Oil: HD-30 or 10W30?

[ernst]

I have been faithfully using HD30 so far because 'the A-4 was designed for it and that is what the manufacturer recommended.' However, I am having second thoughts.

Mainly because in the last issue of Good Old Boat, there is a nice article by Robert Hess about the A-4. Among other observations, he notes that the manufacturer actually changed the specifications, recommending HD-30 for hot weather and 10-W30 for year-round use.

This makes a lot of sense. There is a reason why nearly all modern cars run on multi-weight oil: you want low viscosity (10) when the motor is cold and high viscosity (30) when it is hot. Why should it be different for an Atomic 4?

Of course, early on Universal could not recommend multi-viscosity oil simply because it did not exist, but once it was well established (70s or 80s), that's what they apparently recommended.

I know that Don says one can use 10W30 'in a pinch' which does not make it sound that he recommends it whole-heartedly. I would be very interested in getting the straight dough here. Are there any advantages of using single weight 30 oil over 10W30?

[I will be putting in an oil filter soon and in the process will 'flush' the whole system with new oil several times. It would be great to know which oil will be the best to use. Also, I buy 10W30 for my vehicles by the case while the A-4 is the only motor I have that uses HD30. Using 10W30 would make this part also a bit easier although this is a very minor concern]

--Ernst

[CalebD]

SAE 30 vs 10W 30 SAE oil

Your thinking is along the right track as far as I am concerned. Multi weight oils were not developed when some of our engines were built. There has been a lot of progress with additives that help to make it such that not all oils are equals. The most sophisticated oil I know of for bot gas and diesel engines is Rotella T, either SAE 30 or 10 W 40 (check the API mark for the 'S'xx rating versus a generic oil - the 'xx' should be higher in the alphabet for the more sophisticated oil).
Every can or container of oil has an API (American Petroleum Institute) rating on it and some are better for combustion or spark (S) engines then compression (C) or diesel engines. The A4 is similar to a car or tractor engine that is fired by a 'spark' from a plug versus a 'compression' or diesel engine.
Your intended use of the engine and location also weighs upon your choice of oil. Will it be used in colder temperatures or only when it is relatively warm? It is a personal decision and one which will help you determine what 'weight' oil you use in your engine.
All I can add is to use a good oil like 'Rotella T' to your engine and to change the oil regularly. Once you have the tools to do an oil change it may cost you less then $20 for the oil change - and that is cheap insurance. Old engines like fresh oil and not the cheap stuff.

[marthur]

Unless you run your motor in cold temperatures, multi-vis is probably not necessary but I see no reason to believe it would be harmful. Up here on the Great Lakes we often see nighttime temp's in the 40's at the beginning or end of the season, but during the summer when it is warm, probably not an issue.

On the other hand, you will want to avoid synthetic oils. They are too slippery for the reversing gear in the transmission and some people have reported trouble until they have changed back to natural oil.

You may wish to consider a couple of ounces of Marvel Mystery Oil in the fuel every now and then. It is supposed to help lubricate and clean the valves. I personally use a little two stroke oil from the dinghy outboard because I keep it on the boat already.

BY the way, I installed the Indigo oil filter kit some time ago. I am really happy with it. My oil was significantly and visibly cleaner after installing and the pressure regulator is outstanding.

[ernst]

Thanks, calebd and marthur for weighing in. And thanks to whoever fixed the title line, I could not find how to do it.

I have heard about the synthetic being too slippery for the reversal gear and did not intend to use that. My usage is quite standard, a Chesapeake day and weekend sailor. Neither Michigan ice sailing (though I make my season longer than most Chessie sailors; in by April, out by December or not at all, but the boat incl. motor is winterized at the first serious frost) nor tropical heat.

As you say, I cannot see why 10W30 would be harmful at this point. I am just concerned why Don Moyer (whom I consider the world's premier authority on all things A-4) said it is Ok to use 10W30 'in a pinch.' I wonder if he reads this forum?

--Ernst

[ernst]

Don's quotes

OK, I looked up Don's quotes about oil choice. In the "Recommended oil type" thread, he said

"You can indeed use 10-30 oil in a pinch. Universal actually recommended 10-30 weight oil in a few of their later owner's manuals."


In the Marvel Mystery Oil thread (right above this one!), he said

"In our experience, the Atomic 4 will thrive on any good quality motor oil. We continue to have a minor preference for single viscosity 30-weight oil in most of our operating areas, but 10-30 oil is also OK or even 15-40 in hotter climates."


I would of course like to know what the 'slight preference' is based upon but, altogether, perhaps the choice of the oil type is less critical than I imagine.

--Ernst

[CalebD]

...
"In our experience, the Atomic 4 will thrive on any good quality motor oil. ...

--Ernst

Just do not use a crappy discount type of engine oil and you should be ok. Rotella 'T' is still my choice of high quality oils. Choose your grade, whether plain 30 W or 10 W 30 is up to you. You will have to figure out what works for your intended purposes.

