BTW, Outback Timing Belt

For the record, the Outback got a timing belt a few weeks ago. Was like $850. No water pump needed. Apparently Subaru builds them well enough that they don't need replaced. Automatic transmission, so no clutch needed. Still needs a windshield and snow tires.

Engine Developments

I got a letter back from Flyin' Miata. They'll pull the engine, rebuild it, re-install it for just over $8100. Not sure if that includes $2000 in deluxe pistons and connecting rods or not. Turbo is extra. Wah, waaaaah.

I re-did the leak test on the "bad" cylinder and got results similar to the others. I also go to see the pressure turn the engine a hair, opening a valve and releasing the pressure. Very cool. My neighbor was chatting, so I wasn't paying as close attention as I should have. I'm fairly certain I saw 185, and wondered if it was 184. That would jibe with the consistency I saw from the compression test: 165 +/- 3 across the board.

So what to do? A turn-key turbo from FM would run over $10000 and require a new clutch (maybe the $6800 + 15 hours at $130) includes that. New brakes, wheels, tires?  And the car would still have a rough body and interior?  Restrictive stock exhaust? It would make for an interesting sleeper.

I really like the car as a daily driver, and what I've read about getting into racing suggests staying normally aspirated for the time being is the way to go. I could get a fairly well built  (but not "built") engine installed for about half of what FM wants. Then I could do thinks like better brake pads (not sure about 4-pots), steel brake lines, a butterfly brace, maybe a lighter flywheel, the anti-sway bar upgrade I didn't do with the springs. Stuff like that.

I could also build and install it myself, have the experience and save as much as $2000. I'd spend up to $1000 at the machine shop and up to another $1000 on tools (engine stand, hoist, impact wrench?).

....or say "screw it" and go buy a WRX.

Tired Engine

I recently put 15-40 oil in the car and it seems to be pretty happy with it. But is burning oil and showing some signs of age. When the times comes, I'll have a few different options that I'm starting to explore.

• Sell the car and get a new BRZ: $28k
• O'Reilly sells PowerStroke rebuilt engines for $2350 with a 3 year warranty. Additional labor to do the engine swap could be $1000?
• It's rumored that used engines could be had for $1000, engine swap additional
• JDM engines (partly used Japanese engines) are supposedly also $1000, plus engine swap.
• Treasure Coast Miata sells rebuilt heads for $550 and rebuilt short-blocks for $1250, no core charge. Additional labor to pull the old engine and install these parts once assembled. 
• Get a machine shop to rebuild a head: $500 and to clean the short block $300 (?). This obviously involves the adventure of doing some work myself, but also means there is a chance to upgrade some of the internals:
• forged pistons that are worth having if there are any plans to turbo the engine beyond 250 hp. Seriously, 250 hp in a Miata is a lot. The pistons are something like $1000.
• forged connecting rods are useful in the same situation, also $1000.
• Flyin' Miata does have a stroker kit that includes pistons and rods as well as a larger crank that raises the engine's displacement to 2.0l  $5000!!!
• Special pistons that raise the compression ratio to 11.0 instead of 9.0  are available: $1000. No turbo with these.
• Special valve springs can be had that are good for 9000rpm instead of  7000.  I think these are for a naturally aspirated (NA) engine, not Forced Induction (FI).
• Flyin' Miata has a lightweight flywheel and stronger clutch combination available for about $500. The clutch would ultimately be necessary if a turbo is installed. The lightweight flywheel is more of a race, track day, or High Performance Drivers Education (HPDE) thing.

I'm leaning towards a stock build with the flywheel and clutch.

Leak Down

Driving it regularly, I've become aware of the Miata's drinking problem. It goes through over a quart in 1000 miles. I broke the handle off of the dipstick which was always awkward to read, so I bought a new one. It sucks to read too. After 500 I went to add 1/2 quart and added the second 1/2 too. It was too much and the car was smoking more than usual. That got me thinking, so I bought a leak down tester.

I have done a compression test in the past. If I recall correctly, I was getting 165psi for each cylinder with no more than 5, maybe 10psi difference. A compression tester is a device that takes the place of a spark plug. It won't light the fuel mixture (it's best to disconnect the fuel pump and ignition before testing), but it will measure how much pressure the engine can create when cranking. 165 isn't bad. I've read that when the compression is as low as 130 it's time to rebuild. Its the oil burning that bothers me.

It shouldn't. The car still passes emissions, and I drive a long enough drive that the catalytic converter heats up and must be able to keep itself clean. Catastrophic failure isn't at the top of my list of fears. The "cat" failing from getting gunked up from oil is.

This is a compression tester hanging off the top of the engine.

The compression tester just gives you a general picture of the engine's health. It doesn't distinguish between bad rings and leaky values. That's what a leakdown tester is for. In combination with a compressor, you pump air into the cylinder and find out where it leaks out. You expect a bit to come out the crankcase as it blows past the rings, but just a bit. In older engines  you might get some to come out of the air filter or exhaust pipe if the respective valves aren't doing so well. If the head gasket is going, you might get some bubbles from the radiator cap. I could hear some air coming out of the oil cap.

Here's pictures of what I got from three of the cylinders. You can see the tester here. One hose goes to the compressor (the left one). The hose on the right goes to a cylinder. I set the input pressure to 90 on the left gauge and then measure what the cylinder holds. The first one has me concerned. 90 pounds in and only 75 out. The other two look more like 90 in and 85 out.

Setting this up is a bit more involved. The engine isn't turning on a leak-down, like it is for a compression test. You have to turn the engine to Top Dead Center (TDC) for the measured cylinder so that the valves are closed. In the back of the bottom picture you can see a wooden dowell in one of the cylinders. It makes it easier to see the position of the engine. A common mistake is to get the wrong TDC, since there are two. The wrong one has the valves open and will show awful numbers.

For now, I wonder if the values weren't perfectly closed on the bad cylinder above, so I intend to retest. If it's as good as the others, I might just go for a roll bar and sway bars this winter. If I measured correctly, I will probably go for an engine rebuild.

The good news from the three that tested well (I didn't upload the reading of 83 I got), included silence from the air filter and exhaust pipe: good valves.