I am looking to buy a 20B that has been rebuilt in Japan. They used 13B rotor housings. The engine is removed from the car and trans. Are there any other serial numbers on the engine other than rotor housings obviously, that are easy to find, to identify what series it is A B C D etc

 

my 20b has the number stamped on the steel plates as well

next time search, the info you seek is here in the 20b section

https://www.rx7club.com/20b-forum-95/20b-faq-links-370451/

 

In addition to the plates, the numbers are also stamped on the front cover.

 

Thanks David
I take it the front cover would be the easyest place to find it as its not covered in polution gear?

 

Thanks for that i had already found that page and was more interested in any other location on the engine.
The guy selling the engine said there wasn't any numbers because the housings had been changed but sounds like he may have to look a little harder.
Do the early 20b's have sequential turbo written on the inlet manifold?

 

As I recall, the stamp on the front cover is near the bottom but it is accessible without removing the engine. It is easier though to see the stamps on the irons. They are on the top of the irons and easily seen.

Here is a pic of my center iron and its number, C339:

 

Thanks David much appreciated

 

The importer has looked everywhere you suggested and can't find any numbers. Is it possible that mazda rebuilt this engine and replaced housings and centre plates or that it never had any numbers?

 

Any thing's possible but I have never heard of this before. Every piece of the short block should have a stamp on it.