H22A Swap guide for CD5 Accord
Hey guys haven't posted here for a long while. Not sure how many people even care or would even attempt to do this swap. But here's a guide I posted on another forum back in 2004.
"The fundamentals to swapping a '94 Prelude H22A engine into a '94 accord"
Article Taken from “Honda Tuning” magazine featured February 2004
Engine Removal
Common sense dictates that you should arm yourself with a factory service manual. You’ll spend less o it than all the parts you probably break if you don’t use it. The F22 can be removed from either the top or the bottom, but dropping it from the bottom is easier if you have a lift and engine dolly at hand.
The Trick is to keep the A/C system intact and in the car (including the compressor) during the swap to avoid having to refill it. With compressor removed from the engine, string it up to the lower radiator support to keep it out of harms way.
Keep in mind that a lot of pieces are being reused, so its time well spent making sure you have everything unhooked before you move the engine. Removing the radiator will the engine compartment less cramped, especially if you’re working through the top of the engine compartment, Honda radiators have plastic end tanks that wont hold up to a swinging engine. One tap and they’re toast.
Our swap victim was a very sleepy looking ’94 LX with five speed. Our H2 came complete from HAP Recycling, ad it was from a 94 Prelude-perfect. With the two engines sitting side-by-side you’d be able o quickly piece together all the right bits.
Engine Mounts
Getting the H22 bolted in will require cutting tweaking and general rearrangement of the stock left side mount, or the purchase of Hasports part for this swap. The Hasports part is solid aluminum and comes with a polyurethane bushing, which reduces engine movement but increases vibration compared to stock rubber. The other three mounts are based on original parts. It’s a good time to consider the original mounts you’re reinstalling (hint, buy new mounts). A few decent launches will finish off any old and cracked mounts and its too easy of a job to pass up when the engine is out.
You’ll have to use the softer accord front mount because the stiffer prelude mount is the wrong height – bummer. Either the Accord of the Prelude rear bracket and mount set ( no mixing and matching between them) can be used but the Prelude parts are stiffer and a wiser choice.
If your car started automatic, you’ll need to weld the manual transmission bracket (Honda P/N 60831-SV4-970ZZ) to the right frame rail in place of the automatic part. Or keep your eye out for Hasport-produced mount that will adapt the autos frame rail bracket to a manual transmission.
Wiring
To prep the wiring harness, there’s enough soldering to kill half your brain cells, and plenty of work to stress out the survivors. Hasport also makes one that’s plug and drive. If you go the easy way, you’ll get a modified Accord harness and a separate sub harness, which connects the unique ***** guts to the h22a ECU. To tackle it yourself, get the two engines side by side, add a tasty beverage and get familiar with these mods.
-The oil pressure sender wire, while still using the accord plug, gets extended 5 inches to reach the H22’s sender.
-The electronic air control valve is located near the middle of the fuel rail on the h22 rather that near the throttle position on the F22. To accommodate the EACV plug and its yellow/black and blue/yellow wires gets moved to the center of the injector harness.
-The vehicle speed sensor plug gets moved from the front to the back in the engine, near the O2 sensor plug. Same wires, different location to fit around the h22a.
-Because the distributor is closer to the coil on the accord vs. the h22, the coil, EGR and fan switch circuits need lengthening. While on the EGR wires, change the connector from the accord’s 3 pin square connector to the preludes round one. You can keep the same pins but swap out the plastic connector.
-The intake air temperature sender is located at the end of the intake manifold on the h22 vs. the middle of it on the f22. Extend its red/yellow and green/white wires to fit.
-If your car didn’t come with VTEC, you’ll need to add the wiring for the air intake bypass (AIB), knock sensor, VTEC oil pressure sensor and VTEC solenoid. IF your car was EX, you will only need to add wiring for the IAB and the knock sensor.
-The knock sensor circuit (red/blue) which isn’t there on the stock f22m is added at the same breakout as the oil pressure sending wire by suing the pigtail from eh prelude harness, This wire connects to the sub-harness and then to the ECU pin D3.
