masospaghetti

A local guy is selling a freshly rebuilt (~5000 mile) H23A1 with "high compression Prelude VTEC pistons" and claims a 11.6:1 compression ratio. This seems excessive but he says it will run on pump gas. I assume he put in H22A pistons (that produces a 11.6:1 CR according to this calculator: http://www.zealautowerks.com/hfseries.html)

This is by far the cheapest way to freshen up my car as long as this setup is legitimate. $550 delivered for complete motor, alternator, M2S4 transmission, ECU, and wiring. I couldn't buy another used F22 and transmission for that. Right now the cams and ECU are stock.

Any thoughts? It's going into a 92 EX. Thanks.

Tachi

Iirc, and I did a*lot* of research on this, and the pistons are the same, in terms of compression between the two engines. The h23av has smaller valve reliefs but the compression ratio is the same. The type-s pistons in a h23av give just barely a 11:1 cr.

Also, a stock h23av is $1000 shipped by itself, and that's with a service history more questionable than Hilary Clinton's email security. I would be more suspicious than a Catholic pastor with a teenage daughter about this combo.

masospaghetti

The calculator I used shows the stock H23A1 compression ratio to be 9.3:1 and everything I've found says the pistons between the H23A1 and H22 VTEC are different - Now i'm even more confused. The stock H23A1 in the Prelude ran on 87 octane so there's no way it could have a 11.1:1 compression ratio.

The guy just did a K20 swap into his Prelude and was unloading his garage. I am always skeptical about craigslist buys but the pictures of the motor look extremely clean. I was going to pull the timing cover, valve cover, and try and get my boroscope into the spark plug holes and make sure everything looked OK (and of course, turning the motor over) but I won't be able to hear it run.

GhostAccord

Masospaghetti, you are correct about the H23A1, stock it runs around 9.8 compression ratio.

An H23A1 with regular H22A1/A4 pistons would net you approx. 11.6:1 in an H23A1 block with the stock H23 rods. It will run on high test (premium) pump gas and a proper tune.

Tachi seems to be talking about the H23A VTEC from Japan.

Tachi

I'm sorry. I was operating on not a whole lot of sleep. v_v

masospaghetti

Any other comments before i get this thing? I'm supposed to pick it up Wednesday.

Scott Little

Its been about 10 years but I believe I had a H22a and I put in H23 Rods and it only lasted about a week. I cant for the life of me remember why I ended up doing that but one of the Rods pretty much exploded. Putting some old stock, most likely 150,000 plus mile pistons into 7k+ revving engine was not a good combo for me. I would definitely have revved it to 8k but I was still breaking it in. I was on the freeway heading to work and the car suddenly sounded like a Subaru. lol


Sounds like a great deal since you cant even get a transmission for that price. Without building the engine yourself I would honestly plan on it lasting less than 100,000 before you have issues. I wouldn't be shocked to hear it lasted less then 50k. The more background you can get on the engine and how it was build will definitely help. In my experience any time you touch the bearings in a Honda Engine it changes from a 300,000 mile engine to a 100,000 mile engine if your lucky.


Its a great deal but just make sure to set you expectations reasonably.

masospaghetti

THanks everyone for replies so far.

I assume the H23 rods aren't meant to be revved that high? Do you think the H22 pistons would be a problem?

I am always leery about work done by someone else but the deal seems too good to pass up...

GhostAccord

It's not the F22/H23 rods that are the problem in most cases. It's the hardware that connects them.

What RPM ranges are you looking to operate at?

I believe there are ARP con-rod bolts that you can use for piece of mind.

masospaghetti

It's higher compression but otherwise stock, so I would assume the powerband would be the same? So stock redline ~6500 RPM?

Other than the pistons the motor is all stock, including the cams.

GhostAccord

Those rods will be fine then. I shifted my F22B2 @ 6500 - 7k all the time. Same rods as the H23A1. Unless you are going to be in that RPM range constantly, I wouldn't worry about it. However, if you have your doubts. Look into ARP con-rod bolts.

masospaghetti

Finally got the motor into the car last night. Not hooked up yet though.

Running the H22 pistons with stock tune will it help to adjust my ignition timing? I assume I will want to retard it somewhat due to the compression ratio?