Thursday, April 15, 2021

DIY: Replacing the Rotor disc on Girodisc 2-piece brake rotor

I've helped a number of people replace their existing stock rotors with Girodisc 2-piece rotors. I've used them on three different cars of mine. Great for track and street, they last. long time and provide a bit of extra surface area for better brake performance. When. your Girodisc rotors later wear out, you can replace the rotor disc with a new one, keeping the rotor hat. That makes the brake rotor replacement a bit cheaper.  Here is a video showing how to do the rebuild / replacement, in. this case on my 2018 Mustang Shelby GT350R:









 

Monday, February 15, 2021

Datsun 510 Historic Race Car: a Dream Finally Realized

I've always said that cars are collectible when they hit 30 years old because that is when 46-year old can afford what he loved as a 16-year old. Well, that's not quite the case here, as this isn't overly collectable, and I'm 58 and the car is 51. But the point stands. We never quite get over our first car-love.

I fell in love with cars at a very young age. I was fully aware of certain race cars when John Morton started winning for Brock Racing Enterprises (BRE) in the late 1960s and early 1970s in Datsun Roadsters and Datsun 510s. My first car at age 16 was an orange Datsun 510 2-door that I modified to try to be like the racer guys. I dreamed of racing but went off to college instead. That turned out OK.

For those of you who are too young to remember: John Morton and the Brock Racing Enterprises (BRE) team, under Peter Brock, pretty much shocked the world when their new/upstart race team beat everyone in the SCCA National Championships in Datsun Roadsters, 510s, and 240Zs, and knocked off the established BMW and Alfa Romeo teams with the 510 in the Trans Am under 2.5 Liter Championship. Datsun and BRE were so dominant, that the other teams gave up and left the race series. At the bottom of this post is a link to the YouTube of a documentary called "Datsun 510: Against All Odds", which chronicles the story with some very nice vintage race footage! Meanwhile, here's me at age 17 circa 1979 with my first car,  the 1972 Datsun 510 that started me as a "car guy":

Well, since the original BRE #46 John Morton car is in a museum and the original #35 Mike Downs / #85 Bobby Allison car is now in the hands of Adam Carolla, I had to buy the next best thing. 

This car has racing log books back to 1979 and has been raced by a number of amateurs in SCCA, CSRG, HMSA, HSR, and SVRA. It is a replica of BRE driver Mike Downs' #35 car (before the number change to #85 for "guest" driver Bobby Allison, which is the livery that remains on the original car with Adam C now). This car was sold to me by an older vintage racer named Dan Haney, who had two of these.


It has all the right stuff from the era, including the Nissan Motorsport Competition direct-drive 5-speed dogleg transmission (hard to find these days), which I just had rebuilt by Troy Ermish. It also has the 50MM Solex/Mikunis and competition BRE intake manifold on a race-built 2L engine. The car weighs about 2000 pounds and puts out about 200 HP on 110 octane race gas. Don't even try to drive it under 6000 RPM, the engine wants to rev around the 7000 RPM mark and the close-ratio gearbox makes sure you stay in that range.

My friend Rick heard that I bought the car, and he went to the seller and immediately bought the other one (red/white #46 replica of John Morton's Championship car).so we can go race in the historic races with CSRG at Sonoma, Laguna, and Thunderhill. I am also in the process of applying for acceptance into the Sonoma Speed Festival in September. Ultimately I would love to race in the Rolex Monterey Motorsports Reunion at Laguna Seca, but that is an event that doesn't always have a race group for cars of this era, and this car may not have the full provenance for that event. We shall see.

Anyway, it took me 40 years, but I'm finally getting around to racing that car I dreamed of when I was 16. Here she is at Thunderhill Raceway:

When someone tells you that their race is car is "fully sorted, ready to race...", just know that you might still have quite a few things to take care of. In my case, many things. The car had been checked out in advance by Troy Ermish, a well-known Datsun 510 racer, mechanic, and parts engineer/guru. He had given me the green light on this car after he tested it at Thunderhill a month or so prior to my purchase. but hey, race cars are finicky and high-strung. So once we got the car off the trailer and started prepping it for the race season, it needed much to be up to a proper competitive standard.

So into Troy's shop for a new Quartermaster double disc clutch, transmission overhaul (synchros, shift forks, dogs, sliders, seals and bearings, hub rework, new crossmember and mounts), new rear quarter windows, new fiberglass hood and fasteners, second set of Rota wheels, new set of Hoosier R7 tires, AIM Solo 2 DL lap timer with integrated Smarty Cam HD.  

I took it out for a shakedown at Thunderhill raceway and found that I need to fix a few more things. 

But I'm a dork, so we recreated a well-known photo of Pete Brock, John Morton, and Mike Downs, using Troy Ermish as the Pete Brock character. Poor Troy.





Race guys are great at fabricating stuff. Sometimes it's not what you want, though. The radiator starting leaking on the Thunderhill run because the prior owner had fabricated a semi-solid braided metal connection hose from the radiator to the thermostat housing. So it didn't provide any flexibility, and therefore the shake of the engine translated into creating a nice crack in the radiator. And.... the brakes were scary and pulling hard to the right when I hit them hard at over 100MPH. And, the steering box was so loose and sloppy that I felt like a kid steering a Model A on a frozen lake: the direction the car went bore no relation to my wheel input.

So, back to the shop for new Wilwood brake calipers, a suspension check, a new radiator, new alternator, new hoses and routing of water overflow, new (used) steering box and brackets, etc.

After a couple more weeks, the car was back at home with me and getting ready for my next shakedown test #2.  I am getting prepped for the April 9-11 David Love Historic Races at Sonoma Raceway, so that'll be the next test spot. Meanwhile, it was time to do some basic cleanup, and to set up the AIM Solo 2 lap timer and make sure the car looked as it should as a replica of Mike Downs' #35 BRE race car in 1970-1971. Also, I made sure I paid my license fee to the good people at Brock Racing Enterprises (BRE) in order to legally use their look and feel BRE racing livery (not everybody does, I"m sure you're shocked). BRE supplied the proper stickers to replicate the look, and as every racer-boy will tell you, those stickers are good for at least 10 extra horsepower.

Here is Mike Downs' car in the BRE shop circa 1971:

And here is mine now, note the dashboard signatures from Bob Bondurant, John Morton, and Floyd Link (one of the original BRE engine builders):



















And to make sure my neighbors would continue to shake their heads at me, I tested the new brakes around the block. See video link below for the sound of the angry 4-banger. Next step: on the trailer to Sonoma Raceway for shakedown cruise #2 this week.

For more history on the Datsun 510, Brock racing Enterprises, go to the BRE website. Peter Brock was truly a legend and shaped the destiny of the Japanese performance car market in the USA. See "Datsun 510: Against all Odds" below and also check out his presentation at the BlackHawk Auto Museum a few years ago.