H23 udsm swap to h23 jdm

Fourth Generation Honda Prelude topics

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nicn4k
Prelude Enthusiast
Posts: 1
Joined: Thu Dec 02, 2010 4:59 pm

H23 udsm swap to h23 jdm

Postby nicn4k » Thu Dec 02, 2010 5:06 pm

i would like to replace my stock engine i dont want a h22 swap cause im 18 and low on cash so what will i need to swap to get a jdm h23 in my 92 prelude si i will probably purchase from hmotors please help!!!!!!!!!

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spiffyguido
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Joined: Fri Nov 11, 2005 2:55 am
Prelude Model: 1991 SE-SR
Location: Alberta, Canada
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Re: H23 udsm swap to h23 jdm

Postby spiffyguido » Fri Dec 03, 2010 3:18 pm

You have an H23 now?

If so, most parts will be the same. You'll have to swap the distributor from your engine over to the JDM engine. If the JDM engine comes with an ECU, you'll have to swap it in as well, although I don't think this would be required.

Most things should fit directly in.

bigjohn
Prelude Enthusiast
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Joined: Wed Oct 27, 2010 1:29 pm

Re: H23 udsm swap to h23 jdm

Postby bigjohn » Sat Dec 18, 2010 9:20 am

I just completed this same swap on a 93. It was pretty straightforward, even for one who has never had a FWD powerplant out of a car before. Manifolds are the same, exhaust and intake; you will need to change the top of the air plenum (different vacuum port configuration). EGR valve was different (harness connection). The brace under the intake manifold needs changed becuse of the harness support clip. Change the thermostat housing, USDM has a bolt that carries the back of the coil bracket (JDM uses a coil inside the distributor). You need the knock sensor, mine was broken on the original USDM and the JDM doesnt use one (if yours isn't broken be verrry gentle with it, it's fragile and a hundered bucks at AutoZone). Change the mounts over for the USDM AC comp, alternator, and ps pump. Use the USDM header pipe bracket, different offset. Install the US harness on the motor before stuffing the engine in, that way you won't miss any supports.

What amazed me was how tight the fit is on getting it in and out, getting the transmission (automatic) out from under its mounting bracket was a bear. Invest in one of those tilting hoist fixtures that lets you tilt the motor by turning a crank, trust me, it'll be worth it. I did it with a piece of rope. Be sure to put a thin piece of plywood over the back of the condenser fan side of the radiator.

Carefully inspect the JDM for cracked sensors and bent items, they pile them to the roof of the freght container and seperate the layers with sheets of plywood. It's amazing that they come with as little damage as they do. Maybe I lucked out and got one from the top of the heap...

Tpr_3076
Prelude Enthusiast
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Joined: Mon May 25, 2015 4:14 pm

Re: H23 udsm swap to h23 jdm

Postby Tpr_3076 » Mon May 25, 2015 4:38 pm

I just did the same swap on a 92 5spd non vtec to a 97 vtec but I'm having a problem it runs great at idle but if you give it gas it stalls and dies. I have several plugs with nothing to plug them to and several vacuum lines that I don't know where to hook them to or bypass




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