On top of the RB straight-six’ s cast iron closed-deck block with 86mm bores sits a twin-cam aluminium head equipped with 32 sodium-filled valves. The belt-driven cams operate directly onto solid bucket lifters above the valves, with shims under the buckets. Its forged crank has eight main bearing journals and has a throw of 73.7mm. All solid, strong, but not all that exceptional for a car that was considered a technological masterpiece.
Don’ t worry, there’ s plenty that’ s ahead of its time. The RB26’ s I-beam forged rods include a jet on the outside of the big end that sprays oil onto the underside of the piston to keep it cool. Along with those nozzles are block-mounted cooling jets that squirt oil into a specific location on the underside of the piston: a hole that leads into a cavity that circles the inside of the piston behind the oil ring. A drain hole on the opposite side of the piston’ s bottom allows cooling oil to continually flow through the core of the piston.
Many of the engine’ s more advanced and over-engineered features can be seen from the outside. It has six coils, one for each cylinder mounted on the sparkplug, plus six individual throttle bodies. A huge-for-the-time intercooler is necessary because of the RB’ s most iconic element, its twin parallel water-cooled oil-pressure lubricated Garrett turbos with ceramic exhaust turbine wheels.
Winter 2025 The Engine Rebuilder 21