As for cold starting our engine after nearly 6 months of sitting I use a quick spray of ether (less then a second) on the flame arrestor. It usually gets the engine cranking quickly and helps save the batteries from too deep a discharge. Usually just engaging the choke (which closes the butterfly valve) is enough to get the engine to kick over. Your mileage will vary.

[dvdcnl]

oil type

I was reading an article on motorcycle oils and it mentioned wet clutches, as the A4 has, and it said not to use any oil marked 'energy conserving' or SM as these are not good for wet clutches.

[hanleyclifford]

seriously

Does anybody out there really believe that an oil's viscosity can increase with a rise in temperature?

[sastanley]

I sure hope that is what's going on in my engine hanley, since I only have about 5 PSI at start up and it works its way up to about 20 PSI after 45-60 minutes of run time.

[joe_db]

http://www.westmarine.com/webapp/wcs/stores/servlet/Product_11151_10001_437552_-1?cid=chanintel&ci_src=14110944&ci_sku=437552

I have been using the Penzoil 15-40 for many years now and can't recall any issue with it.
BTW - 10-30 oil is as thick as HOT 30 weight oil when hot and COLD 10 weight oil when cold. That does not mean it gets thicker when hotter, but that it does not thin out like hot 10 weight would. I too have noticed my oil pressure starts at 30 cold and makes it up to 40 when hot, but I always thought the warmer oil was easier to pump.

[Don Moyer]

In cases where oil pressure responds dramatically in the opposite direction from what would be expected, it would probably be worthwhile installing a manual gauge to verify the reading.

Electric oil sending units are nothing more than electrical resistors which vary the connection to ground (through the sender itself) as oil pressure raises and falls. The gauge in the cockpit then compares that variable ground value on one side of its mechanism with 12 volts DC on the other side and translates it to psi.

Unfortunately, the manufacturers of gauges use different ranges in their instruments which will cause erroneous readings if you try to use a sender from one company with the gauge from another. More to the point of how oil pressure could increase dramatically over time as oil thins, we have also found in some tests that some companies bias their equipment so that the gauge responds in the opposite direction of the rising and falling of the resistance values transmitted by the sending unit. In those cases, you would see your oil pressure responding in the opposite direction from normal; in other words, oil pressure would raise as oil thins, decrease as RPM increases, etc.

[joe_db]

I do have a mechanical gauge on the oil filter. It doesn't match pound-for-pound with the electrical one, but it is pretty close.

In cases where oil pressure responds dramatically in the opposite direction from what would be expected, it would probably be worthwhile installing a manual gauge to verify the reading.

Electric oil sending units are nothing more than electrical resistors which vary the connection to ground (through the sender itself) as oil pressure raises and falls. The gauge in the cockpit then compares that variable ground value on one side of its mechanism with 12 volts DC on the other side and translates it to psi.

Unfortunately, the manufacturers of gauges use different ranges in their instruments which will cause erroneous readings if you try to use a sender from one company with the gauge from another. More to the point of how oil pressure could increase dramatically over time as oil thins, we have also found in some tests that some companies bias their equipment so that the gauge responds in the opposite direction of the rising and falling of the resistance values transmitted by the sending unit. In those cases, you would see your oil pressure responding in the opposite direction from normal; in other words, oil pressure would raise as oil thins, decrease as RPM increases, etc.

[hanleyclifford]

hot and cold

I fully agree with Don Moyer's suggestion that the oil gauge is to be checked first. Both electric sender and tube style mechanical gauges are not to be trusted the same as a direct reading gauge attached to the block. I do not like the gauge mounted anywhere near the oil filter (as the Indigo). At start up time a lot of things are possible in the oil galleries, including voids which can mislead the gauges. If you are starting up with 5psi and then going up to 20psi when warmed up, it is NOT because the oil is gaining viscosity.

[ndutton]

Electric oil sending units are nothing more than electrical resistors which vary the connection to ground (through the sender itself) . . . .

Unfortunately, the manufacturers of gauges use different ranges in their instruments which will cause erroneous readings if you try to use a sender from one company with the gauge from another.

Unrelated to this thread but still noteworthy, this applies to temperature senders as well.

[sastanley]

Don & Neil,

This phenomenon that Don explains is what I am seeing with my gauge. It is the stock (1977) gauge that came with my C-30. When I give the boat gas, the oil pressure gauge goes down.

Neil, my stepfather is a retired SAE mechanic (40+ years), and worked at a few different dealerships. He commented to me that Volvo (the car company) modified their temp gauges so that they wouldn't move until there was an extreme change in coolant temp above some certain threshold because they had too many service calls at the dealerships for erratic temp readings on the gauges from them being too 'accurate'

I will also comment that on my old Honda project car I was getting low oil pressure readings at idle...like 12 PSI at traffic lights and 40 PSI or so on the road at 2,800 RPM. It had the supplied-with-the-gauge plastic tubing for the sender...I switched to a copper tube (sender unit is mounted on the firewall and not on the aluminum block for vibration reasons) and the 'new' idle oil pressure is almost 50 PSI.

I agree with Hanley...sounds like I need a new gauge on the A4