As usual in tech articles. Some good info, some bad info, some left out.
They barely touched on the MAIN reason lifters rotate, lobe offset to centerline of lifter.
They mentioned shimming the cam fore and aft..That can get 1 or 2 rotating but screw up others in the process. Sometimes a new block is called for.
A LARGE percentage of cam lobe failures are due to poor production process. Most production cores are induction hardened. If the process is not done absolutely perfect the hardness will NOT be consistent throughout the length of the core. Some areas will be as they should be, some will be rock hard and others will be dead soft. A good example of this is the flathead Ford cams up to 1948. They were excellent. 1949 to 1953, not so much.
They talk like chilled iron lifters are a recent breakthrough.. Isky had them in the 50's.
Pressure oiling the lifter face is nothing new either.
Think about the millions of engines over the years that ran their total expected life with no problems. The small percentage of early failures due to cam and lifter problems are the ones you hear about though. Makes ya wonder if they were end of shift type or maybe cutting corners type or just done at home with used parts type.
In any event it is good tech articles like this that keep up my interest in gardening.
They barely touched on the MAIN reason lifters rotate, lobe offset to centerline of lifter.
They mentioned shimming the cam fore and aft..That can get 1 or 2 rotating but screw up others in the process. Sometimes a new block is called for.
A LARGE percentage of cam lobe failures are due to poor production process. Most production cores are induction hardened. If the process is not done absolutely perfect the hardness will NOT be consistent throughout the length of the core. Some areas will be as they should be, some will be rock hard and others will be dead soft. A good example of this is the flathead Ford cams up to 1948. They were excellent. 1949 to 1953, not so much.
They talk like chilled iron lifters are a recent breakthrough.. Isky had them in the 50's.
Pressure oiling the lifter face is nothing new either.
Think about the millions of engines over the years that ran their total expected life with no problems. The small percentage of early failures due to cam and lifter problems are the ones you hear about though. Makes ya wonder if they were end of shift type or maybe cutting corners type or just done at home with used parts type.
In any event it is good tech articles like this that keep up my interest in gardening.