Rocker Lock for M10/M30

Upgrade part. On factory M10 cylinder heads, the rockers are held in position by a spring - and at high rpm, that spring may allow the rocker to move in relation to the valve stem (sometimes enough to walk off the valve stem which quickly results in a broken rocker arm). With rocker arm locks, you eliminate the spring and positively locate the rocker arm. Locks also make head assembly simpler than with thrust springs. We use these on all our performance engines. M10 4cyl. engine: order 8 for complete set. M30 6cyl. engine: order 12 for complete set.