Flat tappet engine using an oil with no ZDDP in it

[volodymyr]

Hello everyone,

I cam across this article from Blackstone Labs where they run ZDDP free oil (Aeroshell W65) in a flat-tappet GM 350 engine from 1984: article.

Now, I am actually surprised that no-one published the article before on this forum or perhaps I did a bad search. Here are the parameters of the test:

1. Oil used is Aeroshell W65 which is 30W grade, ZDDP free, it's viscosity is close to 10w30 grade

2. Engine is GM 350 flat tappet used 1984 Chevy truck

3. Two OCI done each with 16 month duration and around ~ 1900 miles (~ 3000 km)

4. ZDDP myth busted as there were no significant increase in metal wear numbers

Here are the actual numbers:

Thoughts, ideas?

 

[Ducked]

WHAT ZDDP myth?

And WHY test an aviation oil in a truck? Was it the only one they could find with no ZDDP in it?

 

[volodymyr]

Ducked,

Originally Posted By: Ducked
WHAT ZDDP myth?


This one: https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1049812

 

[Cujet]

So 40 PPM iron in 2000 miles is good?

That incredible Aeroshell oil works wonders on flat tappet camshafts. They last and last...

For those who don't know, that's my aircraft engine. The flat tappet camshaft did not last "till overhaul". It failed at 1700 hours total time, even with 25 hour oil changes. And, I'm not alone as this is a very common problem.

Furthermore, iron PPM of failing camshafts often DOES NOT show up as "obvious" in aircraft UOA results! As the chunks are rather large. Often is the trend that matters, with a very small uptick in iron that signals the problem.

 

[BrocLuno]

Aeroshell has other anti-wear (AW) ingredients in the blend. ZDDP is only one of the AW systems used, but it is the cheapest from a blender perspective, so it is quite common in automotive oils.

You really want to run this test, you use "bright stock" oil w/o any additives and see how long your cam and lifters lasts...

Plus, this is a mild OEM valve spring package on a 181,000 mile motor with a significant system of ZDDP in place on the wear surfaces. And when you read the report, they are showing Phosphorus and Zinc in the report (31 & 46 respectfully) which means they are actually removing some of the already established layer.

Two OCI's on motor that old means nothing. Try the same experiment on a new engine with fresh metal surfaces, not yet broken in and see how far you get

 

[Ducked]

Originally Posted By: volodymyr
Ducked,

Originally Posted By: Ducked
WHAT ZDDP myth?


This one: https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1049812


I've seen that before so I didn't read it again.

The fact that an aviation oil can give low wear metals, for one truck, on a short OCI, proves that an aviation oil can give low wear metals, for one truck, on a short OCI.

That's all.

It doesn't prove that ZDDP isn't beneficial (of course), and it doesn't prove that current low ZDDP automotive oils aren't harmful to some engines.

Anecdotally these engines might be expected to be high performance with high valve spring pressures, which the truck probably wasn't.

EDIT: Bit redundant, sorry. Hadn't seen the above post.

 

[Shannow]

 

[Ducked]

Originally Posted By: Cujet
So 40 PPM iron in 2000 miles is good?

That incredible Aeroshell oil works wonders on flat tappet camshafts. They last and last...

For those who don't know, that's my aircraft engine. The flat tappet camshaft did not last "till overhaul". It failed at 1700 hours total time, even with 25 hour oil changes. And, I'm not alone as this is a very common problem.

Furthermore, iron PPM of failing camshafts often DOES NOT show up as "obvious" in aircraft UOA results! As the chunks are rather large. Often is the trend that matters, with a very small uptick in iron that signals the problem.


That why the oil has been discontinued?

 

[volodymyr]

In other words, we should not trust Blackstone Labs as well as numerous oil manufactures, EPA, ACEA, etc who are in favour of reducing ZDDP in the oils. Right? Sounds like conspiracy lovers

 

[volodymyr]

Cujet,

Originally Posted By: Cujet
So 40 PPM iron in 2000 miles is good?


Please read the whole article. The number you posted is incorrect as it is not specified there. Also, keep in mind that you took an approximation from the first OCI, what about the second one? Also, if you compare the wear numbers in relative terms to previous OCIs (done with ZDDP oils) it actually does not look that bad.

