first of I searched on this and a little light was shed on this topic but not enough for me to completely understand.

The motor that is in my 89si (4ws) is a B20A5 a few months ago my timing belt snapped ( It was replaced when the previous owner had it and only had 40k on the new belt) so i had no clue it was going to break.

This is my second car and it has 229k miles on it and so I was thinking of just going to the junkyard getting another head (seeing as how my valves are bent) a just putting it on. However I have come to find that this is not a very common engine to come across.

So today I was at the junk yard and found a 90 prelude with a B20A in it. Now I know about JDM motors and first thought on my head is that this enigne is a Japan spec motor but my knowledge on the Bastard series is very minimal.

The head I was originally looking at is stamped E-4 PK2

and this B20A at the junkyards head is E-3 pk4


Anyways long story short. I am trying to figure out of this is a good choice motor for me to go with and that way i get a motor with lower miles on it and the possiblity of it being the Japan motor with more hp? or is this a completely different setup?

One more thing this motor appeals to me seeing as the car it is coming out of has body damage (which seems the reason it is in the yard in the first place) and second the car has a local machine shop tags stamped in it (Rebuilt)

EDIT: This motor B20A does not have the twin o2 sensors in the headers close to the head like the B20A5 does. (Is this relevant though? couldnt I just use my headers that came of the B20A5 and it will work fine?)

this car is not for racing so i really dont care about performance in anyway. It is completely stock and will stay that way. its my Grocery getter :D

So if you guys could please shed some light on this subject for me please that would be awesome!

 

Well its almost impossible to find info on 3rd gen ludes ^_^ but i'm here! Yes go with the b20a for more info on what you need to swap them out go to
"p r e l u d e p o w e r.com" basically...O.O is going to be your face when you see the knowledge you can get from that website.

 

also you can check out prelude3g.com that site has some pretty good info on these cars too.

If the b20a is already swapped into a 90 and it has a single o2 sensor, more than likely that car has the intake and exhaust manifolds along with a computer from the b21 that the car originally came with. You can either convert your 89 to a single o2 setup and use the computer out of the 90, or you can take the intake/exhaust manifolds from your b20a5, put them on the b20a and use your stock computer. The easiest route would be to switch manifolds and keep your computer as the b21 preludes were obdI, and your 89 is obd0, so you would need to convert your car to run the b21 ecu.

Either way you must match the intake manifold with the computer it originally had.

As for the b20a, it is a jdm version of your b20a5, it has slightly more power cuz of higher compression.

 

So if i pick this B20A up and use my intake manifold and my exhaust manifold i can utilize all my normal sensors and everything will work together in harmony and I wont have to convert anything crazy. It will just bolt right in is this correct?

 

That is correct

 

Damn, that's some good news. A bolt on to fix the problem and get a little more HP. How much does the junk yard want for the head.

I found this gasket kit for $40 if you need one. no tax and free shipping.
http://www.am-autoparts.com/Honda/Pr...LiveCashbackSF

 

So did you decide what you are going to go with? Years ago I had one of these cars too..