The Resurrection...Not as Dramatic as Jesus but Hopefully it Works Out!

May 18, 2024

The Resurrection...Not as Dramatic as Jesus but Hopefully it Works Out!

So, I've turned the wrenches around! This refers to an old saying my Dad and brother and I used when working on cars. First you disassemble down to the broken bits. Then you buy replacement parts. Up to this point, the ratchets are all set to counterclockwise. At this point, you turn them to clockwise and it's all down hill from here!

Actually, things usually go back together more quickly than they came apart. This is true of cars but not buildings. You can demolish a building in minutes but it takes years to build one. This goes back to the beginnings of the industrial revolution. For most of history, everything was handcrafted. Eventually, the craftsmen realized that, if they measured and controlled the size of each piece, they would not need to be custom mated to each other. You could actually have spare parts! When one wore out, the replacement was within tolerance and fit well enough that it worked.

Sadly, much of this was discovered in the production of rifles for killing other humans. Unfortunately, we've needed lots of those over the centuries. A better use is in engines for driving our families around (or bringing the back end around on a race track turn!). Let's concentrate on those uses! In any case, an engine goes back together more easily than it came apart!

So here goes. First the clutch. I'm fortunate to have spent several decades designing and developing clutches. I found it to be in pretty good condition but took it to work to have it measured as I did for 3 months in my first coop assignment at what was then LuK.

Side note: In order to measure the clamp load of a clutch, which is what creates the torque capacity, one has to insert precise thickness gauge blocks under the pressure plate. This simulates the thickness of the clutch disc, which carries the torque into the transmission. If one leaves one of these gauge blocks a bit too close to the pressure plate when releasing the clutch, it catches the corner and shoots it across the room like a bullet. Not that this happened to a 20 year old college student but just to be aware if you start graphing manual clutches!

Here is the graph of the clutch. The taller curve is the force clamping the disc. The shorter curve is the force it takes to release the clutch. To my surprise, the friction material was nearly worn out. Of course, I have done may drag starts at the autocross, which flays off friction material. And goodness knows how the car was treated in Japan but still, a clutch should last more than 70k miles. In any case, that means that the release load is at it's maximum; part of the reason why my pedal effort is so high. I decided to replace just the clutch disc since the clutch and flywheel were in good condition. Hopefully, this will improve my pedal effort and modulation on launch.

The Mazda manual is very specific and helpful. Lots of measurements with mostly good results. I do need new main bearings. I also need all new seals since they are worn below the limit. It's actually amazing that the seals last as long as they do. These rotors spin really fast! That's many miles of seals scraping on iron.

Of course, all the "soft seals" are melted. It's actually amazing that the rubber seals survive. They are only about 2mm (less than an 1/8") from the actual combustion. Again, this engine is an amazing engineering accomplishment!

Here, I will admit to a character flaw. When I get close to the goal, I hurry and and skip steps. This resulted in many compromises in the engine compartment. Many with respect to wiring. Wires running around everywhere.

This looks like someone dumped a bowl of rainbow spaghetti in the engine compartment. I had wires left of the fuel line, right of the fuel line, along the fuel line. Crazy! Those are getting straightened out. Here's the "after" picture:

Still a ton of wires but the "Rainbow Connection" is organized. I also removed this much wire from the O2 sensor:

I won't describe the part where I failed to remember how to depin an ECU plug, nearly destroyed it, inserted the shortened pins into the wrong holes, and had to depin again! But it's tight now.

Also, I didn't take time two years ago to paint the radiator mounts. They have been rusting. They will now be flat black like the rest of the engine compartment.

Another clean-up job from my haste is the unused cooling ports. I blocked these with rubber hose segments, a bolt, and 2 hose clamps. Not pretty and not effective. A screw thread presents a helical coolant path into which it is very difficult to squeeze rubber with a hose clamp. Therefore, they were a part of my leak problem in other blog posts. Haste makes waste.