Also, keep in mind that we still have ZDDP in our oils, as we do not run completely ZDDP free oils nowdays.

 

[Cujet]

At the moment, there is no "equally capable" substitute for ZDDP. Today, it's engine design that allows a low ZDDP oil to perform properly. With low tension valve springs, light weight valves, roller followers, excellent oil flow, the elimination of pushrods, rocker arms,fulcrums and their associated wearing surfaces.

ZDDP is clearly not essential for many modern engines. We don't build them like we used to.

 

[MinamiKotaro]

I don't think the cam in my 2276 would last long without ZDDP. The Ecotec in my Saturn would probably be ok without zddp.

 

[BrocLuno]

Originally Posted By: volodymyr
In other words, we should not trust Blackstone Labs as well as numerous oil manufactures, EPA, ACEA, etc who are in favour of reducing ZDDP in the oils. Right? Sounds like conspiracy lovers

There is a difference between reducing and going to zero ...

Dropping to ~800 PPM is prolly the logical lower limit for flat tappet motors with more than 100# of spring pressure on the valve seat. And I would not break in on that low a level. Maybe two OCI's with VR-1 or so, say 3,000~5,000 miles and then MAYBE you could live on ...

A lot depends on the cam treatments and the lifter face hardness. Of course going to direct oiling lifters will give you some additional margin

Roller lifters and other cam train systems are not at all the same issue, and they may live happily with lower levels of AW additives. But flat tappet motors with higher valve spring pressures (even mild factory performance ones) will still need a robust AW system...

 

[spasm3]

A UOA really tells you about the condition of the oil not necessarily the condition of the engine.

 

[Ohle_Manezzini]

A S W65 doesn't have zddp because its forbidden in aero engines, but has a lot of TCP, so the AW zddp is substituted by a better one, ashless and more expensive aw tcp. It doesn't prove that zddp is a myth at all. The low P means that the element is on the coating glass, emigrated from the oil to the parts.

 

[Ohle_Manezzini]

Originally Posted By: Cujet
So 40 PPM iron in 2000 miles is good?

That incredible Aeroshell oil works wonders on flat tappet camshafts. They last and last...

For those who don't know, that's my aircraft engine. The flat tappet camshaft did not last "till overhaul". It failed at 1700 hours total time, even with 25 hour oil changes. And, I'm not alone as this is a very common problem.

Furthermore, iron PPM of failing camshafts often DOES NOT show up as "obvious" in aircraft UOA results! As the chunks are rather large. Often is the trend that matters, with a very small uptick in iron that signals the problem.


Lack of usage makes corrosion pitting. That ruins cam lobes, not the oil.

 

[SonofJoe]

ZDDP does a whole lot more in engine oil than just anti-wear. It's the primary antioxidant in virtually all oils and provides a lot of an oil's load bearing capability. If I was exiled to a desert island and there was only one engine oil additive I could take with me, it would undoubtedly be ZDDP.

 

[FCD]

the issue with zddp is certainly not a myth, certainly for older FT camshaft engines it is VERY beneficial, it was proven all the way back in the 70s that a level of around 1200 to 1300ppm is ideal and showed the least ammount of wear for a typical engines of that era.
Engine builders are reporting more cam/tappet failures than ever specially when the engine is first broken in.
If running no zddp apparently shows no ill effects on wear, why do 99.9% of engine oils use it as an anti-wear additive?
I don't buy it sorry

 

[bullwinkle]

Originally Posted By: volodymyr
In other words, we should not trust Blackstone Labs as well as numerous oil manufactures, EPA, ACEA, etc who are in favour of reducing ZDDP in the oils. Right? Sounds like conspiracy lovers

The EPA & equipment manufacturers are reducing ZDDP to make catalytic converters last longer, hopefully out of warranty. Not sure longer engine life is in their best interest.

 

[Oldmoparguy1]

cujet has a Lycoming aircraft engine. The camshaft is above the crankshaft and can rust if not flown regularly. There are fixes for that, but Lycoming should have fixed the problem anyway.