My recent decision regarding oil in a '66 3000 with a rebuilt engine

[John Turney]

Just a note: Oils available in Europe, including the UK, are not the same as in the US. So, those wonderful classic sports car oils available in Europe are not available here unless we wait and pay to have them shipped here.

 

[John Turney]

EV--

I cannot find that Mobil product on this page:

https://mobiloil.com/~/media/amer/us/pvl/files/pdfs/mobil-1-oil-product-specs-guide-2016.pdf

but unless it is a race oil it appears that the zddp content is less than the recommended 1200 ppm.

...

What I do see on the second page of that Mobil 1 table is "plain old" Mobil 1, 15W50, with 1200 ppm phosphorus and 1300 ppm zinc and recommended for "For high HT/HS applications. Racing and Flat tappet applications." API SN.

 

[DerekJ]

I just dug out and re-read a couple of articles published in the Bugatti Owners Club magazine about 4 years ago. They were written by a British oil engineer from a large oil company. His information ties in with the long article I linked to higher up in the thread. In summary the key points seem to be;

- modern synthetics and semi synthetics are always better than plain mineral oils, even for a classic engine.
- Oil doesn't thin when hot, its designed to be thin at operating temperatures. It thickens dramatically when cool.
- Most engine wear (75%-90%) occurs at start up due the inability of the cool, thick oil to lubricate properly.
- Thin oil is better than thick oil. Better flow, lower drag, more power and better fuel consumption. Oil drag can consume up to 8% of power output.
- high oil pressure is not necessarily good. Flow is needed not pressure.
- All modern oils are far better than anything around 60 years ago
- A 5W-30 0r 10W-40 are probably the best compromise for our engines.
- Look for oils marked as meeting SL and SM standards.
- After market additives are unnecessary.
- Best to still use an oil with around 1200 ZDDP content.
- You get what you pay for. Expensive oil is better than cheap oil and if you only do one or even two changes a year the cost difference is irrelevant so why go cheap.

I'm going to switch to a low weight synthetic and see if I can notice any difference.

 

[Bob_Spidell]

Hmmmm ... couple of these 'bullet points' seem contradictory to me:

- A 5W-30 0r 10W-40 are probably the best compromise for our engines.
- After market additives are unnecessary.
- Best to still use an oil with around 1200 ZDDP content.

It's my understanding that the lower weight oils--e.g. 5W-30 or 10W-40--don't contain any/enough ZDDP (1,200PPM). Since 5W-30 is still recommended for many modern engines with catalytic converters, it most likely will not have much if any ZDDP.

re: "Oil drag can consume up to 8% of power output." That's an awful lot; can anyone confirm this? This does not compute for me; e.g. a 100HP engine would lose 8HP to oil drag, while a 500HP engine would lose 40HP, but I find it hard to believe oil drag increases linearly (but there's several ways to interpret 'Oil drag can consume up to 8% of power output.').

 

[DerekJ]

…just done some searches and the problem is going to be finding a modern fully synthetic oil that has enough ZDDP in it. Mobil 1 10W-60 seems like it will be OK but it is difficult to find the ZDDP content. It says it is formulated for older engines but what does that really mean?

I also did some digging on the traditional 'classic' oils with interesting results:

Make Grade ZDDP Base Oil Group

Castrol Classic 20W-50 800 I
Penrite 20W-50 1080 II
Millers 20W-50 1130 I
Millers Sport 20W-50 1130 III
Morris 20W-50 700 I

Castrol Classic does not have enough ZDDP, or shall we say it is well short of the 1200 level that is frequently mentioned as the supposed cut off level. It is also made from a Group I oil that is the cheapest type. Why am I using this!! Miller Sport is clearly the best of the above and is made from the better quality Group III oil and is semi synthetic. But it is still a 20W at start up.

 

[DerekJ]

Bob, you are correct. I should have said '…best for our engines if you can find such an oil with 1200 ZDDP in it'. I am wary of additives. Oil companies spend millions of dollars on scientists developing their products. What exactly happens when you tip in an (overpriced) additive to that product? The article I read said '…up to 8%'. Pushing a thin oil will consume less power than pushing a thick oil.

My current short list for oils now contains only 2 choices. Millers Sport and Mobil 1 10W-60. Hopefully others will be found.

