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I decided to install a new pilot bearing when replacing the flywheel and clutch. Notice that the tip of the propeller shaft, which is supported by the pilot bearing, has turned blue. This is an oxide layer forming on steel heated above 205 °C (401 °F), indicating that the pilot bearing has worn and heated up due to high friction. The surface is perfectly smooth and runout is within specification, so I'm reusing the propeller shaft. A bearing puller is required to remove the pilot bearing. It is necessary to totally mangle the bearing, as the tool does not get a good grip on the outer bearing race. The internal bearing race is crushed and the steel rollers drop out (beware!), at this point the bearing puller can be reinstalled so that it grips the outer bearing race from the top. It took a few attempts to get a good grip, and then it finally came out. New bearing installed. Notice that the chamfered side is out, this side also has an O-ring to protect the needle bearings from contam

I've previously replaced the front engine seals, the oil pressure sender, cam sensor and the oil pan gasket, but oil was still collecting at the back of the oil pan. I think I found the source.The seal lip has hardened and worn down. Signs of a worn seal is visible on the surface of the crankshaft, but it felt perfectly smooth. I'll locate the new seal further in, as the rear cover is designed to allow this. While it was accessible I also installed a new oil gallery barbell, which is supposed to increase oil flow and reduce the amount of unfiltered oil bypassing the barbell - and thereby the oil filter. I drilled a small hole in the OEM barbell and used a wood screw to pull it out. New barbell in place. It has a threaded hole, making it easier to remove if one should ever need that. I managed to sneak the mobile phone camera up to the cam sensor, hiding in a chamber on the top of the engine (used for a distributor on earlier generations of the engine) and right above the rear e

Removing the differential, gearbox and torque tube was not as difficult as I expected. I removed the parts as one assembly. I used a jack for the engine, a jack for the torque tube and a transmission jack for the rear subframe and differential. The torque tube slid out of the bellhousing easily, and I adjusted the rear transmission jack so that it kept the whole assembly in balance as I removed it from under the car. I forgot the fact that the rear subframe is attached to this assembly only by one single point - the differential mount. It is not designed to take this kind of load and was damaged, fortunately I had a new one ready. I disconnected the rear brake lines and removed them, as I found it stupid to bend brake lines this much to get past the drive shafts. I will reroute the brake lines before reassembly. I see no logical reason for the brake lines to run down and behind the rear differential, when they can simply be routed directly to the pickup points in the wheel wells. The m

The previous owner has installed a nice Sparco Evo 2 racing seat, but I don't like how the seat belt receiver is mounted to the seat bracket. The receiver is too high up on the waist, in an impact the driver can slide under the belt and or get  fatal abdominal injuries. After some Googling, I found a flexible seat belt receiver on GM Parts Giant for only $5.80, made for the rear seats of a Buick Envision. GM part number 84690213 (topmost picture). The Corvette clip is slightly wider than the clip out of a sedan, so the Buick receiver has to be modified. I'm used to this in European cars, where the clip and receiver is coded to each other, e.g. making it impossible to install the rear left or right passenger clip in the center receiver. Some seconds with a Dremel carbide cutter and the issue is resolved The flexible seat belt receiver is now routed through the side of the seat, which is far safer for the driver.

Guess what happens when a flywheel, a pressure plate and a clutch disk are free bounce around in a box across the Atlantic Ocean? I purchased a new LUK OEM clutch kit from Summit Racing. The clutch kits from LUK are sent in a cardboard box without any protection and everything inside is free to bounce around. Across the Atlantic Ocean, this is bound to go wrong. Nobody would cover the damage, as I used a forwarding courier to send the kit from the USA to Norway. Summit Racing also refused to send or sell me a new clutch disk. Sold separately it has the same price as a complete kit. Not the best customer service by Summit Racing, I have to say. So, to get my Corvette on the road again - I have to purchase a second clutch kit! "Insanity is doing the same thing over and over again and expecting different results", so I did not order another clutch kit from Summit Racing.  I was lucky to source a lightly used Spec stage 2 clutch kit from a nice fellow in Alabama, who sent the par

Late April, and the spring finally arrived with temperatures making it possible to start on the pending repairs.  I started by draining the oil from the noisy rear differential. This is what the T-1000 Terminator is made of; liquid metal drained from a Getrag differential. A magnet picked up a lot of metal shavings.  The output shafts have significant play, which is an indication of worn clutch packs and belleville washers, and possibly broken output shaft stubs (I will find out when I disassemble the differential later). With all these issues, this differential needs a complete rebuild. It is hard to find specialists with the knowledge and the tools required to perform this work in Norway. The cost of shipping the differential to the USA and back for a rebuild is also excessive, due to the weight. So, the conclusion was to purchase a built 4.10 differential, which obviosly also gave the opportunity to change to a different gear ratio. Built 4.10 differential C6 Z06 output stub shafts

24th of April. Winter has no plans to release its cold claws...

