Well I went and broke my Miata

KendtEklund · **Joined:** Tue Mar 27, 2007 7:29 pm **Posts:** 1204

JamesMilko wrote:

This x4.

I guess I'm in contention for the burnt piston award now being as my current count is 4. Need to spend some time looking at the exhaust valves, at least 2 are burnt.

Ryan Holton · **Posted:** Mon Mar 07, 2011 10:33 am

Damn, that's pretty impressive.

When I pulled the head on mine I didn't find ANYTHING wrong. Weird....

JamesShort · **Posted:** Mon Mar 07, 2011 10:50 am

Well obviously he was that miata in front of the Porsche GT2 or Koenigsegg that was driving dangerously and about to burst into a ball of flames.

FLAT OUT.

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

JamesMilko wrote:

Does anyone have the tool or a tool that works to remove the Miata valve retainers? They are recessed into the head casting so most normal tools won't work.

Not sure what a "real" tool is for valve retainers, but I have one of these style compressors, and I use a magnet to install/remove retainers (works fine on d-series honda motors at least):

JamesMilko · **Posted:** Mon Mar 07, 2011 12:36 pm

Not sure if that will work. The problem is that the valve spring and retainers are recessed into the casting about .75-1". You need a really long crows foot on the end of the tool. Something like http://www.amazon.com/OTC-4572-Valve-Sp ... B000F5ECUY works. I'm likely going to run to sears and get a normal valve compressor, I have some PVC at home I can cut up to make the crows foot.

That somewhat shows the issue, it looks like most people seem to just cut up a deep socket/piece of PVC and use a regular valve spring compressor. I like the PVC idea since it eliminates the chance of marring up the casting.

DickRasmussen · **Posted:** Mon Mar 07, 2011 12:50 pm

JohnByers wrote:

This is absolutely a new piston failure on me. Never seen one fail on the edges like that.

(

The damage on the Spec Miata piston that Dennis Shaw showed me was at the edges also. However, it just looked melted/distorted, not broken/missing.

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

JamesMilko wrote:

Not sure if that will work. The problem is that the valve spring and retainers are recessed into the casting about .75-1". You need a really long crows foot on the end of the tool. Something like http://www.amazon.com/OTC-4572-Valve-Sp ... B000F5ECUY works. I'm likely going to run to sears and get a normal valve compressor, I have some PVC at home I can cut up to make the crows foot.

That somewhat shows the issue, it looks like most people seem to just cut up a deep socket/piece of PVC and use a regular valve spring compressor. I like the PVC idea since it eliminates the chance of marring up the casting.

I don't see why the one I have wouldn't work. The 2nd piece from the top is the valve "topper" actuator. It's about 4-5" long and cylindrical with 2 holes cut out to access the retainers.

Personally I hate the C-clamp style, they are a pain in the ass to use. This one bolts to the top of the head only.

JamesMilko · **Posted:** Mon Mar 07, 2011 1:52 pm

DickRasmussen wrote:

JohnByers wrote:

This is absolutely a new piston failure on me. Never seen one fail on the edges like that.

(

The damage on the Spec Miata piston that Dennis Shaw showed me was at the edges also. However, it just looked melted/distorted, not broken/missing.

This one was melted as well, just pretty severely so. There are no nicks on the head, piston or cylinder wall so no big chunks broke off. Some of the other ones are a bit more roundy and melty looking. This one just looked the worst.

jeremy gast · **Posted:** Mon Mar 07, 2011 2:07 pm

that tool mike has will work. I have used something similar to that many times when i at worked at carquest and mobile auto machine shops back in the day.

JamesMilko · **Posted:** Mon Mar 07, 2011 3:20 pm

Ended up being a non-issue. The shop I'm dropping the head off at (CHS) charges the same if I leave the valves in or take them out for them, they'll also return it with the valves back in.

DickRasmussen · **Posted:** Mon Mar 07, 2011 4:23 pm

JamesMilko wrote:

Ended up being a non-issue. The shop I'm dropping the head off at (CHS) charges the same if I leave the valves in or take them out for them, they'll also return it with the valves back in.

That may be typical. I experienced the same thing in the past. Their pricing structure is for repair shops who probably don't have the time/tools to bother with that kind of work.

Installing rods to pistons is normal also as I recall. Easy for them.

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

JamesMilko wrote:

Ended up being a non-issue. The shop I'm dropping the head off at (CHS) charges the same if I leave the valves in or take them out for them, they'll also return it with the valves back in.

$155 for a 16-valve job?

They haven't changed their prices in years!

JamesMilko · **Posted:** Mon Mar 07, 2011 6:10 pm

You got it.

JamesShort · **Posted:** Mon Mar 07, 2011 7:53 pm

You already have Andrew's old bottom end in there, ready to slap a head on?

JamesMilko · **Posted:** Mon Mar 07, 2011 11:16 pm

Andrew's old motor is sitting in a tire still. Once I get the seals from Mazda I'll tear it down and stuff it in my car. Once it's in I'll get the head on the motor. I have some confidence I'll make the March 20th AX with the Miata.

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Well I went and broke my Miata

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