Engine What kind of oil ?

Grass ala Mowed

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I've read Bob is the oil guy and stand by my statement. Viscosity index improvers thicken with heat. Bob states the importance of low temperature pumpability to prevent start up wear and for that reason I run Mobil 1 0W-20 in my car. I'll concede that even today's cheapest oil is probably better than the finest oils in the 80's when GM issued the prohibition on 10W-40. However, while I am running the 0W-20 in place of the factory recommended 5W-20 in my car, I am not in favor of running thicker oils than recommended because of the aforementioned pumpability. I think we can all agree that oil, in any engine, oil lubricates, clean and cools the engine parts; the last two by flowing through the engine and carrying dirt and heat away from the parts and into the oil sump. A thicker oil moves slower and decreases efficiency of the last two functions.
 

Black Bart

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I've read Bob is the oil guy and stand by my statement. Viscosity index improvers thicken with heat. Bob states the importance of low temperature pumpability to prevent start up wear and for that reason I run Mobil 1 0W-20 in my car. I'll concede that even today's cheapest oil is probably better than the finest oils in the 80's when GM issued the prohibition on 10W-40. However, while I am running the 0W-20 in place of the factory recommended 5W-20 in my car, I am not in favor of running thicker oils than recommended because of the aforementioned pumpability. I think we can all agree that oil, in any engine, oil lubricates, clean and cools the engine parts; the last two by flowing through the engine and carrying dirt and heat away from the parts and into the oil sump. A thicker oil moves slower and decreases efficiency of the last two functions.
Thiner is better until you reach the point where is fails to provide adequate protection.
 

yoyoboy96

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10w30 oil is oil, whether used for cars, mowers, boats, it's all the same. Stores selling oil titled "mower oil" are just trying to make you think thats what you need, so you pay more.
 

Black Bart

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Grass ala Mowed
After rereading your post we are talking about 2 different things.
This statement refers to how the modifiers work


I've read Bob is the oil guy and stand by my statement. Viscosity index improvers thicken with heat

I stated conventional oil will thicken as it ages.
Here is what AMSOIL has to say about that.



Today's engines are running hotter than ever. More horsepower, turbo chargers and aerodynamic styling have created extremely hot environments that receive less cooling from outside air. High heat leads to oil oxidation, deposits and thickening in conventional oils. Because they are made from impure, irregular molecules, conventional motor oils are more susceptible to the effects of heat. The small, light molecules in conventional oil tend to evaporate as the oil is heated, leaving large, heavy molecules behind and leading to oil consumption and an increase in the oil's viscosity. If those large, heavy molecules are chemically unstable, they may also break-down and form deposits on component surfaces, further inhibiting the release of heat into the oil stream.

Even in relatively mild temperatures, oxygen works to break down some of the chemicals in conventional lubricants. The extreme heat in engines actually promotes oxidation. When conventional oil contaminants break down, they coat components with varnish, deposits and sludge and leave the lubricant thick, hard to pump and with very poor heat transfer ability
 

Grass ala Mowed

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Black Bart - come over here on this side and stand next to me or I've come over there; I think we are looking at the same thing from opposite sides. I 110% agree that conventional oil, full of incomplete polymer chains and other crap that's too expensive to refine out, thickens with age as the chains polymerize under heat and pressure. Synthetic oil essentially does not contain these chains and stays truer to vicosity with age. Also, I would never go lower on the "hot" viscosity number. My car said 5W-20 and I'm running 0W-20; my F-150 wants 5W-30 and I will not put the 0W-20 in it, It's 184,000 miles old and running great on Mobil 1 5W-30. I'm not sure I see the value of synthetic in my mower when I have to change it every 25 hours to maintain my Toro 5 year no questions asked, even if it doesn't start in 2 pulls it's our problem warranty.
 

Bam

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An air cooled mower is going to run hotter than a car so the oil is quite important. A motorcycle shop will sell you a basic oil for air cooled engines and that would be ideal.

Having said that, I use automotive multi-grade oil in mine as I always have some to hand, so it is convenient and economic but then I only have a cheap mower and the chassis or wheels will probably pack up before the engine.

