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-   -   Be careful when buying '99 cylinder heads. (https://www.miataturbo.net/general-miata-chat-9/careful-when-buying-99-cylinder-heads-43354/)

bryanlow 01-27-2010 02:11 PM

Be careful when buying '99 cylinder heads.
 
I've noticed a lot of people buying & selling '99 heads lately. A couple years ago I bought a '99 motor complete for $150 & I was too excited and too much of an idiot to really check it out. The motor I bought was trash. Some '99 motors had a problem with the thrust bearing at the #4 main cap. If the thrust bearing fails, little pieces of crankshaft & engine block travel throughout the motor via the oil passages & tear up everything. When this happens the cam journals & the soft aluminum, non-replaceable cam bearing surfaces are some of the first parts to be destroyed.

Buyer beware! Check the cam journals for scoring before laying down any cash. If the bearing surfaces are badly scored, the head is usually not worth buying. There is a chance it could be salvaged by turning down the cams then milling the bearing caps & align boring but unless your machinist works for cheap, this will inevitably cost you more than the price of another used head. When buying a used head make sure the bearing surfaces are clean, or at worst, only lightly scored.



BTW if anyone wants a trashed '99 head & block, you're welcome to have it!

thymer 01-27-2010 02:35 PM

good call-out!

curly 01-27-2010 02:57 PM

Where's the video showing that. Using a piece of 2x4 he was prying from the front, and then pressing on the clutch. The entire crankshaft was moving back and forth a .250" or so.

Savington 01-28-2010 12:55 PM

It is always worth the extra money to start with a working engine when doing a build.

bbundy 01-28-2010 06:01 PM

Been there done that. A failed thrust bearing basically makes everything in the motor garbage. It was a factory manufacturing problem there was too much gap for the thrust bearing and it would fall out. The crank eating its way through the block sent unfiltered ground up bits of cast Iron completely through the oiling system and chews everything up.

Bob

olderguy 01-28-2010 06:03 PM

What did Mazda actually do for the recall. A friends' car has a sticker on the door jam that says the recall was done.

Pitlab77 01-28-2010 06:05 PM


Originally Posted by olderguy (Post 514933)
What did Mazda actually do for the recall. A friends' car has a sticker on the door jam that says the recall was done.

replaced the motor.

Friend of mine that works for mazda looked up my vin and saw that the motor was replaced on my 99 under the recall.

deliverator 01-28-2010 06:06 PM


Originally Posted by olderguy (Post 514933)
What did Mazda actually do for the recall. A friends' car has a sticker on the door jam that says the recall was done.

Replaced the engine, IIRC.

jtothawhat 01-28-2010 06:12 PM

Is this problem fixable? If so I will take that motor off your hands

neogenesis2004 01-28-2010 06:23 PM

If it was caught early enough and there was no wear they likely just installed a new thicker thrust bearing.

hustler 01-28-2010 06:48 PM


Originally Posted by bryanlow (Post 514231)
BTW if anyone wants a trashed '99 head & block, you're welcome to have it!

Can I buy the lifter shims?

sn95 01-28-2010 07:27 PM


Originally Posted by bryanlow (Post 514231)

BTW if anyone wants a trashed '99 head & block, you're welcome to have it!

I'll take the trashed head!

leatherface24 01-28-2010 08:03 PM

Wow if only you posted this back in the fall of 07...

hustler 01-28-2010 09:57 PM

I want the god damned shims!!!!

KPLAFIN 01-28-2010 10:31 PM


Originally Posted by leatherface24 (Post 515002)
Wow if only you posted this back in the fall of 07...

Funny thing is, I actually thought of you and the Noah/CR BS when I read this thread the first time.

Midtenn 01-28-2010 11:14 PM


Originally Posted by neogenesis2004 (Post 514947)
If it was caught early enough and there was no wear they likely just installed a new thicker thrust bearing.

It was thicker and wider. The bad part is that Mazda superseded the old "narrow" thrust bearing with the new "wide" one, but it doesn't work in early motors. I tried every part number they listed for the thrust bearing and got a wide one every time (so if any one needs a wide std thickness thrust bearing, I've got like 4 sets).

neogenesis2004 01-28-2010 11:24 PM

Lol, I just buy ACL bearings when I rebuild.

webby459 01-29-2010 12:12 PM

Fuck, I now know all about trouble with 99/00 heads! The first one I got had alu pitting in the lifter bore area, as if there was H2O laying in there for a while from a blown hg. Now, the head I got to replace that one, my engine builder tells me the cam journals are burned, as if something happened to the motor (as above) and fuxored the journals. So, it looks like we will be working with yet a third solid head. The clock is ticking, I am thinking of minimally cleaning up the '97 hydro head that came with my cherry l/b (thanks deliverator, I fucking stole that thing) and taking my sweet ass time building up a monster BP4W head over the spring/summer. My asshole is gaping.

bryanlow 01-30-2010 05:51 PM

sn95 You can have the head, minus the shims. I'll get a quote for shipping asap.

Hustler you can't have the shims. Those things are fucking gold. You can't get a lot of sizes anymore, not even from Mazda.

I will make a deal for anyone needing shims, tho... If I have a shim that you need, I'll consider trading for the ones you don't, as long as they are in good condition. I'll post up a list soon.


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