I was just curious as to the average spark plug life is on your guys cars. I had to replace mine today after about 8 months and 7000 miles. Mine were toasted completely and replacement every 6 months it seems is the norm. So is every 6 months or like 6000 miles the norm for replacing the plugs?

 

i try to do mine once for three oil changes, or 7500 miles doing changes at 2500 intervals, and they are pretty eaten by then, could be due to the MSD Ignition box that I have as well though. Rotary engines do seem to eat plugs faster than piston engines however.

 

6,000-8,000 seems to be where mine need changing. that or when it floods, which usually comes first...

 

I was lucky if I got 5K on leadings for conventional NGK plugs, but trailings are usually around 15K.

But I do have CDI box on the leadings.

Normally I would recommend plug replacement every 10k-15k miles for a stock engine (and depending on air and fuel filter condition and oil changes).

I put Iridium plugs on the leadings and with the CDI box it looks like they should last to about 10-12K miles.

 

All of mine were scorched. I was curious as to why I was losing high end power becuase it seemd like I had plenty up to 5k then it kinda just bogged. The new plugs definitly fixed it. Anyway to buy these bulk?