See above for pictures of pistons.

 

Its definitely pitting.




Light shines through on the damaged area.

 

Wasn't on this page. You expect me to sift through back pages?

Strange looking pitting. Looks more like Lichtenberg patterns than FOD.

 

https://www.miataturbo.net/build-thr...7/#post1414941

 

Ok, can somebody tell us what that is? I am in the process of building pretty much the same setup and don't want this. Nope, not at all.

 

So its definitely some sort of pitting. Occurred on 6 lifters. 2 pretty bad. 3 a few spots of it. And 1 just 2 small places. I'll take better pictures in a bit. Pretty pissed right now.

Exhaust lifters all look 100% fine. Cam journals look great, cam lobes all look fine.

 

I would put stock shims back in it. My guess is there is a material problem with those buckets, and you probably caught it early enough to save the cam. I would clean off any specs of metal stuck to the lobes and polish them, then go back with stock shims.

 

That's really weird. Typically the cam hits near the center, and fwiw the cams tend to spin the bucket a little. No where near that pitting though.

 

Right? I have no idea what caused it. Especially because the exhaust side looks perfect. But we all know how this market works. It was definitely my fault.....

I'm going to order 6 more tomorrow. Maybe overnight them. Not sure.

Replacing valve seals currently. Using my leakdown tester yo pressurize the cylinder. Leakdown number on cyl 1 looks good at least.

 

My best guess is the lifters are too soft. For sure your fault!

I think it's a lifter problem, cause stock lifters/stock cams don't do that. Are you ordering the same brand lifters as before to replace these?

 

These are lifters from Mazda Motorsports Development. Figured at least something under the Mazda name wouldn't fail me...but who knows.

$10 a piece. And I'll call tomorrow and see what they know about the failures.

 

Does anyone know what color the OEM valve stem seals match up to. I have green and grey seals.

 

Pretty easy to check hardness. I'd grab a stock shim and have the two tested. If you've ever used a spring loaded center punch it's like that but calibrated and then you measure the "crater" diameter.

 

A razor blade doesn't scratch the surface. So they aren't made out of cheese. I'm still stumped on why the exhaust lifters look so perfect compared to intake.

 

Thats so strange.

 

Anyone who has installed valve stem seals lately. Is there 1 "click" or 2? When you push them down.

 

Welp. Lost a valve keeper down the engine. This is going to be fun.

 

Man you're having some bad luck!

From memory there is one firm click, and they are seated. I used a couple light taps with a hammer (I used an extension and deep set socket to push them onto the guide) to make sure they were completely seated.

 

where did it vanish to? I has to be in the head somewhere right?

 

Nope. Fell into the block