-The h22’s AIB circuit that opens the short high rpm runners in the intake manifold also gets added by tapping the black/yellow wire form the h22’s plug to the same color wire that foes to the distributor in the Accords harness. This simply supplies power to the AIB solenoid. The pink signal wire goes from the AIB Solenoid back to the sub-harness/ECU at pin A17.
The VTEC oil pressure switch wiring will already exist on the Accord EX’s, but the rest of us need to add the circuit., The plug from the h22a and its light blue wire gets routed to pin D6 on the ecu. The black/red wire form the switch goes to ground.
-To hookup the VTEC solenoid, connect its green/yellow to pin A4 on the ECU.
-In a futile attempt to throw us off, Honda switched the EGR solenoid valve wire and the O2 sensor heater wire on the ECU’s A connector (pins 6 and 11) on the prelude as compared to the Accord. Swap those two pins in the under das connector and thank the engineers for there effort.
Engine Accessories
Getting the engine dressed with the right combination of parts will be easy if you have everything in front of you outside the car, So resist the temptation before you have a game plan of which parts to use, For engine accessories its all h22 except for the Accord A/C compressor and compressor bracket, Mixing prelude and accord accessories makes either accessory drive belt unusable, but NAPA part number 25-060425 is slightly smaller (42.5 inches, six rib) and works great. The Accords high-pressure power steering line will to be cobbled to fit the h22’s pump. Replace a few inches of the Accord line with a piece you cut from the preludes. Remember. This is the high pressure side of the pump which can run at about 400 times the pressure of the engine oil system, so its not a connection to be made with hose clamps. Brazing or welding required.
Drivetrain
As mentioned preciously, the transmissions are similar, so the accord clutch and slave connection and shifter cables fit without modifications. Don’t you love how Honda makes this easy?
The prelude half shafts are the stronger and should be considered a necessity if you plan to use the extra power. The Accords inner CV joint has a splined section on the half shaft that engages an internally splined section of the half shaft. The preludes assembly has a male spline on the half shaft that engages the beefy CV join casing, a stronger design. Apart from this difference, the sets are dimensionally the same and you’ll have no trouble using the prelude parts in the Accord knuckles and hubs.
Exhaust
The exhaust is another example of great planning (or maybe just laziness) of Honda engineers. How many engine swaps are out there where you can use all OEM parts? The prelude already comes with a nicely made 4-3-1 header. Using the prelude down pipe and cat, the rest of the exhaust system from a 90-93 accord ill bolt up. Another option is to use the prelude SH header, which comes with an adaptor that allows you to use the original (94-97) exhaust system. With either approach, plenty of shops can supply a freer flowing system so the h22’s high end isn’t snuffed out.
Intake
The accord throttle body is smaller than the prelude part, so all the work you just did will be gasping for air right about when VTEC switches. The accord throttle body works fine for regular sedan driving. The h22a will breather deeper and easier, especially at high revs where the Accord engine never ventured. If you don’t need cruise control, you can use the Prelude throttle body and prelude cables. Unlike the accord throttle body’s integrated MAP sensor, the preludes sensor is mounted on the firewall in a mystery box. Use a MAP from a ’90-93 Civic DX mount to the firewall in place of the Prelude mystery box (which has other emissions control functions we don’t need). To keep cruise control, stay with an Accord-like throttle body and cables.
Fuel System
When you try hookup the fuel line, you’ll notice the accords rubber line bolts onto eh opposite side of the fuel rails as the prelude. Fortunately, a ’97-or-newer Prelude fuel rail will marry the fuel systems. The part number from the dealer is 16610-PT3-A00.
Cooling
Heater hoses from the 96 Prelude are slightly longer that earlier prelude and Accord pieces and will fit better, Similarly, Prelude radiator hoses are required to match up the h22, The radiator that came with he accord will be big enough for the h22 in stock form. The h22a accord radiator used in JDM applications is a slightly thicker than the North American five-speed radiator. The thicker radiator was also used in North American automatic transmission cars if you’re going for authenticity.
Thanks for the read. Didn't realise I hadn't received a single rep point in the 10 years on this forum. Thought i should contribute something.
