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High Zinc Motor Oil & Flat Tappets

Ken M

NAXJA Forum User
Location
Anchorage
For years I've been using high zinc oil or a zinc additive in my old-technology British cars because the experts say the old flat tappet engines need the zinc to protect the cam & lifters. It occurs to me the 4 liter Jeep is pretty much old tech. Should I be using high zinc oil in my 4 liter XJ?
 
A lot of people like to run high zinc in these. The 4.0 is based off a 1960s amc engine, in practice I don't think it really cares, as long as it has oil and a little pressure they tend to keep going. I run rotella, because it's cheap and I run so many miles I have to change oil about once a month.
 
I'm running Rotella T6, it has less zinc with the newer formulation but I think its still higher then others. It's diesel oil that's why it has a higher zinc content. Walmart is usually the best place ~$22 a jug.
 
If you have a Rural King near you, their store brand diesel oil has high zinc content at reasonable price. I run it in all my old engines.
 
As others have said, I too run Rotella T6. I bought some at NAPA on sale for $23 or so this weekend. I do have to ask what you consider High ZDDP? I think the T6 and other diesel oils have about 1000 ppm of Zinc. Some of the Hot Roaders or Older Muscle car owners use Brad Penns with 1600 ppm Zinc.
I have also used Rotella T4, both 15W-45 and 10W-30. I see the list posted, but at #12 to #16 T6 will do its job. Also, different engines do different things to different oils.
I also trust and try to use synthetic oils. Still, the new conventional oils are no slouch either. Also, the cats on the 4.0l are older type. So, the Zinc won't plug them like newer cats. Now if I had a 2000 Cali or 2001, with the pre-cats, then I might have to think about it. I actually do have a 2001, but its a shell and I'll have to see who I configure it.
So, Rotella, Delvac and other Deisel Oils should fill the bill. AMsoil would be a good choice along with Shaffer, if you want to spend a bit more.
 
I've been using Valvoline VR1 Racing Oil in my old British cars. Valvoline doesn't address the issue of potential damage to catalytic converters, but says VR1 is good for passenger cars as well as high performance cars. I have assumed that anything sold for highway use must be compatible with cats. Has anyone read anything different?
 
There are differences in the technologies between different eras of smog control. I think the dividing year is about 2004 for cats. It might also depend on vehicle.
 
I just found the relevant info on the Valvoline web site after failing to find it earlier. It seems a bit contradictory, saying it can be used in "modern muscle cars" but "not recommended for use in vehicles with cats." VALVOLINE'S statement: "VR1 Racing Engine Oil is recommended for engines burning gasoline and full or partial alcohol fuels in track and street service. For use in classic and modern muscle cars, race cars and high-performance passenger cars.
Valvoline VR1 Racing Engine Oil is not recommended for use in vehicles with catalytic converters"
 
I just found the relevant info on the Valvoline web site after failing to find it earlier. It seems a bit contradictory, saying it can be used in "modern muscle cars" but "not recommended for use in vehicles with cats." VALVOLINE'S statement: "VR1 Racing Engine Oil is recommended for engines burning gasoline and full or partial alcohol fuels in track and street service. For use in classic and modern muscle cars, race cars and high-performance passenger cars.
Valvoline VR1 Racing Engine Oil is not recommended for use in vehicles with catalytic converters"

ZDDP is a catalytic converter poison. If you have a vehicle that burns oil it can cause your cat to die an early death. This is one reason zddp levels have steadily been taken out of modern oils. VR1 is a "race oil" and Valvoline doesn't recommend it for street use for that reason. I don't even think it actually carries an API cert.
 
Rotella is one of the best oils to run along with chevron. It doesnt have a fancy package or Marketing but is one of the best

I run chevron 15/40 in everything.

Look up sugestions of oils to run for camshaft break in. The list is usually short.

Oils like rotella and chevron make the list.

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