Junkyard Motor And Trany

[crucial]

I went to Pick N Pull today and was looking for a motor and manual transmission. I want to use the A20A3 motor with a carb, but when i was looking through the lx-i's i notice a lot of them have the A20A1 motor with the EFI. So my question is do all the EFI motors either A20A1 or A20A3 have higher compression then the carbed motors? Or is it just the A20A3 that does, because i found one that is a EFI A20A1 that has 71000 miles on it but want that little bit of extra compression.

On the trany what things should i look out for when choosing one?

Oh ya one of the EFI motors i was looking at sad BT instead of A20, what the deal with that? And it was just BT no numbers after it or before it.

[cygnus x-1]

I went to Pick N Pull today and was looking for a motor and manual transmission. I want to use the A20A3 motor with a carb, but when i was looking through the lx-i's i notice a lot of them have the A20A1 motor with the EFI. So my question is do all the EFI motors either A20A1 or A20A3 have higher compression then the carbed motors? Or is it just the A20A3 that does, because i found one that is a EFI A20A1 that has 71000 miles on it but want that little bit of extra compression.

On the trany what things should i look out for when choosing one?

Oh ya one of the EFI motors i was looking at sad BT instead of A20, what the deal with that? And it was just BT no numbers after it or before it.


From the factory, A20A1 is a carbed engine and A20A3 is EFI. The compression on the A20A1 is 9.1:1 and the A20A3 is 9.3:1. And as I recall the 9.3:1 only applies to '88-'89 models. (someone should confirm this)
BT was what the A20A1 was called before I think 1987. If you see an A20A1 with EFI or an A20A3 with a carb, then something was swapped, most likely the block.

As far as the compression goes, my understanding is that the pistons are what determine the ratio. So theoretically you can use A20A3 pistons in an A20A1 block and get the 9.3:1 CR. However, I've also read that the head is really what is different. But I have yet to see where anyone has actually compared parts side to side to make this determination. In the end, I wouldn't really worry about it. The difference of 0.2 is so small that you won't be able to tell the difference. By the numbers you *might* see a difference of 1HP.

If this is a motor you're pulling for a rebuild, the most important thing is that the block is in good shape and doesn't need a serious rebore. I picked up an engine on ebay for cheap and it ended up needing at least a .020" overbore. Honda however does not make pistons that much oversized and so I would have had to use an aftermarket part. But I didn't want to do this because the aftermarket pistons are reported to have a deeper dish which would lower the CR too much. So at the end of the day I had my A18 block bored to fit stock A20 pistons, and I used genuine Honda pistons from the '89 A20A3.


C|

[forrest89sei]

BS is A20A1 on Pre 87 Accords, BT is the code for A20A3 Pre 87

[crucial]

Thank you for clearing that up!:cheers:

[Dr_Snooz]

From the factory, A20A1 is a carbed engine and A20A3 is EFI. The compression on the A20A1 is 9.1:1 and the A20A3 is 9.3:1. And as I recall the 9.3:1 only applies to '88-'89 models. (someone should confirm this)
BT was what the A20A1 was called before I think 1987. If you see an A20A1 with EFI or an A20A3 with a carb, then something was swapped, most likely the block.

As far as the compression goes, my understanding is that the pistons are what determine the ratio. So theoretically you can use A20A3 pistons in an A20A1 block and get the 9.3:1 CR. However, I've also read that the head is really what is different. But I have yet to see where anyone has actually compared parts side to side to make this determination. In the end, I wouldn't really worry about it. The difference of 0.2 is so small that you won't be able to tell the difference. By the numbers you *might* see a difference of 1HP.

If this is a motor you're pulling for a rebuild, the most important thing is that the block is in good shape and doesn't need a serious rebore. I picked up an engine on ebay for cheap and it ended up needing at least a .020" overbore. Honda however does not make pistons that much oversized and so I would have had to use an aftermarket part. But I didn't want to do this because the aftermarket pistons are reported to have a deeper dish which would lower the CR too much. So at the end of the day I had my A18 block bored to fit stock A20 pistons, and I used genuine Honda pistons from the '89 A20A3.


C|

How do you know this? I'm in awe!

[AccordEpicenter]

9.3:1 is any factory efi engine cr (a20a3/4), and yes, if you see an a20a1/2 with efi or an a20a3/4 with a carb somthing was swapped because they never left the factory like that