Well, the hillclimb season is officially over, and the car is officially broken. I'm still not entirely sure what caused all the detonation on Sunday, but my feeling is a combination of bad or marginal gas, some inadvertent timing advance, and just building way more boost than we normally run due to low temps and the taller gearing in the car now.
It's clear that a rod is bent, the crank counterweight is scuffing the piston skirt but otherwise the car is driveable. I feel really bad, I keep thinking about the things I could have changed to save the engine, but in the end there was very little time to tune and as I went through the tank of gas the car just kept running worse and worse.
This weekend was just one thing after another. But it started well before the weekend. Let's rewind a week to last Sunday.
The car was sounding weird after the rallycross, and I noticed the crank pulley wasn't completely straight. Oops. I think someone screwed up a timing belt change on my 1999 motor:
<crying face emoji>
Whatever, the right side of the keyway is fine. I busted out my trusty flat file and got the crank round enough to put on a shiny new pulley, key and bolt from Mazda (thanks to University Mazda and Walker Renton Mazda!). All was well, and the engine was running smoothly.
It's fine, everything's fine.
I button everything up on Friday, don't really have time to shake it down, but it seems to be running ok. I don't set the timing. I left the CPS at the same place it's been in the last two BP motors, given ideal cam timing with a non-stretched timing belt. Should be fine, right? Sure.
We drive down to the Columbia river gorge on Friday, and the car is running fine. There was some spark blowout at first, but I reseated all the plug wires and it was gone. It's true that at some point during the week I realized that the FM turbo kit air filter was basically done, I think because I didn't clean it enough and because of, I dunno, the crushing force of the atmosphere, it had basically turned into a discarded beer can.
Oops. I'm not sure this was flowing as well as it should. So, I managed to jam a big double cone filter on the intake.
The hood closes, I swear. It really does.
What could possibly go wrong? I just improved the airflow to the turbo. That can't be bad, right?
Physics. She be a hard mistress.
Nothing seemed amiss, although the car was, in hindsight, making probably dangerous amounts of boost. I think what happened was the cam timing was retarded when I put the engine in due to keyway damage, I retuned it, and then when I fixed the crank pulley I got a handful of degrees of advance, which in turn made way more boost. I will put a timing light on it before I pull the engine.
ANYWAY.
We get to the Columbia river gorge in the evening on Friday, set up camp, and enjoy the surroundings. It's a incredible location, with random wild vintage racecars everywhere.
Unfff. So good.
Saturday morning dawns bright and early, with the hunters next to our camp rolling out at 5:45 am in their 4" exhaust diesel bro-truck. We headed up to the hill to get teched, and then go to the car show at the Maryhill museum. Everything was going fine, the car passed tech, and as they were handing me my windshield sticker, the tech guy was like "I don't have to see your fire suit, or safety gear, I just need you to have them".
My mind raced. NHA only requires a long sleeved cotton tee shirt and a HANs (I know, we are crazy, don't @ me), and we have to have our windows up or run arm restraints. SOVREN requires a full fire suit, but no HANs or arm restraints and you can probably smoke a cigar as you drive your Bentley up the hill. Really. I'm not kidding, I think that would be fine. The idea is that you can drive old cars with no safety gear and you accept the responsibilty for failure. But, that fire suit thing. Old cars are basically firetraps. But where is my suit? I have my boots, gloves, HANs and helmet, but I distinctly remember leaving my suit in the hallway... In Seattle. 200 miles and four hours away.
Ugh.
We jump to problem solving mode. If we can go back to the campsite we can get cell signal and try and find a suit. We mumble something about needing to spend more time prepping and bail on the parade to the car show and blast back to the campsite. My incredible crew manages to find an e-tailer in Portland who is willing to sell me a suit out of his garage on a Saturday.
I want to specifically call out Ronnie at Product 41. If you're in Portland and you need race gear or data logging you really should be supporting him. He had a bunch of fire suits in different ratings and sizes and sorted us out. So good. Can't recommend enough, he's at https://product41.com
So, we had a suit, and our worries were over. Right? Just had to head back to camp, and run the next day. Right?
Hah. Physics.
So, the competition day dawned. We got up, scrambled some eggs on the grill. Wiped the camp crud out of our eyes, and headed to the venue. I was almost out of gas in the racecar, and I don't like to run it dry. So we put half a tank of 'premium' into it at a EZ-trip chain gas station in Biggs, Oregon.
And then everything started to go wrong
At first, it was a good day. The air temps were very low, but it was pleasant and no rain was forecast. I was a bit worried that it was so cold, the car tends to overboost in dense air. But I didn't think much of it. Things went slowly and casually, it was a SOVREN event. I stuffed myself into my safety gear and lined up for my first run.
I can only be subjective about how the car was running, I'm not a computer. I do know I kept running out of gear, which is weird because we switched to a 3.6:1 rear end from 4.1:1 rear end, and yet I was having to shift earlier. The car was stupid fast. About halfway up the hill the car starts to ping. It feels just like running on California 91 octane, but much worse. I back off and finish the run at a reasonably competitive pace. Ugh. As soon as I get down the hill I pull like 5 degrees of timing at the top of the map, add a half point of fuel and reduce the boost duty table by a few percent.
It's not enough.
My second run, I shift into fifth on the straight and it's just too much. Too much torque, too much timing, too much cold air, too much terrible Oregon shady water gas. My changes to the tune aren't enough. I can't pinpoint the exact moment the rods distorted, but it doesn't matter. As I brake after the straight, I can hear a death rattle from the motor. Still, it's running. I limp it up the hill at severely reduced speed.
My mind is working through the potential outcomes, and it's not great. Still.
The engine runs.
There's a clunking sound with each crank rotation which is almost certainly the crank counterweight scuffing against the piston skirt. It's not fatal. The crank case is still intact, and the bearings all seem fine. There's a deeply unpleasant noise, but one of the other drivers pulls my cam cover oil filler for me and the noise doesn't change. Not a bearing issue. I grit my teeth and drive the car the 3 miles to the camp site.
Now what? The miata isn't going to make it 200 miles back to Seattle. I don't have a way to get it back.
But... our crew vehicle is a Range Rover Sport. All we have to do is drive back to Seattle, install the trailer wiring kit that we happen to have on hand from Atlantic British due to random chance, rent a trailer, and come back to the state park where the broken racecar is. Sure! Fine! Right?
Sometimes things work out. Like, after all the random failures we had all weekend, it was crazy to just install the wiring kit in the Rover and just have it work. Plus the seats in it are amazing.
We drive home. We rent a Uhaul trailer. I install the wiring kit. It works perfectly. We drive down to the gorge. Nothing breaks.
The race car is home.
I need to regroup. I'm clearly struggling with boost pressures on the BP. I need to build a bottom end, and I'm fine with that.
I still don't feel like the car has let me down. It's still the answer. I swear.
