spark plug question

[Bb5280]

Getting ready to seal up valve covers etc - quick question on spark plugs.

Running a crankfire ignition (74 case - vintage racing build) and was wondering if any one had ideas on spark plugs - do they need to be anything special - I should have kept them when I tore the engine down but was a complete rebuild and just pitched them. Do I run the gap in the handbook or should I gap out a little? Thanks -

[rsscotty]

As far as getting any recommendations on spark plug heat range from the amount of information you have provided.......good luck.
Maybe Steve @ Rennsport would chime in and lay down the list for you.

[Bob Kontak]

Originally Posted by rsscotty

As far as getting any recommendations on spark plug heat range from the amount of information you have provided.......good luck.

I say factory recommended plugs with a wee bit fatter gap. Like thirty five to fourty thousandths.

Aftermarket ignitions talk of sixty thousandths but that highlights every weak point in your secondary ignition.

Once you get some burn time read your plugs and make a call. There are myriad posts here and elsewhere explaining that procedure.

[Trackrash]

If you post the details of your build in the Rebuild Forum, you may get some advise.

FWIW, I use NGK BP8ES in my 3,0 carbed hotrod. I'm using the CDI and stock gaps.

[Bb5280]

Originally Posted by rsscotty

As far as getting any recommendations on spark plug heat range from the amount of information you have provided.......good luck.
Maybe Steve @ Rennsport would chime in and lay down the list for you.

Thanks - not sure what is needed but here are some specs:

10.5 CR; Elgin 310/296 profile cams; twin plug; crank trigger ignition.

Hope that helps - I rebuilt the engine and comfortable w/ that but struggling with the ignition and the older nutek/crankfire system in the car (I did not install).

[T77911S]

you need to start with a cold plug and work your way up in heat range to find one that works best.