Hey everyone,

I’m new here and hoping to get some help identifying the engine in my car. I have a 2013 TSX SE Edition, which originally came with the K24Z3 engine. The previous owner installed some aftermarket parts (not sure if that’s relevant to the engine identification), but I recently had a major issue where I hydro-locked the engine and had to swap it out.




The mechanic who did the swap told me that the replacement engine came from a 2014 TSX. When I looked at the bottom block, I noticed it has a stamp that reads K24A R40 (I’ve attached a picture of it below). However, I’m finding conflicting information when I search online as to most say the 2014 TSX comes with a K24Z3.





Additionally, while inspecting the engine, I found a sticker on the K24 head that says “RBB.” I've read that some K24A engines in Japan may have different specs or designs, which has added to the confusion.


Can anyone help clarify if the K24A R40 stamp corresponds to a 2014 TSX engine and what the "RBB" sticker might indicate? I’d really appreciate any insight or further resources on this to help me determine how I wanna build out my engine whether that is an NA or Boosted set up.

Thanks in advance for any help!