Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: merrill on July 11, 2020, 12:43:03

Title: spark plug gap inquiry
Post by: merrill on July 11, 2020, 12:43:03

hello All,
after following the "spark plug discontinued thread"
https://www.sl113.org/forums/index.php?topic=31179.0

and then some additional reading using the search tool (link below)
https://www.sl113.org/forums/index.php?topic=30312.msg219498#msg219498

I decided to go double check my ignition wires to make sure i was setting up my spark plug gap correctly
for my 66 230sl.

the car has a bosch red coil,  1.8 ballast and turns out my plug wires are 1 ohm resistance not 5 ohm.

my inquiry is what is the proper gap to use for this set up when installing non resistor plugs (w7dc) with 1 ohm wires?

I suppose with my current set up i suppose i could use resistor plugs since i only have the 1 ohm wires...

thanks i advance
matt

Title: Re: spark plug gap inquiry
Post by: merrill on July 13, 2020, 13:35:11

i think i will give .35 a try.

after reading many threads and the various manuals is seems .35 would be ok


since i have a red coil , 1.8 ballast non transistorized ignition i have some leeway to increase the gap.

my haynes manual recommends the spark plug gap be set to the following.
for non resistor plugs .28 to .32
with resistor plugs .35 to .39

Title: Re: spark plug gap inquiry
Post by: merrill on July 13, 2020, 14:52:08

interesting i found a spark plug chart in an old chilton manual. 

they reference champion spark plugs with a gap of .020"  (picture)

Title: Re: spark plug gap inquiry
Post by: merrill on July 14, 2020, 13:00:42

just for fun i sent this inquiry to Gernold at sl tech.

he said to use. 8 mm or .0314"

Title: Re: spark plug gap inquiry
Post by: wwheeler on July 14, 2020, 15:14:42

I have similar ignition equipment and that is close to what I have run for years. Mine is .031". Can't quite get the last .0004" though.  ;)

Title: Re: spark plug gap inquiry
Post by: Benz Dr. on July 14, 2020, 17:15:38

I run .032" or whatever the stock plug is set at. 

.020" is too close.