Nerd’s Eye View: Inside Fredric Aasbo/Papadakis Racing’s Amazing V8 eating 2AR Toyota Engine


The valves are custom Supertech parts.  The intake valve is nitrided stainless and the exhaust valve is made of heat resistant Inconel.  The valves are stock head diameter but have a stronger 6mm diameter vs. the stock 5.5mm stems.  The valves are swirl polished for flow improvement and the exhaust valve head is tuliped for better flow.  The valve stem above the keeper groove is longer to accommodate the deeper rocker arm pocket.
Port Flow Design does the headwork on the 2AR head.
Viton spring loaded valve seals are used.  Bronze valve guides are used since rocker motors put more side load on valve stems and the guides and Inconel can gall conventional valve guides.
The rocker arm bosses have been milled down to set the rocker lower to maintain proper geometry with the reduced base circle camshafts.  The base circle is smaller because the cams have to be reground to change their specs since billets are not available in the aftermarket for the 2AR.  You can see here how deeply the modified rocker now engages the top of the valve stem.
Port Flow Design performs a radius valve job for maximum flow, lays back the edges of the combustion chamber around the valve to reduce shrouding and blends and opens the valve bowls.  The short side radius floor humps in the port are blended and the bowl is blended to the port.  Not much material is removed, just mostly blending is done.  Unshrouding is important for the 2AR because the combustion chamber wall is very close to the valve, you can see it in this picture.  This is the primary reason why oversiszed valves are not used, they would offer no flow improvement.
Port Flow Design fully ports and opens up the exhaust ports and knife edges the port splitters as shown here.  The intake ports are left stock.

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