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.

[secondchance]

Originally Posted by 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.

Well, I figure it's a lot easier to find Moil 1 when I need it and I just hate to mix the oil with another brand just because I forgot to carry an extra quart. Also, I prefer 5W30 to 10W40 during the winter months. Colder temp lower viscosity...

[tomtom72]

Okay, I'm guilty of using M1 w/the silver cap from COSTCO also! I do add the ZDDP from the turbo buick site. I alternate doing the 4oz/5qt and the next time it's just one 4oz bottle. I worry as NYS does test and the cats take the hit.

I have resisted long enough, ever since Marc's write up on Amsoil. I am about to order enough quantity to get me thru a yr at a time. I recently bought two 5qt jugs of Valvolene full syn @ autozone. They were destined for the Z, but upon further review they will be used in the Cobalt.

You guys down at WAZOO should open up a commercial account because there are enough of you to make it worth while, JMHO. You could do "oil change days"!

I guess what I'm saying is that I give up as I can't take the nightmares any longer with the ZDDP levels and our beloved LT5's. I'm going the mail order route. Hopefully the anxiety will cease!

[secondchance]

Originally Posted by tomtom72

Okay, I'm guilty of using M1 w/the silver cap from COSTCO also! I do add the ZDDP from the turbo buick site. I alternate doing the 4oz/5qt and the next time it's just one 4oz bottle. I worry as NYS does test and the cats take the hit.

I have resisted long enough, ever since Marc's write up on Amsoil. I am about to order enough quantity to get me thru a yr at a time. I recently bought two 5qt jugs of Valvolene full syn @ autozone. They were destined for the Z, but upon further review they will be used in the Cobalt.

You guys down at WAZOO should open up a commercial account because there are enough of you to make it worth while, JMHO. You could do "oil change days"!

I guess what I'm saying is that I give up as I can't take the nightmares any longer with the ZDDP levels and our beloved LT5's. I'm going the mail order route. Hopefully the anxiety will cease!

That's an idea!
Chances are current level of ZDDP in Mobil 1 is most likely fine for our ohcs/tappets. Being 4 valves/head it's possibly not as stiff as typical worked on ohv motors. It's just that I tend to agonize myself when I find out what I filled with does not meet what was spec'd.
For now, I will add 2oz per 8.5 qts since the oil was changed 300 miles ago and somehow feel bad about draining it out.

[xlr8nflorida]

Marc,

On the registry there was a thread on ZDDP. I know you recommended Amsoil in the registry newsletter so I have a few questions.

1. Do you feel its a huge concern if one continues to use the Mobil Synthetic since its shy of the ZDDP or is it more for guys who crank up major mileage?

I belive that with about 100k miles of use, that there could be significant unnecessary wear on the lifters.

2. If you wanted to fix the zinc problem, would you go with Mobil 1 High Mileage or Mobil 1 Turbo and what weights would you recommend?

I'm not familiar with the EP additive levels for those products. I recommend the levels that are used in the SG formulation. The LT5 was designed for the SG formulation. I think that viscosity should not be greater than 40. For example 10W-40.

3. High Mileage Mobil is alittle shy of the Zinc numbers, would you add some ZDDP to the mix?

I would not. Why get into additive experimentation when there are several oil products that are designed to solve the EP problem with flat tappet engines.

4. I know ZDDP is an issue if you use too much but most ZR1 guys are running without cats etc.

It could cause other problems. I don't know for sure. I don't like to take risks when I don't know enough to calculate the risk.

Thanks for sharing and I'll share with the other guys once you respond.

Best regards.

Marc