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Spark plug gaps 1917 Roadster Model 'R'


Stutz in the UK

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Just a thought, can anyone advise on spark plug gaps please?

I have a Bosch Type ZR4 Dual ignition setup on my car

This means I only have one set of plugs (4, one each cylinder), but two ignition systems (battery / trembler for starting) and Magnito for normal running

Can someone advise me of what spark plug gaps I should run with please?

Thanks

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Stutz wasn't much help on this kind of info. It wasn't until the 1920s that Stutz started a service manual and by then they had gone to distributors rather than magnetos. I think they expected us to go to the supplier of the specific component, ie: carburetor manufacturer for carb info, Bosch for magneto info, etc. This is from the Bosch Encyclopedia, their manual for parts, service and application. Be careful that you do not exceed .035" as it puts undue stress on the armature winding insulation. This info is for most magnetos, NOT 2 sparks that fire 2 spark plugs per cylinder.

post-34894-14314242371_thumb.jpg

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Thank you Layden, I will try a .030 gap, my plugs were set at .015 right now, I am wondering if this has been adding to my rough running at hogher speeds (i.e. wider throttle openings, more fuel than a .015 gap can ignite easily)

I will report back - the cars is definately better with the water heating (manifold) pipes back in place, I think the frosting issue has been resolved

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Hi Layden, we ran the car today for about 20 miles and it ran fine - the spark plug gas are now .030. So far so good. As you say many issues (and in most cases fun and satisfying to fix). It was very cold here today so we came home to get warm. I will try the car on a longer run at the weekend and see how it goes. Thank you for your replies and help!

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