In this image you can see the effects that a worn camshaft has on lift, if it is worn by 0.020" then it will have that much less total lift. To calculate the lift you measure the width of the lobe and subtract that from the height. By removing that same 0.020" from the entire perimeter of the lobe, keeping the same centerline, the entire lobe is smaller but the effective lift is restored to 0.400". That 0.020" now can be made up with the extra preload the factory gives hydraulic lifters, or on a solid lifter valvetrain you just reset your clearances.
This can also be done on camshafts that are not worn out, to achieve more lift for a performance application by removing a greater amount from the base circle. Keep in mind the tip of the lobe cannot exceed the height of the bearing journal on cams that slide through the block or head. So even when grinding blank billets to performance, the base circle quite often is smaller than stock. On cradle type bearing caps we still need to be cautious of too much lift and stock base circle for clearance reasons.
Because of slight variances in different camshaft models, we find it is safer to use our customers own factory core. Using our customers core will not only lower the costs but result in a better quality product for some applications. This is because of extremely high grade metal used in factory cams, especially with certain import cams like Honda.
BREAK IN PROCEDURE
- Cam Lube on all lobes, lifter faces, distributor gears and oil pump gears.
- Oil all bearing journals and lifter barrels.
- Always turn engine over by hand before starting, check for clearances and proper timing location.
- Fire up to 1800 – 2000 r.p.m. for 18 – 20 minutes.
Note: Most oil companies have taken out a percentage of additives that are meant for anti-scuffing for break in on flat tappet cams, so please ask your local auto parts professional for the best zinc additive they have and add it to your oil before you fire up your engine for the first time. (We prefer ZDD Plus.)