Intake and exhaust rockers are billet.

Press-fitted spark plug pipe fits between forked exhaust rocker arms, further contributing to compact cylinder head design.

Each exhaust valve on the J37A4 corresponds to one primary and one secondary exhaust rocker arm.

Bolt at least one of each inlet and exhaust rocker to head for single shaft or one pair for twin shaft.

The primary exhaust rocker arm contacts a low-profile camshaft lobe during low-RPM engine operation.

The inlet rocker shaft had additional cams which drove horizontal pushrods acting on the exhaust rockers on the opposite shaft.

I connected the outlet breather pipe from the exhaust rocker cover to a breather bottle, and the only liquid that collected was a small volume of water.

Therefore, there are a total of twelve primary exhaust rocker arms and twelve secondary exhaust rocker arms.

Oil from the camshaft is collected on the opposite side of the passageway leading to the intake rocker shaft to provide oil to the exhaust rocker shaft.

The intake and exhaust rocker shafts contain primary and secondary intake and exhaust rocker arms, respectively.

De-rated, uncowled versions of Niagara I-III with simple inter-cylinder baffles for cooling and trickle-down lubrication for lower exhaust rockers.

Available for most parallel valve race applications, each intake and Exhaust rocker pair is joined by a shaft much larger in diameter than other brands to provide greater rigidity and resistance to breakage.

Failures are more common on exhaust rocker/pushrod combination, this is most likely due to the additional pressure exerted on the interface due to high positive cylinder pressures as the exhaust valves open.

The exhaust rockers act directly on the valves, whilst the inlet rockers act on pushrods running up to a second set of longer flat rockers operating the inlet valves.

On lap 3, Arthur Wheeler riding an MV Agusta retires with a broken exhaust rocker and Len Harfield at the TT Grandstand with gearbox problems.

The high-profile camshaft lobe which normally contacts the secondary exhaust rocker arm alone during low-RPM engine operation is able to move both exhaust rocker arms together which are locked as a unit.

It has a single camshaft with pushrods running vertically to a rocker shaft on the inlet side of the engine and further horizontal pushrods running in 6 tubes over the top of the engine in order to reach the exhaust rockers.

This is because VTEC requires a third center rocker arm and cam lobe (for each intake and exhaust side), and, in the SOHC engine, the spark plugs are situated between the two exhaust rocker arms, leaving no room for the VTEC rocker arm.

Once VTEC engagement occurs, the oil pressure flowing from the exhaust rocker shaft into the primary exhaust rocker arm forces the VTEC switching piston into the secondary exhaust rocker arm, thereby locking both exhaust rocker arms together.