hey i need some help here. i picked up a b18a to take to the machine shop next week to get bored 20 over and have a block guard installed. im running a 98 LS with the p75 head, where the PCV valve is on the valve cover. Problem is the b18a block has a vacuum box that goes into 1 of those 2 big holes on the opposite side of the alternator on the block, and thats where the pcv valve goes. So...what are my options here? I guess i could run a b18a valve cover on my b18b head? Or is there a way to plug the hole in my b18b valve cover so i can use that one? Also, im wondering what to do because ive done some research and alot of people are saying that the b18A has no Knock Sensor?! im running a obd2 computer and p75 head..im confused..ive looked in archives and recent and nothing is hitting the nail on the head. Anyone whos done this before let me know whats up. thanks


Modified by hollums2k at 7:22 PM 8/7/2008

 

plug the block

 

OK so for anyone else out there wondering why everyone says that the b18a and b18b blocks are exactly the same, and then they get one and find out they're not - ive finished my project here so i ll let ya know what the deal is:

First off im gonna go ahead and say that i put a B18A block under my P75 head (OBD2 computer) and had no engine lights afterwards.

The b18A has a vacuum box on the backside of the block like b16 or b18c vtec motors, where the PCV valve goes into. this causes a problem with the p75 head because the newer LS valve covers have a spot for your pcv valve.
Solution:
1. plug the block with a 34mm freeze plug (found at autozone)
2. buy a plug from z10 engineering (expensive but shiny)

Next the b18A does not have a CFK sensor, b18B does
Solution:
use the oil pump from a 96+ integra LS and run the CFK sensor

Lastly the b18A does not have a Knock Sensor
Solution:
drill out the upper alternator bracket hole in the motor (right side) to 11mm. tap hole with 12mm x 1.25 thread pitch. open up the alternator bracket hole. screw in knock sensor there with bracket installed.

hope this helps someone because i know i was confused when i got my b18A block and it was different from my b18B.

 

good write up, but you can still use the newer valve cover, just get a good machine shop to weld the hole up, g/l and please let us know how it goes, as i am looking at a similar build