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

[T Peterson]

Why does the manufacturer recommend 30w when there are "superior" oils out there? There must be a reason, will I screw it up using 20w-50w or even a synthetic? I use this genset in heat up to 110 degrees. Thanks in advance for any advice.



Tom

 

[JFaughn]

Every air cooled eng. for gen. lawn mower , ect. recomend a staight 30wt .
They are expecking that your going to run at outside temp. of 60-90* and thats what straight 30wt is for , you can buy any oil you want but should stay with a straight 30wt , the prob. is if you feel the need to spend too much $$$ there is'nt a lot of choise , I think that Amsoil would be the best , becouse they offer more blends to specificly match your needs.

 

[MColp]

Why does the manufacturer recommend 30w when there are "superior" oils out there? There must be a reason, will I screw it up using 20w-50w or even a synthetic? I use this genset in heat up to 110 degrees. Thanks in advance for any advice.



Tom

T Peterson,

Most folks in general are behind the times and the advances that have been made in oil/lubrication technology whether it be for a generator or marine application etc.

My 5. 7 L (350 cu. in. Chevy) sterndrive on my Sea Ray called for SAE 30w. I switched to Mobil1 20w-50 a long time ago and immediately noticed easier starting, decreased oil consumption and lower oil temperature (20 deg. f. ) I have since switched to 10w30

Amsoil about 3 years ago. (I can get it cheaper) I use 10w30 synthetic in my generators and pressure washer. If you look at the test data comparing dino oil vs. synthetic the synthetic gives you a substantial margin of protection especially in high temperatures among other things. Hope this helps!

 

[WestTN]

The manufacturer decides which oil gives the best results considering the bearing clearances and the stated operating conditions. If you have warranty concerns, don't run anything other than the manufacturer's recommendations. If you like to experiment on your own dime, try something else.

 

[moparguy]

Could be showing my age, but my understanding has been that aircooled engines are much harder on oil than vehicles. Multiweight oils when subjected to extream high temp operation break down and trend toward the lower number of their rating.



All that being said, 30w stays 30 weight, more protection if you fail to change oil on time.

 

[REFLOYD]

I am a generator mechanic in the Marine Corps and we used 30wt oil in our gen sets from 3kw all the way to 200kw when we where in Iraq. And we had no problems with the engines.

 

[T Peterson]

Thanks for the responses

Everything taken into account, I guess I'll stick with the 30w. Maybe look for a 30w synthetic, or just change frequently. Its not so much warranty, I've already upgraded the circuit breakers, I just don't want to abuse my equip. if theres something better. Thanks again, Tom

 

[Peter Campbell]

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.

 

[T Peterson]

Thanks Peter, makes sense.

 

[GaryCarter]

I would not use conventional multigrade because as Moparguy said, the viscosity extenders tend to break down over time and your 10W-30 reverts back to just 10W. Faster in air cooled engines due to temperature extremes and high speeds.



Synthetics typically have a higher viscosity index with fewer viscosity extending addititives required.

I use full synthetics in all my small engines after break-in. No problems to report, and noticably improved fuel consumption on the gensets.



Gary

 

[CPittman]

I may be wrong here but don't the higher viscosity straight weight oils have a higher capacity for dissipating heat in air-cooled engines - where a straight 30w would be better and 10w30...

 

[Diesel Nut]

I run Amsoil Series 3000 5w-30 heavy duty diesel oil in my lawnmower and 1500 watt gen set. Works great.

 

[klenger]

FWIW, Onan recommends 15W40 for my 3600 LP. Same stuff that goes into the CTD. They also recommend some other types, but I can't remember what they are.

 

[keimmmo]

I was doing small engine repair back in the late 60 and early 70s when the multi-weight oils came out. Briggs had always recommended 30 weight oil. When the multi-weight oil came out, the changed to recommend 10W-30. They had more warranty claims that first year than in like the 5 previous years due to things like thrown rods, scored cylinders, etc. They did research to find out why. They determined that the multi-weight oil acts as multi only up to a certain temp. The small engines were generating WAY over that temp. When the motors needed the most protection, the oil was the thinnest!!! They responded by saying to use ONLY 30 weight... and the use of 10W-30 will void the warranty! After a few years, they mellowed and RECOMMENDED 30 weight... but if not available (like as opposed to running without oil) 10W-30 is acceptable.



If you run the motor hard and in high heat applications, DO NOT use multi-weight oil!!!



Steve Keim

 

[BDeMartile]

I was doing small engine repair back in the late 60 and early 70s when the multi-weight oils came out. Briggs had always recommended 30 weight oil. When the multi-weight oil came out, the changed to recommend 10W-30. They had more warranty claims that first year than in like the 5 previous years due to things like thrown rods, scored cylinders, etc. They did research to find out why. They determined that the multi-weight oil acts as multi only up to a certain temp. The small engines were generating WAY over that temp. When the motors needed the most protection, the oil was the thinnest!!! They responded by saying to use ONLY 30 weight... and the use of 10W-30 will void the warranty! After a few years, they mellowed and RECOMMENDED 30 weight... but if not available (like as opposed to running without oil) 10W-30 is acceptable.



If you run the motor hard and in high heat applications, DO NOT use multi-weight oil!!!



Steve Keim

Onan recomends 15w40 I use Delo in my CTD and my 5. kw gen set change it every 75-100 hours and have had 0 problems.

 

[keimmmo]

A lot of the bigger generators run at 1800 rpm. They are not worked as hard. The ones that have to run at 3600 rpm are pretty stressed! No matter what, if the factory recommends it, it will probably work fine unless you are doing something the factory did not plan for you to do.



Steve Keim

 

[bkroupa]

I run 15-50 Mobil one in all of my aircooled engines except the two strokes.

 

[Gary - K7GLD]

There's a difference between running an engine - and it's oil - at varying speeds and loads, in areas where there are large temperature swings in relatively short time periods.



THOSE are the situations the multi-grades were designed for. But that ability to cope with wide temp and RPM/load swings usually comes at a price, and stability of the oil over it's normal lifespan is what is usually sacrificed. The wider the grade, the greater the instability. Thus, a 5-30 will usually break down faster than a 10-30.



The straight weight oils are the most stable, due to lack of the added blends that are inserted not for lubrication, but only to provide the multi-grade characteristics.



Obviously, items like gensets usually operate in rather stable environments, and at steady speeds and relatively stable loads - so a single grade of the specified weight should provide the greatest available protection.

 

[klenger]

This is an interesting discussion and I am learning a bunch. Thanks guys.

 

[RustyJC]

A 10W-30 oil utilizes a 10 weight base stock and achieves the 30 weight performance at elevated temperatures through the use of viscosity improvers, part of the additive package. These VIs are long-chain molecules that are subject to deterioration through shearing over time, leading to a drop in viscosity.



For this reason, many large industrial engines that are subject to extremely extended drain intervals (4000 operating hours and up) still call for the use of single viscosity oils. Of course, many of these engines utilize circulating oil and/or coolant heaters as well. Customers who use multi-vis oils for improved cold starting, etc. generally do so knowing that drain intervals will be shortened.



Rusty