Miata Lessons

I learned basically two things from having owned the Miata over the years:

1. With a high mileage car, you can run through a long list of tests, but you can't really tell what's going on inside an engine. You have to be suspicious and look for weaker signs of proper care or abuse. You want maintenance records, you don't want a dirty engine bay or sooty exhaust pipe. Even a compression test and leak-down test wouldn't reveal the mis-mounted and scratched cam caps on this car. If you could know the oil and filter had been run for 3000 miles (and not just 30 since last Saturday), you might crack open the filter and check for bits of metal. In the end, it is a bit of luck. You have read tea leaves, be suspicious, and choose a false negative over a false positive. Better to let a dirty good one go, than take a bad engine that left a sign of it's state.
2. A suspension can make a big difference, not just power. I hadn't written about it much, but I enjoyed driving the car this summer much more after I put the new suspension on it. I didn't drop it to get the "slammed" look, I wanted bette cornering and I got it.  The stock suspension is pretty soft on that car.
3. I also learned about the 90-10 rule for cars. I've long thought that all you really need from a car is reliable transportation to work, so buy whatever is fun. That worked when I bought the Integra. It wasn't tested too hard because the Integra was front-wheel drive and decent in snow. It also had a decent sized hatch for hauling things. The Miata doesn't have either and flips the rule around: Anything, even a motorcycle will get you to work, it's the 10% that matters. With rear wheel drive and no hatch, it's useless for anything else. The soft-top means it needs to be babied or kept inside to be protected from thieves and vandals, so it's high-maintenance on top of the other issues. I saw this over the years and would have predicted a Fall or Winter sale. I loved the car in Spring and Summer, but once the snow was flying, it was just a nuisance.  
4. Finally, you can't always trust a mechanic not to take your good money to throw at/after a bad engine. After I was already in for most of replacing the timing belt, and only because I asked him to look at the shims, did he discover the scratches and mis-mounted cam caps. I was curious that he didn't reveal the results of a compression or leak-down test until I did my own: there was nothing unusual. The only thing beyond the tea-leaves of a dirty engine bay, sooty exhaust would have been to try changing the oil filter and cutting it open. A leaky rear main seal is obvious enough and not indicative of a bad problem, but it might have lead to a low-oil situation. He managed to bill some 4-figure jobs from me, but I won't be back.

Cam Caps and Journals Redoux

When my mechanic, as part of a job to replace the timing belt a few years back, found that the exhaust side cam caps where on the intake side and vice versa, I knew the engine wasn't long for this world. I also knew it might not die immediately. Much more recently, curious about what doom awaits us, the opportunity for looking more closely presented itself with a needed oil change. After pulling the oil filter (see earlier post) I got curious and removed the valve cover to have a look at the cam caps and the cams themselves.

What's hard to see in the picture above is a ridge on the cam about 1/4 way up. I think that was the source of the sparkles in the oil filter.

Sadly, in the process of reassembling that cam cap, I managed to shear the bolts. Had I not, I might have been able to run the car for a few thousand more miles before engine replacement. My thoughts were, it's probably better to replace the head now, than the whole thing later. The plans were to pull the head and find a replacement.  Replacment BP4W heads were about $900.

I found used BP4W engines for $1200 or so. 1.6l JDM's were a bit cheaper. A full-on rebuild was $4k. Any of those would require either $500 (?) in tools to do it myself or $1000+ to have it done.

Its also worth noting that many of the replacement heads and engines for this car are BP5As not the BP4Ws that the 1999 and 2000 miatas came with. The later are better heads. The former are engines from MX3s.

Sold

After mothballing the car and starting to consider somewhere between $1k and $5k for a used engine and paying someone (or not) to install it, I saw someone asking for a "shell" on the miata facebook group. Somebody had an engine, or figured they could find one easily enough. Opportunity knocks sometimes. It was easy enough to sell it to someone who had the space and motivation to continue with it. Jack and Devon came to rescue the car, and its journey will continue with them.

I'm aware I could have done some minor repairs and sold the car for 3x what I did sell it for, but I did the right thing.