For a 4 stroke engine, I would advise against the practice of adding upper cylinder lubricant or any other oil to the petrol. I used to do this on the last mow before laying up for the winter and suspect it may have caused premature failure of the membrane in my carburettor. Better to remove the plug and squirt a drop of oil in the cylinder with a syringe, turn the engine over once or twice and replace the plug ( I use 2 stroke oil for this as I always have a can of that for another purpose).
 

benski

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Ah hah!:wink: Another oil thread. I'll just keep putting in my 10-30 Amsoil and relax.:biggrin:
 

Giles

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Some have talked about problems GM was having with camshafts "caused" by using 10w40 oils.
Strange that, to my knowledge, no other manufacturer was having problems.
It might be noted that GM has been having problems with worn camshafts since the 50s.
I have replaced MANY camshafts in Chevy engines, latest being 1996:thumbdown:
The only other camshaft I have had to replace is Toyota 20R 4 cylinder. Probably about five, and the replacements never gave a problem.
Now for the OP---A person should use what the manufacturer recommends. I have been using Chevron Dello 400 30W in my 31 year old WH since new. No problems.
Some time back, I posted that I purchased a Gravely G16 with 234 hours run time. The owner stated that he used 30W Mobil 1 full synthetic. I searched everywhere and could not find this oil. Contrary to the owners manual, I decided to use 5W30 Mobil 1 full synthetic oil. After app. 8 hours of operation, I noticed that there was a small amount of oil going into the air cleaner housing, from the crankcase breather tube. I cleaned this oil up and after my next mowing it had returned.
I drained the oil and replaced it with Chevron 30W and after two mowings there is no oil escaping from the breather tube.
 

Oddball

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JMurray, its funny that you can't find 10W-30. Over here I have the opposite trouble. I have a hard time finding straight 30 weight, but 10W-30 is everywhere.
 

goodolboydws

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Here's my $.02. worth.

All our mower and air cooled engines here are at least 10 years old, (some are over 20) and I wasn't aware that apparently the newer ones manuals are now recommending using a multigrade oil, which is interesting, because that's all I've ever used-once a machine was past warranty (or after the first oil drain). Everything (4-stroke/4-cycle) that we have manuals on hand for reccomends using SAE 30, although some said 10W30 or 40 use was permissable, but to check the oil level more often for increased oil consumption if using those oils. In high hour usage, this seems to bear out as true-which I attribute to the increased volitization of the lighter weight oil from an air-cooled engine's high heat levels in normal operration over that of a typical water cooled-engine (for which multigrade oils were originally designed). In fact, I've even taken to using oil up to 20W50 synthetic in the garden tillers as they get such heavy load usage here in our mostly clay and rock soil that they tend to run on the hot side.

I previously used 10W40 "semi synthetic" by Castrol, but switched to their same designation version of 15W40 "truck" and then to their as-labeled "diesel" oil a few years ago for most things with no oil filter and especially for those that I operate only in the warmer months. I figure that all other things being equal (meaning similar additive packages), that since a diesel engine typically puts a much higher pressure load on it's rod and crank bearings, an oil designed for use in one should hold up longer/better to pressure breakdown in a non-diesel engine too, and that it might actually resist temperature degradation better as well. Another side benefit of a diesel engine oil is that most good ones are designed to carry and still function well while carrying higher soot (think of dirt) loads than a typical "car" engine is designed to carry-which ANY engine that has no oil filter on-board should theoretically also benefit from. (If someone has better information or info to the contrary, I'd be happy to be better-educated on this aspect.)

BEFORE the warranty period expired I'd already started using 10W40 semi synthetic Castrol for the gas powered 4 cycle 1997 garden tractor's engine, and when it became more available in our area (east Tennessee) I switched to their slightly heavier above-mentioned 15W40 version synthetic (or semi synthetic) or a mix of weights of semi sythetic and full synthetic "truck" or diesel oil. That machine I use year-round, (mostly for pulling a cart in colder weather) and aside from the reduced available battery amperage in Winter making for a slower cranking speed it has no trouble starting in colder weather with this oil, which is actually theoretically a "lower" viscosity under cold conditions than a straight 30W would be.
The tractor's engine has well over 2000 hours on it by now. I pull the plugs to check them from time to time and regap them as necessary, but they tend to stay very clean. I think that I'm on the 2nd set of plugs now-but then I ONLY change spark plugs when their electrodes actually get too thin for my taste if they're working properly and are in good shape physically otherwise. I've changed the head gaskets once so far (which was shortly after the warranty period expired, to de-carbon the heads. As it turned out there was minimal build up then. Synthetic oil typically does form carbon deposits much more slowly than a conventional motor oil will in a properly operating engine, but it's probably time to check the heads again. This engine has had a long-term slow oil leak, so I can't say how much oil it's actually losing from internal consumption vs leakage.

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P.S. IF I recall correctly, I believe that the camshaft problems GM was having years back that has been referenced in this thread was actually later proven to be from improperly hardened camshaft lobes and that it was brought out in court that the "wrong oil" excuse was a calculated corporate cost/benefit analysis attempt to escape eating millions of dollars of legitimate warranty coverage-one that was fought by a class action suit after too many customers got screwed and one of those with good records got very mad and started to raise a stink. This would be only one in a long string of times that an auto company has done this cost/benefit of warranty vs litigation calculation sort of thing. But I could be wrong about this particular one.
 
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