Granted. And you might be correct. I'm going to disassemble an MDS lifter as well as a solid lifter to examine the internals. I have just examined the lifters again tonight and I found another common factor from the damaged lifters to the good lifters. The damaged lifters are all stuck, without any spring action on the pushrod seat. In some or most cases, this will not cause oil flow to stop, but might causing tapping as this happened to my 5.7 Vortec on my Suburban prior to rebuilding the engine. I do not yet know the cause for the seizure, and I am not yet certain if a stuck lifters would prevent oil flow to the rollers. I read somewhere that on some of the lifters, the oil flows from the bottom up towards the pushrods, while on other lifters the oil flows from the top down. I am trying to determine how the lifter rollers receive oil. Does the oil flow from the top of the lifter and down? Does the roller get oil from as passage way in the block? There has to be a logical reason why the #8 lifter was bone dry and its roller gone/destroyed. Some on here have suggested the problem to be with a faulty lifter design. But is it a design flaw, or a lack of lubrication flow, or even both? I know I'm being stubborn guys, but that is how I've always been. I will not repair an engine or any equipment until I first understand the reason for its failure. So bare with me if I seem to pushy and adamant. Some of you on here appear to be engaging with me with great patience and understanding. But there are a few of you on here that are just here to stir up trouble and detract a discussion to flood our examinations with ill intentions...these are often called trolls or schills being paid to detract a debate or discussion by smearing it with emotion and lies. I'll just ignore them from now on. Finally, I tested the plastic keeper, and I was able to rotate the lifter by a few degrees merely by twisting the lifter in the plastic keeper by hand. A valve spring and camshaft both provide more torque than what my wrist can apply, so there is no doubt now that some of the lifters (as a Chrysler mechanic informed me a few days ago) that the lifters can rotate, some as far as 90 degrees, thereby destroying the roller no matter how much oil it gets. Summary: All damaged lifters are stuck and the push rod has no spring action. Moreover, the MDS lifters with off-centered lock pins are also stuck. I also plan on testing the MDS lifters by unlocking the pins (pushing them in) in a vice and using a press to see how far I can compress the internals of the lifters, if even at all. It's hard to do this when the roller is not stationary.
Originally Posted by OVERKILL
Nothing. The passages for the conventional oiling don't overlap with the MDS cavity as can be viewed in both cutaway diagrams I posted.
Originally Posted by JosephA
That being the case, what happens to the normal oil flow if the lock-pin hole is left open during "locked" operation? You already know what my theory suggests....but for the record, I did not come up with this myself.....This came from an automotive engineer. Joe