[Skyline] PRP R35 coil conversion

The next modification on my plate was an upgrade to the stock ignition system. The stock coils and stock harness have a tendency to cook underneath their cover, particularly after 30 years of use, which can cause misfires and rough running at higher RPMs. I had noticed this, and while some of that could be attributed to the timing issue that ZCG identified and corrected, I figured it was worth an upgrade anyway. There are a few different options for the RB26 - some developed for this application specifically, others retrofitted from other vehicles (Audi R8, GM LS series, Nissan R35 being the most popular options in that category).

I selected the Platinum Racing Products kit, which uses the factory R35 coils, largely because their complete kit fits under the factory cover and requires no modifications and really no compromises. They've also done a great service to the RB26 community with testing and research. Here are some useful links on the topic:

PRP: R35 versus Yaris coils
PRP: R35 conversion product page
PRP: Installation instructions
Sean Morris/GTRusablog: harness crispy like bacon
Sean Morris/GTRusablog: ignition system info

OE R35 coil and approximate length (camera distorts a bit, but it's ~150mm overall)

The complete kit includes OE Nissan R35 coils, PRP's unique stalks engineered to seal the spark plug wells, a complete harness, mounting bracket, and required hardware.

Installation requires a little modification to the factory R35 coils, so I wanted to include some detail on the installation process for curious minds. The R35 coil just pulls apart with a bit of twisting.

Disassembled R35 coil. The spring needs to be trimmed down ~5mm for the new, shorter stalk.

Stalk length comparison.

You will need to trim 5mm from the original spring for RB26 fitment. You will notice that the spring is symmetric, with a larger diameter portion in the middle. You want the trimmed end to point toward the coil end, not the spark plug end.

Ready for reassembly. Trimmed end of spring visible, ready to fit up against the resistor.

Ready to rock.

Installation was straightforward. A hard copy of instructions was not included, but there's not much to figure out. Disconnect the harness, unbolt the stock cover and igniter, and thread it all out so that the cover comes free.

Stock.

Unplug the harness and release it from the bend-over retainers. Unbolt the brackets carrying the stock coils and pull them out.

This is a good time to inspect the condition of your plugs and check that they're gapped correctly. Bolt in the PRP machined bracket. Coils go next, then harness.

Things get really tight at the back with the harness. I had to stuff the harness a bit under the final coil to get it all routed out the back of the stock cover. PRP would do well to add another 20-30mm to the main connectors back here to make this easier. In the photo below you can see the ground coming out of the body harness - this was originally tied in to one of the igniter mounting screws. With the igniter gone, I found a shorter screw and fastened the ground to one of the igniter mounting bosses on the factory cover.

Ignore the fact that you can see the OE igniter in this picture, exposing me as a fraud. That's kind of the point though, pre- and post-install it looks the same.

Rob had a little surprise for me after I brought the car home - a robin's-egg-blue Nissan OE oil filter. I guess the color wasn't selected with a filter relocation kit in mind.

I was not expecting a big or particularly noticeable bump in performance from the R35 coils, especially after Rob found my car's incorrect timing and alleviated some of the symptoms that had made me order this kit in the first place. However, I immediately noticed an improvement in smoothness and response from the motor. It simply revs more smoothly through all RPMs, and it's particularly noticeable on rev-matched downshifts. The blips are quick and clean. It wasn't bad before, but there is suddenly a silky smoothness I didn't know I was missing. Cool!

What's next for the Skyline? A clutch. The more I drive the car, the more the clutch bothers me. It's an OS Giken twin-plate unit, and the plates are sticking together. This means that the bite/engagement point moves around on me, which is frustrating and makes me look like I don't know what I'm doing. Without a clean and reliable clutch action I find myself clunking through the gears. I thought that I needed a new transmission, but I am beginning to think that what I perceive as rough shifting and worn synchros is actually caused by poor engagement and disengagement of this clutch. On top of that stuff, the twin-plate rattle drives me crazy and the pedal is way heavier than it needs to be.

