Oil and ZDDP

[secondchance]

When I read the thread titled "which oil do you use in the beast" I started thinking about this ZDDP level and it's possible implication on our LT5s.
Owner's manual and FSM for 94 states "SH" rating for the LT5.

According to Marc Haibeck, his reasoning behind recommending Amsoil AMO 10W40 (phosphrus .125% and zinc .138%) is due to current Mobil 1 5W30 and 10W30 with SM designation having reduced level of phosphorus (800 ppm - .08%) and zinc (900 ppm - .09%).

Upon search there are a lot of pre 1990 car forums where concerns are being expressed and even Mobil seems to acknowledge these concerns to a point of recommending their 0W40 or 15W50 racing oil. Some are resorting to motor oil intended for diesel or turbo diesel motor for this reason.

I for one, do not care to run around town or resort to mail order and pay $8 for a quart of oil. Quite frankly I have been using Moil 1 since 1985 and I can get them for $34 a six pack at local Costco. Also, I appreciate the fact that I can run into Moil or Exxon and get a quart in a pinch.

Then, I ran into this product called ZDDPlus. This seems to be ZDDP (zinc dialkyl dithio phosphate) concentrate being marketed to address reduction in ZDDP in most readily available motor oil reformulated to meet concern over catalytic converter longevity possibly at an expence of ignoring needs of older cars.

Based on ZDDPlus calculation comparing phosphate and zinc level boost relative to other similar products, I calculated one 4oz bottle when mixed to 8.5 quarts (because that's what gets changed and for the first application a little extra would be needed) will boost phosphate by 616 ppm and zinc by 873 ppm.

When added to Mobil 1 5W30 or 10W30 with phosphate 800 ppm and zinc content of 900 ppm resulting mix will be 1415 ppm and 1773 ppm respectively. Now, ZDDPlus recommends adding one 4oz bottle to 5 quarts but based on my calculation one bottle would be sufficient to end up with a brew w/ slightly more levels then the Amsoil AMO blend.

As for the cost, I bought 3x4oz bottles for $25 and free shipping on ebay.

Based on my quick review of web posts, perhaps not as severe as ohv high performance engine w/ after market cams and springs but I do feel uncomfortabe that SM grade I have been using in my car has deficient level of zinc and phosphate then what was specified for our LT5.

For this reason I will be adding a bottle of ZDDPlus in the crank case. But, just in case, I wanted to post this and get your reaction to my logic and decision.

Some useful websites that helped me whether I should be concerned and also helped me with calculation:

http://www.zr1specialist.com/HAT%20W...5%20Engine.pdf
https://www.mobiloil.com/USA-English...duct_Guide.pdf
http://www.crower.com/dl/ZDDP_clr.pdf
https://www.mobiloil.com/USA-English...ssic_Cars.aspx
https://www.mobiloil.com/USA-English...t_Engines.aspx

[xlr8nflorida]

You have done your research.

You need to be careful with that product or anything that adds zinc because it can be detrimental to your Cats. If you measure out everything good, you should be good to go and also sending your oil away for an oil analysis might be a good thing as well. (old Mobil 1 that is spent and then ZDDP mixed up with Mobil spent)

I would just go with Mobil 1 High Mileage or that new Turbo oil they have.

I don't know too much about the Turbo so I'd be more inclined to go with the High Mileage version.

That being said, even if the Zinc is low in the regular oil, I don't think it will matter much unless you are piling on ton of mileage onto your LT5.

Being proactive is a good thing though.

[secondchance]

Originally Posted by xlr8nflorida

You have done your research.

You need to be careful with that product or anything that adds zinc because it can be detrimental to your Cats. If you measure out everything good, you should be good to go and also sending your oil away for an oil analysis might be a good thing as well. (old Mobil 1 that is spent and then ZDDP mixed up with Mobil spent)

I would just go with Mobil 1 High Mileage or that new Turbo oil they have.

I don't know too much about the Turbo so I'd be more inclined to go with the High Mileage version.

That being said, even if the Zinc is low in the regular oil, I don't think it will matter much unless you are piling on ton of mileage onto your LT5.

Being proactive is a good thing though.

I agree with your concern over cat. That is why oil manufacturers started to reduce ZDDP level. I figure I would rather risk my cats then engine internals. That is why I ran the calculation and settled on 4oz per change as opposed to 4 0z per 5qts.
I have considered high mileage Mobil 1 also. But according to the Mobil chart it's phosphorus content is 900 and zinc is 1000, still shy of SG level.

[xlr8nflorida]

Originally Posted by secondchance

I agree with your concern over cat. That is why oil manufacturers started to reduce ZDDP level. I figure I would rather risk my cats then engine internals. That is why I ran the calculation and settled on 4oz per change as opposed to 4 0z per 5qts.
I have considered high mileage Mobil 1 also. But according to the Mobil chart it's phosphorus content is 900 and zinc is 1000, still shy of SG level.

Opinions are like asses, everyone has one. I'm not oil expert. My father has some machinery where the engines are several hundred thousand a piece and he relies on constant oil analysis. It's amazing what an analysis can tell you.

I also gather from speaking to some of the oil guys that when you add additives to oil, it can change the overall oil characteristics which is why I call stuff like STP etc Snake Oil.

For myself, I think I'm going to use an oil that is almost on the # of zinc content. If the Mobil High Mileage is it then I'll use that with the minimal amt of ZDDP to meet the standards. I have no concern for Cats in my particular situation.

I spoke with the Mobil guy at Petit Lemans and he said use the Turbo version coming out. I'm not going to say he did not know his stuff but honestly he seemed like a lower level employee who was there to represent Mobil. I'd rather hear it from a high level engineer at Mobil.

Sounds like a good ? for Haibeck especially since he did the article for the registry newsletter and recommended Amsoil. I emailed him to get his thoughts on it.

[secondchance]

Actually SG designation did not stipulate minimum but rather a maximum.
Also, since zinc and phosphate additive in oil is added in form of ZDDP (zincdialkyldithiophosphate) proportion between zinc and phosphate proportion is constant.
Based on my calculation I can control final ppm level of phosphate and zinc level is determined by final phosphate percentage. For an example. 2oz would result in 1108 ppm of phosphate and zinc will end up being 1335 ppm.
In essence any oil with 1108 ppm ends up with 1335 ppm of zinc, if I am not mistaken.
The fact that it only takes 2oz to do this would mean minimal effect on basic formulation of oil before the addition.
It seems reduction of ZDDP probably occurred back in 2006 or 2007. Since then I have put on about 10,000 to 15,000 miles.
I will most likely add a set of headers next year at which point I will leave the cats off and go to metallic cats later if I decide to register in VA anyway. Perhaps it's the best time to try this out and see.
For sure, after say 2,000 miles I will have a sample sent for analysis and see if indeed my calc was correct. One thing for sure, I will not go by manufacturer's suggestion and use 4oz per 5 qts.
I am curious about Marc's thought for sure.

[32valvZ]

Its a whole lot easier to just buy the damn Amsoil and be done with it. I dont "like" paying the $8./qt either, but its not really that big a deal.