Q. here. How long has the motor been in your car and how far have you driven it since the swap was done? if you did the swap, did the long block come with a flyer of instructions and recommendations from the builder/distributor regarding initial break in? If you didn't do the swap, did whoever the installer was offer or provide you with any details on how the motor was broken in? Have you ever filleted or cut open your oil filter during an oil change to check the filter material for debris?
Do have to agree that if a reman, it could be a mutt with different years of parts combined into one. Reman builders don't generally keep the core components together; they tend to dismantle and lump heads in one pile and cranks in another and rods in a third, etc, measure and mike everything and throw away the marginal or absolute junk and go from there. Also have to agree that the basic casting could easily have the provisions for the roller cam casted into the block's cam valley but never machined or finished out. Blocks got casted up to a year or more ahead of projected use or need and then thrown out into the bush to age for a year or more before being brought back in to finish machine. The theory back then was that a "green" casting, that being one fresh from the foundry, could shift or move internally and that leaving them to "age" allowed them to assume their final internal shape prior to being machined. Aluminum blocks don't suffer that indignity. (LOL)
Point here is that Zinc is an additive that is used during several situations, such as when running in a new cam with new lifters and associated components or when starting a motor up for the first time, post priming the oil pump. Most contemporary oils don't come with Zinc as an additive any more due to the EPA interfering again. Specialty Chemists such as Royal Purple do offer Zinc rich versions of their oil and Zinc can be bought as an additive.
Do fully agree that you need to identify what type of cam system, flat tappet, or roller, you are dealing with, before the engine tells you what version it is but does so by going...………………….. boom.
