1. Just brought a new set of Spark Plug Wires set from the dealer for a 88 260E. It came in the Mercedes-Benz box with the “Silicone Spark Plug Wire Set” and “Custom Tailored” printed on the box. PN# is Q-4-15-0027. When I looked inside the set were made by Bosch.
2. I thought the Beru was the original replacement. Because when I’d replace the set in my 190 a year ago they where Beru.
3. I’ve read on one of the post that Bosch supplies Spark plug wire sets both OE and in the aftermarket. The aftermarket is sub-standard (to OE) quality wire & ends. At the dealer sometime they get these aftermarket quality wire sets from Bosch.
4. How can I be sure that I got the OE quality Bosch set and not the aftermarket sub-standard ones?
5. Could I tell by looking at the wires itself, because the box that it came in is just a box.


Thai GI sends...

__________________
GI but not GI Joe
They call me "The Thai GI"
Thai in the US Arsenal

IF the wires are COPPER core then that is OE style! IF they are braided fiber core then that set is AFTERMARKET!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

MB DOC... Is there a noticeable decrease in performance with the aftermarket? Silicone braid wires have been around for a long time and work well on other cars.

The copper core wire sets last on many cars for over 10 years!! If fact I've seen cars 25 years old with the original sets!
The aftermarket Bosch don't last even 5 years. THAT is all that MB used to supply to the dealers in a complete set. But now they ARE back to copper cores!!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

The copper core wires never "wear" out. They often get destroyed by heat or chemicals. The TVRS carbon core wire used in US style wiring is responsible for the common conception that replacing wires is a maintenance item. The european style of wires never need wholesale replacement; only the necessary repairs. Occasionally I will replace all the ends where I have had more than one fail. They are easily seen on a scope when bad.

The part that goes bad is the resistor end that goes on the plug. These are easily replaced and the Beru ends are easily available. The job is cheap and easy.

My trick for replacing the ends is designed to save the wire. The wire has a metal "male" screw made to it (which is also available separately to repair those done in haste) which screws into the "female" connection inside the plug wire end.

I slit the rubber boot on the end and peel it back. this uncovers a white ceramic insulator. I wrap it with a rag and squeeze it with strong pliers/visegrips till it fractures. Pick away the pieces (watch they are sharp) and you will see the metal connection made to the wire. This can now be grabbed and the end turned from it. If you turn the wire from outside the boot the wire will probably break from the metal end instead of unscrewing properly.

Since the end is being thrown away a little destruction can save having the wire end ruined. By doing this instead of wholesale wire replacement one saves money, restores the original ends, maintains the factory coverings and solves the electrical problems.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Mine (103 engine) developed a misfire condition. I used the "Shadetree Scope" to diagnose cracked and torn Beru ends on three wires. Upon inspection I found that someone had improperly pulled the wires at some point, probably with a pair of needle nose vise grips. Aware that the ends were replaceable, I began to pull each wire and check the resistance. One of my wire ends pulled loose at the distributor and separated. Thinking I might as well replace the whole set I purchased a replacement . They are fibercore so I'm stuck with them for a while. I just wondered is there a "performance" reduction.

The performance of solid copper core is hard to beat.
If one goes with resistance wires, you can not use the Benz resistor ends or you simply wind up with too much R.
But the real reason the Benz solid core /resistor end wire setup is hard to beat is that resistor wires ohms are by the FOOT. So, each wire will have a different resistance according to length.
Whereas , Benz solid core wire has trace ohm and length difference is of no concern.
By putting the resistors on the ends, all plugs
get equal voltage, equal resistance.
Plus , being solid wire [ actually stranded ] , they last as long as any copper wire will [ very long]

OKAY OKAY!! I'm sold on longevity. Will my motor suffer any noticeable depreciation in performance ?

Nah...
As long as you didn't use resistor plugs....

I say that only because I have seen it done ...

HALLELUJAH!! I'll be able to sleep tonight! Alright boys and girls... let this be a lesson... make sure you get solid core wires. Don't do as I have done even though you can get away with it for a while. By the way, isn't anyone curious as to what the 'Shadetree Scope" is?

Well, I hope in isn't the kid next door ?????

" OK Johnny- that one seems fine. Get up and how 'bout tryin' the next one? "

No.. That's the Redneck Scope . The Shadetree is waiting till dark and starting the engine, raising the hood and watching for electrcal arcs around the wires. Then grabbing that wire to confirm electrical leakage. You can forgo step two if you like.:p

I still use the nite -time one..
Problem with it is when you put new wires on and you still see 'em faintly jumpin.
Pretty hard to get perfect ones

That's why it is best to cross them at right angles instead of side by side......

Keep them away from as much ground path as possible.

For M.B.DOC,

1. Printed on back of the box it described some tech data with “COPPER CORE WIRE” references.
2. The wires themselves are gray with white writing stating “BOSCH-7MM OPTI-LAYER COPPER CORE ULTRA-PREMIUM”
3. So these are the OE like you described yes?


For Stevebfl,

1. What title is a Bosch Master?
2. Do you get certified for this every few years?
3. I’m a network tech we have “Associates”, “Professional”, then “Expert”. I’m sure it’s different in the automotive world.


Thai GI sends…

__________________
GI but not GI Joe
They call me "The Thai GI"
Thai in the US Arsenal

Thai,

Actually the auto repair industry in the US is probably the least standardised/regulated industry around. I have often said: "if you wanted to exist as a fugitive and earn a living the best place would be auto service or farm labor".

I think this is a result of the extent and variety of techniques and technologies involved not the other way around.

The only real criteria of meaning in the US is the ASE testing/certification. Master means you have passed all 8 levels that have been tested since 1973. I passed my Masters in 1973 while working at a Chevrolet dealer during my fifth year of engineering school (B.S. Metallurgical Eng UofF 1974).

A number of years ago the catagory L1 was added. It is advanced level engine diagnostics. It is required in emissions testing states/communities for local smog certifications.

The status Bosch Master really only refers to the fact that one has passed the first five levels of Bosch training and has proven training in basic electronics. The training is valuable and in Germany (where auto techs are definitely regulated) it is one form of accepted certification (I've been told - by Bosch training people). I have been through all 6 levels of Bosch Training.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician