[W126 Coupe] HELP! resistor vs. non resistor plugs

[Shayegan, Richard]

Bosch specifieD .032 I think is more accurate. The .9mm they ship with
is better.
Richard 

-----Original Message-----
From: mbcoupes-bounces at mbcoupes.com
[mailto:mbcoupes-bounces at mbcoupes.com] On Behalf Of Mister McGoo
Sent: Wednesday, September 21, 2005 9:24 PM
To: mbcoupes at mbcoupes.com
Subject: RE: [W126 Coupe] HELP! resistor vs. non resistor plugs

Tom;

I didn't see anyone reply to you. (Maybe I missed it.)

DO NOT USE RESISTOR PLUGS.  The resistance is already designed in.

Bosch specifies a spark gap of .032 throughout, not .040.

If you can't find Bosch plugs anywhere, you can use foreign plugs like
Champion N 12 Y, or cross reference to NGK.

I'd try .035 +/- if you are burning oil.

If you have the AC Rapid Fire #4 plugs are you sure the cap doesn't
unscrew from the lead stem?  Use pliers gently to try unscrewing.  I
have never used them and have no information on them.  Obviously someone
here has used them and thinks they are slicker'n snot.

If you have a Mercedes Benz Dealer in the vacinity, and if you are ever
unsure of what you are being told, try asking the service people there.

Don't be shy. Remember, you are a potential customer for them.  If they
refuse to go out of their way to help find your answers, Mercedes Benz
want to know about it!  I know.  (Just don't try it every second day.)

-Bellamy



>From: "Tom Oelsner" <toelsner at mindspring.com>
>Reply-To: Mercedes Coupes Mailing Lists <mbcoupes at mbcoupes.com>
>To: <mbcoupes at mbcoupes.com>
>Subject: [W126 Coupe] HELP! resistor vs. non resistor plugs
>Date: Wed, 21 Sep 2005 17:14:21 -0700
>
>This afternoon I replaced my plugs to see if I could smooth out my idle

>that occasionally ran a tiny bit rough.  RH...you cannot use Rapid Fire

>#4 plugs as they have a one piece top that does not mate with the Bosch

>wires.
>Also,
>AC Delco says do not use any anti seize lube on threads...
>
>So here is my problem.  The parts store did not have W9DC plugs in 
>stock but had WR9DC (resistor built in).  I queried him really hard 
>about them and he said they would be fine and would not impact 
>performance.  So I gapped them to .040 and put in new ignition wires 
>(even though the old ones were only a year old, I broke one pulling it.

>So I replaced all.).  Well the car idles really badly.  This is in 
>spite of the fact that 3 of the older plugs were really fouled.  So my 
>question is obvious.  Are the resistor plugs causing rough idle 
>problems?
>
>Tom Oelsner
>90 560SEC
>
>
>The MB Coupes Website!
>W126 SEC Mailing List
>Postings remain property of MB Coupes, L.L.C.


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