 

[Gearhead_Garage]

I have always heard 10psi per 1000 RPM was a minimum not the ideal. My car has around 60psi at 4000 RPM and I have been told this is a good number for a Healey.

I vote for Valvoline VR-1 20W50, FWIW.

 

[Bob_Spidell]

... I vote for Valvoline VR-1 20W50, FWIW.

We should have some anecdotal 'data' pretty soon. The clutch is going out on my BJ8 and I've decided to pull the engine and gearbox/OD together and overhaul (at least) the short block. I've run for over 110K miles on Chevron 20W-50 (until Costco quit selling it) and VR-1 (for the last 20K miles or so), and a couple changes with Castrol. I had the timing cover off a couple years ago and it and the gears and chain were spotless, so I want to see what surprises are in the pan. I've also run a PCV valve for 30K miles--give or take--and want to see what kind of gunk might be in the head, cylinders and manifold.

Stay tuned (it'll take me at least a few weeks to do the teardown). I also just finished my annual road trip--3,427 miles--of all-around driving and averaged over 22MPG.

 

[DerekJ]

Looking at Valvoline oils it seems that Valvoline VR1 20W-50 is a mineral oil. They also do a VR1 5W/50 fully synthetic version which is more what I'm looking for. The product spec sheets for both have the same description for 'a zinc wear protection package' but neither give the actual amount of ZDDP. Does anybody know? If its a 1000 or above I might give the synthetic version a try.

 

[shortsguy1]

In post 36, Michael posted a link which provides all the zinc and phosphorus concentrations in Mobil synthetic oils. It doesn't list 10w-60 because perhaps that oils isn't sold in the U.S.

Can anyone weigh in on why synthetics oils and classic cars were considered to be incompatible? Multiple articles and videos posted here suggest they are just fine, but I have heard for years to not use synthetics in old cars. Even when I inquired about an oil recommendation from Joe Gibb's Driven oils, they suggested a mineral oil formulation when they do also sell a similar synthetic.

 

[DerekJ]

I don't know where it comes from. It may be as simple as the fact that synthetics are associated with modern cars and it is known that ZDDP was reduced in modern oils for modern cars in order not to damage the catalysts. The synthetic oil itself is much better than normal Group 1 based mineral oils in almost every way possible.

I found some additional reports, one produced by an engineer who was actually testing the wear prevention characteristics of many different oils. He said focussing only on ZDDP content wasn't really correct as manufacturers had introduced other wear prevention elements to compensate for the lower ZDDP. He also tested several ZDDP 'additives' which, incredibly were actually found to reduce the wear protection of the oil and made it worse! Moral is don't add after market additives to a product that has been made to specific formulas.

I have come to the conclusion that a full synthetic oil meeting the SM designation which includes 800 ppm is OK to use in a car that has been 'run in'. It is probably not good enough to use when breaking in a new cam.

 

[Bob_Spidell]

The 'conventional wisdom' (pun intended), is that the syns had a) detergents or other compounds that dissolved deposits that were preventing leakage, and b) that the syns were so 'slippery' that our old-school gaskets and seals couldn't contain them. When I put Redline MT-90 in my gearbox and OD it did leak more--as measured on the dipstick and my garage floor--which I attributed to 'slipperyness' (there's a scientific term I'm sure). In most other ways, a synthetic is superior to a dino oil, but unless you are really punishing your oil it's cheaper/better to use a good dino and change it more often (the main advantage of synthetics is extended oil changes, which is not really useful in lightly-driven classics, whose oil should be changed at least once a year or more regardless of mileage). There is no credible 'incompatibility' that I've heard of.

There was an incident in the aviation community, however. Many years ago Mobil--leveraging their success with Mobil 1--produced Mobil 1 for piston-engined aircraft (IIRC, it was called 'Mobil 1AV' or similar). There were claims--not sure if they were validated by scientific testing or not--that the full synthetic did not do as good a job of scavenging lead residue as dino oil. This caused lead deposits to gunk up the rings, esp. in large-displacement Continental engines. Mobil bought some owners a rebuild or new engine, and pulled Mobil 1AV off the shelf (of course, lead buildup is not an issue in our engines any more). Last I checked--it's been several years--Shell was selling Aeroshell 15W-50, which is a dino/syn blend--best/worst of both worlds?--and Ford calls for their own 5W-20 dino/syn blend in my Mustang (which I've used religiously).

