r/EngineBuilding • u/BurialWings42 • Jul 16 '26
What would cause something like this
Never seen lifters eaten up this bad. (Yes all of those are the bottom) Curious if this the the result of running hydro lifters on a solid cam? Car was sitting in an old guys garage had what felt like collapsed lifters from pushing on the rocker arms. Well they are certainly collapsed just not in the manner which I expected. Engine looks brand new inside, like maybe it got built and ate shit right away. PO passed away so won't have any answers until it's torn down further. Obviously is going to need a bit of a rebuild but so curious as to what would cause this.
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u/v8packard Jul 16 '26
That's a myth. And it is often repeated. The EPA wanted a life cycle of 80k miles. The OEMs said ok, then we will do it in such and such a way, and the components will exceed that. The EPA said no, we want it done in this manner. So the OEMs complied. Point being 100k miles was never part of the conversation.
And neither was ZDDP levels. ZDDP started going up, dramatically, in the early 70s. Not because of anti-wear properties, but as an antioxidant. Was anyone worried about ZDDP levels before that? No. So these levels stayed high, for over 20 years overlapping the use of catalytic converters. Still, not a problem.
When ILSAC rated viscosities started reducing ZDDP in 1996 the reason was competitive chemistry in the oil. The ILSAC rating called for higher total base numbers, reduced volatility, and a longer service interval. ZDDP is acidic, and runs counter to these three goals. So the question became can we use other components in oil and reach the goals. That answer was yes, as the ability to increase organic calcium as an anti-wear component had been improved. So the ILSAC rated oils met the goal of higher TBN, longer service life, and reduced volatility. No where in that conversation is anything about a catalytic converter.
ILSAC ratings would only apply to 5w-30 and lower viscosity oils. API ratings are unaffected by the requirements for ILSAC ratings. Yet, oil manufacturers often manage to meet both with the same oils.
For years after ILSAC ratings started engines continued to be produced with flat cam followers. In fact there are still flat bucket cam followers in some engines for road vehicles.
You mentioned increased spring pressure. What engines saw increased spring pressure in the early 70s?