Hi everyone. I have a question for the Honda K24 experts as I'm having a hard time getting an actual clear answer from searching on Google. I'm currently planning to purchase a K24A JDM engine from a JDM engine depot about 2 hours from me for my K swap r50 MINI. Now, on their website, I see there are K24A RBB1 engines and K24A RBB3 engines. From my search, it seems that the only difference between the 1 and 3 are the casting date, otherwise everything else is the same?
Do all JDM K24A engines have actual VTEC like our USDM TSXs and not the "eco" VTEC that our USDM 7th gen Accords came with? Is there an easy way to tell that I'm getting whats advertised when I go to look at the engine?
Alternatively, if anyone has a lead for a lowish mile K24A2 out of a TSX near PA/DE/MD/NJ/NY thats not too expensive, I'm all ears as well. 
Sonic
UberDork
3/12/25 9:54 p.m.
All the JDM K24 RBB motors have proper performance VTEC. Not sure the exact differences between RBB1 and RBB3, I have a K24A2 from an 07 TSX in my Civic, it is wonderful.
In reply to Sonic :
Thanks! So sounds like, as long as the head has the RBB stamp, it *should* have the proper performance VTEC? I guess I can also try and peak into the oil fill cap and try to see if I can count 3 lobes on the cam.
No appreciable difference between RBB1,2,3. But RBB on the head is the key.
If the place is only two hours away, they should have no problem with you popping the valve cover off to verify both the presence of the three-lobe cams, but also to inspect the general nature of the engine internals.
Look for pitting on the cams, which can happen if the car sat for awhile in a moist climate. Or perhaps really gunked up oil, if it had never been changed -- I had one like that.
You can also easily take off the exhaust and/or intake manifolds to eye up the combustion chamber insides. Or if you have a boroscope/endoscope tool, you can peak in through a spark plug hole.
You don't want any surprises.
As for low-mileage USDM TSX motors? Good luck with that. :)
Best option for that one is LKQ -- they are nationwide and can ship stuff around between locations.
PS: Another option that has started to pop up is imported Euro spec K24A3 motors. Same basic engine. The JDM supply is getting thin and what remains are not always in the best shape.
Andy Hollis said:
No appreciable difference between RBB1,2,3. But RBB on the head is the key.
If the place is only two hours away, they should have no problem with you popping the valve cover off to verify both the presence of the three-lobe cams, but also to inspect the general nature of the engine internals.
Look for pitting on the cams, which can happen if the car sat for awhile in a moist climate. Or perhaps really gunked up oil, if it had never been changed -- I had one like that.
You can also easily take off the exhaust and/or intake manifolds to eye up the combustion chamber insides. Or if you have a boroscope/endoscope tool, you can peak in through a spark plug hole.
You don't want any surprises.
As for low-mileage USDM TSX motors? Good luck with that. :)
Best option for that one is LKQ -- they are nationwide and can ship stuff around between locations.
PS: Another option that has started to pop up is imported Euro spec K24A3 motors. Same basic engine. The JDM supply is getting thin and what remains are not always in the best shape.
Thanks I appreciate all the info! They'll probably let me walk around and look at a few of the engines if they're reputable I'm sure. They have decent enough reviews so we'll find out.
They do have some K24A3 engines as well. So they're the same thing then? Same internals, oil squirters, all of that?
Japanspec said:
They do have some K24A3 engines as well. So they're the same thing then? Same internals, oil squirters, all of that?
Essentially, but not exactly.
Some info here: https://en.wikipedia.org/wiki/Honda_K_engine
Andy Hollis said:
Japanspec said:
They do have some K24A3 engines as well. So they're the same thing then? Same internals, oil squirters, all of that?
Essentially, but not exactly.
Some info here: https://en.wikipedia.org/wiki/Honda_K_engine
So from that link it seems like a bit lower power but a bump in torque? Didn't see much about internals though unless I missed it.
