Custom designed Tappets by No Limit MFG. Over the last few years we have noticed large inconsistencies in the crown, and hardness of Cummins OEM lifter tappets. We have found that some sets contain lifters that have low hardness. Sometimes it is just a few lifters, and not the entire set. The low hardness makes the lifters susceptible to premature wear of the camshaft, and lifter.
We have also found that the Cummins OEM lifter tappets have a non sufficient amount of crown. We have even found some with a concave surface. This is the #1 feature to guarantee rotation onthe Cummins. We have addressed this by adding crown to our lifters, similar to that found on International Harvester, and also other aftermarket lifter tappets. The addition of the crown will make the lifter rotate more. This disperses the wear more evenly across the lifter.
These are for use on cast iron camshafts.
Can be used on steel camshafts when used with stock springs or springs that have no more than a total of 375 lbs of pressure at open. If your spring pressures exceed this take a look at our tool steel line of lifters for ultimate performance and reliability.