Best air cooled engine oil for mowers and the like

[cwatkin]

I was curious if anyone has done a scientific analysis of oil in small engines. I have overhead valve as well as the old style flat head type engines. I have been running Rotella T6 in my riding mowers with the Kohler Command and they seem to do very well on this oil. I run them hard and there doesn't seem to be any consumption as far as I can tell and the oil still looks clean when I change it. Both these engines came to me used consuming oil/smoked and with the hydraulic lifters clattering. There is no more of this and it went away quite quickly after switching to the T6. I figure this oil is the right one for these engines.

I have been told the 5W40 might be too thin for some of the splash lubricated flathead engines. Many of these call for 30W. I also see ATV/motorcycle or marine oil with more additives for anti-wear. These are usually 10-W40 or 20W50. I was wondering if these would be best in these units as I don't need to worry about fouling the emissions systems as they don't have them.

Then there are some that are splash lube yet have have overhead valves. Some of these even use PLASTIC camshafts these days. What is suggested as the best oil for these? I kinda liked the idea of a one size fits all 5W40 but correct me if I am wrong. I recently junked a Briggs plastic camshaft unit when the cam lobes finally wore down to where it would barely run after a decade or so have hard use.

 

[KingCake]

5W40 T6 is close to a 30 weight when hot. It even works with wet clutch shared sumps. It's a truly universal OPE oil.

 

[OneEyeJack]

I use the left over Red Line 0w-30 from my vehicles for the lawnmower and change it once a year. I have a couple of acres that get mowed whenever the mood strikes me. The air filter gets changed whenever it gets dirty and the foam prefilter gets washed and oiled with Red Line 2-stroke oil, frequently. I change the spark plug now and then but it never looks bad. I just change it anyhow, maybe every other year or so, I just don't remember. It's a Honda commercial push mower and it's 10 or 12 years old. I let the neighbor kid use it to mow his lawn and the old lady that lives down the street along with a few others he does for some spending money.

I have no idea if this oil is better than some other oil for the mower but at least the mower is holding up and still starts on the first pull almost every time. I did install a large inline fuel filter and I use Costco gas with a few ounces of Chevron fuel treatment in the gas can and once a year I run a big dose of Chevron fuel treatment thru it when I change the oil.

I also use Red Line 2-stroke oil in my Echo weed whacker with Costco gas and just a tiny bit of Chevron fuel treatment. I mix the gas/oil at 50:1. It's the same age as the mower and is also used by the neighbor kid. I've replaced the priming bulb and the usual tune up stuff but that's all.

 

[ARCOgraphite]

I had to step up to Valvoline Vr1 10w30 synthetic Racing oil in the generator as it became way too clattery and knockey when warm on other oils Including rotella T5 10w30. I really didn't want an SAE30HD in there for sub zero starts.
I also tossed in a 1/2 oz of LiquiMoly. Don't recommend it in a modern pressure lubed & filtered engine but seems OK in the splash and scupper lubed GENERAC chonda OHV.

 

[cwatkin]

OK, good to hear that the Rotella T6 is pretty much a good universal. I will stick with it unless I hear anything out of the ordinary. I picked up a bunch of trash picked equipment this weekend from a fall bulky trash pickup day. The mower had a dirty carb and I got it started in about 5 minutes. I did change the oil as it looked like gray sludge and it sounded a little noisy so there may be some wear in this. It is a Tecumseh so I know those are famous for throwing rods through the block when neglected. It ran for an hour before it ran out of gas and held together so that was a good sign. I figure this is a free mower and I am not going to worry a whole lot about it if it comes apart. I have others that run fine.

I have also seen some Mobil 1 products that are thicker and figured these might be in order for a worn engine. I have some other pressure washers and two strokes I picked up from the trash as well. At least one of the pressure washers is locked up hard (Honda GCV) but I hope the pump is OK.

As for two strokes, I have always had good luck with the Stihl silver bottle synthetic. I am not sure what the difference is between the white bottle and the silver bottle but my local dealer always stocks the silver.

Conor

 

[HerrStig]

I use T6 in an L head Briggs powered generator, as well as a mower, and my vehicles. The genset engine doesn't burn T6 in an amount I can measure despite being run hard. It started a few years ago at 4 degrees on the first pull.

 

[DoubleWasp]

I always have plenty of spare 20/50 racing oils laying around, so that's what most of my small engines get.

