Segment 2 of the LS3 Conversion focused on the cylinder heads. Matching the camshaft, combustion chamber volume and port design will yield excellent results in power and reliability. For help with this, The LSX Dr. called upon West Coast Cylinder Heads (WCCH) in Reseda, CA. WCCH is one of the premiere machine shops in the country for LS cylinder head work. The shop is fully equipped for CNC porting, decking and complete valve grinding. There are several options available for porting depending on the intended application.
The LS3 in this project is naturally aspirated and will be mated to a 6L80 automatic transmission. The cam profile was custom designed by Patrick Guerra and matched with a Yank 3000 stall converter. For our combination, the Stage 2 CNC design will work best.
The first step is disassembly of all the original springs and valves. The heads are then blasted and cleaned in a hot tank. Next they are mounted in a fixture that will hold them in place while the combustion chamber porting is done.
Shown here, the CNC machine is porting the combustion chamber to exact specifications unachievable by traditional hand porting.
Here is a shot of the intake port before any machining.
Each intake port is machined the same to ensure that each cylinder receives equal amounts of air.
As you can see from these pictures the intake and exhaust ports are completely smooth allowing for maximum airflow.
One of the most important things to consider when installing a new camshaft is Piston to Valve (P to V) clearance. This is the measurement between the edge of the valve and top of the piston. Installing an aftermarket camshaft with increased lift and duration will affect P to V clearance. Decking the heads removes material from the surface of the head where it contacts the engine block. With material removed the valves are now closer to the pistons and will raise the compression ratio. Shorter pushrods and correct valve timing will be necessary to maintain proper clearance. Every engine is different so before and after measurements is critical.
After the CNC porting and surface decking is complete, the valves, seats and guides can be installed. All new lighter stainless valves were installed but not before getting a competition valve job. Each valve is ground with a matching angle on the seat.
The finished valve seats and combustion chambers look great. Next step will be installing the valve and springs.
The LSX Dr. contacted Brian Tooley Racing for their .660” Platinum Valve Spring Kit. These are some of the best springs on the market for LS engines and have had a zero failure rate. The kit includes dual polished springs, matching tool titanium retainers, locators, locks and seals.
The heads turned out fantastic and should net some significant extra power. Segment 3 will cover the camshaft installation and other valve train related components.
A big thank you to our sponsors for helping us on this engine project! Stay tuned for Segment 3!