Is the level of ZDDP in motor oil an issue?

[stxray]

While discussing diesel engines with my mechanic, he mentioned how the reduced levels of zinc (ZDDP) in modern motor oil is not good for older engines. Seems the older engines (pre-1980) use a Flat Tappet Lifter and the zinc is necessary to prevent premature wear or failure. Here's a link explaining the issue https://zddplus.com/how-it-works/. They sell a ZDDP additive so they may have a bit of a bias.

Most of what I found searching the internet deals with older cars, not diesels. I'm running a Volvo Penta MD3B which does have flat tappet lifters. So, should I be concerned?

I checked Chevron's Delo LE Synthetic and the ZDDP level is .8%. Converted to PPM, that's 800 ppm. Their 400-SD is listed at 1200 ppm. According to Shell Oil's customer service line their Rotella T4 and T5 are at 1200ppm. Checking Amsoil Synthetic 12 TBN SAE 15W-40 Premium Heavy Duty Diesel & Marine Motor Oil, the ZDDP is listed at 1-5 percent. That converts to 10,000 to 50,000 ppm!

I'm thinking if the reduced levels of ZDDP in modern motor oils is an issue for those of us trying to keep our old engines alive, wouldn't the Amsoil be the best choice?

Your thoughts and comments please.

[WillieC]

Ray, we've been talking about this and I've read other articles and I still don't know what to think. I rebuilt my ancient VP MD17C and am using the old cam, the old lifters, only fitting new rod bearings, rings, valve regrind, with all old parts. All new seals. I mixed and matched the pistons a bit so I could get a better fit on the gudgeon pins. (Wrist pins for all you 'Mer'cans out there.) These kinds of reports drive me nuts. The RPM Delo 400 15W-40 I use says for all diesels and some bs about for improved protection for metal surfaces. I think it has an SI rating which I read somewhere is ok, with higher zinc content. Now I've got 100 hours on this engine (knock on cast iron) and it is running quite nicely. A few leaks and a little blow-by coming out the oil fill/hose to air cleaner. I used to have a two hour engine and have run this baby for fifteen hours on one of our legs this summer.

Just changed the oil and filter and hope to get plenty more hours this summer, but this report is troubling. The issues seem to be more at break in if I read it correctly, and how do I count break in on 45 year old engine parts? AACCKK!!! No guarantees I guess.

I met a First Nation fisherman on our latest trip who has been on the water for 35 years and swears by RotellaT. Never turns black. So is it not cleaning and where is the soot going? Mine will change color after about 30 hours. I guess I could change every 30 hours and I would still be ahead of a 15 Large repower. Decisions, decisions. If I start adding zinc additive to my engine, when did I become a petrochemical engineer? I can barely figure out how to operate my vhf!

Thanks for the info, just the same.

[stxray]

I'm right there with you. Hey, great news on you becoming a petrochemical engineer.

Here's what I have been able to determine so far:
1. ZPPD (Zinc) in motor oil is good for engines with flat tappet lifters but bad for catalytic converters or the environment.
2. EPA regulations have mandated a reduction in zinc. Older oils had in access of 1200 ppm. Newer oils are around 800 ppm.
3. Most product data sheets make reference to their zinc content by percentage. According to what I've found, 1% is equal to 10,000 ppm.
4. Some oils have more zinc than others but I haven't been able to determine what the proper/correct amount should be for a vintage diesel.
5. Most information online deals with vintage gasoline engines. Still trying to determine if it's an issue for vintage diesels.
I have reached out to tech support at Amsoil for answers. I'll post their replies if/when I get their reply

[WillieC]

Ray, since you are better versed than I, would you consider contacting Chevron as well? You might mention a lot is floating on this issue.

[catalina_mike]

Here is a sample report from my 28TE. There is plenty of Zinc in the additive package LE uses. These reports tell you what's going on in the engine. I have also included some light reading...

[WillieC]

Good stuff Mike. I do have an oil report on the old engine I will have to double check. Thanks for the idea.

[stxray]

Thanks Mike for sharing some great information. Once I launch and rack up enough hours for an analysis, I will send off a sample.

[stxray]

Here's the reply from Amesoil:
"The reason for most information relating to gas engines and ZDDP is because the amount of ZDDP in gasoline engine oils was lowered when API SM came out in 2004. Most of your current gasoline engine oils will have about 800-850ppm of Zinc in them. This is not really an issue with older diesel engines as diesel oil still has higher amounts of ZDDP for anti-wear protection. As far as what the recommended amount should be, there isn’t a set amount as different engines have different needs. Generally with higher Zinc oils, a good amount is 1200-1600ppm. When Zinc is given as a percentage, an example would be 0.14% = 1400ppm. The 15W40 Heavy Duty Diesel and Marine contains about 1400ppm of Zinc. Typically what we recommend for Volvo-Penta engines is the 10W30/SAE 30 Heavy Duty Diesel Oil (product code ACD), however either of these oils would work. "

As suggested by WillC, I will submit the same questions to Chevron and see what they say about their Delo Diesel oil.

[Northern Spy]

The real concern is breaking in a newly installed cam and lifters. Lower ZDDP in modern engine oil has been associated with an increase of cam failure during break-in when the part actually have to wear together. Also high performance racing cam failure has increased. If rebuilding a motor with a used cam and lifters you should be O.K. but I would still recommend break-in specific oil.