Possible alternative for flat tappet motors

[frnkeore]

I was told by an oil company tech here in Australia yesterday (Nulon) that ZDDP gets 'used up' as ash. So as it is loaded between surfaces it turns to ash & is carried away by the rest of the oil.
Not saying its true or not. Just what I was told.

That is what I read about it, also.

[My427stang]

  My understanding is that zinc does get used up.

paulie

Does zinc embed? If so, x amount would do so and "appear" to be depleted. If not, then why not continue using 2200 ppm after break-in? If so, is there an advantage to soaking a cam and lifters with break-in oil for x days prior to assembly.

And for rings, has there been a discussion here on plateau honing?

My understanding is that it is sacrificial, as far as completely used up in a 5-9 quart system?...I have no idea.  Maybe scouring some of the used oil analysis information on Bobistheoilguy could tell us that, but I haven't done it

I'd also be interested in seeing how fussy a modern ring pack is, seems like the hone, thickness and shape of the ring, and ring material would make a huge difference on break in, but in the end, fire it on the pump, always checking for leaks, dumping the oil/filter, why waste the expensive synthetic...when you can waste expensive dino oil?  LOL

As far as continually needing zinc, to a significant extent, a lifter and cam, under pressure and heat, will burnish, which essentially "pressure-polish" which hardens and smooths the surface, that's why the break in is important, and why, in theory, once break in is done, it usually stays done

I do think though that flat tappet cams do need "enough" zinc after the fact too.  I think that number is lower though, but at that point, why bother going that much lower?  At the levels provided in a specified oil mix, it's not hurting anything, and every wear point gets to use it

[Falcon67]

Ah yes, but you wouldn't want to run right in there and pour in the synthetic.  I have seen the rings come undone and start losing power if you switch over too soon.  I won't put the synthetic in until the 18-20 dyno pull mark, which is a fair amount of loaded run time after the power stops going up after the initial few pulls.  Those rings need time to find a home before the really slick oil goes in.

I'm sure that the 7.3L gas motor in our new 2020 F-350 never had conventional oil in it.  Just as a point of reference.  I haven't felt a need to run synthetic in any of my race engines, VR1 10w30 does what I need and its reasonably affordable.  Everything else here gets full syn, especially the trucks. 

[chilly460]

Sorry for the tangent, but what do you think of the 7.3 so far?

[blykins]

I tend to think that cars/trucks leaving the assembly line do not have synthetic in them, but a break-in oil.  Not 100% sure on that, but knowing that we, as engine builders, are 100X more careful with honing techniques, ring filing, piston/cylinder clearance, etc., than the OEM assembly lines, I can't see how they just throw synthetic in from the get-go. 

Most vehicles now don't get their first oil change until 3000-5000 miles, so that would be a great time to introduce ring seating procedures with conventional oil.

[machoneman]

I tend to think that cars/trucks leaving the assembly line do not have synthetic in them, but a break-in oil.  Not 100% sure on that, but knowing that we, as engine builders, are 100X more careful with honing techniques, ring filing, piston/cylinder clearance, etc., than the OEM assembly lines, I can't see how they just throw synthetic in from the get-go. 

Brent, I do know for a fact that Corvettes and my Audi (all Audis I was told) do leave the factory with syn oil and syn oil is recommended thereafter. It is (or was) a head-scratcher to me when I learned this some years ago. Yet, I do think the reason why is captured in your post: finely honed cylinders, moly-type tight and narrow ring packs and carefully set clearances. Just my opinion on that.

On edit: I was curious and found this from Consumer Reports. 70% of US made cars leave the factory with syn oil or a blend. I was surprised by that little factoid!

 https://www.consumerreports.org/car-maintenance/should-you-use-synthetic-oil-in-your-car/

[RustyCrankshaft]

I can't say for sure about Ford assembly line, but I know that a big truck manufacturer I did some work for filled everything with synthetic right off the end of the assembly line no matter who's engine, transmission or drivetrain the truck was spec'd with. They used whatever spec oil was called for, but it was all synthetic. Those engines are not pre-run before they are installed in the truck. First time they get started is with the synthetic oil in them and end up with about 1.8 miles on them with a quick chassis dyno to test for rated power and brake force and then parked until they're shipped to the dealer.

The "level" of EP additive in the oil (traditionally a zinc based EP additive package is used but there are others besides ZDDP and some not even based on a zinc compound) doesn't make the additive "work" better, it just lasts longer so the additive makes it until you're next oil change. The higher the additive levels (typically measured in whole by comparing TBN/TAN numbers) the longer you can theoretically run the oil before the additive package is depleted. An oil with 500ppm of zinc doesn't work half as well as preventing a lifter from going flat as an oil with 1000ppm.

Having had the chance to work with some oil companies directly, and having ready 100's of thousands of used oil samples (they add up fast when you go through 800 gallons of engine oil a week) and having done some testing on my own, any good quality oil CHANGED on a reasonable mileage or time basis will work fine for 99% of anything that needs oil.

There are always exceptions where an engine on the dyno doesn't seat the rings correctly with synthetic, or insert failure point of your choice here. But with the modern additive packages and clean stable base oils we have now it's just a lot less of an issue. I think that for flat tappet cams making sure you order max taper on the lobes and not buying a shelf cam does wonders for durability. I've had very little trouble since I started ordering them that way, but I don't do nearly the HiPo gas engines as the builders on here so my results my not align quite the same. And I've mostly switched to running hyd rollers in most stuff that isn't real racey, for the little extra in cost I personally feel the gains are well worth it on several levels.