Any opinions as to whether zinc additive is beneficial to use in an XK engine. Mine is a 4.2 L which was rebuilt about 2-3 M miles ago and installed in my 1961 E-Type. Only mod to engine was a .030 over bore. Have had Jags since 1959, never had to rebuild any engine before and never used zinc additive before. Thanks HB
This has been talked about, ad nauseam.
Here’s my take: buy any good oil, on sale, change it and the filter every 3000 miles/once a year.
Given the few miles most of these cars get, plus relatively low spring pressures, that’ll get you through your natural life.
Search the Jag-Lovers archives for “ZDDP” and you will find all the opinions that you could ever dream of. Have fun.
What oil are you using?
It’s only real known benefit is reducing mental anguish. If your cams still have lobes…did it work? Kind of like hearing the tree falling in the woods.
I use a Lucas additive with Mobil 1.
I also wear suspenders and a belt at times.
Zinc is in nearly every modern car engine oil. The major oil manufacturers list the amount of zinc and phosphorus levels in the product specifications. They also recommend zinc level according to application.
So how much do “they” reccomend for an E type xk 6 cyl?
Here are some resources to help inform zinc level choices.
Robert M. Orlee in the GM Powertrain Fuels and Lubricants Group has written several Society of Automotive Engineer articles on zinc. While those articles typically have a purchase price, here is a summary article from him on oil myths.
oil_myths.pdf (16.7 KB)
Amsoil has an informative discussion at https://blog.amsoil.com/do-older-vehicles-need-high-zinc-motor-oil/
Here is a Mobil Oil spec sheet for various applications
mobil-1-product-guide-rev-31.pdf (122.8 KB)
And here is a review article on zinc in motor oils
Hope these resources help. Cheers.
The takeaway quote: “Despite the pains taken in developing special flat-tappet camshaft wear tests that these new oils must pass and the fact that the ZDP level of these new oils is comparable to the level found
necessary to protect flat-tappet camshafts in the past, there will still be those who want to believe the myth that new oils will wear out older engines.”
I believe that: “new oils will wear out older engines”.
Before misquoting me, or the oil experts, you might want to be a bit more intellectually honest in your selective quoting.
“Despite the pains taken in developing special flat-tappet camshaft wear tests that these new oils must pass and the fact that the ZDP level of these new oils is comparable to the level found necessary to protect flat-tappet camshafts in the past, there will still be those who want to believe the myth that new oils will wear out older engines.”
IOW, new oils will not wear out old engines.
hows this then…It is not a quote:…I believe that: new oils will wear out older engines.
OK: personal opinion, or is that backed up by science?
Ran Tweety on “new oil:” worked fine. Cut open filters a few times, nothing to show any damage.
Run Margaret on “new oil:” so far, nothing showing any damage in the filter.
Quite a few thousand others, and I’m not reading about any credible evidence of damage.
All the above is anecdotal, to be sure, however, Ive yet to read or hear of any credible report of engine damage.
I also inspected both their 60s-vintage flat tappets, after 5000-ish miles: not an indication of any cam or tappet damage.
uh oh…your quote of me…left out the “I believe”…so I stated a personal belief based on what I have read…plenty of very credible sources on both sides of this…no need to cite them pro or con. We do know: that ZDDP levels in oils now, are less than prior to about 2000. Flat tappet cams are the ones cited in needing the higher level of zddp protection. We know that too much zddo is also not good, so I prefer the oils that have zddp already in it, rather than add my own. IMHO…if zddp level is as it should be, (as it was prior to whenever it was reduced…then no harm done…and just maybe some benefit. .The question may be…so why not> My only anecdotal is my own: I did have a 1974 Dodge 318 V8…flat tappet…cams wore out…why? who knows…but it was well after 2000…and I was using modern oils…frequent changes as always. I would not jump up and down and insist everyone use a zddp enhanced oil…but I would advise it and say…why not. Hooray to those whose engines have run since 2000 without it and with no issues: …my condolences to those who may have had cam wear…and maybe not know it…and fiddle with valve adjusts and timing…to no avail. I also use non-ethanol, add Techron and Lucas top oil, 30 wt in the gearbox, real air in the tires, with tubes. with new tires every 8 yrs. Stock points ignition. Prestone…not Evans…, My redline…is 4,000 rpm…call me cautious. Cheers…Nick
Now, you’ve gone too far: NOTHING wrong with synthetic air.
On the street, very little reason to exceed that: it’s generally what I stuck to, with Tweety.
so back to topic…a quick search of web articles will show a LOT of what I will call trusted sources that say YES to zddp of 1000 to 1400 ppm for flat tappet cams. …and a LOT of various. "forum talk " that says…nah, my brothers cousin had a tractor that ran for 40 years with no oil at all and by the way Apollo on the moon was in a soundscape in Hollywood…so I am an old fart, non-expert, farm-hand forum opinion floater-talker…that says use zddp. Nick
And, being a free country, you can do that, even using real air…
However, the VAST majority of the hyperventilating about ZDDP …is just that. An important part of this discussion, left out of most of this, is the valve spring pressure. WRT the XK engine, that is quite low.
Racing is racing…street is street: most academic writings on this support my thesis, that any good-quality oil will not damage your older street cams, with generally-lower spring pressure…
Who is Steve Maas, and why is his opinion any more credible than anyone else?
Did I assert it was?
No. It is a seemingly-informed opinion, one of many, and one that tends to comport with the science, little of which I have or will post here, simply because this seems to be a topic most approach with their hearts, rather than their heads. Facts and science, like so many other areas of discussion on here, seems to not matter that much.
My readings–pretty voluminous, ever since this became a Big Deal–is that any good-quality oil, will be adequate.
I tire of the back and forth, and am completely happy to let anyone think anything they wish.
I’ve heard the MMO has fantastic results in high-speed F1 two-stroke bikes, though…