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ZDDPlus vs ZDDP Maxx

AUSMHLY

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It's recommended that we add ZDDP to our engine oil for our Healey, being the reformatted oils are removing ZDDP.
I've googled ZDDPlus vs ZDDP Maxx and can't find any reviews comparing them.

ZDDPlus:
https://zddplus.com/how-it-works/
"When a single 4oz bottle of ZDDPlus is added to a normal 5-quart oil change, you will restore the proper amount of ZDDP that was found in into pre-1996 oils."
DDP to give at least 0.18% zinc and 0.13% phosphorus level when a single 4 oz. bottle is added to a normal 5-quart oil change.
ZDDP Maxx:
https://www.zddpus.com/Default.asp
"Simply add 1 2oz. bottle of ZDDPMaxx to 4 or 6 quarts of your favorite oil, and for racing engines, add .5oz per quart."



ZDDP Maxx seems to be the better dollar value.
Quick search on Ebay for 5 bottles including shipping.

ZDDPlus (5) 4oz bottles $38.00
ZDDP Maxx (5) 2oz bottles $34.50

Any thoughts?
 
Last edited:
Not an answer to your question, but I found this thread on Castrol Synthetic "Edge" having sufficient ZDDP for flat tappet motors interesting: https://www.mgexp.com/phorum/read.php?1,2532440

Good reading.
It does say...Only Castrol EDGE with SYNTEC Power Technology (SPT) SAE 5W-50 has been recently reformulated to have a boosted level of ZDDP (1300 ppm) to help protect flat tappet cam engines in classic cars.

I use Castrol GTX 20-50 as what's recommended by most for the Healey.
I don't think Castro makes EDGE in that weight, plus it's syntec and that's not what's recommend by Healey either.

I'm very happy with Castro GTX 20-50 and adding ZDDP I believe is the closest to what is recommend by the manufacture.
 
Hi All,

I appreciate that the ZDDP in oil today is far less than what was recommended for our period engines, however, as many of us, my total driving has dropped down to possibly less than 2500 miles per year and I doubt that adding ZDDP would make much of a difference in my engine’s longevity … even with my continuing to shift at around 5K.

Am I wrong?

Ray (64BJ8P1)

 
Hi Ray,

The issue is that with too little zinc in the oil, there will be more metal to metal contact and it is certainly possible within a few thousand miles to wear through the hardening on a cam lobe since it isn't all that thick...maybe 10-15 thousands. The Castrol Edge is actually rated for use by VW (which has ridiculous testing standards) in my 2005 VW diesel, with the pump injectors, which is one of the worst possible applications for oil due to the narrow cam lobes. I wouldn't hesitate to use it in my Healey at 5W50 if it showed decent oil pressure.

Hi All,

I appreciate that the ZDDP in oil today is far less than what was recommended for our period engines, however, as many of us, my total driving has dropped down to possibly less than 2500 miles per year and I doubt that adding ZDDP would make much of a difference in my engine’s longevity … even with my continuing to shift at around 5K.

Am I wrong?

Ray (64BJ8P1)
 
Good reading.
It does say...Only Castrol EDGE with SYNTEC Power Technology (SPT) SAE 5W-50 has been recently reformulated to have a boosted level of zinc

I'm very happy with Castro GTX 20-50 and adding ZDDP I believe is the closest to what is recommend by the manufacture.
zinccastrol classic.jpgProbably Castrol is a solution for Air cooled PORSCHE - BUT it exist also at 10W-60 gradation
more nearest at AH recomandation
my solution is RED LINE SYNTHETIC OIL 20W/50- have ZDDP inside 1200

note: ZDDP inside synthetic oil, appear to have a specific formula-so I am not sure if ZDDP additive are the correct solution for synt
 
Wow, damage in a few thousand miles…

Chris, thank you for sharing your knowledge, it really started me thinking. Was ZDDP around in the 1950s and 60s? I, as many other LBC owners, have neither added nor even selected oil for its ZDDP content. I do want my Healey to, at least, last to its 50[SUP]th[/SUP]
birthday this coming April. I guess my choices are to get the additive or not drive till then.


