B20A heads

[racerx]

Alright, now we know that the JDM 3G Accord B20A and JDM 3G Prelude B20A are 2 different motors.

BUT, are the heads interchangeable?
What about the cams?

I here on preludepower.com that the intake cam from the Prelude's B21A1 is a little more aggressive than the B20A's. I just so happen to have a B21A1 motor in my shed. Anyone have any thoughts?

Also, how would a B21 head do on a B20A motor? better? worse? no even worth it?

[L3G10N]

i don'T know about your questions, but i did my research about the cam for the B20A. And i've discover that the B18B cam fit the head with a really mirror mod. So, you can buy any agressive B18B cam for the B20A(what i did)

[mouchyn]

Alright, now we know that the JDM 3G Accord B20A and JDM 3G Prelude B20A are 2 different motors.

BUT, are the heads interchangeable?
What about the cams?

I here on preludepower.com that the intake cam from the Prelude's B21A1 is a little more aggressive than the B20A's. I just so happen to have a B21A1 motor in my shed. Anyone have any thoughts?

Also, how would a B21 head do on a B20A motor? better? worse? no even worth it?

i'm pretty sure the intake cams are the same on the prelude b20a5 and the b21a1. the b21's exhaust cam is slightly more aggressive, though.

I'm pretty sure the b20a5 head will not bolt on to the a20 block. the head gaskets aren't even close to being the same.

[racerx]

oh, i wasn't asking about A20 and B20 interchangability.
I was saying, it is possible to swap a head from the Prelude's B20A to the Accord's B20A and vice versa.
Just curious.

Also, how much of a difference do you think the B21 cam would make? Worth it?

I have a B21A1 block (almost blown engine), so I could grab the exhaust cam and do a switcheroo...

[mouchyn]

the differences in cam profiles is negligable.

[racerx]

i figured. doesn't the 3rd gen prelude have a ton of different cam specs between years and engines? i heard something about that a while ago. something like a new set of cam specs every year.

[mouchyn]

i figured. doesn't the 3rd gen prelude have a ton of different cam specs between years and engines? i heard something about that a while ago. something like a new set of cam specs every year.

more or less. the 3G prelude was honda's red-headed step child. nothing about makes sense, matches the rest of the honda family, or is supported in the aftermarket. honda just beat on it until the put the 4G out with stuff that actually worked.

[racerx]

except the electronic 4WS system. :D oops.

[mouchyn]

except the electronic 4WS system. :D oops.

true that. the all-mechanical 4WS is pure magic. I'm still very impressed with that system. I sold all my 3G ludes when I found out my fiancee was pregnant. I sold all of them but one -- my 88 4WS race car. The only thing that will make me get rid of that car is a bad accident that twists the frame beyond repair.

[racerx]

so, does anyone have an idea about the heads?
I assume that the engines are more identical than we might think. for all we can see, the engines are the same except for the power rating, motor mounts, and tranny bolts.

If that's true, than Accord B20A engines can take a B21A1 head, if you wanted to bore it out.
Also, a Prelude's B20A block can accept an Accord's B20A head and bump up the juice.

[carotman]

Some of the oil passages do not match. The B20A uses a different intake manifold.

The cams can be swapped tough.

[racerx]

Some of the oil passages do not match. The B20A uses a different intake manifold.

The cams can be swapped tough.

which B20A? are you saying the heads are not swappable between B20A's?

[RobT5580]

You cant swap a JDM Accord B20A head with a USDM Prelude head. Im not sure why you would want to unless you had only the block in that case i have a spare JDM B20A head for sale right now. The Accord head is different in other respects so i wouldnt mess with it.

[racerx]

ok, i'm saying:
Are these 2 heads swappable: JDM Accord B20A and JDM Prelude B20A

[RobT5580]

No, not without work!

[racerx]

ok, that's what i was afraid of... dang...

[RobT5580]

I have a spare head im willing to sell if thats the issue. But i would never swap the heads even if they physically lined up because i think you would loose some of its performance.

So if you need a head PM me otherwise im not sure why you would want to swap them. You can use B20A5 parts on the B20 head the only thing thats an issue is the headgasket. Yasu found a great vendor in Japan but every seems to make a big deal out of buying out the country but you can get everything you need and fast.

[racerx]

no, i don't really need one. i was just thinking that if the short blocks were the same, than swapping the heads would bring the Prelude's B20A to 160hp, like the Accord's, or at least closer to it.
But if it won't line up, I don't think I'll bother.

[RobT5580]

The prelude blocks are not the same and wont even work in the accord at all.

[Civvy]

Why dont u try the cams in ure car(B20?) from the dead B21?

[racerx]

well, it probably wouldn't be worth it. i think the specs are so close it's just not noticable. i looked it up, but i can't remember what the lobe specs are...