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Safety Wire and Rotor Hats
The stock Wilwood rotors have held up well, but really aren’t intended for extended track use. Earlier this year I upgraded to calipers with steel pistons and no dust boots, so when it came time to replace the rotors, I thought I’d upgrade that as well. The Spec-37 rotor is Wilwood’s Premium Grade, Heavy Wall Casting Rotor suitable for race use. The street rotors I was using came with round head, Torx Bolts. I saw a different bolt part number in the instructions, and found instead a bolt kit with drilled heads intended for use with safety wire.
Since I love to buy specialty tools that only serve a specific purpose, I had to get this set of safety wire twisting pliers.
A quick search of the inter-webs turned up this video, which is now one of my all-time favorites.
And a little while later, belt-and-suspenders-level confidence. (Or Red Loctite and Safety Wire.)
Wheel Studs
Last weekend brought the final track event for NCC BMW CCA this year at Summit Point. Although I had a great time as usual, the weekend wasn’t completely worry free. If you run wheel studs instead of bolts, you may not be aware that you need to replace them every couple of years. I know this, but I tried to delay for the winter, but the gods of oxidation thought otherwise, teaching me a few important lessons.
Lesson 1: Don’t cheat time. If you know a part should be replaced based on time and not wear, don’t push your luck.
Lesson 2: Just because something tightens to torque, doesn’t mean it isn’t about to snap. I broke two bolts. Both tightened to torque when cold, even though both had already rotted half-way through.
Lesson 3: Buy a bolt extractor before you need one.
Lesson 4: Assenmacher makes a really cool stud removal tool which will make your life so much easier. (Assenmacher, that’s funny…)
Here’s a lap when everything went right.
MINI R53 Manual Transmission and Differential Fluid Change
The oil MINI uses in the Getrag 6 speed manual transmission is supposed to be a lifetime fill. I’m not sure what that’s supposed to mean: If you kill the transmission because of bad fluid, that’s the end of its lifetime. A safer bet is to change it yourself every 30-50,000 miles. It’s cheap and easy insurance, and will probably give you smoother shifting as well. The fluid you want to use is Manual Transmission Fluid with the GL-4 specification such as Redline 75W/80W MTF. You’ll need 1.5 quarts for the R53.
Safely place your car on jack-stands with the car level, and make sure you get it high enough to get your bottle of new fluid with pump attached underneath it with enough room to actually pump the fluid. On the R53, the there are two 8mm hex plugs on the side of the transmission across from the PS fan. The lower plus is the drain and the top one is the fill.
If you just want to check the fill, work with the transmission cold and remove just the top plug. You should be able to stick the tip of your little finger into the hole and just touch the fluid. If a little fluid drains out, that’s OK, you either don’t have it quite level or when it was filled it wasn’t level.
If you’re going to change the fluid, it’s a little quicker if the transmission is warm. Make sure you have an oil pan that’s big enough for at least two quarts of fluid. Remove the top plug and then remove the bottom plug. I drained it through cheese cloth and over a magnet to see if any metal shavings came out. I drove the car home from Summit Point in a driving rain storm with no clutch — I fully expected to see bits of my second gear synchro in the drain pan, but was happy to see it was relatively clear and metal shaving free.
Once all of the old fluid has drained, clean the plugs and the threads on the transmission housing. Use a Q-tip or rolled paper towel to get anything that may be left behind. Replace the bottom plug and torque to 32 ft-lbs of torque. Use your fluid oil pump to pump oil into the upper plug opening until it starts to come back out. Clean the threads, install the plug, and torque to 32 ft-lbs of torque.
Go for a test drive and enjoy the silky shifting smoothness you had forgotten about.
MINI Brake Ducts, Part Tres
Getting the brake ducts right on the MINI is slowly becoming my white whale project (call me Ishmael). In Part Deux of this adventure, we found a good cooling solution using brackets from Chris Sneed, but the location on the passenger side ducting was less than ideal. First we got the hose caught in the crank pulley (which was fixed by use of a sleeve before any real damage was done), but most recently, the hose got pinched under suspension compression and the wire from the hose shredded the (brand new) CV boot forcing yet another axle repair and massive grease clean-up.
This time we’re trying a smaller diameter hose — 2.5 inches vs 3.0 previously. The brackets at the wheel carriers were modified for a smaller diameter fitting, which we’ll weld over the winter break if this works out.
We got a Mishimoto reducer to fit the 3 inch brackets in the bumper and some aluminum tubing to form connectors and to protect the crank pulley.
The eventual solution turned out pretty well. Since the hose still matches the opening in the bumper there shouldn’t be any loss in cooling, and now with the reducer in place, it will be easier to remove the front bumper cover. There doesn’t appear to be any binding at steering lock. And when we jacked up the hub, there doesn’t appear to be any binding at full suspension compression either. We’re running at Summit Point in a couple of weeks so we’ll know more after that event.
Leave a comment if you have a better way to route the hose on the passenger side.
Closing the Diverter Gap
I installed a new Alta IC Diverter when I changed the IC couplers the other day. One of the steps in the Alta installation instructions is to remove the plastic diverter mounted to the hood. This helps to create a larger pocket of air for the intercooler, but also leaves a gap between the scoop and the leading edge of the IC mounted diverter. Alta closes some of that gap with a piece of trim, but a gap of more than an inch still remains. In this post, I’ll attempt to close that gap. (Sorry about the quality of the pictures. This proved difficult to photograph — black scoop, black diverter.)
When observed from the front, a couple of things become obvious: some of the air entering the scoop misses the diverter entirely and a good quarter of the airflow hits the leading edge and presumably drops down the front of the engine rather than through the intercooler.
What’s needed is about a 1.5 inch extension to the lower edge of the scoop. We cut some material to size, formed it to shape, and then attached it using sticky heat shielding material.
When seen from the front on the bench, you can see how much further the lower edge extends toward the IC diverter.
Once mounted on the hood, you can see how the extension lines up with the marks on the hood from the diverter.
We did some test fitting and ended up blocking the last two inches on the driver’s side to force the airflow into the IC diverter channel. Now we just need to go for a test drive and see if it rattles at all since the heat-shield covered extension is now resting on the top edge of the IC mounted diverter.
