b18 with b21 crank. . . possible???

Just as the title states, can it be done?

My current DD runs like a champ, but I am unsure of its mileage. Not to mention it leaks oil and smokes at high RPM.

I already have a spare B18a1 block that’s been decked and machined for rebuild.
Just have no idea what route I wanna take with it.

I’ve read about N/a builds for that motor WITHOUT vtec and it seems good.

But I know I will have that Vtec hitch.

So after browsing through some prelude forums I came across a thread where a guy did what I want to do but vise versa.

He used a b18a crank into a prelude b20a5 motor. He’s outcome was pretty good and had a reasonable 155 whp. Except for his case he was DE-stokin the motor.

So what if I stoke my b18 into a 2.1 motor?
I have a the parts for this build.

Which would be a PK3 2.1 crank along piston to match it up. The crank and pistons came out off a 90-91 Prelude B21 motor. And would also use H23 rods for reinforcement.

Hope this makes sense guys.

So any usuable info would be apreciated. And if I am able to pull this build off I would include a write up to have a true 2.1 motor

Jozey

This doesn’t seem like a good idea. First of all, the prelude setup is different than the integra setup and the motors, im pretty sure, are also quite different. Like the F series… the prelude f series isn’t aaaaanything like the s2k series.

Im not saying its not possible. I just think your going to be in way to much shmonies for results that might be dissapointing. Id say do a gsr swap. Easy, much more fun, and more reliable!

No.

You might as well do a h22a swap.

From my understanding the H22 swap is too much work involved, but I wouldn’t mind having one. I would assume it would have good results over all. Most ppl swap b20 into their Da/Db so why not built a true 2.1 motor?

Internally meaning crank piston etc is the same as the B21a1 Prelude motor. That motor is just a stoked out crank to achieve the 2.1 #s. If its been done vise versa, where someone swapped a b18 crank into a b20a5, which resulted in DE stokin the motor and had good #s and a good power curve, why can’t the same same be done to a B18 block usin a b21 crank. If I remember correctly everything lines up perfect except for the shims, which a little machining fixes that.

I will do some more research, I need to do this soon cause my current motor sounds like its going to be on its last leg soon /: