Break in oils, zinc and all that jazz

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This Bad Demon

This Bad Demon

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Ok....I have a question....I understand about the need of zinc in older flat tappet cam engines and not needing it in a roller cam type setup...Now my question is lets say a 1998 Nissan ( I kno it ain Mopar don't shoot...lol) Altima 4 cyl with an overhead cam uses a cam an bucket style lifters/plungers/followers...Any way I know it's not a roller between the cam an lifter....Why is it that those engines don't need the zinc additive even though it's not a roller lifter style?
 
They all need zinc. Rollers included.
 
What is factory valve spring pressure? Done a few Datsun/Nissan builds. 98,is OBD-2 . Continued use ,zinc can cause deterioration of 02 sensors. Usually ,the Nissan company runs low valve spring pressure,and flame hardened OEM valvetrain equipment. What is your situation?
 
No situation in particular...I was just reading the thread about the cam bearings that went bad on the 340 and other various threads about zinc additives and flattened cams and what not....It got me to thinking about different engines I've worked on...Typically newer stuff but never heard of needing zinc in those engines ( without roller cams) and having a cam go flat but have heard/seen pics of the failures of cams in various V8's.....I've never gone as far as to see what spring pressures Nissan run...
 
I know this is a bit off topic (of mopars) but how do these engines get of with cam break in, when you almost need to remove the head to remove/refit the inner valvesprings? And some of those motors pull to 7-8k standard. So the valve spring pressures can't be that weak?
 
This Bad Demon said:
Do you mean older engines or the newer ones? I thought that the zinc was hard on the catalytic converter on newer cars....
Click to expand...

Zinc and Phosphorus will screw up converters in short order so it's only for non converter applications. Rusty is right though it should also be used in roller motors - mainly because anyone who spends the money to build a roller motor usually has high performance in mind, with high lift cams and high spring pressures. If you are running a high performance roller motor, use the added zinc oils.
 
Oils today are NOT zinc free. They simply have less than they once had. It is still necessary.
 
This is the first I've heard of a zinc issue with oil. Someone else mentioned zinc on 'another' forum, and when I asked, nobody responded. So - is there a particular type of oil we should use in our old flat-tappet hydraulic cam engines? What do I look for when I go to Napa auto parts? Also, what's the recommended oil weight for a V8 (recently rebuilt) with old technology?
 
You'll get a lot of different opinions on viscosity. But 10w-30 is usually a good, all-around rating. Diesel oils tend to have a little more zinc than passemger car oils, but they have gone down too. Especially from around 2007, because they have been getting catalytic converters and other emissions related hardware that zinc affects.

There are some "racing" oils that have a good bit of zinc. Some advertise it on the bottle. Personally, I use Amsoil and they have a wide variety of choices with published data.

http://www.amsoil.com/techservicesbulletin/motoroil/tsb mo-2007-08-08 flat tappet.pdf
 
When I spoke with the rep, at Brad Penn, in April this year, he told me that as of 2011, they removed the phosphates and zinc as well as nickel, copper and other additives from conventional oils, but carried over their original formula, for the plant's Kendall GT1 oil. I may call him back to see if he was speaking on behalf of the company, or the industry, in general. I want to say it was the latter, but I'll pick his brain soon.

What I do know is that phosphate plays a bigger roll in anti shear and wear, than zinc, which has to do more with extending the usage. I also know that higher detergent levels of conventional oils, play the biggest role in murdering cams, even with additives that can be used in combination with conventional oils, that have added detergent percentages. It will just clean anything along with carbon, away from high pressure areas.

You want some detergent, or you will see sludge carbon buildup, but not to the levels that new conventional oils have. Race applications don't see enough extended use between changes and rebuilds to be concerned with the use of detergents, which is why the race formulated oils don't include detergents.
 
OHC has less valve train mass typically. Small engines and small valve train components with modern materials have less valve train mass. Combined they need less valve spring pressure. Even with slider cam followers or direct lifter to cam contact, they have less pressure at the nose. Probably means less need for zinc or similar high pressure additives, even with out rollers.++

Joe Gibbs has HR which is a line of oil for hot rods. That Amsoil Z-rod looks promising too. Redline claims that all their oils are chocked full of high pressure additives.



Valvebounce said:
I know this is a bit off topic (of mopars) but how do these engines get of with cam break in, when you almost need to remove the head to remove/refit the inner valvesprings? And some of those motors pull to 7-8k standard. So the valve spring pressures can't be that weak?
Click to expand...
 
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