my head might be fuked due to a recent breaking of my timing belt. if it is, will a b20 head fit on my b18a1? i found one for sale that’s built and a good price, which would be easier than fixing my head.
Nope, the combustion chamber would be 84mm accross where as your cylinder is only 81mm. That would cause problems.
If you’re looking for an improvment, you should look into putting a 94+ B18B head on with the B18B headers, intake manifold and cams. You’ll pic up around 12 more hp and you’ll have a newer head with less wear. Total cost is under $300 I believe.
-Steve
Yes a b20 head would work on your motor. It’s the same head as the b18a/b. On the b20, only the block has an 84mm bore not the head. Don’t ask me why but that’s how b20s are.
REALLY?!?!?!?!?!?! Then why is it when you put a PR3, P61 or P72 head on a B20 block, you’ve got to widen the Combustion chamber to 84mm from 81mm? If the B20 head’s Combustion Chamber is at 81mm too, then whats the deal?
-Steve
Originally posted by DAY U IZ
[B]REALLY?!?!?!?!?!?! Then why is it when you put a PR3, P61 or P72 head on a B20 block, you’ve got to widen the Combustion chamber to 84mm from 81mm? If the B20 head’s Combustion Chamber is at 81mm too, then whats the deal?
-Steve [/B]
…to take advantage of the 84 mm bore of the block.
I dunno about widening combustion chambers on vtec heads but i think it’s more of a “it’s better to” than a “must”.
Taken from crvtec.com…
The B20 blocks, the bore is 84 mm. and most B series VTEC cylinder heads, the bore is 81 mm. This means that if you were to use a B16A head, there will be a small lip around the top of the deck created by the smaller cylinder head. This difference will affect performance and increase the chance for detonation. If you don’t take advantage of the breathing afforded by the larger bore (opening the chamber up), you’re losing a lot of the benefits of the combination. We spot face the quench pads to the same diameter as the bore on B16 heads and we open the sides of the chamber as well, so you achieve the same relative “fit” as the head would on the 81 mm bore engine.
you don’t have to widen the combustion chamber to 84mm. Some people like to do it (like on crvtec.com); enlarges the quench area and reduces the possibility of detonation they say. But these turkeys are running high comp. pistons, and the 0.4 cr loss can be made up for.
If you think about it, the difference from block to head will only be 1.5mm all the way around. hardly enough to cause problems. Honda was just cutting corners i’m sure.
Also, wouldn’t quik92teg have a 140hp '92 teg, the '94s have 142hp, for a 2hp gain, not 12.
even if they do widen the comb. chambs, what about the head gasket? Is that still 81mm? I’m sure they’d make them a little bigger, so when you torq the head down, it’ll flatten and widen. Forgot to check the head g dia. last time i had one apart.
d
Originally posted by daver
Also, wouldn’t quik92teg have a 140hp '92 teg, the '94s have 142hp, for a 2hp gain, not 12.
I didn’t catch that, and yes you’re absolutley right.
-Steve
I can also vouch for the combustion chamber being the same size.
Would the B18b be a direct fit into our cars .Same wireing and ecu or wouldnt that work . If not what would be different?
Originally posted by g2tegger90
Would the B18b be a direct fit into our cars .Same wireing and ecu or wouldnt that work . If not what would be different?
The 96+ B18B’s are OBD2, not cool. But that is easy to fix with OBD1 parts.
yeah i think i’m just gonna get a 94-95 b18b head. i found a few that are much cheaper than the b20 head i found. of course i still have my fingers crossed that i won’t have to get a new head in the first place(i’m a poor college student).
Originally posted by g2tegger90
Would the B18b be a direct fit into our cars .Same wireing and ecu or wouldnt that work . If not what would be different?
Wiring in a head?