2 plugs per cylinder is fairly common.
My V8 has 2 plugs per cylinder, so I get to buy 16 every 30K miles.
The final diagnosis is that it was probably a spun rod bearing.
I got the car back today, it's great! :thumbsup: Even better than it was before. The total cost ended up being under $3K, and I had some maintenance items replaced while the engine was out.
Did you know that the Honda Civic Hybrid has 2 spark plugs per cylinder, so 8 total?
2 plugs per cylinder is fairly common.
My V8 has 2 plugs per cylinder, so I get to buy 16 every 30K miles.
I've yet to encounter a application where the oem plug wasn't the best choice. (Assuming there aren't any power mods)
Yes, OEM plug is plain old copper.
OEM plug was copper because that's likely what they had back in the day. Occasionally I've seen OEMs update suggesting the upgrade to something like platinum or iridium. The idea that because straight 30 weight oil was the only thing that was available when the car was manufactured making it the best oil for the vehicle is wrong. A multi weight oil would be far more desirable. However, if your concern is not enough ZDDP and your engine doesn't have a catalytic converter, then you'll definitely want to find an oil with sufficient ZDDP.
The main advantage of fancy plugs is they last longer so the manufacturer can have those 100k service intervals. There's nothing wrong with the performance of copper plugs.