Spark Plug Gap
 

What's the best spark plug gap to use on Bosch Super W8DC's (Made in India) going into a euro no emissions high compression (premium fuel) 117 V8 500 SEL engine?

Is rounding up the square tips with a file (old racer tip) produce better spark?

The gap is 0.9mm or 0.036in. Torque to 15 ft/lbs./20Nm.


As an aside I’d pass on the made in India Bosch and go for some made in Germany Beru 14 – 7Ds.

I've always been advised to square up the tips..

That aside, I run all my V8's @ .042..typically helps keep a nice idle.

Jonathan

No need to reinvent the wheel.

Install the Bosch plugs recommended by Mercedes.

These plugs will be correctly gapped as you remove them from the box and that gap will be indicated on the box. Check it, of course.

Perhaps not, but older Benz V8's are not renowned over for their idle quality.. Opening up the gap some is a generally accepted way to improve said idle quality.

Jonathan