How important is spark plug gap?

[doyall]

I just replaced the factory installed spark plugs on my [acquired this year] 2007 Volvo 5.0 GXi for the first time. I used the OEM ACDelco 41-993 plugs. The VP owner's manual specs a .060" gap. The plugs that came out of the engine had a gap of .050". There was no noticeable carbon build-up on the old plugs. The new plugs all had a gap of .050" out of the box. So, is there that much importance in a .010" difference in spark plug gap? Or maybe does ACDelco pre-gap at .050" and GM just slaps them in their engines without any concern as to what the gap is because it doesn't matter all that much?

 

[Another retired guy]

Re: How important is spark plug gap?

Difference between 050 and 060 not critical but I would regap to engine manufacturers specifications
Check this link for info on importance of gap

http://www.howrah.org/spark-plug.html

 

[Silvertip]

Re: How important is spark plug gap?

It is not the plug manufacturer that determines gap for each engine. One plug may be used in many different engines, all of which may require a different gap. Set the gap to what the application specifies, not what the plug manufacturer has set it to. High energy ignition systems may require .060" while an old point system may require .030".

 

[Glaspar_Fan]

Re: How important is spark plug gap?

It depends on how important getting the peak performance out of your engine is. (And whether or not that was the goal in the engine manufacturer's gap spec.) If it were me, I'd gap them per the spec. But if you already put them in the engine, don't sweat it - you'll never notice a difference. If you've never gapped plugs before, you might cause more damage that good by re-gapping.

Just my 2 cents worth.

John