 

[cwatkin]

I have to say I am kinda disgusted that many of the cheaper engines these days have gone to plastic cams and timing gears riding upon steel parts. It seems the plastic is destined to wear out before the metal and that both parts should be made of a durable material. That being said, I am sure most people throw away equipment due to bad gas or rust before the engine is shot these days. Many people just go out and buy the cheapest mower and run it until it quits or doesn't start one spring.

I know synthetic oil is probably overkill but I have gone way beyond the rated life of many cheaper engines by using it.

 

[KingCake]

Originally Posted By: ARCOgraphite
I had to step up to Valvoline Vr1 10w30 synthetic Racing oil in the generator as it became way too clattery and knockey when warm on other oils Including rotella T5 10w30. I really didn't want an SAE30HD in there for sub zero starts.
I also tossed in a 1/2 oz of LiquiMoly. Don't recommend it in a modern pressure lubed & filtered engine but seems OK in the splash and scupper lubed GENERAC chonda OHV.


In a splash motor all that moly is just going to make a layer of sludge on the bottom of the crankcase.

 

[KingCake]

Originally Posted By: cwatkin
I have to say I am kinda disgusted that many of the cheaper engines these days have gone to plastic cams and timing gears riding upon steel parts. It seems the plastic is destined to wear out before the metal and that both parts should be made of a durable material. That being said, I am sure most people throw away equipment due to bad gas or rust before the engine is shot these days. Many people just go out and buy the cheapest mower and run it until it quits or doesn't start one spring.

I know synthetic oil is probably overkill but I have gone way beyond the rated life of many cheaper engines by using it.


It's not just plastic. Glass Filled Nylon 6 is stronger than cast aluminum. Also, the spring pressure is ridiculously light. You could push a valve open with your finger.

 

[KingCake]

Originally Posted By: ARCOgraphite
I had to step up to Valvoline Vr1 10w30 synthetic Racing oil in the generator as it became way too clattery and knockey when warm on other oils Including rotella T5 10w30. I really didn't want an SAE30HD in there for sub zero starts.
I also tossed in a 1/2 oz of LiquiMoly. Don't recommend it in a modern pressure lubed & filtered engine but seems OK in the splash and scupper lubed GENERAC chonda OHV.


Been my experience with 10w30, too. A good 5w-40 is usually quiet. Often I juse use SAE30HD. But coldest it gets down here is about 30 degrees for 3 days lol.

 

[cwatkin]

I understand that the Honda nylon cams are pretty decent. How did I wear a Briggs one down to where it wouldn't run but the tappets looked pretty much pristine? Cast aluminum may be pretty strong but it still isn't as strong as steel. How come they put steel inserts and sleeves into aluminum blocks for valve guides, cylinder bores, etc? It is because iron still beats all the rest for wear resistance.

Also, Liquimoly is a brand of European oil that is highly rated unless there is some other product with this name. I am sure it has some moly in it but that isn't all it is. They spec this stuff for Mercedes, BMW, etc. I understand it is really good stuff if you want to pay for the cost and it isn't cheap.

 

[crainholio]

Originally Posted By: KingCake

It's not just plastic. Glass Filled Nylon 6 is stronger than cast aluminum. Also, the spring pressure is ridiculously light. You could push a valve open with your finger.


That was my experience with a Honda EU2000i generator project I bought a few years ago. It had been thoroughly abused, rings were stuck and no compression. After a few days soaking in Dodge combustion chamber cleaner I was able to get enough compression to run it, then eventually get things back to normal with a few hot feeds of the Dodge stuff and finally water vapor.

The plastic/Nylon-66/whatever camshaft in that engine looked like new despite the abuse. No wear grooves or surface abrasion. The valvesprings were super light as you described...could push them open with one finger.

I loaned that gen to a neighbor during a power outage, it ran his fridge, central heat (natural gas hot water baseboard), TV, etc. for 4 days without a hiccup. He ended up buying it and still has it. Tough little engines.

And because this is BITOG...Shell Rotella T5 10W-30 oil fills.

 

[cwatkin]

It seems the Honda setup is more robust than the Briggs one when it comes to the nylon cams. I found a lot of issues with the nylon cams on Briggs like I experienced but not so much with Honda.

I am sometimes amazed at the abuse small engines can withstand. It seems they either hold together after you get them running again or come apart quite quickly. I swear that sometimes changing the oil on a badly worn engine can hasten their demise. I guess all the sludge acts to cushion worn bearings. Some of these come to me smoking but running relatively well. I then change the oil and you hear knocking almost immediately and the thing comes apart.