I am going to stay close to stock power levels, so I'm eyeing a Nismo single Coppermix clutch. I believe that Rob is installing one next week on a local GT-R, so I'm hoping that the owner is willing to let me drive the car around the block and confirm that I like how it drives. It's a big job to get to the clutch so I want to know exactly what I'm doing before ordering parts or grabbing a wrench. Stay tuned.

[Skyline] Let's let someone else turn the wrenches

I took my car over to Custom Alignment in Mountain View to get everything squared up after dropping the ride height. This was 3/5, or "san-go" day, a celebration of the R35. I parked my car next to its great-grandkid.

Unfortunately the news was not all good from Custom. They informed me that they would not be able to align my car, because the front-lower ball joints and upper link bushes are worn. With these issues they did not feel it could hold the alignment, so it wasn't worth the expense. I was a little bit irked by this because I hadn't noticed a huge amount of play on the front wheels in my short period of wrenching.

Better luck next time.

I can't stay mad at that face.

I added "check bushings" to the list of items that I wanted inspected just a few days later, when I took the car to Z Car Garage in San Jose. I hit it off immediately with Rob - we ended up talking a long time about a lot of cars that weren't Nissans - and I was excited to have his experienced eye look over my car.

I thought these were rare?

At this point I would like to point out that Rob and his team have a staggering CV when it comes to Nissans, more than I can cover here, so I absolutely encourage you to check out their fantastic blog, as well as their feature on Speedhunters. Rob and co. owned a MotoRex R34 GT-R back in the day, how's that for street cred?

I took the car in for a general inspection, to figure out what exactly I've gotten myself into on the oily side of things. I had a few specific issues I wanted reviewed (i.e. bushings) and also asked Rob to install my Nismo braided brake lines. I've done braided brake lines on a few cars, and I have learned to avoid handling brake fluid when I can. So, what did I learn?

• "You have a really, really nice car!" This is the best news I've ever received from a shop in a phone call. That being said:
• My clutch is a twin-plate OS Giken unit, and Rob suspects that the plates are sticking. This feels correct, based on the way it drives. This is next on my to-fix list, the rattly, heavy, inconsistent twin plate is driving me nuts.
• Timing was out - Rob fixed it which cleaned up the mid-range and top end.
• Plugs were gapped incorrectly - fixed.
• Rob confirmed that the items Custom pointed out are worn, but disagreed with the assertion that the car would not hold an alignment. So, he performed an alignment.
• Oil change, brakes bled with the hose installed, clutch adjusted, transmission fluid changed.

Rob and his team wrote a nice blog entry with some photos of the work in action, you can read there right here. (I do not like to post other peoples' photos on my page if I can possibly avoid it)

Another GT-R fresh from Top Rank. R33 GT-R wheels suit it well.

Rob had me run the car around the block before we settled my bill, which is a first for me when working with a shop and a cool signal of pride in his work. A half hour disappeared while we talked about the car and what I had in mind for it, and what plan we could come up with to make it the best little R32 it can be. I have some ideas and I'll be returning to ZCG in the not-distant future.

JDM golden tint, yo.

This wet weather is finally starting to break, and spring is around the corner, which means one thing: Cars and Coffee. I went to the second Menlo Park Cars & Coffee in so many weeks, going so far as to park in the same exact spot in the same lot. This time I rallied Michael and Miles and we did a little caravan action.

The GT-R is frequently a crowd favorite, even in the Bay Area car scene where a Model 3 is a beater and there's a GT3 in every hedge fund parking structure. I think the Skyline strikes people as a "hero car" of sorts, something special built off of a standard-production platform, yet more than the sum of its parts. The video game lore and racing accomplishments only enhance the appeal. Half the fun of owning a car like this is the opportunity to meet other people and share the car with them.

Michael and Miles were both nice enough to let me drive their cars around the block. My mission was to feel the stock clutch, and also get a baseline for how the car is supposed to shift. Their generosity gave me a data point as I select a new clutch to replace what I've got.

I came home to a special package from Australia - installation in my next entry.