Multi-viscosity motor oil question.

[Guest]

Working on an old tractor. Manual calls for using 10 weight oil for temperatures below 10* F, 20 weight oil for temperatures between 10* F and 60* F, and 30 weight oil for temperatures above 60* F.

Is this the ideal situation for using 10w-30 oil? Any negatives? Should be a no-brainer for me but just want to make certain.

Don't think I've seen a straight 10 weight oil or straight 20 weight oil for quite some time so I may not have any choice but to substitute.

[A.K. Boomer]

How old is it? might have been "pre-multi viscosity era"

My take on it is this,,, the greater the range of multi-vis. the more polymers they have to add to the oil, this makes the oil subject to thermal breakdown, but with the invent of synthetics and better base stocks you can actually achieve great protection - there is actually synthetics that cover a 0 w 50 range and have great protection against thermal breakdown,

I don't recommend you run synthetics in and old tractor like that though - multiple reasons - increased leakage and burning to name a few not to mention just plain overkill and having to toss it out early and not get your money's worth due to excessive blow-bye contaminants

so what to do? I see nothing wrong with going a 10W30 Castrol or Valvoline conventional oil and as far as being worried about thermal break-down not a chance, that engine does not produce enough power or heat to hurt itself as it can barely get out of it's own way in the first place...

[strokersix]

I think 10w30 would work great. One caution however, is modern oils have detergents. If this engine has been run with non-detergent oil there will be sludge accumulations. Modern detergent oil can loosen the sludge and potentially damage the engine.

[A.K. Boomer]

SS that's wise advise indeed - that's going back even further than the multi-grade clause but if it is indeed N/D then by all means stick with it unless of course you plan on pulling the pan and cleaning everything out...

[JoeLee]

My 1964 Simplicity tractors have a sticker on the Briggs motor that recommends a specific oil weight for a given temp. range. Don't remember exactly what it is with out looking, but like AK says it may be prior to the multi viscosity era. I've used 10W 40 in both of them for years with no problems. The heavier weight was recommended for summer use and lighter weight oil for winter. I do remember using straight 40W one summer and when winter came the motor was hard cranking in cold weather.

JL...............

[pgmrdan]

The tractor is from the 1940's. Massey Harris Pony. Very small engine.

As far as loosening up sludge someone I knew years ago would use kerosene instead of oil in an engine to free up sludge. Run the engine for a few minutes with a new filter and shut it off. Repeat and rinse. Then change out the filter and kerosene for a new filter and correct oil.

Sounds like a good idea but I never tried it. Any harm in it?

[strokersix]

Might consider multiple oil changes instead of kerosene.

Kerosene mixed with sludge is probably not a good lubricant...

[pgmrdan]

Okay. Probably much safer.

[firbikrhd1]

My guess, and this is only a guess, is that your tractor, depending upon it's age, was built before multi grade oils were available, perfected or common. You are probably OK with using a modern multigrade as far as viscosity goes, however there may be other concerns. You didn't mention whether it is gasoline or diesel, however, older gasoline engines were designed for oils with higher zinc and phosphorus content which protected bearing surfaces under high pressure loads, like camshaft lobes. Those substances have been largely eliminated from modern oils because they damage catalytic converters. People with classic cars with flat tappet cams (including hydraulic lifters) have had cams wiped out by using new oil formulations. Those that still run flat tappet cams are using special oils with additional zinc and phosphorus, the rest have switched to roller camshafts so they can use commonly available oils.

These articles may be of some use:

http://www.amsoil.com/newsstand/classic-and-vintage/articles/flat-tappet-cams-in-classic-cars/

http://www.enginebuildermag.com/2017/03/exhausting-your-options-2/

Perhaps the valve spring pressure in your tractor isn't high enough to cause a problem, but it would be worth investigating before destroying a cam and having all those metal particles run through the entire engine.

In the end you are probably best to contact a reputable oil manufacturer with questions about your specific needs. Most times their tech people are pretty good and willing to help.

