Fast Marina Magazine

I buy Mobil 1 Vee Twin in cartons - although the actual containers are 1 US quart - appears to be aimed squarely at Harley owners.
My price is $20 per US quart (946ml).
This is enough to make me defer my oil changes a little longer - but as yet it seems to be paying off in reliability.

My old air cooled motorcycle is far more critical of oil types than any of my Marinas, and I routinely check with my bike and those I work on, how their oil pressure is looking - it tells a lot about the condition of the bottom end.
Currently my Trident gives a reading of 60psi at hot idle on this Mobil 1.
This is an as-good-as-new condition, although the bike has now covered 60,000 miles and is still on standard bearings.

I am not wishing to change anyone's mind about what oil they use - but I want to give my engines the best chances of survival I can - the Trident engine would cost me the equivalent of 2 Marina purchases to overhaul, and that is not on my wish list.

However - the point I am intending to make, is that in order to ascertain what works and what doesn't, you have to study the wear for significant mileages, and actually determine the condition of the engine in question in order to see if the data stacks up.

I am thinking that any Marina engine - let alone a modified one - that can outlast two body shells, must be running pretty happily..

thank you everyone, for your replies. i think 20/50w it is ,but now the brand?! too much to choose from! Perhaps Morris is an obvious choice?!

Im bemused, confused & need to lie down in a dark room...
Gil.

Brand is not so important the API & SAE numbers and letter are the specification of oil after the viscosity
Dave

Kilroy, can you tell us more about what the zinc does to protect the cam followers? And does it do the same for any other components (valves, bearings etc). You've piqued my curiosity...

Where do you buy your oil from, a Harley dealer (or are they even more expensive )?

On a side note, what is the recommended procedure for replacing the oil on an engine that hasn't been run for some time. Should it be drained, filter replaced, refilled, run up to temp and then drained and refilled with another new filter?

When we talk about “Zinc” in motor oils, what we are really talking about is a family of additives called Zinc DiakylDithioPhosphates – better known as ZDDP.

Many different types of ZDDP additives exist – Primary, Secondary, and Ary. These different types of Zinc have different activation thresholds. You see, Zinc is not a lubricant until the ZDDP reacts under heat and load to create a phosphate glass film that protects the metal surface.

This is critical to protection.

Zinc needs heat and load for it to activate and then lubricate the surface. Some types of Zinc activate faster under less heat and less load than other types of Zinc. These “fast burn” Zinc additives provide better protection during engine break-in because they react faster and establish that protective Phosphate glass coating quickly during the critical break-in phase.

All types of ZDDP function in the same manner. Zinc is a polar molecule, so it is attracted to steel surfaces. Under heat and load, the Zinc reacts with the steel surface and creates a phosphate glass film that protects the steel surface by forming a sacrificial film that covers the peaks and fills in the valleys of the steel surface.

There is heaps of information about ZDDP additives on the web. Such info is best gleaned from people who are not selling such a product.
ZDDP is particularly important in engines that have conventional cam followers - such as A, B and O series engines - they comprise of camshaft lobes that bear directly on followers and thus rely totally on lubricant adhesion to their surfaces to avoid rapid wear.
I currently have an A series engine whose cam followers have been reduced to something like lego blocks. I would assume that it has been run on very bad oil for a long time.
Engines that feature double valve springs - like my modified B series engine and my 70's motorcycle, experience even greater loading on these vital wearing surfaces, so some degree of thought is necessary when choosing oils.
There has been a tendency for oil manufacturers to reduce zinc additives as they have been linked to problems with catalytic converters. Boo hiss.

Interestingly enough, Amsoil who were one of the first to market a fully synthetic oil, have done a huge amount of research on such things.
I have placed a detailed study on my website for a short time - you can get it here..
http://www.kilroy.co.nz/Amsoil_Study.pdf
I was very impressed by the fact that they rated Mobil 1 Vee Twin as better than their own oil in several fields - but both oils stand head and shoulders above many others in the study.

Regarding your "old oil" situation, I would get it out of the engine as soon as possible, as old oil tends to contain rather acidic residues that cause deterioration even when not in use.
I would change oil and filter without running the engine at all - Supercheap Auto often special Castrol GTX 20W/50 - I have picked up 14 gallons of it at $20 per 4 litre - perfectly suitable for our engines and my first line product when not using synthetic.
Once the vehicle is in regular use I would give it a second oil and filter change - and would do that warm.
There is absolutely no danger in moving to 20W/50 fully synthetic from mineral oil - but considering the cost of it - I would not bother if I needed to make several changes in quick succession - nor if the engine proved to have a major thirst for oil. I would rather rectify the problems than continue to pour oil through it...

I buy all my Mobil oils from Allied Petroleum. As I am a business they give me a healthy discount. Here in Christchurch they also have some very knowledgeable people behind the counter - and they have been able to answer all my technical questions.

Hope that is of use.
Cheers.

Thanks, Kilroy, a most informative answer (as usual).

Supercheap have Castrol GTX 20W50 on special at $18.99 until Sunday.

Now I just have to sort out an oil filter, as the Z83B seems to have been unique to BMC Australia and their E-series models (but changed to an out-of-production Z23 from 1973)
Seam OD 112 mm
Seam HT 83 mm
Gasket ID 67 mm
Gasket OD 105.5 mm
Relief Valve
Thread 3/4" X 16UNF

locost_bryan wrote:Supercheap have Castrol GTX 20W50 on special at $18.99 until Sunday.

Now I just have to sort out an oil filter, as the Z83B seems to have been unique to BMC Australia and their E-series models (but changed to an out-of-production Z23 from 1973)
Seam OD 112 mm
Seam HT 83 mm
Gasket ID 67 mm
Gasket OD 105.5 mm
Relief Valve
Thread 3/4" X 16UNF

Picked up the Z83B oil filter that I ordered from Repco last week for $68, to go with 4 litres of Castrol GTX 20W50 I bought the week before. Courier delivered a second filter, bought for $29.50 from a parts supplier in Pahiatua, a small town in the middle of nowhere (thanks to my Old School "wanted" ad).