Never use Bosch on a Japanese Vehicle.. Same with Denso on a european vehicle....
Stick with what the manufacturer recommends, if it's NGK, stick with NGK, if it's Denso, stick with Denso, if it's Bosch, stick with Bosch... For what ever reason, if you use Bosch on a Japanese vehicle and Denso on a european vehicle, they don't run too well on it. My theory is that when the manufacturers are tuning their ECUs, they're basing it upon electronic devices not only sold with the vehicle but with what is commonly sold in their respective countries and electronics aren't all made the same, when you put in a different electronic device, it will output a given signal for a different scenario, however small of a difference, than the car would have expected to be. For example, for a given fuel mixture, a Bosch sensor may say it's 14.1 while the Denso might say 14.0 or 14.2, etc. People say Bosch is crap but it's usually from those who are installing it in their Japanese Vehicles.
Yes, those are the same plugs and are currently installed. I did wind up pulling the plugs from each of the other 3 cylinders and they looked clean compared to cylinder 1.
BTW, how many of you use the anti-seize grease on the threads? If so, every time or just when new plugs are installed for the first time?
I've been installing spark plugs and giving them a 1/4-1/2(at most) turn as a general rule since I don't have a torque wrench.
I tried the indexing(made mental notes etc) and I couldn't index these plugs FWIW. In order to tighten the old plugs it wound up being perhaps 10-15% more of a turn to get them back to being torqued down(by hand) compared to when I pulled them(so relatively speaking it made indexing harder).
There is no need for anti seize unless your plugs like to rust out and you have very poor maintenance habits with your car. Those spark plugs should not be difficult to remove at all in a few years time..
I use anti-seize. I wouldn't need to in northern CA maybe, but here in New England everything seizes within a year (and usually sooner).
I installed new plugs last year (or was it the year before?) on Christine (which I only started actually driving last fall). I took one out a few days ago to inspect and it came out easily. I didn't put new anti-seize on it and the old stuff looks nasty, but if I had taken them all out I would have.
Come to think of it I think I'll post a thread, see if someone can read my plugs, because I just don't have enough experience reading plugs.
Yeah but those vehicles have an iron block and head...The vehicle in question has a 100% aluminum engine so anti seize wouldn't be necessary. There really shouldn't be rust down there unless you have a poor seal over the spark plug holes which would mean condensation is getting in and possibly screwing with the spark ignition.
Use the anti seize and use plenty of it. Several years ago I had a plug seize in my '88 Escort with aluminum head and stripped all the threads out, but I was able to use the old plugs I just removed and lots of pressure on a spark plug socket and ratchet to tap the threads back into the head by only turning the plug about 1 or 2 rounds then removing it cleaning the threads out on the plug and repeating, it took some time, but was much easier and quicker than having to pull the head and take it to a machine shop. There are spark plug hole taps available, but it was too large to fit down into the pocket where the plugs sit. Ever since this incident I've used anti sieze every time I remove the plugs and put them back in and have never had any other problems with siezures.
I don't like the idea of using anti seize because it affects the electrical conductivity between the block and the spark plug. Maybe someone should do a test of electrical conductivty of the spark plug to ground and see if it's affected by the antiseize.. If it's not, then I guess it doesn't matter but since you're adding a foreign material, I'm concerned it will affect conductivity and reduce the strength of the spark.