Targa Miata
April 12, 2013 - I found the cause of the axle failure.
The spring clip on the end of the shaft broke, allowing the shaft to pull most of the way out of the CV. The small number of splines remaining just weren't up to the task and ripped apart.
On the other side, one of the CV boots ripped and was slinging grease, but I haven't taken it apart to find out just what's going one. It wasn't ripped last time I was under the car and since it was slinging grease on to the exhaust, I would have been able to smell it if it had been happening for a while. I'm curious as to what I'll find in there.
No matter, I've got a new set of halfshafts in the car now. Not a cheap fix, but an easy one. I did check to make sure I wasn't exceeding the amount of allowable change in length of the shafts due to excessive travel, but it looks as if I'm dead on the correct amount.
entry 1079 - tags: failure, axles
April 22, 2013 - Short test session.
The new tall wing mounts were wobblier than I liked. Pulling back hard on the wing also showed a bit of bowing in the lower section. I looked at a few ways to fix it and decided to try guy wires. Excellent result, it's stronger both laterally and longitudinally. The lower guy wire points are right where the greatest deformation was when I yanked on the wing, and the whole assembly is solid. The fact that the wing attaches to the uprights with a big plate helps as well.
On Saturday, I took the car out to Grand Junction Motor Speedway to test it out. And I only got in one session. The track was cold and the car was pushing around, but more importantly I could hear a thumping from the rear when accelerating out of left turns. It appears the new axles might have a bad CV joint, I'll dig into it later today. I have to get it fixed by tomorrow night!
entry 1081 - tags: testing, aero, axles
April 29, 2013 - Time for the big Laguna Seca event.
It was not easy getting here. It turns out that my new axles did not have proper heat treatment, so they failed almost immediately. I decided to upgrade to the stronger G2 setup partly because that's what was on the shelf at Flyin' Miata, and I ran into a series of problems with the new parts. Finally, after working most of the day before I left, I ended up with the used parts from Elvis on the car - rear uprights (including hubs), rear upper control arm and axles. Finally, after all that work, the car was ready for the trailer. Then the long tow began.
Finally, we got to Laguna Seca. My first lap was uneventful, then an alignment cam slipped. Argh. Still, the car felt strong. I went out again and on my second lap, the clutch hydraulics failed. Argh.
Much prodding and poking at the clutch ensued. I got it back again briefly, then it went away. I thought it was a bad clutch master or slave. After working on it all day Saturday, I called Bill Cardell that night and he suggested there might be some debris in the hole between the clutch reservoir and the master. I worked on this the Sunday morning and had a clutch within half an hour! I took it out for some exploratory laps and it was coming and going. I seemed to have about three shifts in rapid succession, then it would go away - which made the front straight and the braking into turn 2 fairly interesting. A bit more bleeding and it came back 100%. Time to go drive.
This car is a beast. I'm certainly not the fastest driver on the track at an event like this, but the car is a great equalizer. With the big engine, I could pass just about anyone as we climbed the big hill up to the Corkscrew. The aero seemed to be working nicely, as the car remained well balanced in the high speed turns as well as the slow ones. I was having a fantastic time working my way through the pack.
Janel finally got a few laps in it after the disappointment of last year and the non-functional Saturday. Her biggest adjustment was to the braking points - the car builds up speed so quickly that you have to brake a lot earlier for the turns. She was starting to get more comfortable, though, and looking forward to her last couple of sessions.
entry 1082 - tags: testing, axles, failure
August 22, 2013 - It's been a long time between updates.
Mostly because it's been a long, long wait for parts. The replacement axles took forever. I took the opportunity to upgrade from the standard axles to the G2 version, which have stronger CV joints and come with the new, beefier hubs. Good thing, too - you'll see why soon.
Elsewhere on the car, I replaced the bent-up muffler, fixed an alignment problem up front and went over a few other things. One bent wheel and one questionable wheel were replaced as well. Since the muffler had burned the rear bumper cover during a dyno run, and then it got all scarred up in the crash, I decided to cut it out further than before. I liked the look better before, but not all the damage.
The car is now back on the ground and self-propelled for the first time in forever.
entry 1089 - tags: repair, crash, axles, exhaust