1984 Honda Accord LX engine swap

[AsterQuasi]

Hi, I have plans to buy up an decent milage 89 accord (preferably a crash victim) and gut it out for the engine to convert my 84 to EFI and maximize horsepower w/o custom fabrication, and reading the forums I've seen various info on this a20a3-4 swap. What I'm curious about is the axels, as I'm seeing that I may need to buy some from a different vehicle (prelude SEI iirc). Is this still the case if I use the axels from the 89, or should I keep the ES2 tranny and put it on the a20?

I've also read that the AC will no longer work if I swap, but given the fact that I'll have an entire accord to work with then wouldn't I be able to put in the AC from the 89 or even just swap some parts here and there? I don't mind the car being modified, but the idea of my car having missing functionality bugs me a lot since this car is bone stock and in mint condition.

[MustardCat]

I did this swap many years ago and I reused the ES trans and original axles. The inner CV splines are different on the 3g Accord. You would need to open the A20 trans, disassemble the differential, and switch out the spider gears for the old ones. The outer CV splines are different as well so you can't just pop in 3g Accord axles.

I know that works in reverse at least. I was able to use an early 2g Prelude carb. trans in an 89 LXi by swapping in those spider gears from the LXi trans.

FYI an easy way to check spline compatibility is rockauto. Brands like GSP list the inner and outer spline count. So it's easy to compares between years and models. Sometimes this isn't the full story though, as other things like spline length may be different. (But they aren't really in my experience with similar-year Hondas)


My 84 didn't come with A/C and frankly at that time I didn't know enough to deal with it correctly if it had. Now in 2025 I've done a number of fully custom engine swaps on old Hondas and made the A/C work. I am 100% sure you will be able to make A/C work on this swap. It might just be as easy as bolting the ES bracket and compressor onto the A20 and doing nothing else.

[ShiRen]

Axles depend on what trans you use. Though, whichever way you go, I highly suggest disassembling axles before the trans, you can just swap the joints.

Idk why the ac wouldn't work if it's plumbed, it needs one wire going to the compressor and two wires on the overpressure switch to break the connection.