Old age likely got that gasket.  4 banger mazda heads don't warp easy.

Mike

If you have a reliable straightedge, you can eyeball it for serious
warping... an optical flat would be a lot more accurate but the straightedge
is better than nothing in a pinch.

If the valves are bad, it won't pass a compression test once you have it
back together.  So yes, you waste a good bit of working time by not taking
the head to a shop, but you save a lot of waiting time.
--scott

Well, at least mostly alive...

It's running - There's no denying that.

Trouble is, besides "pistons going up and down turning gasoline into
exhaust and making crankshaft go 'round and 'round" style running, it's
also running water - a steady trickle, maybe an eigth of an inch
"thick". And I'm damned if I can spot the source! Wherever it is, it's
somewhere on the front of the block - At first, it appeared to be coming
off of the harmonic balancer shaft, which makes very little, if any,
sense - There shouldn't be anyplace there for water to come from!
Putting it up on stands and crawling underneath with it running changed
the "where it falls off the engine" location to just below the "hatch"
to the timing chain tension adjuster (which is just above the harmonic
balancer - Moved the "drip point" up about 6 inches, basically). THAT
makes no sense - There's noplace for water to come from there - OIL?
Sure - Oil *COULD* come from there *VERY* easily if it wasn't properly
gasketed and permatexed. (it was/is) But not water.

Which pretty much narrows it down to the water pump, I guess - there's
noplace else on the front of the engine that *CAN* leak water - The
timing cover, with chain beneath it, is the only thing there, and *WAS
NOT* removed from the block yesterday while I was tearing the stuff off
the front of the engine. It has one water passage - a pass-through from
the water pump to the block, and the front of the timing cover makes up
the back of the water pump.

The water pump had to be removed to allow access to the timing chain
adjuster hatch, but it was put back on with a new gasket, doped heavily
with permatex blue on both sides, and *VERY* carefully tightened and
inspected, showing a plainly visible bead of permatex mooshed out of the
seam all the way around.

I wonder if the water pump seal/bearing is leaking? But I can see no
sign of water there, either.

Can't see the bottom half of the water pump now that everything is back
together - stuff in the way, including the lower radiator hose, and
harmonic balancer/crankshaft pulley. All hose clamps are tight by feel,
but two of the ends are impossible to see now that things are back
together - it COULD be one of those two hoses leaking, I guess...

Only other thing that's worrying me is what looks to be a small amount
of oil in the cooling system now, but I can't rule out the concept that
oil spilled from the oil galleries into the water jacket when the head
was lifted. Gonna do a multiple drain and refill to try to rule out
and/or clean up that possibility. Crankcase is water-free, as far as I'm
able to tell from looking at the dipstick, and the amount of oil in the
cooling system seems to be quite small - just a "skin" on top when I
look into the radiator after shutting it down and letting things settle
for a minute or two. No pressure, suction, or foaming at the radiator
when it's running, so clearly no compression getting into the system.
(unlike the other day when the gasket let go, and there was *ALL KINDS*
of pressure and foam happening)

Aside from that, it *IS* running, and miraculously, I managed to get the
timing to within about 2 degrees before ever hooking up the timing
light. I expected it to be *COMPLETELY* out of time, since I rolled the
crank (both directions) several times while dinking with getting the
harmonic balancer bolt broke loose, then torqued back down yesterday,
and fumbled the distributor twice, both times visibly moving the gear on
the "recovery".

Timing chain was, *OF COURSE* wired (OK, actually zip-tied, but close
enough, right?) to the camshaft sprocket before the sprocket was pulled
off the camshaft, and there's not enough room on the crankshaft end to
jump a tooth in either direction (due to multiple "chain guide/keeper"
flanges around the crankshaft sprocket - I know from tearing down the
other, identical, engine to prepare for a full rebuild that unless the
sprocket is removed from the crankshaft, it's impossible for the chain
to move far enough off its seats on the sprocket to skip a tooth) but it
still seems like a miracle that I was able to stab the distributor so
close to perfect after moving both the gear on the camshaft *AND* the
distributor while they were unmeshed!

This thing *HAS* to roll out on a roughly 600-700 mile journey tomorrow
morning, so any advice on finding/killing the water leak is more than
welcome, especially if it comes *FAST*.