40 V8 Sprak Plug Gap

[TomT/Williamsburg]

I have a stock 40 engine with a "Y" adapater and 2 deuces with progressive linkage in my 32 project - nothing fancy, just for the "look" of the early 50s. I'm running a crab style distributor, I'm 12 volts and running ballast resister.

Now, I'm nearly ready to fire the engine and my question is about spark plug gap. I've checked the engine specs and they say to set the spark plug gap at .025. But, it seems most are running .030 gap? I'm either going to run Autolite 216s or NGK 6BLs for plugs (that's what I have around) - the other set will be a spare set I'll carry.

Thanks for your help ....

 

[Henry/Kokomo]

I'd try the .025 gap first. If it starts and runs well, I'd re-gap and check for ease of starting, etc. Remember, the wider the plug gap, the more the spark hunts for a lower resistance path like in the distributor cap, between wires and the loom, between plug wires, etc. You might want to check JWL's book for other ideas.

 

[TomT/Williamsburg]

Thanks!!

 

[Buford]

I think .025 will work just fine.

 

[Ross in East Texas]

Also, the wider the gap the more load it places on the coil to be able to ionize the gap and initiate spark. This can, eventually shorten coil life.