I purchased my Skyline in November and noticed that at High RPM, I'm getting some odd engine knocking. Since then, I stored it for winter and never reved past 4000 rpm. I plan on sending it off to paint now and I starting taking it apart and decided I'd look at my plugs just to see how they looked because the previous owner said they were due when I bought it.
Upon first inspection, the plugs didn't seem too fouled and the gaps weren't abnormally large. I then decided to shop for new ones using the code that was on them to get the same ones or equivalent because I figure that whoever put them there did the research too. My mistake. I was running Bosch FR6DP1X Spark plugs which have all the correct specs except the height. There are 2 types: ISO and JIS. These were ISO which are a few mm shorter than the JIS spec. Uh oh.
After realizing the plugs were wrong, I carefully observed the top of the plugs and noticed corrosion and some pitting. New spark plugs were required. So after more research, I decided that I was going to purchase the NGK 5691 which are also known as BCPR7EIX-11. Great!
Since I have the coil packs off, I figure to myself that I will take the time to test them. So I take out my trusty multimeter, set it to Ohms and check the primary coils. The spec is from 0.6 - 0.9 ohms. They were all perfect. Yes! I then proceed to taking the rubber boots off to inspect the leads. Fudgesicle. Here's what I found:
Long story short, Make sure you run JIS spec Spark plugs in your Skylines and Never trust that someone else did the research.
I do have a question, Does anyone have pics of the internals of their OEM coil packs so I can compare? I've been speaking with Paul at Performance Wise and he showed me the internals of the Yellow Jacket Coil Packs that he sells. They don't seem to have a lead at the end of the spring (I dont have any leads on Coil 2 & 4, but the rest seem to). Thanks for the help. Cheers!
DynamiX