Here is a question for the flat tappet cam guys....

[Kern Dog]

Most of us have heard of the increase in flat tappet camshaft and lifter failures over the last 20 years. Some of us have actually had it happen, even more than once.
I have. FOUR times too.
The blame has never been able to be attributed to one issue but is often spread around a few things. The reduction in the Zinc in the oil, stiff valvesprings, too little taper in the lobes or the lifters, improper break in, etc.
I've read that extended idling is bad since the cam relies on splash oiling from the rods spinning and spitting oil past the bearings. This is the reason why during camshaft break in, the RPMs need to be above 2000 to properly supply oil to the lobes.
Here is the question....
Once the cam is broken in, what harm is there in idling? The engine is under no load and there still is some oil being thrown around.
What about when you're rolling down the road and the RPMs are under 2000 RPMs? People with overdrive transmissions can be rolling down the road in 5th gear and be under 2000 RPMs for a few hours at a time. I do. I have a 3.55 axle gear and a .64 overdrive with a 26" tire.
I was out for a drive today and as I saw 1500 RPMs, I wondered if it could be doing harm.
There is a roller cam on the shelf that I intend to swap in over the winter but this issue of low engine speed at cruise has me curious.

 

[Strato58]

Do you think there is any credence to this QS oil being excellent for a flat tappet engine? And possibly break in procedures being done improperly thinking it was the way to go for all these years? Is the oils high film strength a reality? Its amazingly high in PSI. Maybe this blog shouldn't be poo pooed as much as it has.
https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/

 

[493 Mike]

Iron surfaces "work harden" with time so that will most likely explain why after a break in period cam material can withstand lower oiling conditions and survive.
Mike

 

[Ray70Chrg]

I've read, here on site, that excessive idling is not good but that was intended to mean 700-800 rpm idle and then turning the engine off. Like you stated 2000 rpm long hauls at 70-75 mph are common and have had no ill effects on my cars.

 

[Gunner1]

I worked for a large engine builder. We had 3 wet spin stations. Every long and short block got hooked up to a warm 45psi oil supply and spun at 800 rpm. We adjusted valves and checked compression I can tell you that without an oil pan or intake the amount of oil spun up on the cam was amazing.

 

[Geoff 2]

I see no harm in idling. It [ wear of lobe & lifter surface ] is about the amount of time that the two parts are in contact. Taxis can spend a lot of time idling at the taxi rank, yet the engines are known for long life.