Datsun 510 and Z car love
Dirk bought his first Datsun in 2014, a 1970 510, to learn how to work on cars himself. After learning more about the history of Datsun, and the significance of both the 510 and the 240Z in establishing Japanese cars in the American market, he knew he had to own a Z as well.
A year later, the right Z showed up on eBay in Texas, a 1973 silver gray one. Nice to look at, mostly stock, but not so nice that it’d feel bad to drive and streetpark. And after pouring over the photos and talking to the seller, Dirk bought the car sight unseen. The idea was to have a nice Z to enjoy and drive, while continuing to work on the (sometimes not) rolling restoration of his 510. The car was lovingly restored by a dad and his children and in mostly stock condition.
The tires were a bit old, so some sticky Bridgestone tires were acquired, which revealed the suspension as the next weak spot. T3 coilovers were installed, and the next weak spot was the open differential which Dirk broke driving the car around a hairpin on Page Mill Rd. He bought a limited slip diff from a late-model Subaru, modified it to fit and kept driving the car. The original plan had gone awry, and the Z was both driven and worked on a lot more than the poor little 510.
After many more tweaks, different induction setups, spring rate changes, rebuilt stock brakes, and 24K miles of driving including a few track days, Dirk’s Z was inching closer and closer to his vision.
“After installing a Datsun Spirit STR-3 engine with a set of Nismo Mikuni PHH44 carburetors, the biggest weak spots left were the rest of the drivetrain (especially the stock 4-speed transmission, but the Subaru diff had also developed some bearing issues), the stock brakes, and of course the loose nut behind the wheel – but sadly that last component typically takes too much money and time to modify thoroughly.”
After comparing the Z to his Subaru BRZ on the track, it was clear the Z was better at everything except for shifting gears. Since his engine made a healthy amount of torque, but not enough to warrant a CD009 (350z) transmission, Dirk kept looking for alternatives. He also wanted something with slightly closer gear ratios to better suit the engine’s power band. An S15 Silvia 6-speed seemed like the perfect fit. It had almost exactly the same weight and dimensions as the original box, nice close gears (in fact identical to those of his Subaru), and Dirk found a HybridZ member who would modify the bell housing for him to make the box fit an L-series engine.
S15 6-speed transmission
Through mutual friend Brian K, Dirk got connected with Rob at Z Car Garage and they immediately hit it off:
“After I bought and installed a set of their amazingly well-built CV axles, it was clear to me that ZCG’s reputation for high-quality work was very well-deserved. If I didn’t get the chance to work through the project myself, this is who he wanted to do it for me. I was excited to work with ZCG to take a few ideas over the finish line.”
We fabbed a transmission mount installed the 6-speed unit:
When we got to the clutch of the Datsun Spirit 3L we noticed that the rear wick seals were leaking from at the back of the last main cap. The wick seals were removed and replaced properly:
“The S15 transmission fit surprisingly well. ZCG built a custom crossmember to locate it, and the shifter lined up almost perfectly. No transmission tunnel mods were necessary. The modern shifter did stick out like a sore thumb in the otherwise period interior, so ZCG went to town on it and built Dirk a custom shifter that would look stock, and that works with the Datsun competition shift knob. A small 6-speed shift pattern sticker modeled after the one used in the Silvia is the only clue there’s something different going on under this car. And of course the driving experience.”
Making the S15 shifter look factory, we are happy with the result and Dirk’s subtle shift pattern sticker:
The Datsun Comp shift knob complements the steering wheel:
Engine Bay and Sorting
After a good long chat, a baseline dyno run, a drive, and going over the various odds and ends in the car that were on Dirk’s wishlist besides the 6-speed project, Rob become a great collaborator in further refining Dirk’s vision for the car.
“We actively talked about my goals, and Rob shared his opinion on how to best achieve it, and really talked through the pros and cons of various options. Along the way, Rob was able to source some really choice parts to take the car to the next level.”
A beautiful competition oil pan was installed to maximize ground clearance, and a new custom-built PCV system helped mitigate oil fumes. ZCG also deleted Dirk’s aftermarket A/C system that never worked correctly, renewed all fuel lines, tested the fuel tank, and recreated the expansion tank setup that was deleted by a previous owner.
Rob and Dirk were not crazy about the Arizona Z Car oil pan. It was removed and replaced with DP Nismo comp pan from Rob’s parts stash:
Chassis and Driveline Upgrades
Together we found a balance between taking the car a major leap forward, while also leaving a few major areas untouched for a future revision, to keep the budget under control and get the car ready to enjoy for the summer.
“We landed on a ZCG-built 4.11 OS Giken limited slip differential, a custom aluminum driveshaft, a Fidanza Aluminum flywheel and a Jim Wolf Technologies clutch to round out the drivetrain project, and the entire drivetrain works together beautifully as a perfect package. The car is quick out of the corners, there’s no longer a need to go down to first gear on Page Mill Road, and it still has long enough legs to be quiet and comfortable on the freeway.”
We changed the final drive, installing a R180 4.11 OSG LSD built in in-house:
The clutch hydraulics were replaced to work with new alumimum flywheel/JWT HD clutch combo:
Dirk had a GPS speedometer setup from SpeedHut that we helped setup and read accurately:
Dyno Tuning
Rob massaged the Nismo Mikuni carbs, and after a dyno tuning session, unlocked an additional 30 whp from the car over the baseline run and the car is now putting down a healthy 200hp/200tq at the wheels.
Enjoy the dyno video and L-series music!
“To make sure the car was ready for the track with almost twice the power at the wheels over a stock 240Z, ZCG also installed their big brake kit, which has improved front to rear braking balance significantly over the stock setup, where the rear drums feel great for a week after adjusting, and then become mostly ornamental. The brakes feel a lot more reassuring, while remaining easy to modulate, and thankfully without being overly grabby, the car is still incredibly easy to heel and toe. As an added bonus, it’s really nice to have a handbrake that will hold hills with ease.”
ZCG Big-Brakes and CV Axles
Calipers: Stoptech ST42 4-piston front & rear race calipers (Alum 6061 mil-spec Type III anodized)
Rotors: 280mm x 20.6 with Alum 7075 hats
Pads: Stoptech 309 sport street pads
Blog posts documenting all of our customers running the ZCG Big-Brakes can be found HERE.
A few closer detail shots of the calipers, rotors and hardware:
We removed Dirk’s stock brakes and installed our ZCG Big-Brake kit.
At the rear, the factory drum brakes were replaced with our ZCG Big-Brakes. Factory handbrake functionality retained!
Also visible on Dirk’s Z are the excellent adjustable lower control arms from Techno Toy Tuning.
The Z got a full alignment, though tackling the suspension setup is on future list of projects:
Enjoying the Ride
Dirk continues to enjoy his Z which is now equally at home on the street and track. We enjoyed working you Dirk and it was rewarding to help you improve your Z.
Enjoy these pictures of Dirk Enjoying The Ride and of course more photo documentation of our work in the gallery below. LONG LIVE THE Z!
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- Processed With Darkroom
