[Sirrotica]

Originally Posted by Cliff R

The cam/lifter thing is a completely different deal and far as I'm concerned ALL of the issues we see there are due to the market being flooded with "soft" imported lifters instead of good USA made high nickel iron lifters that are crowned/finished correctly so they spin on the lobes their entire life.

No type of oil, break in or otherwise, or special "break-in" procedures are going to save your cam/lifters from a miserable death with "soft" parts in the mix. I also do NOT believe in any type of "break-in" oils or additives. I so smear the lobes and lifter bottoms with Moly Grease during assembly because I know it will still be there if the engine sits for weeks or months before being started. No other reason for that move other than any type of oil or sticky stuff they supply with cams is going to run off those parts over time.

Another contributor to the cam/lifter failing deal is the use of HEAVY valve train parts and "battleship" spring pressures which have pretty much become the norm in this hobby. There is NEVER any need for springs with much over 100lbs seat pressure and 200lbs over the nose for 95 percent of these builds that will never see the high side of 5500rpm's and most are DONE making power well before that. This assumes you haven't added big heavy retainers, rocker arms and anything else to add weight above the lifters.

Maybe I just got lucky with these things but have never had the first issue one with lobe failure on one of these engines and never really paid much attention to "break-in" one way or the other.

I have added to the engine assembly process (about 25 years ago) taking a paint marker and putting a white line on the visible portion of the pushrods just below the rocker arms. Once the "fresh" engine is warmed up, timing set, and fluids topped of I idle it really slow and remove the valve covers for a quick verification that ALL the pushrods are spinning like they should. I then dump the oil and catch some of it in a clear glass jar and cut the filter open for inspection. If all looks well we commense to run them like we stole them!.......

The late 70s is whe I first started seein HFT failures in GM products. This is the same time the pennypinchers at GM tried changing the nickel content in the cast iron parts cast for engines. This made the blocks incredibly wear prone.

The 2.5, 4 cylinders had cylinder ridges that you could catch your nail on at 30,000 miles. The #1 cylinders were notorious for going out of round, and having severe taper. That promoted the piston slap noise in the ealy FWD cars that you could hear from 50 feet away.

The 301 blocks wore so quickly, and had so much ridge that unless you used a ridge reamer you couldn't get the rings past the ridge.

Along with this money saving measure to cheapen the cast iron parts the wear in those late 70s early 80s engines was way above the rates that GM engines had for decades previously.

As Cliff has already touched on, the off shore low quality parts with poor metalugy, along with poor finish machinig added to the compounding problems of FT valvetrains. Aftermarket was hell bent to put valve springs out that just added to the stack of problems already in play. The ramps trying to be as fast acting as possible, defied physics. Add in questionable machining to the litany of other problems, and you end up with what we have today.

There is no one specific problem that caused all these flat tappet failures, just a comedy of errors stacked one on top of another.

I have often wondeed if mushroom tappets would alleviate some of these problems. Before roller tappets they were used by the aftermarket to add reliability to flat tappet applications. NASCAR in it's early days prohibited roller lifters, and for years NASCAR engine builders circumvented the rules by using mushroom tappets. More load bearing area, plus a better lever action further from the center of the lifter to promote rotation. It has worked for small engines, like B&S for decades. B&S now use composite cams in their later engines with mushroom tappets. The only bad thing is they have to go in from the bottom, complicating the labor needed to change them.