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

I am one of those people who spends way too much reading and researching things before I ever make a purchase. (It once took me two years of researching mountain bikes before I was ready to make a particular purchase. But 10 years later, I still ride that bike several times a week)

After reading all of the countless oil threads here and elsewhere, I originally decided to use Castrol GTX 20W-50 with ZDDPlus added at the recommended dosage. Sadly, I only got to do one oil change before it became clear that the engine had major problems (unrelated to the oil brand or viscosity, by the way).

The car is still a month or two from being done, but I have already decided to change to a new oil plan. Recently, I have read more and more recommendations to not add ZDDP to oil, as the detergents in the oil work against the zinc attaching to surfaces to protect them. So I decided to avoid using an additive, and instead find an oil formulated with an appropriate level of zinc in the oil itself.

As you know, there are many options out there for classic cars. I didn't want to use a racing oil as it may not be intended to last 3000 miles between changes. Racing oils may also not be well suited for a car that sits for weeks between use. I also wanted to use an oil for its intended purpose, so that meant that diesel oils were out. In the end, I contacted Joe Gibbs Driven oils for their recommendation.

They recommended their HR1 15W-50 conventional oil for a Healey 3000. This oil contains 1200-1300 ppm zinc and is designed for older cars and for cars that may not be frequently used. It costs $10 a quart, but there is a web vendor who sells it for $7. So it is not cheap, but not too expensive in the context that my engine rebuild will cost $8K.

They also said to monitor the oil pressure at idle when the car was warmed up. If the pressure at these conditions is 45 psi or higher, they recommend that I switch to their 10W40 oil at the next change. I will post my findings along these lines when they are available.

Anyway, I don't claim that my decision is better or worse than anyone else's. But I just wanted to share the thought process that I went through recently. Thanks for reading and I would enjoy hearing how others have come to use whatever oil they prefer.

Use Valvoline VR1 30 to 40 weight and sleep well at night.

IT is formulated for racing engines.

N :" What's good for racers is good for old engines,"

Oh !! your valve train-Flat Tappets- will thank you too.

Over this side of the pond I use Castrol 20/50 specially made for Classic Cars. I understand that isn't available in the States but I would have thought one of the US companies must make a special oil for classics.

I've used Shell Rotella Diesel Oil for the last 15 years. No sign of burning oil or engine damage.

I think there are several brands that are suitable for our cars, but like Shortsguy1, I use HR1 15W-50. The HR stands for Hot Rod, and it is supposedly specially formulated to cling to vertical surfaces for longer than regular oil. This provides more lubrication on initial startup, particularly for cars that don't get driven every day (like most of our LBCs). I have no idea how true this claim really is, but it sounds good. eaceful:

It's expensive for sure, but how often do you change your oil? Once a year, if you're like me. I buy my oil from the machine shop that did the work on my engine, and they sell it to me for around $7 a quart. With a spin-on filter instead of the original canister, my Healey takes 6 quarts, so that's $42 a year, plus filter. In the grand scheme of things, it's just not that much.

Of course, if your car burns or leaks a lot of oil, or if you have a fleet, then the price goes up accordingly.

I use Mobil 1 10W60 for Classic cars and one day the same stuff turned up but with a label saying is was for racing cars, so I rang Mobil and discovered that the two formulations are identical. What's good for racers is good for old engines, which seems eminently logical. One is highly stressed because it revving extremely hard, getting very hot and being beaten up by a driver anxious to prove himself. And the other suffers all the same issues because it's and elderly over stressed design.

I'm doing 500 miles on cheap 20W50 then back to Mobil 1 after I watched lots of Mobil videos on YouTube explaining all the benefits and its suitability for old crabs. Then I found the one where a BMW 325 did 1,000,000 miles on it without any wear and various Merc engines the same.

vette said:

I've used Shell Rotella Diesel Oil for the last 15 years. No sign of burning oil or engine damage.

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Same here. Diesel oil may not be originally designed for classic cars, but it meets every spec it should for an older engine.
There is a new diesel oil spec in the works, and the upcoming CK-4 standard is supposed to be backward-compatible as well.
I can't find any published data as to proposed ZDDP levels for it, so we will have to see how it turns out.

Straighten me out here. I have always been under the impression that the first, low number was for cold weather starts. Too thin for above 60-70 degree weather. The higher number for running when the engine is hot/warm to keep lubricant working. Why would you want to increase the wear when warming up with a weak oil?

Well,Not really TH:

When you see a W on a viscosity rating it simply means that this oil viscosity-it's ability to flow- has been tested at a Colder temperature. The numbers without the W are all tested at 210 degrees F

OH!! Faster engine turn over at low temps starts sooner.,less wear.

Not quite.

If an oil has only one viscosity listed, like SAE 50, it has the viscosity of an SAE 50 oil at 210 degrees and at the colder temperature (IIRC 32 deg.)

If the oil has two viscosities listed, like SAE 20W50, it has the viscosity of an SAE 20 oil at the cold temperature and the viscosity of an SAE 50 oil at 210 degrees. To do that, it usually requires some modification of the oil (viscosity modifiers).

The viscosity ranges are listed in the SAE Standard for each temperature.

Check out this very detailed article by an oil expert. Very interesting and it can be confusing so be prepared to study it in detail.:nightmare::nightmare: And note that your engines should be running at 212 degrees F.

Enjoy the read.

https://www.minimania.com/Motor_Oils_-_It_Is_So_Very_Misunderstood

That's going to take some time to read. It is, however, less expensive than Which Oil? Choosing the right oils & greases for your antique, vintage, veteran, classic or collector car by Richard Michell.

John,

I have now read it twice and will read it again. At the moment however I am planning to change to a thinner synthetic oil at the next change. (Maybe EVV can comment on why he goes for the 60 grade at operating temp). One interesting stat is the 'optimum' oil pressure of 10psi per 1000 revs. Mine is higher than that as are most others I suspect. But as he says, flow lubricates the engine not pressure. High pressure may simply be the result of clogged 'arteries'. Enjoy the study!

I somewhat disagree with his wording:

In fact the relationship between pressure and flow is in opposition. If you change your oil to a thicker formula the pressure will go up. It goes up because the resistance to flow is greater and in fact the flow must go down in order for the pressure to go up. They are inversely related. Conversely if you choose a thinner oil then the pressure will go down. This can only occur if the flow has increased.

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The flow rate of oil is determined by the speed of the positive-displacement oil pump. For any given RPM, the flow rate of oil will be close to constant regardless of oil viscosity. A higher viscosity will increase the pump discharge pressure and sap power by making the pump work harder, but the flow rate is only slightly affected. He is correct that oil flow rate is more important than pressure, mostly because of the cooling provided by the oil.

John,

Although the flow rate will remain the same the pressure will increase if you use a higher viscosity oil. He seems to say that an optimum pressure is 10 psi per 1000 rpm but I don't really know why and whether that applies to all/most engines. I am at 50 psi at 3000rpm. Thinner oil is clearly not a bad thing and will increase fuel consumption and aid cold starting amongst other things.

After reading this I have come to the conclusion that you guys are all retired and spend way way way to much time reading stuff and specs and and and .......Put in some 20/50 Castrol GTX and drive her like ya stole it:eagerness::welcoming::eagerness::welcoming:

Okay, then why the 10W and 15W for an older engine?

Valvoline VR-1 Racing Oil
20W50
It's got ZDDP also.

tahoe healey said:

Okay, then why the 10W and 15W for an older engine?

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Better flow rate at lower temps makes staring easier-[Faster]- minimizes wear.

What Keoke said. Castrol makes a 5W50 EDGE with 1% to 3% zddp for classic cars.