GM debunks ZDDP myths for flat tappet cams

[Kuato]

I don't know about GMs, but our Grand Cherokee has the 4.0 with flat tappets.

Mobil 1 0w30 produced more than twice the iron in sample as any other oil (including Amsoil, Valvoline conventional, and Super Tech Synthetic) that I tested.

So although all Mobil 1 oils are very good, I wouldn't recommend them with a flat tappet application.

 

[Shannow]

Do you know that's where the iron was coming from ?

Holden V-8s only needed a slight mis-alignment of the lifter bore, and it would stop rotating, and make for a flat lobe...

I don't disagree that oils need to protect cams, but oil can't be blamed for everything, or stuff that hasn't been identified as actually happening either.

 

[Clevy]

Originally Posted By: tig1
Originally Posted By: Garak
Originally Posted By: cadchris
Your thoughts are highly valued and appreciated.


Good thread find! I missed this one. In my view, GM debunked the ZDDP myth before the myth even existed, by creating small block Chevs that would eat cams no matter what oil was used.

Nonetheless, like Doug said, the 15w40 is a good choice, and in my view is the path of least resistance. You can get plenty of good 15w40 oils all over the place at decent prices. There's nothing wrong with VR1 either, especially if you can get it at a decent price. Quaker State Defy is another option. ZDDP additives certainly have their place, if you can find a decent one that doesn't cost an arm and a leg.

Oddly enough, the mention of EOS in the thread reminds me; last week I saw a bunch of EOS on the shelf at a local tire shop.


But the problem with the GM cams was the cams themself. They became known as "soft cams". Friends had to have them replaced with after market cams that never failed. Correct me if I am wrong.


I believe you are correct. It was the 80's small blocks that had the issues iirc

 

[Shannow]

Just one to throw out there, and I'm not making judgement...see my last post.

If the lube is doing it's job, then the chill hardened lifter face, and the cam never actually touch, either through a hydrodynamic film or through the action of boundary layer operational additives...hardness shouldn't be a major factor in extreme wear.

All three (oil, additive and metallurgy) "coming together" can create a "perfect storm"

 

[MinamiKotaro]

We had three cam failures, two ACVWs and one Corvair. One was a 300HP turbocharged VW, one a 100% stock VW, and one Corvair with a reverse-rotation cam in one of our buggies.

The cam in the turbo one went flat pretty much the first time I cranked it over after a fill with Royal Purple 5w30. The stock VW's cam went flat a couple of weeks after a fill of SuperTech 10w30. The Corvair had Castrol 10w30. All three cams and the lifters looked like someone had taken an angle grinder to them. These were proven engines that had been running perfectly for years until those sudden failures.

Having three engines fail in exactly the same way after an oil fill led me to the internet to figure out what might have happened. I learned about the ZDDP theory. We switched to high-ZDDP oil (mostly the kind you used to could get from Summit) or at least the use of additives in all of our flat-tappet engines.

There have been no failures since. That's reason enough for me to keep using T6 in my Bug. Dad's going to use it in his cars when he runs out of the Summit oil he stockpiled.

 

[Kruse]

I would like to see if GM still stands by this bulletin 100%. They probably wouldn't comment on it any more because most engines today have roller lifters.
And speaking of, I know on some engines you don't have a choice, but why go with a flat tappet on a new assembly if a roller is available?

 

[Garak]

Originally Posted By: tig1
But the problem with the GM cams was the cams themself. They became known as "soft cams". Friends had to have them replaced with after market cams that never failed. Correct me if I am wrong.


You're probably quite right, tig. We did replace cams, but that was generally only once in the lifespan of a taxi engine, which is hundreds of thousands of miles. It was generally in the first half of the cycle, and never a problem again. The one we ran to a million kilometres was probably changed somewhere around 3 or 4 hundred thousand km, and never caused a problem again. But we did the job on just about every small block Chevy we ran in that era. I even spent a fair amount of time helping friends and neighbours do the work on their private vehicles with the engines. As Clevy mentions, it was the 1980s era. The first one I had to do was in a 1979 Impala, and the last one to be touched was a 1986 Caprice.

 

[cadchris]

Thanks guys for all the comments. I was never notified by e-mail even though I have the topic on my "Watch List".

I'll pass this link along to that guy on in Finland who I'm sure will also value your advice and guidance on what oil to use for his 69 Cadillac Deville.

Regards,
Chris

 

[cadchris]

Hey guys, "just for the HOI", I'm posting a link that was discussed here by another member about, now; Lubrizol's Hyper-ZDP from the Lubrizol ad banner I clicked on here at BITOG.

The first link doesn't work, but the orig. posters 2nd link to Lubrizol video presentation works:
BITOG Thread re; Lubrizol Hyper-ZDP

Or go to the Lubrizol Page Here
See the pane titled Performance Additives on the left side of the page. There are two "Performance Additives" showcased.

"Trident HEI" which looks like it could affect everyone using even 10% Ethanol fuel.
And the other subject title is "Hyper-ZDP"

How can one tell WHICH OILS have these additive packages developed by Lubrizol and Oronite?

Just like Sgt. Schultz says:
:....."I see nothing.....I know nothing....!

 

[ueberooo]

because 800 ppm "seems" a bit low i've often of late thought it decent to add around 300ppm of zinc. it surprised me to see that no zddp can sometimes be better than some very low concentration of it (just as there can be a point of where of where excess zddp is destructive).

Originally Posted By: David_Navone

There is on the other hand, research that concludes that the minimum ZDDP requirement is directly related to the lifter foot pressure. In one SAE paper it is reported that: “at a ZDP level corresponding to 0.02% phosphorus, scuffing occurred at 200 pounds lifter load, while it required 240 and 480 pounds lifter load for oils containing 0.04 and 0.06% phosphorus, respectively, to initiate scuffing. At 0.08% phosphorus concentration, no scuffing occurred up to 600 pounds lifter load, the test hardware limit. Scuffing occurred at 350 pounds lifter load with no ZDP (0% phosphorus).”

The older engines and high-performance engines we are concerned about may have lifter foot pressures several times that of a low-performance engine such as those used in the Sequence III tests, and their wear characteristics are not predicted by common Sequence III testing methodology. An additional factor is the dynamic load at the lifter foot. Sequence III engines run at 3600 RPM maximum during the test. Most high-performance TR engines are regularly run to 6000 RPM. The inertial contribution to the lifter foot pressure increases as the square of the increase in RPM. This means that the inertial load at 6000 RPM is 2.67 times it’s value at 3600 RPM.

 

[buster]

Originally Posted By: cadchris
Hey guys, "just for the HOI", I'm posting a link that was discussed here by another member about, now; Lubrizol's Hyper-ZDP from the Lubrizol ad banner I clicked on here at BITOG.

The first link doesn't work, but the orig. posters 2nd link to Lubrizol video presentation works:
BITOG Thread re; Lubrizol Hyper-ZDP

Or go to the Lubrizol Page Here
See the pane titled Performance Additives on the left side of the page. There are two "Performance Additives" showcased.

"Trident HEI" which looks like it could affect everyone using even 10% Ethanol fuel.
And the other subject title is "Hyper-ZDP"

How can one tell WHICH OILS have these additive packages developed by Lubrizol and Oronite?

Just like Sgt. Schultz says:
:....."I see nothing.....I know nothing....!

Valvoline uses LZ additives and I believe worked with LZ developing the Hyper ZDP.