If you read this column regularly, you know that the engine in my Spec Miata blew up on the last race weekend of last season. I found out when I opened the motor that the head gasket blew between cylinders one, two and three. There was no water in the oil nor any oil in the radiator. It seemed a bit strange, but others tell me they have seen it happen in other Miatas, too.
That engine failure set the stage for what has been an interesting winter offseason. In the spirit of Chinese philosophy, I chose to treat the blown engine as an opportunity rather than as a problem. As I would soon find out, the word “opportunity” might also be Chinese for “expensive.”
I went with a crate engine from Mazdaspeed Motorsports Development because I wanted all the brand-new hardware — cams, lifters, valves, valve springs, rods, pistons, crankshaft — that comes with a new engine. However, after hearing stories from around the paddock about crate engines and their cylinder heads, I decided to have it “gone through” to try to maximize power.
So, when I got the engine home, I didn’t even take it out of the back of my truck. I tore down the front of the engine and removed the cylinder head. The whole process took less than 30 minutes. It’s amazing how easy is to work on an engine when there is nothing in the way. The next morning I took the short block to an engine builder about an hour away from home.
After that, I had to take three heads to the cylinder head shop for flow-bench testing and machine work permitted under Spec Miata rules. The idea was to determine which was the best-flowing head, then run further tests on it and next best head after the machine work. You can read about our findings deeper in this issue of Speed News. Suffice it to say, we learned a lot using a flow bench, which confirmed what I had heard about cylinder heads on crate engines. It flowed the poorest of the three heads I had, two of which came from regular production engines in donor cars.
Then, of course, there was the car, which I had to get ready for a new engine and a refreshed transmission. It’s either a personal quirk or a quality that I couldn’t see fit to install a new engine in a dirty engine bay, so I when I wasn’t shuttling parts to the machine shop or going back over to shoot photos of the different processes involved in machining a Spec Miata cylinder head, I was in the garage prepping the car for the new engine.
I didn’t seem much like work at the time, but as I write about it now and reread what I’ve written, it seems like quite a process — and I guess it was.
At this point, I don’t know whether all the effort will pay off. I still haven’t reinstalled the engine, let alone had the chance to run it on a dyno. I do know that I gave it my best, and I hope the stories that come from the experience reflect that, and help NASA’s Spec Miata racers across the country with decisions regarding their own engines and cylinder heads.
The whole process reminded me of those circus performers who keep plates spinning atop short poles. As soon as you get one plate up and spinning, the other two are wobbly and need attention. It’s a bit like trying to cook three different food items so they’re all ready at once. I like to think of it as a three-part harmony. Each member of the trio has its own part to play, but none is of much use without the others.
