So I checked my plugs. - PeachParts Mercedes-Benz Forum

PanzerSD · #1 03-06-2010, 04:52 PM

...and didn't find anything out of the ordinary.
They all pretty much were all in the same condition (photo 1) and #4 (photo 2) was the dirtiest of all 8. All gapped good. cleaned them up put them back in.
They ARE Bosch Platinum plugs, and I hear conflicting reports on these plugs, saying they don't idle well. I did have some in another vehicle and I really didn't like them. If I replace, I won't be putting Bosch plugs in there. Any suggestions?

Tomguy · #2 03-07-2010, 07:37 AM

NGK non-resistor plugs. Bosch no longer makes non-resistors so you'd ideally want the spark plug boots from a newer engine (IE 420SEl or 560SEL) w/1k resistance instead of the 5k resistance you should have on yours right now.

http://catalog.peachparts.com/item.wws?sku=W0133-1641869&itempk=75979&mfr=NGK&weight=0.10

PanzerSD · #3 03-07-2010, 01:21 PM

They are 1k boots..says so right on them..made by Beru, of course..need to replace them anyway..

Why would there be a resistor in there anywhere? isn't full on, un-restricted spark energy a good thing?

Tomguy · #4 03-07-2010, 06:40 PM

Nope! You need resistance to help it jump the gap. Plus the resistors help reduce radio interference. With the 1k boots you should use the Bosch resistor plugs. Someone replaced your wire set with a non-OEM type. The boots usually last forever. The wires need replacing, not the boots. Screw the boots right on to new non-resistor (solid-core) wire of the same length. If you are going to replace the wires, maybe pick up the proper set w/5k ohm resistor and use NGK plugs - otherwise, Bosch resistor WR7DC or WR8DC.

GGR · #5 03-07-2010, 06:52 PM

I ordered Bosch plugs for My 3.5 and got the resistor ones. I also had to change my wires which were old and brittle and happend to have a salvaged harness complete with boots in good nick that had 1kohm total from one end to the other. Fitted all that in the car with new points and now it works like a charm.

PanzerSD · #6 03-07-2010, 06:56 PM

K, now I'm REALLY confused, and enlightened at the same time.

These Beru 1K 'boots' have the metal shield, but the wire is part of the rubber casting(?)
the coil wire is Bosch. Are the solid core wires, better or worse than say, something like Accel wires or the US aftermarket high performance wires? Which can be had (by me) alot cheaper than OE Bosch..

PanzerSD · #7 03-07-2010, 06:58 PM

Quote:

Originally Posted by GGR

I ordered Bosch plugs for My 3.5 and got the resistor ones. I also had to change my wires which were old and brittle and happend to have a salvaged harness complete with boots in good nick that had 1kohm total from one end to the other. Fitted all that in the car with new points and now it works like a charm.

Did you notice any improvements in mileage or drive-ability after that?

PanzerSD · #8 03-07-2010, 07:31 PM

Yeah, Ok I've done some reading, and I think I'll match NGK wires and plugs...

Tomguy · #9 03-07-2010, 08:44 PM

The plug connectors (boots) should be separable from the wires and, as long as the ohm values are still correct & they are not broken or corroded internally, it should all be good.

http://12.153.160.115/images/catalog/full/0001564110.jpg

PanzerSD · #10 03-08-2010, 02:21 AM

I have two that did pull out of the boot, but taking the top half of the boot with it. I sort of jammed it back in there and it works. Corrosion yes. Brittle, no, but it's all gonna get replaced anyway...
Cap and Rotor: If it cleans up easily, should it still be replaced? I didn't see any carbon tracking or anything in or outside the cap...