H23A1 swap into a 92 EX

[masospaghetti]

I looked for info on this and didn't see anything (everything seems to be H22 or H23 VTEC related), so apologies if I missed it.

Someone local is advertising a freshly rebuild 94 Prelude H23A1 using Honda parts, non-grindy M2S4 transmission, ECU, and harness for $490. That seems like a steal and a cheap way to freshen up my car, AND get an extra 20 ponies out of it.

I know the transmission needs a couple holes tapped and I assume I should use the Prelude ECU - correct? Any additional wiring I need to run? I already have the IABs since I have the EX. Will my power steering pump from my F22 work?

Thanks everyone!

EDIT: Forgot to add this motor is advertised with "high compression vtec prelude pistons".

[93redcb7]

well if its high(er) compression you will likely need to get a tune, rather than that if its obd1 it should be PRETTY much drop in

[judonoh]

like ^ said its pretty much a straight swap. be sure to confirm the injectors. You can tap the transmission or buy a conversion bracket. I would still change out the rear seal, just for peace of mind. As for the pistons you have a couple options.
>run premium fuel and you may have to retard the timing if pinging
>get chipped/tuned

[masospaghetti]

Thanks for the replies. Will the stock injectors work? What do you mean by "confirm the injectors"?

[Jarrett]

I'm sure he means to confirm that they are the factory H23A1 injectors (which are the same as F22A injectors). If they are, then the suggestion to run a facotry P14 ECU is a correct one. If not, then it's anyone's guess as to what they are and a tune will be required.

There's a 95% chance that they're just stock injectors, though.

The only issue you'll run into is the power steering brackets and pump. That would all depend on whether or not you plan to keep them, too. If you do, you'll need a P39 bracket, P11 pump and a '92-'96 Prelude high-pressure power steering hose.

[masospaghetti]

Can you elaborate on what the P39 bracket, and P11 pump are?

I thought the F22 pump would work, is this not the case?

[Jarrett]

No, the pump that comes on the '90-'93 Accord (it's not F22A-specific) can only be used on a DOHC engine with a PT2 power steering pump bracket. Those are incredibly rare, and you likely won't be finding one. The came on cars in Japan and Europe and haven't been made in 23 years.

The P39 bracket is the power steering pump bracket for the H23A1 or DOHC F22B. The P11 pump is the pump that came on all '92-'96 Preludes.

[masospaghetti]

Thanks. The P/S pump bracket is still on the motor, so looks like I need a prelude pump and high pressure line.

[deevergote]

If they used stock spec H22A pistons with H23A1 crank and rods, you're looking at an 11.66:1 compression ratio. That's pretty high (and not something I'd expect the stock P14 to be able to handle properly.) That's using H22A4 pistons. If they used JDM H22A pistons, you'll be at 12.47:1, which is pushing the limits of streetability. Anything more, such as Type S or Euro R pistons, and you're at 13:1.

I'm always wary of anyone that rebuilds any FRM-sleeved block. Not everyone knows what they're doing when it comes to that. Do it wrong, and you've got yourself a paperweight.

The H23A1 swap is pretty much the same as the H22A swap, minus the VTEC wiring.

[thumping_accord]

I have done this swap in my 92 lx, except I used my stock trans and the F22a1 wire harness. For that I had to run a couple extra wires, one for the knock sensor and two for the iab's, and if my I can remember correctly I think you will need to use the front water neck off the f22. It is a direct swap though for the most part.

I too would be cautious about the rebuild, given my experience when I rebuilt mine. The FRM sleeves that Deev is talking are super finiky! If there is any kind of wear on the sleeves when it was rebuilt it will cause issues down the road. Also since I've been through sleeve issues with my h23a1 I have found that not all mechanics or machine shops know much (or anything) about FRM sleeves. I can say this if the sleeves were bored or honed using typical methods you can pretty much scrap that puppy. I would get a lot more info on who rebuilt it and how it was rebuilt.