Speedwell High Ratio Rockers

Speedwell High Ratio Rockers for 25HP / 36HP engines.
available ratios either 1:1. 25 or 1:1. 4
By fitting these high ratio rockers both inlet- and exhaust-valves are opening at higher lift. The stock rocker ratio of the 25HP and 36HP engine is 1:1 and thus valves have a lift of about 9/32th of an inch. Speedwell 1:1. 25 rockers cause a valve-lift of nearly 12/32th and the 1:1. 4 rockers cause a valve-lift of a little over 13/32th of an inch.
Using high ratio rockers needs higher valve covers to prevent the adjuster touching them. You either can solve this issue by modifying the stock covers and spring fasteners, or fit our MP Aluminium valve covers, which are high enough to clear the rockers and adjusters.
When using these rockers in combination with a high lift camshaft You have to observe blocking of the valve springs.
Besides the higher valve-lift, the special design of the Speedwell rockers, with its valve-clearance adjuster at their pushrod-end and a precise contact surface touching the valve stem (as Porsche 356), minimizes valve-guide wear due to less valve-shaft lateral forces. Another benefit of the Speedwell design is the Allen style adjusting-screw.
Test runs on our Schenck dynamometer showed no improved torque or power with the stock single carb 36HP engine. With twin-carburetor- or supercharged engines, high ratio rockers are a straightforward method to power up Your engine by just “screwing on” some more horses. A Judson engine on our Dynamometer showed a power improvement from 55HP to 58HP.

Speedwell high-Ratio Rockers 1:1,25 oder 1:1,4: 553,45 €

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