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With this in mind, Skunk2 recommends that the older design hydraulic LMAs be swapped out for the newer spring type LMAs when using camshafts with a max lift over .496″. This includes the Skunk2 Pro 1+ intake and exhaust camshafts as their lifts are .469″ and .498″ respectively. We replaced our LMAs with part number 14820-PCB-305 along with the shims, part number 14820-PCB-003.
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| Skunk2 adjustable cam gears were installed on the end of each of the Pro 1+ camshafts. |
A Skunk2 adjustable cam gear was installed so both the intake and exhaust camshaft could individually be retarded and advanced. To most enthusiasts, the purpose of the adjustable cam gear is to use this adjustability to optimize the engine’s power band for its specific use or perhaps eke out that last bit of power for bragging rights.
However, our main intention behind using the Skunk2 adjustable cam gears was to compensate for the resurfacing of both the cylinder head and the engine block. Basically, removing material between the head and block changes the relationship between the crankshaft and camshaft. This means, the valves are opening and closing at the wrong time in relationship to the piston’s vertical movement.
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After starting and stopping the degreeing process several times over the course of six months, we eventually decided to leave our B18C1 in Howard Watanabe’s capable hands at Technosquare. If you have the time, tools and patience to degree your own cams, Aaron Bonk has written an excellent article on how to degree camshafts here.
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After Technosquare finished degreeing the camshaft of our B18C1, the intake cam was advanced by one degree and the exhaust cam by 3 degrees.
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If you recall from part III of our engine build article, we verified the piston to valve clearance (PTV) at .150″ on the intake and .085″ on the exhaust. This verification of PTV was done excluding the thickness of the head gasket and with the cam gears both set at zero advance. After advancing both the intake and exhaust camshafts, our PTV clearance changed. The only question was did it change for the better or the worse? The good thing is, advancing the intake cam decreases the intake PTV clearance but at .150″ clearance, we have more than enough clearance to accommodate a one degree advance. On the exhaust cam, we initially had minimal PTV clearance of .085″. However, advancing the exhaust cam increases the PTV clearance and should give us a nice safety margin. Score!
In the next segment of Project Honda Civic EJ, we will put the final touches on the build of our B18C1 with the completion of the intake and exhaust system. In the meantime, why not catch up on the Project Honda Civic series or visit some of our partner sites below?
1 comment
Honda still recommends the overly expensive P73 LMA for their B18C5 (& JDM B18C Type R) motors for whatever reason. They recommend PCB-305 for stock B16/17/18C1 heads. Would you guys recommend using the PCB-305 LMAs on the stock Integra Type-R valvetrain instead? I want to replace the aging P73 cylinder-style ones in my R cause I believe they are getting sticky and causing noise at startup.