Project EJ Honda Civic- Fixing a Leaky Head for more Power!
By Mike Kojima
We were planning to methodically add parts to our project Civic’s B18C engine one bit at a time to see how they affected power and powerband. Unfortunately, our car had other ideas. Although Annie had driven the Civic for over 200,000 miles on a daily basis with not a single hitch, a trip to the track exposed the car’s age.
|Tom Fujita of Portflow Design uses a Serdi valve machine to crank out good performing heads. The Serdi makes doing a high quality valve job pretty fast and accurate. Tom is leveling our head in the machine. The Serdi has a floating head that moves on air so it can be accurately and quickly positioned over each hole.|
A bubble level on an old valve helps Tom set up the head perfectly level.
|As a first step, Tom cuts the exhaust valve guides shorter. On the B Series head the guide blocks a lot of the port area. 15 CFM can be gained by cutting it down. Tom conservatively cuts it flush on the Serdi with this cutter. This makes the exhaust valve guide the same length as the intake so it is not unreasonable and still gives the valve plenty of side support. This cutter uses an old valvestem as a guide and faces off the unwanted valve guide that protrudes into the port.|
|Here is the cutter about to be put into the exhaust guide.|
|The dial indicator is used so Tom can consistently cut the guides to the same length.|
When at Buttonwillow, her car started to overheat and even though she stopped right away, the head gasket was blown. When the head was pulled to fix the gasket, we noted that the head’s deck was warped 0.0005-0.005”.
|A cut vs uncut exhaust valve guide. The cut on is on the left.|
Since we had to machine the head’s deck, we decided to have Tom Fujita of Portflow design clean the head up at the same time with a mild port job and a good performance valve job. This low cost bit of head work can be turned around by Portflow quickly and economically.