3rd gen engines - Honda Prelude Forum

PreludeDude90 · 02-22-2002, 02:45 PM

Ok, now here's my question. I am going to need to replace my motor in my 90 Si eventually. It has a b21 in it, and i have noticed they are hard to come by. I can get one, but it is more expensive. Which is more reliable the b20, or the b21? Also, how can one distinguish a JDM motor from a USDM motor?

LUDE'Z · 02-22-2002, 06:52 PM

I have heard from some luder's that the B21A1 has a tendency to burn oil. The B20A has steel valve's compared to the B21's aluminum valve's. The JDM motor has a slightly increase in horsepower and lesser mileage.

orgasm_donor · 02-22-2002, 09:28 PM

I have heard the same things. Better to go with the 88-89 unless you plan on rebuilding a newer one. Its cheaper and has less chance of burning oil. Cheers!

PreludeDude90 · 02-23-2002, 07:40 AM

Ok, but still, how can u tell a JDM motor from a USDM motor?

Preyluder · 02-23-2002, 10:43 AM

The JDM B20A (USDM's B20A5) has a little more horsepower, and you will get lesser mileage. There's really no way of distinguishing between the two, except the VIN, and the engine code that's stamped on the block.

RedPassion · 02-24-2002, 10:29 AM

JDM B20A has I think 135lbs of torque and 145hp on the block it says B20A instead uf B20A5 or B21(whatever). Also a lot of shops tell me the JDM is a better built engine then the usdm's

JAP-SPEC B20 · 03-15-2002, 02:23 PM

The jap-spec JDM engine says B20A on the block.

The USDM engine says B20A5 on the block beside the headers.

PreludeDude90 · 03-15-2002, 06:28 PM

Well, guys, I did it. It was sooner than expected, but i now have a JDM B20A riding in my lude. Painted the valve cover red, and put a civic shortram intake on it. Runs like a champ