Working on the Miata, part 1


The Miata is old. Which means two things: it's cheap and it's simple. Both things play in favor of my intention of taking on more mechanical projects with the car. Interior and detailing be damned! I want some fun with engine, drivetrain, etc.

The "cheap" aspect is twofold: both the parts should be relatively inexpensive, and if I screw up the max damage will have a low upper bound. The "simple" aspect is pretty straightforward: the engine bay is not super cramped like in the Z, and the technology is something more likely to be (1) understood by me and (2) serviceable by me, a total n00b.

Here's a recount of all the stuff I've done to it. This is going to be a mega post, light on images but with links to the full albums if you're so inclined. Edit: this is just part 1, there will probably be a part 2 with other stuff I've worked on, if I'm not lazy.

Let's get to it.

Valve Cover Gasket

I already mentioned the car was leaking, or more like seeping, a bit of oil. It didn't leave a puddle or had any sufficient amount to drip, but you could see the block moist with oil and with dirt and grime sticking to it. The occam's razor explanation for it, given the location, is the valve cover gasket. Since it's simple to do and they have the part at AutoZone, (~$25 to $40) I selected it as the first item, barely one day after I bought the thing.

In the Miata, the valve cover gasket is made of rubber and, like in every other car, it seals the union between the cylinder head and the valve cover. With time the rubber gets brittle and can crack and leak oil. The standard procedure is to take the cover out, clean it real good, and install a new gasket. The 14 bolts have to be precisely torqued and in a specific order, for the pressure to build evenly across the whole mating surface.

The image below shows the gasket (the black rubber thing), which fits in a groove in the valve cover edges. The two indentations on the right are for the cams; the indentation on the left is for the cam angle sensor (this is a distributorless setup), and the four holes in the center are for the spark plug wires to go through and reach the spark plugs.



Here's a bunch of pictures I took along the way.

Tie Rod Ends

I mentioned in the first post about the Miata, that while test driving it I noticed a knocking noise from the front end. The most common explanation is the tie rod end. It's the part that connects the rod from the steering rack to the steering knuckle in the wheel hub, which actually steers the front wheel. I quickly checked by removing the front wheel and wiggling the wheel hub. Sure enough, there was play in there and you could see the tie rod end being displaced. I ordered the parts, to be sure I included the outer rod ends as well as the inner ones. I also rented a special tool to remove the tie rod end from the knucle: essentially it applies force to separate the two pieces that become pretty wedged with time.

Upon inspection, the inner rods appeared fine so I proceeded to replace just the outer rod ends.
The following image shows how the full assembly looks in the car. The new part can be identified as it is clean, of course.



The following pictorial shows some details and steps of the procedure:


Front Brakes

I didn't know for sure, but it looked like the front pads didn't have much life left in them, but that's just an excuse. I wanted to learn how to do this job. So I ordered new slotted rotors from Flyin' Miata and slightly better pads, and after the compulsory DIY writeups and YouTube videos, I did it. Oh, I did have another excuse: I wanted to take the car to the track so I would probably need to start with decent brakes. Really any improvements to the engine should be done after you upgrade other aspects that will enable the car to (1) perform better at less cost than horsepower upgrades, and (2) cope with the extra power when you do increase engine output. Typically this means breaks and suspension.
Suspension is kind of expensive (1 grand give or take for a full coilover kit with sway bars), so the brakes were the immediate option.



I kept the same stock calipers and rotor diameter; you can achieve significant gains in braking performance just upgrading to better rotors and pads.

Here's a set of pictures I took of the procedure, with as much comment info as I can remember from back when I did this.

That's it for part 1; I was pretty happy with the results and it was a lot of fun doing all this stuff for the first time. I can't imagine myself taking a car to the shop again for these things in the future.


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