Did a leakdown test on my 99 H22.

It's got about 170k miles and 30 track days, so it's been excercised but I don't abuse it. The motor is stock.

I did a compression test also and it was within the acceptable range (~ 190 psi across the board, with Cyl #2 showing about 175).

The leakdown test was done at 100psi, the results are as follow:

Cyl #1 100psi, held 83

Cyl #2 100psi, held 73

Cyl #3 100psi, held 83

Cyl #4 100psi, held 88

And it was leaking out of the crankcase breather, so it's the rings.

Good news is that the headgasket is ok since the coolant didn't bubble over during the leakdown test.

My questions now are:

1). The car needs a new timing belt service, do I go forward dropping more cash on this motor?

2). How do ring failures usually occur? Spontenous, or just greater and greater increase in oil consumption?

3). I guess it's time to start using 15W50

4). The cylinders in this engine are lined with Nikasil and the motor, from the factory, runs rich (which has a tendancy to "wash" the cylinder walls), should either of the factors (or could either of these factors) have any mitigating effects on the greater than avg. leakdown %?