Cylinder head casting number

[brock]

Does anyone know the casting number for the 99/00 miata?

I think that the one for my 97 is BP. I found the letters BP on the exhaust side near the front half of the head. I am asking, because I may have found an extreme TCB deal on a rebuilt 99/00 head. The guy was telling me that they changed head castings halfway through the 97 model year, but I can find nothing to confirm this.

[Mark52]

Brock, this may not make any diff to you, but I believe that if you put a 99 head on a 97 block, you will get bumped into the Prepared category in autocross. I would have done the same thing long ago if not for the silly SCCA rules :mad:

[altiain]

Brock, this may not make any diff to you, but I believe that if you put a 99 head on a 97 block, you will get bumped into the Prepared category in autocross. I would have done the same thing long ago if not for the silly SCCA rules :mad:

Yep. Section 15.1.C of the 2005 Solo II rules - which deals with allowed mods in SP - reads (in part):

...The updating and/or backdating of engines, transmissions or transaxles must be done as a unit; component parts of these units may not be interchanged...

[Mark52]

Sorry for getting off the subject. My 96 head has a casting on the exhaust side of BP. I believe the 99 & 2000 heads show BP also, if I remember right. Maybe one of you 99+ hotdogs can verify this. The telltale casting is on the back of the head where nobody can see it. Based on the Mazda parts manual, a 99 & 00 head would have BP-4W cast on the back vs a 96/97 BP-E8. Hope this helps :-D

[Kags1969]

I think mine says BP4W.

Chris

[brock]

Yep. Section 15.1.C of the 2005 Solo II rules - which deals with allowed mods in SP - reads (in part):

Section 16.1.D.1 of the 2005 Solo II rules states:

Engine block must be a production unit manufactured and badged the same as the original standard or optional engine for that model.


Does this mean that you cannot put one of the 99/00 1.8L BP engines in an NA that was originally equiped with a 1.8L BP engine?


I finally found the casting number on the back of the head after a couple of hours of searching with a dental mirror and a couple of parts being removed. The casting on my 97 is BP-E8.

[Mark52]

Section 16 is for Street Modified class (as you prolly know) and yes, you can put a 1.8L BP into an earlier Miata as long as it is swapped as a complete unit (the whole engine). I'm not sure about SM, but SP won't let you swap just a head or just a block. You gotta swap the complete engine. Actually in SM you CAN swap just the head if i'm reading the rules correctly(but don't take my word for it, ask an SM person).