Zinc additive recommendation

Is that an oil blended with Zddp, or Zddp added as an aftermarket additive?

Zddp is a hard material designed to coat the surface. Too much Zddp causes catastrophic wear and damage in a very short time.

All one needs to bother about is the running clearances in the engine. Use a suitable oil for the metal types, running clearances, operating temperature and conditions and all will be fine.

From what I see older Jaguar engines were built with standard running clearances and as such Jaguar specify standard oil viscosities.

Use a quality blended oil and don’t add anything, it will end in tears.
Engine oils are regulated to approved standards, oil additives are unregulated and the marketing is mainly based on opinion and hearsay.

Hopefully, you can see I’m trying to avoid opinion.

well…you could simply pay for my new cam in my 318 Dodge v8–flat cam…due to oil with very low zddp.not just a little flat…engine with no power and barely running flat. but of course that guy with a tractor knew someone who had a Jugwire car and it ran on cooking oil for years.

How do you know the oil caused the cam damage? Had the cam analyzed metallurgically? Oil analysis? Or the cam manufacturer voiding a warranty claim saying it was the use of modern oil?

I’ve seen numerous statements of this nature - it would be great to see scientific analysis showing modern oil was the cause.



anecdotal: flat tapped cam lasted and lasted.a long time, then oil changed…zddp levels way down…cam wore flat.and quickly, New cam–zddp in correct level in oil…cam happilly lobing itself along…not flat.
engine oil made for flat tappet cam engines will state somewhere…maybe on a web page…the zddp level…1,000 to 1200ppm and some to 1400 which is upper limit mainly for high load. Mixing your own:? how does one know the ppm. AND…it has been found that a zddp oil requires a different detergent package…so adding zddp additive to an oil will NOT give you that revised detergent formula…and thus increases wear.

I ran Castrol Edge 20W-50 for 421,300 odd miles in an '88 Range Rover and replaced the camshaft about every 120,000-130,000 miles, then sold it. The wisdom was those engines had “soft” cams, so I replaced the cams with aftermarket cams and still replaced two of them at the same mileage. Maybe not enough ZDDP?
So in the XK150S I should run a different oil? Jag cams are more costly and more effort to replace.

the most optimal engine oil will be an oil specifically made for flat tappet cam engines…Most will now have 1,000 to 1200 ppm of zddp (some to 1400–high but ok…those for high spring rate muscle cars…but ok…pushing the upper limit of zddp). those will also have the new detergent formula that is necessary for a zddp 1,000-1200ppm oil. Mobil 1 but ONLY in the 15-50, or Castrol Classic, or Valvoline ZR1…and you are all set. There are some others…specifically for flat tappet cams…but I do not know if those have the new detergent formula. There is NO reason not to use one on the ones specifically made for flat tappet cams. Walmart has best price on Mobil 1 15-50. (Millers Oil has a very good classic oil-UK oil with one distributor in USA–and they also have correct mono grade 30 wt for the std trans gear box).
It is NOT a good option to add a zddp additive to some other oil–you will have difficulty knowing the ppm, and the detergent package will not be the one for zddp oil.

Another potential cause of cam wear is lack of lubricant supply either due to a problem that has developed in the engine or poor original design. There were some cases in the early 1980s in some European engines. Eventually, the manufacturers adopted much harder grades of steel for the camshafts and hydraulic lifters. It seems it was cheaper than providing an adequate oil supply.

I have always used Valvoline VR1 with ZDDP. 50W in my Ferrari 308 (Flat buckets) and my Alfa Romeo Montreal ( also Flat buckets). Recommended by Ferrari Club and Alfa Romeo Club guys. Owned the Montreal for 47 years and rebuilt it once due to a blown head gasket. Complete tear down and the Tappets / Buckets were fine . The Ferrari shows no Tappet wear after 10 years of ownership and a lot of driving, 4 rallies of 1,000 miles each and no one was hanging around! I run a container of ZDDP additive along with the Valvoline. So as far as I’m concerned, I’m doing the same with my 1951 Jaguar XK120. No reason to change, because for me it has worked!