If I understand Andrea’s note, if there are different ZDDP formulas, what formula and method of application would best apply to the Healey?





All the best,
Ray (64BJ8P1)

 
Zinc and Phosphorous always come in the same ratio in oils due to the chemical formula of ZDDP. Any oil of the proper weight (or one that give good oil pressure when warmed up) that has 1200-1600 PPM Zinc will be fine. I'm no oil expert but have had to watch things closely in choosing oils for my VW since it is highly stressed. I'm using Valvoline 20-50 VR1 in my Healey for the time being.
 
Anyone else catch the 'Fast 'n Loud' episode where they started a rebuilt 'Rent A Racer' Shelby Mustang? They used regular oil with a ZDDP additive and flattened a couple cam lobes in just a minute or two of running. Either a) for some reason, an additive doesn't help or work as expected, or b) they dumped the additive in without mixing it with the regular oil, so the cam didn't get the ZDDP in time. It's got me thinking.
 
Getting back to my original question, has anyone used both ZDDPlus or ZDDP MAXX or read about them and can comment if there is any difference besides one being a 4oz bottle (ZDDPlus) vs 2oz bottle (ZDDP MAXX)?
 
Not an answer to your question, but I found this thread on Castrol Synthetic "Edge" having sufficient ZDDP for flat tappet motors interesting: https://www.mgexp.com/phorum/read.php?1,2532440
A quick check of the MSDS for ZDDP (or ZDTP, take your pick) https://msdspds.castrol.com/ussds/amersdsf.nsf/Files/4F5CC6443367512480257BBA00527D2F/$File/221024Castrol%20EDGE%20with%20Syntec%20Power%20Technology%205W-50.pdf does not list ZDDP. If the oil contains it, it must show on the MSDS because of its hazardous nature. Now, the MSDS is dated July of 2013, so if they reformulated since then, they better get the updated MSDS out soon, or the EPA and OSHA will get on their case.
 
Getting back to my original question, has anyone used both ZDDPlus or ZDDP MAXX or read about them and can comment if there is any difference besides one being a 4oz bottle (ZDDPlus) vs 2oz bottle (ZDDP MAXX)?

I haven't seen a comparison. If the differences are minor, it probably wouldn't show up. All ZDDPs have the same basic central structure of one zinc, two sulfurs and four phosphorus. Attached to each phosphorus is an organic radical. These can and do vary, but are not the heart of the molecule and are thought to have little effect on the anti-wear properties. BTW, after reading numerous published papers on the subject, there doesn't seem to be scientific agreement on why ZDDP works.
 
View attachment 30306Probably Castrol is a solution for Air cooled PORSCHE - BUT it exist also at 10W-60 gradation
more nearest at AH recomandation
my solution is RED LINE SYNTHETIC OIL 20W/50- have ZDDP inside 1200

note: ZDDP inside synthetic oil, appear to have a specific formula-so I am not sure if ZDDP additive are the correct solution for synt
Certain models of BMW ///M cars (the S-54 & S-62 engines, specifically) require Castrol RS / TWS 10w/60 oil. Only thing is, Castrol doesn't directly import that product to the USA, and it is only available through BMW dealers (at something approaching $14.00/litre__fortunately, I buy enough BMW parts, >$20k/yr, to get more favorable pricing). I've looked into ordering it from some UK Healey suppliers, mainly because I could "show off" the 5-litre jugs (BMW only imports 1 litre bottles) but that's genuinely cost prohibitive; makes the retail BMW prices look like a steal!

Edit: I should mention that the S-54 engine, at least, is a flat tappet (actually a finger follower) cam design.

Getting back to my original question, has anyone used both ZDDPlus or ZDDP MAXX or read about them and can comment if there is any difference besides one being a 4oz bottle (ZDDPlus) vs 2oz bottle (ZDDP MAXX)?
I use the stuff Moss sells (4 ounce bottle) and given that I only put on enough miles to warrant changing the (Castrol 20w/50 GTX) oil every couple of years (and it's still nearly clear amber in color) I see no reason to experiment with other products.
 
Walmart has the STP version of the of the ZDDP additive...it was something like $3.80 a bottle if I remember correctly.
 
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