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ZDDPlus oil additive

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yelsink

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Recently heard about ZDDPlus oil additive and the need for Zinc for the valve tappets. I have been running the engine for about 4000 miles since engine rebuild w/o ZDDPlus additive, using Castrol GTX 10w-30. Anybody want to take a guess as to wether any damage has been done. I have ZDDPlus in the oil now.
 
Look at the MSDS sheet for that oil. It may be in there if you dig down deep enough to find the spec.
 
I have just switched this last oil change to Valvoline 20-50 with ZDDP after years of running with Castrol 20-50. I have no information of value concerning damage, but I'm supposing none. Next change, I will take a sample and send it to Blackstone Laboratories then I can compare results before and after. I quit sending samples after doing so for a year, because I had a leaky head gasket that was fouling up any evaluation, though their information did confirm what I already knew. I would like to get back on a schedule with them on both my toys. I think if done properly and regularly the information would be informative.
 
I just rebuilt and started my TR3 engine and did lots of research on this ZDDP issue. I did add a ZDDP additive to my oil for the start up and will use a additive at each oil change for the first several thousand miles. I do believe that Castrol has ZDDP in it. If you used break-in oil when you did the rebuild, it also has ZDDP in it and from everything I've read, if there is going to be any damage, it should be noticable within the first 1000-2000 miles. I feel you've past that and your engine should be O.K., just remember to use oil with it at oil changes.
 
The topic that won't die!

I'm not saying it's not important; it is! But there is so much diverse opinion on what oil brand has the "proper" levels of zinc, and what doesn't. And, believe it or not, whether it even matters as much as everyone is saying that it does.

For me, since my car doesn't get driven that much anyway, the point is almost moot. However, I'm using Valvoline VR1 20/50 - said to have enough zinc to protect the tappets. I did the proper break-in procedure, which some say trumps a lot of the hype about zinc anyway, so whatever the case, I feel I'm safe. As I said, the car doesn't get that much use, and will probably outlive me!

There are plenty of articles in cyberland to read up on - some of which corroborate; others don't. Bottom line is: do your own research, and then make your own informed decision.
 
Mickey Richaud said:
The topic that won't die!

Just went back through my Blackstone reports and realised that I had never had the Castrol tested. I was running Trop Artic 20W/50. and once had Citgo Supergaurd 10W/40. Five samples over 23,000 miles, zinc averaged 894 ppm, phosphorus 719 ppm, molybdenem 40 ppm. I still think oil additives are snake oil and the most important thing about oil is changing it often.
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yelsink said:
Recently heard about ZDDPlus oil additive and the need for Zinc for the valve tappets. I have been running the engine for about 4000 miles since engine rebuild w/o ZDDPlus additive, using Castrol GTX 10w-30. Anybody want to take a guess as to wether any damage has been done.
Click to expand...
Sure, you've used up perhaps 5% of the lifetime of your rebuild. If it's 10% instead of 5%, what are you going to do, tear it down now?

I'm with Dale, I think it's mostly hype. What's interesting to me is that the stories of cam & lifter failures started long before the ZDDP levels went down.
 
TR3driver said:
yelsink said:
I'm with Dale, I think it's mostly hype. What's interesting to me is that the stories of cam & lifter failures started long before the ZDDP levels went down.
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From the research that I've done, ZDDP levels started dropping in the mid 90's. About when OBDII compliance started. Camshaft failures in the V8 hot rodding crowd, with very high ratio solid lift cams started to become more commonplace in the early part of this century. Those also coincided with a large influx of Asian made cams and lifters. Then the ZDDP levels were dropped even more, early eliminated, which is when the lower ZDDP levels became more public knowledge. So cam and lifter failures really started after the ZDDP levels were lowered below the minimum levels that they are now citing for solid lifter cars and before the near elimination of ZDDP from the modern formulations. The hard to determine part is actually if the poor quality reproduction items from overseas are more a cause, or accelerated the wear from lack of ZDDP.
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Hard to refute that, Shawn, but it doesn't match my recollection. I can recall people talking about premature cam & lifter failure way back in the 80's, while at least Valvoline (the only brand of oil I use) didn't start dropping their ZDDP levels until after 2000. Of course back then we weren't all tribologists, so we blamed the failures on poor materials or poor workmanship (or general cussedness).

Best hard evidence I can offer is a Triumph mail list post in 95 (oldest year for archives) https://www.team.net/mharc/archives/html/triumphs/1995-04/msg00127.html
and Ed Hackett's venerable FAQ dated 1999 showing as much as 0.20% zinc
https://micapeak.com/info/oiled.html

And I wouldn't call .08% (in the Valvoline full synthetic I use today) "near elimination" either, especially since my understanding is that more zinc does NOT provide more protection, it only makes the protection last longer in the presence of metal-to-metal contact. Hopefully, for a stock motor operated below redline, you never get that anyway and so the zinc is irrelevant.
 