Purely for reference and as an example, old Briggs and Stratton "L" head engines specified straight 30 weight oil for temperature ranges while later engines of the same type could use multi viscosity oils or straight weight oils. Living in S. FL where it is hot year round I chose straight weight for my lawn equipment equipped with that type engine.

[JoeLee]

Might consider multiple oil changes instead of kerosene.

Kerosene mixed with sludge is probably not a good lubricant...

Sounds like a good way to wear the motor out real fast.


JL............

[A.K. Boomer]

yeah would not attempt that even at idle its not good on the connecting rod bearings, the forces might not be all that extreme but you have to consider that these engines had a hard enough time creating good oil pressure at idle to begin with - now throw in something with the viscosity of water and imagine how much is bleeding past the old worn out pump and all the bearings, it's the bearings last in line that might not even be getting anything

[A.K. Boomer]

My guess, and this is only a guess, is that your tractor, depending upon it's age, was built before multi grade oils were available, perfected or common. You are probably OK with using a modern multigrade as far as viscosity goes, however there may be other concerns. You didn't mention whether it is gasoline or diesel, however, older gasoline engines were designed for oils with higher zinc and phosphorus content which protected bearing surfaces under high pressure loads, like camshaft lobes. Those substances have been largely eliminated from modern oils because they damage catalytic converters. People with classic cars with flat tappet cams (including hydraulic lifters) have had cams wiped out by using new oil formulations. Those that still run flat tappet cams are using special oils with additional zinc and phosphorus, the rest have switched to roller camshafts so they can use commonly available oils.

These articles may be of some use:

http://www.amsoil.com/newsstand/classic-and-vintage/articles/flat-tappet-cams-in-classic-cars/

http://www.enginebuildermag.com/2017/03/exhausting-your-options-2/

Perhaps the valve spring pressure in your tractor isn't high enough to cause a problem, but it would be worth investigating before destroying a cam and having all those metal particles run through the entire engine.

In the end you are probably best to contact a reputable oil manufacturer with questions about your specific needs. Most times their tech people are pretty good and willing to help.

Purely for reference and as an example, old Briggs and Stratton "L" head engines specified straight 30 weight oil for temperature ranges while later engines of the same type could use multi viscosity oils or straight weight oils. Living in S. FL where it is hot year round I chose straight weight for my lawn equipment equipped with that type engine.

It's a good point but I think they got that fairly ironed out now - their is a substitute additive they are using that's compatible with cats, Mobile one had some serious problems for awhile or I should say created some serious problems
with cam lobes and lifters

the engines most effected were the horizontally opposed twins fours and sixes - if they were pushrod engines they use the same camshaft lobes to do "double duty" anotherwords the same lobe that actuates #1 on an opposed twin also takes care of #2

[J Tiers]

yeah would not attempt that even at idle its not good on the connecting rod bearings, the forces might not be all that extreme but you have to consider that these engines had a hard enough time creating good oil pressure at idle to begin with - now throw in something with the viscosity of water and imagine how much is bleeding past the old worn out pump and all the bearings, it's the bearings last in line that might not even be getting anything

If you just "cut" the oil with 'some' kero, or similar, that may do the same thing as far as cleaning, but not be so draكtic as running kero straight. Kerosene has nearly no lube capability.

[engineerd3d]

On slugged up engines I generally pour 1 quart of cheap ATF in there and run the engine lightly for 10-15 minutes, then I use some of my older used up oil and drain the sludge atf combo and pour in used oil from my car, run another 5-10 minutes and then swap filter and oil. This should remove most of the sludge and keep it liquid enough to not clog up the pathways with a flush of used motor oil to carry out the remaining crap. New oil completes the treatment and a nice clean crank case is the result. Just don't over stress the engine. The main problem with such flushes is trying to keep enough viscosity in the oil to not clog up passage ways while still providing lubrication.

ATF has a very very aggressive detergent pack in it that basically eats away sludge and turns it into a yougurt consistency.

[Hal]

You might ask this question over on the yestrdaytractor forum ams see what they say,

Hal