Well bolstered and encouraged by the support and education of my BITOG brothers I removed the spark plugs today. I have never done a spark plug job on a car with coil packs so it was as an interesting experience. I was meticulous about cleaning all sand and dirt away from the coil packs before removing them. I had to zip tie connectors and other peripherals out of the way so would have an unencumbered access to the plugs. Coil packs came right off. To my pleasant surprise, there was zero dirt/sand actually down in the spark plug holes but I gave each a good blast of compressed air by taping three of those straws together so it would reach way down into the hole.
For the first three, I cracked them loose about 1/4-1/2 turn. Here I appreciated the tip about attaching the spark plug socket first to get it well-seated and THEN attaching to the ratchet. I probably would have done this anyway, but thanks for that tip. It definitely took a considerable but not too excessive amount of tug on my 3/8" ratchet and certainly more than 18 or so ft lbs speced to tighten them and I was pretty nervous about having to apply that much tug on the ratchet but it slowly gave way as I carefully bore down on the shaft on the extension. However, it probably felt like more torque due to the short length of the 3/8" drive ratchet. I don't know. I did not put any penetrating oil before starting as it seemed folks here thought it wouldn't make it past the tight gasket and I suspect they are right. After loosening the first three 1/4" or so turn, I drizzled down a few drops of PB Blaster letting it run down a long screwdriver right to base of the gasket. I let it set a few hours. In the meantime, I tackled the rear three which were somewhat more challenging to get to simply reach-wise but not terribly difficult. I found that after getting those loose by about 1/4-1/2 turn, they spun out relatively easily so didn't mess with the oil. I wrapped up the afternoon by wrapping a paper towel around a screwdriver, dipping it in isopropyl alcohol and then inserting it down into the spark plug hole to carefully clean any residual penetrating oil and debris from where the new plugs will contact the top of the cylinder.
A few questions now:
1. My only regret is on the first one after breaking it free by about 1/8" of a turn, it seemed so hard to turn that I thought perhaps retightening it to just short of the original location might help break free crud in the threads. I did not
apply oil before retightening. I didn't do that with the others and just maintained steady CCW motion, in between repositioning the ratchet handle for another short swing. Should I be OK with that first one?
2. I tried in vain to get a good look at the threads. They are so deep it was really impossible to get a good side-on view of them. I have a very tiny inspection mirror I was able to insert down the spark plug hole shaft hovering over the threads. They seem OK as much as I can see.
3. No need to do any thread chasing right? Would it be a good idea to run each new plug into finger tight point and then pull them out again to sort of clean out any crud in the threads? I would wipe out the treads of the spark plugs of any debris collected.
4. NGK states that with anti-seize to reduce torque by 20%. I got to thinking that having used a few drops of penetrating oil in the first three which now is certainly on the threads, does this now act like anti-seize such that I should drop the torque down by 20%. My manual says 14-22 ft lbs and I was going to torque to 18 ft lbs figuring mid point was good. That is still almost 20% lower than top torque so I'm guessing I will still be good at 18 ft lbs. I plan on inserting the new NGK plugs (same ones that came out) dry per NGK instructions. I could detect no trace of antiseize on the threads although maybe a small amount would be undetectable anyway. For sure, I will never wait this long again to do this job although in all honest with about 76k miles on the car and about 3-4k miles a year, not sure I'll even be around when it comes due for the next change assuming the car is still running then anyway - but it is in spectacular shape so who knows!
5. the top of the pistons were pure black (if that is what I was looking at). I didn't really know what to expect here other than I know folks like to look at them when they remove plugs and even insert borescopes down for a better look.
Attached for your viewing pleasure that only a member of this forum could appreciate are some nice zoomed in photos of one representative plug from various angles and a new identical one. I was really interested to measure the gap thinking it was perhaps at least 0.005" larger than spec but to my surprise they were at most about 0.002 off the high end spec! I was hoping that the gap had really increased and that new plugs with the resotred gap would provide more hp now but perhaps gap change alone is not a reason to change plugs as I have read on this forum resistance changes too so we will see. I read on the NGK site that new spark plugs really don't increase/restore hp but rather fuel efficiency. I have read on this forum some folks experience a real or perhaps perceived hp/performance change. The tip was definitely not sharp like the new one although who knows if the NGK design has changed since 1995. The electrodes look tan like I read is a good sign.