Way back in the 80's could have been more incorrect break in procedure than ZDDP. Same could be said for many of the more recent cam failures but most won't admit that they took one little shortcut that could have made the difference. Plus its not like cams or lifters never failed before reduction in ZDDP, its just become more frequent.

I was speaking in general terms of content and 0.08 is quite a bit less than 0.20. Many stock motors may not have anything to really worry about. The higher the spring pressure the greater the chance of metal-to-metal contact when there is not enough ZDDP to insert itself between the rotating assemblies. It is also a destructive process on the ZDDP, it wears out, the less there is the faster it wears out and breaks apart. I'm not aware of spring pressure on the cam increasing with RPM so I'm not sure how operating at or near redline is that necessary of a requirement for ZDDP.
 
swift6 said:
when there is not enough ZDDP to insert itself between the rotating assemblies.
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The tappet & cam lobe get rebathed with oil at every other engine revolution.<div class="ubbcode-block"><div class="ubbcode-header">Quote:]I'm not aware of spring pressure on the cam increasing with RPM [/QUOTE]Not spring pressure, inertia. The faster the engine turns, the faster the valves move, which means more force to accelerate the lifter, pushrod, rocker arm, valve. 'Performance' cams also aggravate the problem, because they are ground to open and close the valve faster (to allow more time with the valve fully open and hence more airflow). Higher spring pressures are a side-effect, as the spring has to supply the force in the opposite direction (since these aren't Ducatis).
 
I also switched recently to Valvoline 20-50 racing oil. Costs a little bit more than Castrol 20-50 but I figure better safe than sorry. Espically since I only change my oil 4 times a year.
 
Spring pressure is the major determiner on metal to metal contact where the ZDDP is important. Higher lift cams require more spring pressure which places more stress on the camshaft due to the higher pressure of the lifters on the camshaft surface. Which is why the failures associated with ZDDP are with solid lifter engines. Roller lifters redirect large amounts of that pressure through the rotation of the roller which also reduces friction.

I don't think inertia is as big of deal as your thinking it is. First, the mathematically useful definition of inertia is the measure of an objects resistance to changes in momentum, or simply a body's inertial mass. and if your going towards F=ma (force = mass X acceleration) the acceleration, and deceleration for that matter, of the valves, lifter etc... are fixed by the camshaft profile. They do not change with rpm. The frequency of the acceleration changes, but not the acceleration factor itself. Momentum ceases at the top and bottom of each items travel as well.

Yes, higher lift cams increase that acceleration rate with the steeper profile inherent in the higher lift, especially if it has a short duration.

The force applied to the camshaft and lifters, the items needing ZDDP is determined by the mass X acceleration and the resistance to that force from the spring pressure, are the forces that are jamming the lifters and the camshaft towards each other that the ZDDP is supposed to intervene in.
 
jerrybny said:
I also switched recently to Valvoline 20-50 racing oil. Costs a little bit more than Castrol 20-50 but I figure better safe than sorry. Espically since I only change my oil 4 times a year.
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Every three months is more than most LBC owners.
 
swift6 said:
the acceleration, and deceleration for that matter, of the valves, lifter etc... are fixed by the camshaft profile. They do not change with rpm. The frequency of the acceleration changes, but not the acceleration factor itself.
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Simply not true, Shawn. Basic high school physics, distance traveled from stop is <span style="font-family: 'Fixedsys'">(1/2) at^2</span> where '<span style="font-family: 'Fixedsys'">a</span>' is acceleration and '<span style="font-family: 'Fixedsys'">t</span>' is time. Which can be rewritten as <span style="font-family: 'Fixedsys'">a = 2d / t^2</span>

The distance is fixed by the camshaft design, but the time per cycle depends directly on engine rpm. And since the time is squared in that equation, the acceleration required goes up with the square of rpm. In other words, going from 5000 rpm to 7000 rpm DOUBLES the force required.
 
Anyone read the article in 'AutoWeek'(weekly mag)of that 1966 Volvo1800 with over 2,500,000 miles on it :winner1: its a daily driver and looks new.Maybe he used ZDDP?
Mileage certified by the Volvo OEM....read the article its outstanding.THEN here we are ;-)...I use premium 93oct with 10%alcohol :thirsty: & WhiteLighting never feels the pain
 
Volvo must have studied and conquered Cadillac's cam problems that resulted in a high failure rate (if not 100%) with the introduction of the OHV motor in '49. Zinc and lead were abundant and not much valve spring pressure; just sorry manufacturing with the cams.
 
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