what's the correct spark plug gap for a 300e
(bosch copper plugs)
thanks for the info.

Mercedes suggests 0.8MM, however most dealers set them to 1.0mm.

What is that in imperial please?

I think it is about .035"

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

0.8MM = 0.0315 INCH
1.0MM = 0.0394 INCH

Here's a handy webpage for doing unit conversions:
http://www.speckdesign.com/Tools2a.html

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Bill Wood - Webmaster
MercedesShop.com, LLC

I just changed my spark plugs on my 86 300E, purchased Bosch Copper Cores, I have gapped the plugs at .032, what would happen if I change the gap to .035 or .040?

thanks



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85 911 Carrera
81 300SD
86 300E
95 325i

If you have a weak link anywhere else, like the cap, rotor or coil, it will show up quicker.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Opening the plug gaps to 1.0 mm(.040")will make the car idle much better. It exposes more of the air/fuel mixture to the spark and uses a bit more of the potential current from the ignition system without overloading the coil. The only complaint I've ever heard of was one customer that said the wider plug gaps lowered the top speed of his 560SL by 5 mph. I use a modified ignition system from the mid-eighties on a 69 300SEL 6.3 and run the plug gaps at 1.4 mm with no problems.
Try it...it works.
Randy D.

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W.R.Durrance
ASE Master Tech
Mercedes Tech 19 Years

On my race car 190E 2.3 I use (copper core) Beru plugs w/4 electrodes. Gap is set at 1.4mm. Complete flame travel allows for complete combustion in each cylinder. On all but the newest of cars stay with copper core plugs.

Hello,

Sorry to rekindle this post which dates back almost 3 years ago. I'm about to change my plugs on my M103 300CE and most forumers have suggested 0.04'' gap. Is this the maximum we can gap our plugs? The rest of my ignition system is brand new.

Thanks.