The head gasket on my '99 let go (#1 cylinder, I thought the rear was supposed to be the problem??) on Saturday at VIR. I'm ordering parts to fix it, what else should I look into while I have the head off? Cometic gasket? ARP studs? Coolant re-route? EGR delete? What's a waste of money and what's prudent bulletproofing?
Subbd. Going to need this information at some point.
They're generally quite solid, headgasket-wise. Takes a lot to pop one. The factory Mazda unit is a fine replacement. Of course, check the head to make sure it's flat now.
So I'd be looking at why it popped. If you were overheating, then have a look at your full cooling system. If the radiator is original, that's the first probably point of failure.
EGR delete gets you nothing. Coolant reroute can help if you're having trouble staying cool. ARP studs are nice to have but may not save another gasket if you perpetually run hot.
Change all the coolant hoses. The ones behind the engine will be much easier to do with the head off.
It's a crate motor with approx 30k miles on it, aluminum radiator installed at that time. No obvious coolant leaks. Blew out on the warm-up lap so whatever damage was done would have been before that, I don't think it overheated until it lost compression.
Stock except for header and exhaust. Sigh. "Buy a Miata," they said, "they're slow and reliable." :-P
I'm going to say that someone screwed up on that crate somehow. Miatas just don't blow head gaskets.
send the head to me to free up a bit of power.......... 
Help me out with the post-mortem GRMers. I pulled the head and there was a substantial amount of water in all 4 cylinders. I cleaned it out, installed a new head gasket and ARP studs torqued to spec. Now it won't start. Compression results (roughly speaking, I'm not sure I trust readings this low to mean anything): 25, 10, 10, 25.
I'm open to the possibility that I've set the cam timing wrong, but I've read the internet and to my eyes everything looks correct. I can take pictures if the symptoms still strongly point to the timing being off and you all want to double check my work (pretty please let that be it).
I'm at a loss to explain the initial failure, how water could pour into all cylinders, and why I have no compression now despite water not pouring into all cylinders. I'm stumped about what to try next.
Get us those cam timing pictures.
Sorry, I should have pulled the timing cover off...
I found TDC with a screwdriver and that puts the leftovers timing mark at T and the right timing mark off into the ether. Looks like the cams might be a couple teeth off if that's how it's supposed to be...
Well that had no effect, it was only 1 tooth, and now I'm as confused as ever about these timing marks. Back to square 0.
Yeah, there should be 19 teeth between the two marks. You need to have all of the slack in the belt between the crank pulley and the intake cam, otherwise when you release the tensioner one of the pulleys winds up off by a tooth.
Did you check the head & block for flatness while you had it apart? Do you have a leak down tester?
19 teeth, check. But honestly being off a tooth or having some slack on the wrong side shouldn't give me these sort of compression results, right? It spins like there's no compression but even still I didn't trust my autozone compression tester so I trucked all the way down to my basement for my Craftsman just to make sure I wasn't seeing things.
I did check the head and block with a carpenter's square, I don't have a leakdown tester.
You are confused about the timing marks :)
For ignition timing, you want the leftmost mark at your ignition timing when using a strobe. But for static cam timing, it should be pointing at the T. Ignore the one on the right. It's a lot more obvious when you have the accessory pulley and timing belt covers off, doing it with the lower half of the engine still assembled is more of an advanced move. The car will actually start and run if you're off by a tooth on the cams, but the cams are properly timed relative to each other as far as I can tell. You just have to get them synched to the crank.
Spins like there's no compression with the plugs in? Are you sure the cams are turning? With the plugs in, do you get the load up and release (with a sigh) when you turn the engine over by hand?
I think you're pulling that head off again. The head isn't sealed to the block.
Thanks for the clarification on the timing! Sounds like I have it correct now, then.
Spins like there's no compression with plugs in, yes. More of a steady whirring than a chuck-a-chuck-a. Never even feels like it's trying to fire. I'm sure the cams are turning. I haven't tried turning it over by hand with the plugs in, I'll try that in the AM.
Dumb question -- if the head weren't sealed to the block wouldn't coolant be leaking out everywhere?
steronz wrote: Thanks for the clarification on the timing! Sounds like I have it correct now, then. Spins like there's no compression with plugs in, yes. More of a steady whirring than a chuck-a-chuck-a. Never even feels like it's trying to fire. I'm sure the cams are turning. I haven't tried turning it over by hand with the plugs in, I'll try that in the AM. Dumb question -- if the head weren't sealed to the block wouldn't coolant be leaking out everywhere?
if coolant isn't leaking... the odds are the head is mounted correctly.
What you might try and do is find TDC by sticking a screwdriver (10" long blade with handle large enough not to fall into the spark plug hole) down #1 spark plug hole. Turn crank back and forth till the screwdriver stops at its highest point. At this point you might check the crank pulley to see if the marks align with zero on the timing cover. Now check your cam timing.
If after this is all done and checked and your compression remains bad - your problem is either piston rings, or valves and valve seats.
another brainfart: Are the valves correctly adjusted??
Update -- I don't have a leakdown tester but I was able to get a compressor and pressurize the cylinders, and air just rushes out past the exhaust valves. Maybe the intake valves too but it's like the exhaust valves aren't even trying to seal and that's all I can hear. This is all 4 cylinders with the camshafts removed. I'm still at a loss to explain exactly what happened, but given the questionable state of the rings in cyl #1, I know I need to pull the whole thing out at this point. The question now is what to put back in.
1) I'm having a hard time finding a low mileage NB1 motor, but I could expand my search to a half-day's drive and pick one up at the going market rate of around $1200.
2) Have this one rebuilt. I have no interest in doing it myself at this point, so whatever the market rate is for a rebuild, which I imagine is more than a used engine but I'd have some piece of mind.
3) There's a couple of very low mileage MSM motors in the area, Figure between $2000 and $2500 to get everything I'd need from the donor car to get it running and then a MSPNP on top of that. Upshot is turbo power for substantially less than the cost of, say, a used engine + and FMII, downside is that I'd be saddling myself with a lot of the less desirable MSM components like the intake, small intercooler, and downpipe, or shelling out to replace those anyway. Also, more heat for something that's going to spend a fair amount of time on track.
4) Crazy engine swap, because the kids don't really need college anyway. I was pricing out the J32 swap but it started to feel like I was kidding myself about how much I'd spend in total, and this was the "cheap" option. K or LF swaps aren't in the budget.
One note about the MSM option - the IC routing only works on cars with 2001-05 headlights. The hole for the piping is occluded on your car IIRC.
Look up Thing 3 Racing. Then stuff the J32 in there. 
There's a thread out there where someone said he was able to modify his headlight enough to make it work. Regardless, the closer/better of the two MSM motors was just sold out from under me, so that option moves slightly further down the list, from 3 to 3.5. 
KyAllroad wrote: Look up Thing 3 Racing. Then stuff the J32 in there.
I've been watching their progress closely, and I joined the J-Miata facebook group to get some ideas. There's a lot of compromises with the swap that are acceptable for a race car like Thing 3's that I'd want to spend my way around for streetability. Things like working gauges, softer mounts, skid protection for the starter and oil pan, and A/C. All of those things seem to be possible but they'd elevate the cost considerably.
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