,
The intake valves are made out of a hard nitrided stainless steel. The nitriding provides a very hard wear and seizure resistant skin on the valves and reduces friction and the chances of the valve sticking at the stem. The intake valves have a flat nail head profile which helps flow. A cut-down smaller diameter part of the valve stem near the valve head also improves flow.
Forced induction engines produce a lot more heat- heat that the exhaust valves have to deal with. To deal with the heat, the Supertech exhaust valves were made from Inconel. Inconel is a very hard and heat-resistant metal. Inconel is a superalloy made of chromium and nickel which was developed for the aerospace industry.
The Supertech exhaust valves have a tulip shape which improves flow exiting the combustion chamber. This is opposite to the flat shape of the intake valve. The valve does not have a reduced stem near the valve head, as it doesn’t help flow much on the exhaust side, and a larger diameter stem helps conduct heat out of the valve head better. The valve head is swirl polished which also helps flow.
ARP studs are made of 8740 chromoly steel. 8740 has superior strength over a more common chromoly like 4130 because it has a higher carbon content and responds to heat treatment better. It also makes use of nickel as an alloying element which increases toughness. 8740 has a very high tensile strength of around 200,000 PSI.
We are also going to be using ARP bolts to hold our case halves together for improved structural integrity.
The ARP studs and bolts also have several design features like rolled (superior to cut threads due to good grain formation in the thread root) asymmetrical J-form threads with more engagement area on the stressed side and a reduced center diameter to reduce stress risers. ARP studs and bolts, when applicable, also have high quality forged nuts and precision ground and hardened washers for accurate torque and positive retention.
Stay tuned, in the next edition of the story of Michele’s engine, we will be applying some tricks like WPC Treatment, thermal barrier and anti-friction coatings from Swain Teach and putting it all together! Hopefully, Michele will get more power and more durability from her new combo!
SOURCES
JE Pistons
King Bearings
Supertech Performance
WPC Treatment
ARP
CP Carillo
Piper Cams USA
SwainTech Coatings
