I've done some looking and cant find an answer to this. I have 2 used rotor housings. They both have 2 small cracks in the same place. One on each side of the leading plug hole on the trochiod surface. They are located at 90* and 270* and approx 1/8" long. Now Ive read at Mazdatrix that this type of cracking at the trailing plug holes is bad juju, same thing for the leading?

 

its early in the morning so im kinda having a hard time with my pictorial memory. is it actually cracking or flaking. if its more than 1/8 flaking then, thats bad. also, you maybe able to re-use it if the cracking is between the leading and exhaust port. the reason behind is that the flaking will go out of the exhaust.

Are you building a new motor?

 

i got a t2 housing here, that had the same problem. Then one day, the stationary gear gave way, and.. well lets just say the hosuing is completely busted now, its kinda impressive.

 

I'll try to get a pic up this week. No flaking, chrome is like new, just these damn cracks. They radiate from the spark plug hole (leading) going forward and aft, like 1/8" long. Never seen this before. I'm thinking of building a fresh engine to replace the worn out POS in my daily driver. Or at least have it as a ready spare as I only have that car to get back and forth to work.

 

the 97 mazda motor sports catalog says its ok if the cracks not too big, i forget their spec though. you need colder plugs

mike

 

I didnt think to look there, thanks! I'll check it out when I get home.