A V8 engine shouldn't be covered by plastics, so I removed the plastic valve covers. This only reveals a new layer of connectors and sheet metal brackets, this is clearly not an engine designed to be put on display. I replaced the sheet metal brackets with ICT billet ignition coil brackets, which helped somewhat (I also have to do something with the coil pack connectors). In hindsight, valve covers with integrated coil posts would have been even better.

Winter is coming The C5Z is in hibernation until spring time. I don't have a heated garage, so working on the car in freezing temperatures is not an option. At least I can start to make a plan for the next season. The car in front is an MB R350 with a stretched cam chain, lots of work to get that fixed on an OM642 engine. Drivetrain maintenance I returned from the last trackday with a load humming from the rear end of the C5Z, which is probably a differential failure. I'm hoping for a simple fix like broken belleville springs, draining the oil will give a telltale. There are already other issues that requires attention, so I guess the time has come to have it all sorted: Broken rear differential Engine rear oil seal leaks (which requires removing the torque tube anyhow) Worn slave cylinder ("clutch pedal stuck to the floor") Clutch and flywheel replacement Torque tube couplings and bearings

Don't drive with your nannies on! With active handling in competitive driving mode, yaw control is still active and using the rear brakes to correct excessive yaw on corner entry/exit. This is not an issue on regular street driving, but on a racing circuit this continuous correction causes the rear brakes to overheat. In my case one of the rotors cracked as the car cooled down in the pit. I even heard the *PING* as it happened. 305 to 330 mm brake rotor After some research, I found that the C6 with the Z51 option code uses a larger 330 mm brake rotor, but still share the same caliper and parking brake dimensions! Plus Increased thermal capacity. The EBC Z51 rotors are ventilated on both sides, have a higher mass and increase the swept diameter of the brake pad Better looks, the brakes fill the 18" wheel and looks more in balance with the front big brake kit. Reuse of stock brake calipers and parking brakes Minus Change of brake brake bias. The increased rotor diameter causes a

Finally time for a new trackday, Vålerbanen again. Now with a larger 30 row oil cooler and a Trackspec hood vent installed, but to my frustration the oil temperature still exceeded 130 deg C after a few laps. So there will be a "Never ending oil temperature story - part 4" Except for the oil temperature, the car ran great. Engine, clutch, gearbox, brakes, tires - not a single hick-up. [Edit: Incorrect. A rear brake rotor cracked and the differential failed] I did set a new personal best time, and judged by the video, reducing the lap time further should be possible. Less braking, more precise lines, higher cornering speed. The Hoosier tires provide amazing grip, which I still have to learn to use. Corners can be taken at a much higher speed than my brain thinks, which is evident as I didn't have a single mid corner incident (like carrying too much speed) the whole day. My focus was on driving, so I didn't notice the broken audio cable or that I mismatched the on/off

High up in the mountains in Norway, close to freezing temperatures, the driver side window regulator broke down. Perfect timing. Fortunately, I managed to pull the window up by assisting the motor. A broken piece of plastic was all it took I had to twist my brain to get the parts back in the correct orientation. Notice that as pictured, it will not work. The wire coming from left (door B pillar) needs to pass below the right wire, otherwise it will conflict with the window. Mounted incorrectly here: I also noticed that the regulator power cable and the door latch switch cables interfered with the mechanism as it moved up and down. so I used some high strength duct tape to move them out of the way. New window regulator in place. I ran the window all the way down so that there wasn't any tension on the mechanism before tightening the bottom nuts. I followed Chris Askew's guide to replace the regulator:  https://www.chrisaskew.net/blog/2020/12/8/how-to-replace-window-regulator-200

Heat management is still an issue on track days, so I decided to add a Trackspec hood vent. Trackspec T1 hood vent Optimized louver design to maximize extraction flow velocities within a vehicle in motion Reduces under hood pressure delta to reduce front end lift and increase net vehicle downforce. Significantly reduces under hood temperatures by extracting heat and allowing fresh cold air to enter the engine bay. Maximize life of engine accessories by reducing overall operating temperature. Increases dense, cold air flow through radiator to promote lower coolant temperatures. -exactly what my C5Z needs! I managed to source a second hand T1 hood vent in good condition. For the install, I decided to use countersunk hex screws rather than pop rivets, as I don't like the look of pop rivets (it is not a kit car, after all). To countersunk a screw, you need enough material thickness for the screw head. I looked up some tables and concluded that M3 (3 mm) screws would work. An Ø6.3 mm 90