I lost a cam that was running fine for years.....not long after I switched to this oil:
View attachment 1716073947
Seems like a winner, right? Synthetic, extra ZDDP ....
View attachment 1716073949
Uhhh....
View attachment 1716073950
SN is a VERY high detergent oil.
THIS is bad because the detergent wipes away the ZDDP. What sense does this make? Add ZDDP to the oil but also add in detergents that don't allow it to cling and protect?
What has changed in the last 20 years?
Yeah, the oil has changed but there are oils that still protect.
Bigger cams, stiffer valvesprings are a factor but what about the camshaft and lifters?
Testing has shown that most aftermarket cams and lifters have similar hardness as stuff from the 70s so it may not be a matter of metal durability.
What is left to blame?
Some claim that the cams don't have enough taper and the lifters don't have enough crown. These two things MUST exist to allow the lifters to spin. A lifter that does not spin will fail.
