once that new car hit a certain age, many of them lost their luster and many became simply nice drivers. Dealer servicing may have changed to local independents, using the best parts they could find or the cheapest depending on the client. So maybe your fan belt was changed from MB to Continental and eventually to NAPA...when the independent went to change the wires, They used what they could get. Far too many mechanics in the interest of their client's pocketbook (invoice) will change what's necessary only when broken. How many times have we had new owners/members here look at their wires in puzzlement to see a mix of horizontal and vertical as well as Bosch, Beru and unnamed ends? Or a mix of actual wires? It would be nice to think that a wire problem somewhere in the car's life would cause the entire set to be changed but that wasn't always the case.

When my car was restored, I pulled what looks like the original wire set off, and replaced with something I could find. Don't know what it was, but I'm sure it wasn't correct. About 12 years ago, I had a set custom made for me from some firm whose name I have long forgotten in California. At the time it wasn't cheap, well over $100 when a cheap set was about ⅓ of that at any local parts store. But it featured metal Beru ends, Beru solid copper wire, and all vertical ends for the distributor. Somewhere in my parts bin is a nasty old distributor cap with the old wire set attached. Also all Beru, though I cannot say with certainty it's original as delivered. My uncle drove my car hard as a daily driver for 10 years in New York, for an additional six years as a daily driver. Most of its maintenance over the years was at HIS father's Taxi garage! So anything was possible.

In Classic Mercedes (UK) magazine that came to my mailbox yesterday, there's a nice story about the provenance of the Sir Stirling Moss 230SL. At the end of the story there's a line that says the car "was delivered from the factory with a Blaupunkt radio" which may be a typo, but if accurate flies in the face of everything we believed about radios and Mercedes-Benz. I've always been told that from the factory, it was only Becker.

I guess we can always keep on wondering about everything.
Michael Salemi
Davidson, North Carolina (Charlotte Area) USA
1969 280SL (USA-Spec)
Signal Red 568G w/Black Leather (Restored)
2023 Ford Maverick Lariat Hybrid "Area 51"
2023 Ford Escape Hybrid
2024 Ford Mustang Mach Ex PEV

MikeSimon

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Re: Spark Plug Wires
« Reply #9 on: December 09, 2022, 15:39:44 »
Although my car is 52 years old, I have a pretty solid history including ownerships and can make a pretty good assessment of what may have been done to it. I bought the car in 1982 and have all those details for the last 40 years myself, of course.
The first owner was the wife of a fur dealer in Frankfurt and I have no doubt that the car was serviced during her 8 years of ownership at the Mercedes Benz Niederlassung where it was bought.
The second owners were a young couple who owned the car for 4 months only and had an accident with it, after they sold it to the person I bought it from, who owned a body shop nd bought it to repair and sell it. That is the period of unknowns, but it was in the late 70s when the cars were not "sought after" and original parts were plentiful and inexpensive.
The original reason for the post was, to solicit opinions of how I should handle the wires. Should I go all vertical or all horizontal?
Knowing that the Beru 1K horizontals are hard to come by, I could go all Bosch vertical (which may have been original?) I would like to know what cars the spare Bosch horizontals were typically used on. My car is not and will never be a show car and I am not necessarily a stickler for "original". Trying my best wherever it makes sense. But I would never go as far as duplicating "fender notches" during a repaint but I would like to preserve some unique and rare original features of my car, like the cylinder head for example
1970/71 280SL Automatic
Sandy Beige
Parchment Leather
Power Steering
Automatic
Hardtop
Heated Tinted Rear Window
German specs
3rd owner

Benz Dr.

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Re: Spark Plug Wires
« Reply #10 on: December 09, 2022, 22:01:12 »
Use ignition wires that contain the least resistance you can find. The ignition rotor is already 5K ohms and spark plug terminal should be 1K ohms. Try to find non resistor spark plugs Auto light 64 is what we use right now. I aim for 6K of total ohms for the entire system.

If you have the late USA CD ignition system you could probably use the 1K ohm 90 degree distributor cap ends. 
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

MikeSimon

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Re: Spark Plug Wires
« Reply #11 on: December 11, 2022, 13:30:32 »
Does anybody know what the resistance of the horizontal Bosch plugs would be that are in the last picture? I assume, they are from a later model car.
1970/71 280SL Automatic
Sandy Beige
Parchment Leather
Power Steering
Automatic
Hardtop
Heated Tinted Rear Window
German specs
3rd owner

Benz Dr.

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Re: Spark Plug Wires
« Reply #12 on: December 12, 2022, 03:44:43 »
Usually 1K. Junk you don't need. Resistors that work for AM radio that few listen to these days.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC