30w oil in 3500 watt genset, why 30w?....

[T Peterson]

Ditto what klenger said, I'm glad I asked.



Thanks again

 

[SRehberg]

For giggles concerning air cooled engines, most air cooled motorcycle engines use multigrade oils so I would think that kind of undermines the "runs hotter, breaks down" argument. The mfg's specify multigrade, and Harley for one, says to use a multigrade diesel rated oil if their particular oil isn't available.



The oils are API rated for service to specified temps, corrosion control, flow, break down, foaming etc etc. During warranty I would probably stay with the specified oil to eliminate any chance of a warranty denial.



I, like an earlier poster, have been using Delo 15-40W in my previous and present mower, & 4cycle weed whacker. I had over 10yrs on the previous mower when I gave it to my son who is still using it w/o burning oil. By the way, it's a Briggs. The key element with any oil is: change it regularly with any air cooled engine, it's the cheapest insurance you can buy.



Just my opinion.

 

[keimmmo]

Yes, it is VERY IMPORTANT to change the oil in air cooled motors often! I change it in my mower about every 8 hours!



I don't think a motor cycle motor will run as hot as, for example, a lawn mower motor. The motor cycle usually gets a good source of cooling air while moving down the road. The lawn mower is working hard and often gets the cooling fins plugged with dirt and grass. A generator that is not running in a hot environment and not at maximum load is not worked that hard. However, if the environment IS hot and it IS producing close to its capacity, it IS working hard and WILL run hot!



Steve Keim

 

[SRehberg]

The air is just as hot whether it's passing over a motocycle engine or a lawn mower. In fact the mower has an advantage. It has a continuous flow of air, while the motorcycle when stopped does not. I don't think we're going to convince each other anyway. I personally believe the 30wt recommendation is due to the fact the mfg. doesn't know whether the unit will be sold or used in Michigan or Arizona. By using a single weight oil, they cover the majority of the temperatures encountered. Actually, they probably should include a lighter weight oil for cold temps to insure adequate lubrication when used in the cold climates. I'm sure there are hunters or skiers etc that use their RV's in cold temps. Maybe the mfg's just haven't really addressed the cold temp issue. 30wt at 30* or below I imagine is a little sluggish. I for one would use a multi weight oil and will.



Each has to use what they are comfortable with and go from there.



Thanks for the comments, as we all have opinions on this and there is no "wrong" answer.

 

[Speedo]

I have some machines with Detroit diesels- a 4-71 and a 3-53 ( two stroke diesels) The manuals on both insist on straight weight oil. I checked more recent revisions and that recomendation still holds. The viscosity extenders break down and gum up certain components. If a synthetic gets the performance of a 10W-30 with no viscosity extenders there should be no problem, but you would have to know the additives to be sure. If it is listed as a straight weight there are no viscosity extenders. If the MFG wants oil without them, oil with them will do more damage than the proper quantity of "cheap" oil.

The use of multi vis oils in these 2 stroke Detroits will cause problems unless shortened drain intervals are followed. One of the first things that happens is the failure of the slipper bearings. This can plug the cooling oil passage to the piston crown resulting in damage to the liners. We had a fleet with 2 stroke Detroits and started integrating 4 strokes and switched to 15w-40 for all engines without changing the change interval. I did a lot of overhauls on 2 strokes with shortened life spans. I've seen street maintenance equip fail because the operators would run low on oil and just stop into a conveninece store and pick up any kind of cheap oil they could find and throw it in the engine.



Gus

 

[Gary - K7GLD]

The use of multi vis oils in these 2 stroke Detroits will cause problems unless shortened drain intervals are followed. One of the first things that happens is the failure of the slipper bearings. This can plug the cooling oil passage to the piston crown resulting in damage to the liners. We had a fleet with 2 stroke Detroits and started integrating 4 strokes and switched to 15w-40 for all engines without changing the change interval. I did a lot of overhauls on 2 strokes with shortened life spans.

Good example from real life - thanks Gus!



Far too often, some of us "shadetree engineers" like to second guess the folks who actually engineer, design and manufacture some of this stuff - and then grandly assert that for all their engineering skills, they aren't really smart enough to recommend the proper oil for the finished product...



Just maybe, they're smarter than we give them credit for, maybe even smarter than WE are... :-laf

 

[SRehberg]

Is the failure of the 2 stroke Detroits due to more fuel contaminated oil, thereby reducing the lubricity of the oil and not necessarily the oils fault? I would think the bearings would be the first place failure would show as the loads are high, just as was mentioned regarding the 2 strokes. Just a thought.

 

[DJW]

Thanks, I also wondered for small air cooled engines, why the maker advised for SEVERE DUTY to use only 30wt, instead of the much vaulted 0 to 90 wt oils. On many foreign air cooled motorcycle engines, the engine and gearbox is all in one, and the same oil is used to lubricate the engine, gearbox, clutch and engine to gearbox chain, so therefore the oil has to be compatable to both engine demands and gears, plus clutch linings and chain. Some other air cooled motorcycle engines have Dry Sumps, meaning under normal use no oil is stored in the sump, the oil after passing through the engine is returned to a separate tank, surprisingly referred to as the Oil Tank. (humor?) I have always found simply following Manufacturers' advice can avoid very Costly mistakes.