Renault S1 Spark Plug Gapping

[My S1]

Yet another simple minded question.  I have too many spark plug gaps to choose from;

Shop Manual         Marchal 34HS   .025/.028"

Owner's Manual        Marchal HS   .023"

As installed in my car     Renault   .035"

I just purchased a set of NGK BP6ES.  What would you guys recommend for the NGKs?

[BDA]

When I looked into that it seemed like a pretty squishy subject. Presumably, your car ran with a 0.035" gap which seems like a lot to me. I think I'd go to 0.025" or 0.030". I don't have the same motor, of course but I run BKR6EIX or similar with a 0.030" gap". Not that much different from what you have.

[Bryan Boyle]

Yet another simple minded question.  I have too many spark plug gaps to choose from;

Shop Manual         Marchal 34HS   .025/.028"

Owner's Manual        Marchal HS   .023"

As installed in my car     Renault   .035"

I just purchased a set of NGK BP6ES.  What would you guys recommend for the NGKs?

Typically, the higher the coil output voltage, the wider the gap.  If you're running a normal 3 ohm coil, gapping in the .025-.030 range is probably going to get you to where you need be. 

It's not rocket science...you can set to the gap spec in the workshop manual and it will be good enough to get you going.  I think that the heat range will be more of a factor than the gap at this point, so, if you go with a good plug (IIRC, the original spec was Champion N7Y; I believe the NGK cross I used is BPR7ES I think yours are just a tad hotter...forget how NGK scopes their heat ranges...) and run it, the plug will tell you what is going on. 

Bottom line: it is not going into the old space shuttle main engine ignition circuit.  It's just a spark plug. 

[My S1]

Roger Dodger.  I'll go for .030" and play it by beer.  Thank you.

[jbcollier]

Wider the gap, the higher the required voltage to fire it.  The higher the voltage, the greater the current through the points to generate it.

35 thou is fine with electronic ignition and a 3 ohm coil.  With points, I’d stay 30 thou or under.  If your points seem to pit quickly, or change colour, set your gaps even narrower.

[My S1]

I'll hang onto your notes.  Thanks.