Long story short, if you've got a modern, tight engine use a full-syn and change it out every 10-15K miles. If not, unless you're rich--we all know Healey owners are rich (or were before we bought Healeys)--use any good dino oil or blend and change it out at least once/year, even if the car has been sitting. Syn's a better oil, but even with a modern additive package blowby will contaminate it quicker and you still need to change it (relatively) often.

Also, have heard that some newer 'synthetics' actually use highly-refined mineral oil as a base stock.

 

[Bob_Spidell]

re: "... an engineer who was actually testing the wear prevention characteristics of many different oils. He said focussing only on ZDDP content wasn't really correct as manufacturers had introduced other wear prevention elements to compensate for the lower ZDDP"

But was he testing with flat tappet cams? There aren't very many flat-tappet cam engines--relatively speaking--in use today (and no new ones being built AFAIK). I doubt the oil companies are going to devote much research ($$$) to flat-tappet engines; what we get from Castrol, Valvoline, etc. is most likely a legacy, niche product with all the R&D already sunk.

 

[PHulst]

Bob, you are correct. I should have said '…best for our engines if you can find such an oil with 1200 ZDDP in it'. I am wary of additives. Oil companies spend millions of dollars on scientists developing their products. What exactly happens when you tip in an (overpriced) additive to that product? The article I read said '…up to 8%'. Pushing a thin oil will consume less power than pushing a thick oil.

My current short list for oils now contains only 2 choices. Millers Sport and Mobil 1 10W-60. Hopefully others will be found.

Castrol "Edge with Syntec" 5W-50 also works:
https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2365766

I just bought two cases of 6 bottles each to try out.

 

[dougie]

Joe Gibbs Break-In Oil when new, https://www.drivenracingoil.com/dro/br-break-in-oil-15863html/ and Joe Gibbs HR Oil https://www.drivenracingoil.com/dro/hr3-synthetic-15w-171html/ after that, and forget everything else.......

 

[Bob_Spidell]

Side note: if you're running the flat disk spin-on filter adapter--the kind that bolts to the block--this is a pretty good deal on appropriate filters:

https://tinyurl.com/jkt37ab

NFI ... just thought I'd pass it along (you might find them cheaper elsewhere, but I haven't).

 

[DerekJ]

Bob, I believe he was testing the overall protection that the oil gave so i don't think it matters what he was testing it on as its an absolute.

Just checked the articles again and the oil drag loss comment was '…up to 6%' not 8%…apologies for that. I agree with your general summation but I'm interested in trying a low viscosity, low drag, synthetic mainly to see what the affect is on start up, power and fuel consumption. I'll also be checking to see if I have more oil on the floor or not!

The synthetics have esters in them which cling to the metal and give added protection, this helps a lot to minimise start up wear. You will be familiar with this as all aircraft oils have them.

I suspect there are some big mark ups being made out there, Castrol Classic, I'm looking at you. Over here the Castrol Classic made from Group 1 mineral oil sells for £25 for 5 litres, the Morris Classic oil, also made from Group 1 oil sells for about £14. Thats why 'Brands' are worth a lot of money! Either way, given that I change oil maximum twice a year the cost difference is very minor.

 

[Bob_Spidell]

Derek,

Please keep us posted on your results.

 

[DerekJ]

Will do.
I was looking at the Mobil 1 Oils available over here and it seems like the 10W-60 is the only one that meets the 1200 ppm level. It looks like they are using that one product to cover pretty much every classic guy that wants to use synthetic oil. Thats probably why they have gone to 60 but that is really unnecessarily heavy for us. The service manual recommends 30 Weight SAE

 

[steveg]

Will do.
I was looking at the Mobil 1 Oils available over here and it seems like the 10W-60 is the only one that meets the 1200 ppm level. It looks like they are using that one product to cover pretty much every classic guy that wants to use synthetic oil. Thats probably why they have gone to 60 but that is really unnecessarily heavy for us. The service manual recommends 30 Weight SAE

This should be a really good oil - has the right zinc; the 10W is good for winter and the 60 is great for summer.

Just saw a presentation by Lake Speed, Jr. from Joe Gibbs Oil and he discussed all this.