I have a set of Crane Gold rockers for a BBC and I am puzzled by the number and symbol stamped on the lower portion of the rocker body. Some have a Triangle on the left and a -4 on the right. Others may have an O on the left and -12 on the right. All of them are 13-1.7 ratio, but the difference in symbols and numbers at the bottom has me curious since you would think they would be the same.
08-06-2012 08:27 PM
those are id markings the triangles show direction markings the numbers are off set sizes all big block chevys have cantered valves the markings made on the rockers are measurements they took while matching the set on a motor to help equalize the horrible geometry of the cantered valve design Crane actually did hands on adjustments and machining too there products which is why up to there recent management problems they were one of the best valve train companys in the world
08-07-2012 12:19 PM
So, it wouldn't be unusual to have a set of rockers with different markings at the bottom?
08-07-2012 01:17 PM
These symbols and numbers are manufacturing date codes. If the triangle is pointing up, that's 1986, if it's pointing down, that's 1991. The O is for 1996. the number to the right is the month of production. Regards, Chase