Downgear

These have only about 35,000 miles on them and have developed a pretty crazy build up. Car is bone stock other than K&N intake/filter.
Almost looks like it has been lean and hot and I am curious what others have experienced. Should I replace these plugs?




Typical AP1 with 75k that uses around 1.5q oil between changes with compression of 220-221-220-214 as of yesterday. That plug was the worst and coincidentally pulled from my "loser" cylinder.

windhund116

Looks pretty good, for that oil usage. You use fuel additives? Change them and re-inspect after a few thousand miles.

Apex1.0

Insulator looks fine to me. A little oil buildup, but not bad. I would replace them, but not with stock. Buy the copper equivalent. It might be BKR7E??? You will have to search.

Why copper?

They make as much power as any plug. The freshest plugs always do.
They are cheaper.
They increase the service interval.

Why is the last point valuable? For someone like yourself (not afraid to do work), having a cheap replaceable plug makes it easy to monitor performance. I change mine every year regardless of mileage.

I guarantee you will feel a benefit if you replace those plugs. If you go copper, you can pull them and throw them out whenever you feel like it.

If you don't like working on cars, go with the OEM plugs.

nibble

if you are NA, it doesn't matter between copper or platinum. but if you are FI, I strongly recommend copper and change every or at least every other oil change.

following is some mishap 10 yrs ago i had to do some research on.

https://www.s2ki.com/s2000/topic/326...00+rpm__st__50

zeroptzero

Not bad overall. The deposits are ash from the oil burned in the combustion chamber, won't harm anything. If you could get oil consumption a bit lower it would help but everything looks reasonably normal otherwise.

Downgear

Good advice! Greatly appreciated. I am going to throw some new plugs in and I have switched back to OEM air filter.

I wish I could lower oil consumption but I have tried everything (different oils, pcv, tune ups) nothing seems to matter. The car just had a valve adjustment, runs fantastic and had great compression so I am "trying" to put it out of my mind.

windhund116

1.5 quarts between changes (5,000 miles?) is fine. No worries. Torque new plugs to 22-24 ft-lbs.

Good luck!

zeroptzero

^ I misread the initial post as 1.5 quarts per 1000 miles instead of 1.5 quarts between oil changes. I guess it depends on how many miles he puts on between oil changes. 1.5 quarts per 3000 miles is decent, 1.5 quarts per 5000 miles is really good for an ap1. I think 1.5 quarts per 1000 miles is the tipping point between normal and excessive consumption. But if the car is running well who cares, enjoy the ride.

Downgear

I should have clarified....it is 1.5q per oil change of around 4500miles. I can only assume it's just the nature of the engine and just add oil as required. If the oil consumption causes premature spark plug damage/buildup, I will just start replacing more often with copper as suggested.

Glad to hear the build up is just ash though and nothing out of the ordinary.

zeroptzero

That rate of oil consumption is really good, I'd say lower than average with average being 1 quart per 1000 miles on an ap1. You are probably getting more consumption in the one cylinder.

Ash deposits are nothing to worry about they don't damage the plug as they only build up on the outside surfaces of the ground electrode and centre electrode, the firing area of the plug is usually clean. The market has moved to some low SAPS oils with lower ash content for emissions reasons, but I'm not a fan.

I am not a supporter of 100k mile spark plug changes so I tend to replace my plugs more frequently than that. I'll run Iridium plugs and I change them every 2-3 years max.