I’m banging away at ‘The List’. It’s getting shorter and the goon is getting closer to hitting the track. But whenever you think you’re going forward, there is a step backwards. Today I found out my new Water Temp gauge sending unit doesn’t fit the Wagon’s thermostat housing. Looks like some careful milling and a little JB Weld should do the trick. I’ve got the FireCharger system in after fabricating a bracket for the t-handle. The rear brakelines are now in using an angled fitting at the caliper. And since I’m running out of time, I decided to buy a TWM airbox instead of making one like I did for my last car. The fit is a bit too tight (a recurring theme in this build), but I’m sure a solution is just a good nights sleep away…

The electrical system was given a satisfactory initial test today. After a careful rechecking of the entire wiring harness, I flipped the battery master to ‘On’ for the first time (with a fire extinguisher standing by just in case) and was pleased to see the voltmeter register a steady twelve volts. I then flipped on the ignition switch and went about testing the circuitry with a voltmeter to find twelve volts everywhere it should be. Then a flip of the fuel pump switch and heard the racket of the electric fuel pumps. Yeah, it felt good.

My rear brake lines didn’t quite hook-up the way I planned, they are running into the rear coilovers. One solution would be to switch to a banjo bolt adapter, but I think I’m going is to use a 90 degree adapter at the caliper and a straight ended brake line, instead of the straight adapter and 90 brake line. I’ll have to do some adjusting to get the clocking of the 90 degree caliper adapter correct, but it will give me the room needed to clear the coilover. 

“Tick tock goes the clock, and time waits for no one.” Who ever said that must have missed a few deadlines as well… I’ve got a new self-induced timeline for completing The Race Wagon: our first test day is on August 20, and the first race weekend Sept. 11, 12. I’ve been working on finishing up some of the subsystems – battery master switch (on the driver’s A-pillar, thanks Bryan) and battery mount, brake bias adjustment knob and brake light pressure switch, but many left to go. So I’ve definitely got a few late nights ahead of me this month. 

Datsun used several different sized differentials in their independent-rear-suspensioned sports cars. The 510 sedans used the R160, the early Z’s used the R180, and the later Z’s used the R200. There are also several other variations out there (R190, R230, LSDs, Ks, clip-ins, bolt-ins, etc). The diff name refers to the size of the ring gear in millimeters, ie the R160 has a 160mm ring gear. Here’s a link to more info than you could ever need - Hybrid Z diff info.

The R160 and R180 are known to be direct bolt-in swaps in the 510 and the early Z, but there are a few important differences. The larger ring gear in the R180 allows it to handle higher torque motors before destroying itself, but the R160 can still stand up to some pretty surprisingly powerful motors. Also the R160 weighs about 5 lbs less and the case is 1/2″ narrower, thus leading to this story. The R160 and early R180 use the same inner bolt-in stub axles (properly known as the side flange). But since the R160 has a narrower case, it needs to use a longer dust cap. (Left – R160, Right – R180).

 

The dust cap size difference keeps you from being able to swap them between diffs, so don’t get them mixed up in your parts bin! Doh…  The dust caps are not that critical of a part, you could just cut them off and use the stubs in either diff if you had too. When I had my CV joint adapters made, I had a R160 in my 510, but now that I have a R180 in it, they didn’t fit. So I cut off the caps, and welded on a pair of caps that I cut off some R180 stubs. Problem solved. If I use them now in my R160, they will just have a 1/4″ gap between the dust cap and the axle seal.

Today I went out to the old Castle Air Force Base in Atwater, CA and watched the Fresno Chapter of the San Francisco Region SCCA do some autocrossing. The purpose of my trip was to pick up some Z wheels from a fellow Datsun racer, Steve Carlson, who was out racing his prepped 240Z. Steve’s car is a regular in the Central California Solo scene, and he set fast time of the afternoon while I was watching. Sporting a potent 2.8L, a well sorted suspension, and weighing in at under 1900# makes his Z something to be reckoned with.

My path into roadracing did not come through autocrossing, as many of my competitor’s did. I never quite understood getting just 5 one minute laps over the course of an afternoon. I came from racing motorcycles, and just always enjoyed getting hours of seat time. But after seeing today’s competition, I think I understand the allure a little bit more, and might just have to give it a try some day soon. And getting to check out all the historic Air Force aircraft at the Castle Air Museum while I was there definitely made my day. Now we’re talkin’ some horsepower!

I’ve been plumbing the fuel system this weekend. I’m using -6 AN Aeroquip socketless hose and fittings (also called barbed or push-on) inside the fuel cell compartment and under the hood, and then using stainless steel braided hose between the firewalls and through the cabin. A tip that really helped when assembling the socketless connections is to soak the hose ends in boiling water for a few minutes then use lots of lube. A pair of Earls inline fuel filters leading to a pair of Facet fuel pumps will reside within the fuel cell compartment. A Holley low-pressure fuel regulator followed by a Y-splitter and a pressure gauge wraps things up under the hood.

I’ve been working on the plumbing and wiring in the Race Wagoon. Fuel lines, brake lines, oil cooler, radiator – geez, a whole bunch of hoses!  Then wiring the battery master, coil, starter, MSD, gauges – all this stuff adds up in both weight and expense…

My Lil’ Red Wagon finally got its motor. Since I don’t have a lift in my garage (wouldn’t that be nice), I hooked the transmission up before the installation. I discovered that the length of the early ‘A’ type comp trans combined with the motor makes for one very tight fit. Tilt the motor, lower the motor, tilt some more, lower some more, wiggle to the side, repeat ten times, and it finally dropped in. Just don’t try it with the radiator in or any accesories hooked up. I had to extend the trans tunnel hole rearward about six inches to make room for the shifter. Then I discovered what most 510 owners already know, you have to remove the steering box to install longtube headers. The number three primary tube still hits the steering box, so a little more fitting is still required.