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F23 swap in Gen 5


Old 05-27-2012, 01:24 AM
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Default F23 swap in Gen 5

@250K miles the F22B2 in my wagon was using oil and sounding like a tractor. Low mile F22s are getting pretty hard to find so I bought an F23A1 with 116K miles out of a 2000 EX sedan for $325. I have a wagon which has a lower 4.29:1 final drive than the coupe/sedan's 4.13:1 and, since most of my driving is on the highway, I decided to buy a 160K auto trans out of a '97 EX coupe for $200. This is how I did the swap:

Parts to grab off the F22:
  • flex plate
  • IACV
  • throttle body
  • alternator
  • EGR valve
  • fuel rail & injectors
  • upper radiator hose flange with thermoswitch B
  • temp gauge sender (if swapping a 2000 or later F23)
  • power steering pump bracket
  • driver's side engine mount bracket, or swap out the F23's 101mm stud with the F22's 60mm stud
  • distributor and coil*
*Note that I used the separate coil/distributor from the F22B2. If swapping from an F22B1 then the F23's internal coil distributor may not have to be swapped.

Part to buy:
  • Three-wire to two-wire IACV adapter. I got mine from Rosko Racing. BlackTrax Performance makes one too. They're $40 - $50 shipped.

I replaced the water pump, timing & balance belts, all front seals, rear main seal, axle seals, input shaft seal, torque converter O-ring, fuel filter, and adjusted the valves while the engine was out. So much easier to do the front stuff while the engine's out.

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IACV adapter installed; three-wire IACV shown.

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One of the 2-wire IACV's steel coolant line runs right into the TPS. It could be cut down enough for a hose to fit but it would be pretty short, and no barb on the end. I decided to cut it down and braze a 1/4" copper plumbing elbow to it, then sweat soldered 3/8" copper pipe and a 3/8" elbow to route the hose up above the TPS.

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The F23 fuel rail has no hole for the banjo bolt. The F22's rail & injectors fit perfectly using the F23's stand-offs.

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F23s don't have a thermoswitch B, at least not where the F22's is. On my 2000 F23 the hole for the temp gauge sender was plugged. I think 2000 and later Accords' temp gauges use the ECT instead of a separate temp sender.

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Unbolt the F23 EGR, put the F22 EGR in its place.

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The F23's aluminum A/C bracket geometry is identical to the F22's cast iron bracket and weighs about half as much.

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Alternator plugs are different. Swap out the F23's power steering bracket before you mount the alternator.

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The IAT harness is about 10" too short. To keep splices to a minimum, unwrap the F23's harness - if you have it - and take the IAT plug/wire out of it and solder/heat shrink it to the F22's harness. Otherwise just make the wires longer.

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6th Gen Accord automatics don't have throttle control cables, so no place to attach the cable to the throttle body. The F23 throttle body may work on a manual trans car for for the throttle but I don't think the cruise control cable will fit right. I've read that F23s & F22 have the same size throttle bodies, 60mm, so no performance hit using the F22's.

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The F23 throttle cable bracket is too far away; not enough adjustment for the cable to fit right. A hole drilled in the middle of the bracket and the bracket mounted on the manifold hole closest to the throttle body seems to be about right.

I also had to rig up a coil mount because there's no mounting holes for the coil bracket to fit on the F23A1 head, and even if the holes were there the VTEC solenoid is in the way.

I'm currently running the car with the P0J, non-VTEC ECU. The F23 has quite a bit more grunt on the bottom end although it runs out of breath on the top end because the VTEC solenoid isn't getting turned on. I had to wire the VTEC solenoid wire but didn't include that in this post because it's covered in plenty of other posts.I have a junkyard P0H (VTEC) ECU but I get a solid CEL while pulling the codes so I'm pretty sure it's junk. I'll have to buy a new one, preferably a wagon-specific P0H-A71 or P0H-A72. No CELs with the P0J. No pinging with regular (85 octane) gas @ 85F ambient; I was worried about that since the F23 compression is a half point higher than the F22. The thing I really notice is how quiet the engine is; it's much quieter than the old, worn out F22. And the engine is turning about 250 rpm slower @ 80mph with the higher final drive.

Cost was $325 for the engine, $200 for the trans, $40 for the IACV, $565 total (not including the maintenance items), less $320 I got back selling the old engine & trans on Craig's List: $245 net.

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Last edited by Roader; 05-27-2012 at 01:29 AM. Reason: ...mounted on "the manifold" hole closest...
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Old 05-27-2012, 08:25 AM
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Nice !
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Old 05-28-2012, 09:02 PM
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Default Update w/new ECU

Installed a P0H-L51 from a '96 EX sedan. Car runs great, no CEL's, and pulls very strong from idle to 6000 rpm, noticeably stronger than the F22.

One thing I didn't mention: I've read that an F22 intake manifold bolts right up to an F23 head. Probably lose five or so horsepower but it would eliminate the need for the IACV adapter.
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Old 05-29-2012, 12:20 AM
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Nice job. I think I'll move this over to DIY.
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Old 06-26-2012, 06:25 PM
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Default Pinging

Noticed very slight pinging in around-town driving but only in 100+ weather - never heard it in cooler weather. Switched from 85 octane to 91 octane and no more pinging. If looks like the F23 will need premium in really hot weather.
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Old 10-26-2012, 01:19 AM
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hey roader i don't wanna sound dumb but at same time wannaq be sure .my car.....97 honda accord lx..engine...auto f22b2 non -vtec 2.2L sohc 16 valve.withi the F23a1 this link------>'98-'01 Honda Accord Engine 2.3l Vtec F23A1 40K MILES!!! fit in like you said and did kina easy.and bolt up with my [email protected] thanks for your time
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Old 10-26-2012, 09:08 AM
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Dan, it's the right engine.
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Old 10-26-2012, 11:16 PM
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Talking Great Post Roader

Very good post with great pictures ..Thanks for your thread on this..


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Old 11-15-2012, 10:14 PM
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Nice dude! I swapped an F23 into my CB7 back in the day. It was a torque monster!
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Old 11-16-2012, 12:57 AM
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I've always thought about this swap since I had done the f23 intake manifold swap in my f22. My mom has a 98 accord which ive found is bigger than my 97. Feels a bit more powerful to accomodate the size of the car.

One trick I found in the manifold swap was that a throttle body spacer works perfect for the IACV coolant lines. It creates enough distance from the tps not to cut off the coolant flow. But then theres a tight squeeze of the air intake depending on whether its stock or not.
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