Any that meets the manufacturers recommendation for SAE, API etc...

They are using all brands and think theirs is the best.

I haven't decided yet on dino v syn for my lawn equipment. A couple of good web forums for oil are bobistheoilguy.com and tractorbynet.com has a good oil and filter discussion. You almost have to be a PhD in chemical engineering to understand some of what the folks are talking about. I tend to get wrapped around the axle over which is better when I should just change the oil/filter and feeergeet 'boutit. I've used Mobil 1 in my autos the last 8 years with absolutely no problems.

The only gas engine I use synthetic oil in is my JD325 Kawasaki 18hp Air cooled twin engine. I use Mobil 1, 10W-30. I change it once a year with 50 to 60 yours on it. It does not leak or burn any oil. I started using synthetic oil after 60 hrs of break-in. I would check the compression during break-in, and waited until the compression leveled off. Charles Ranheim

Briggs and Stratton Synthetic oil. It is recommended in all Briggs air cooled engines as there top of the line pick. Check out the link.

Here is a link that might be useful: Briggs synthetic oil

I emailed B&S about it,and here's the reply I got :
Thank you for your inquiry. Yes, the oil you mentioned will work just fine and will also keep you under warranty. Nay synthetic oil with the letters SJ or higher (ex. SK, SL, etc) will work. Keep in mind that using synthetic oil does NOT alter the oil checking or changing recommendations.

However, make sure you are getting the correct grade of oil. To find more information on our oil grade, please visit:

Title: Oil recommendations
URL: http://faqs.custhelp.com/cgi-bin/faqs.cfg/php/enduser/std_adp.php?p_faqid=1419&p_created=948406560

Mobil 1 10-30wt and when it has about 50 hours,I drain it,and reuse it in my old push mowers.Works for me.Oil never "wears out,

Royal Purple synthetic air cooled engine oil, a high quality pure synthetic oil, engine runs at least 20 to 30 degrees cooler than on crude oil products.

Dan

I agree with the Royal Purple synthetic - its expensive ( aboot $8 a quart) but supposed to work good. Im going to run it in my '86 18.5HP twin cylender Briggs thats going on my experemental tractor. They also have Royal Purple synthetic gear oil, Im thinking of trying some of that too.
Kidd

Hogwash!

Show us objective emperical data validating the claim of "at least 20 to 30 degrees cooler" with Royal Purple or other.

Shell Rotella T 5w-40 synthetic. One oil for your gas or diesel lawn equipment, available at your local Wal-Mart, and about 60% of the price of Mobil 1.

Here is a link that might be useful: Shell Rotella T

I been running conventional 10w30 in the winter and conventional 30w in the summer in my 40 year old briggs cast iron engine. Never a problem and still running strong under hard use.

I guess I screwed up and should have been running synthetic. Maybe then it will run 100 years.

Don't buy all the marketing.

I think you're forgetting you can't buy an engine like your old cast iron B&S.

pgtr, I guess I screwed up, it's 24 to 44 degrees cooler. It has been a while sense I have looked up information on Royal Purple synthetic oil on royalpurple.com.

Dan

mowerdan- you getting that info off the website, or third party confirmation?

24 or 44 degrees either is likely the result of a reality distortion field than empirical data.

Someone on this thread posted an oil with some good sense - Rotella. An oil that stands out from the rest is one that has an aggressive additive package. Rotella is a good example of this (and there are others, even house brands in this league) and is a great choice for a number of 4stroke OPE ICEs.

But ANY oil, let me repeat: ANY OIL that meets the current API spec is more than good enough regardless of it's base stock. If you look at your manual - it is precisely what they recommend.

If you like crude oil, fine, I have been using synthetic fluids for years now and switched over to Royal Purple because of its high oxidation rate and it's ability to run cooler then crude oil including Rotella, I have used Rotella also, very good crude oil, but not as good as Royal Purple synthetic oil, JMHO.

Dan

More then likely it doesnt matter if y use synthetic or regular oil. Older synthetics supposedly let the seals leak, hence oil spots, the newer synthetics are better ( according to Popular Mechanics). Most lawntractor engines ( including old ones like mine) are not pressurized systems with an oil pump/filter. Being of the 'splash variety', any decent brand of oil will work. Most manufactures prefer SAE 30 weight oil since most automobile grades have teflon in them for heat dissapation, good for cars, bad for tractors. Even before i knew that, i ran havoline 10w40 or castrol 10w40 motor oil in all my tractors ( most were used but had one brand new 92 White LT12 and that still runs fine today) - Ive put 5w20 castrol in my current tractors with some Lucas oil aditives ( 15 of them), with no ill effects ( considering they were highly abused before i bot them). Basically it comes down to normal maintenence, the more you change the oil , the longer it lasts, the less y change it , more likely youre looking for it to blow up. To get the full effects of synthetics, itll probably take a few changes to clean out the oil. Originally i herd y cant change back to oil once you run synthetic, but thats a fallacy, again according to Popular Mechanics. More then likely Synthetics will reduce engine heat and lubricate better then conventional oils. Me personally , im trying Royal Purple oil for more HP in my racing tractor, if itll keep my '96 vintage 18.5HP twin cylender briggs together, ill be convinced and most likely change em all over to synthetics , keep em running for another 20 years.
Kidd

I'm a big fan of Royal Purple too. I use it in my wifes car, my daily driver, both of my camaros. I just switched my power equipment over to it. I used to use it mainly in my camaros, but last year I tried it in the daily drivers. My cars all start easier in the winter, I noticed an 1.3mpg increase and the engines run smoother and they run cooler. I also prefer the extended oil change intervals as well since my wife and I both average around 3000 miles a month. The speed shop I go to recommends it too. They tear down race engines at the end of the season and the bearings look brand new after running RP.

I know when I bought my Briggs generator it calls for a synthetic. The owners manual warns that if you use conventional oil, it will run hotter. Also GM started using synthetic gear oils in the rearends of their cars and trucks because they reduced heat and improved gas mileage. I don't believe the running cooler is marketing hype.

Kidd,
Just an FYI. The manual for my new tractor does not include a single weight oil. Scale is 5w & 10w - 30 or 10w-40 based on temperature. I too have used 30w for a long time in mowers, but times change. Guess the new engines are more flexible. Wonder if it has to do with full pressure lubrication and filters.

Kidd, I use royal purple in my 93 18hp twin Vanguard engine and Hydro-Gear tranny and they run better than new, it was like doing a complete overhaul, great stuff.

Dan

Rotella isn't a real synthetic oil, its a Group III highly refined conventional oil. So is Castrol.
Real Group IV/V synthetics include Mobil 1, Amsoil and Redline. I'm not sure about Royal Purple but based purely on cost I'd expect it to be real synthetic.
That isn't to say that Rotella isn't good oil but if you're going to use it save your money and use the conventional version.

I've been using Mobil 1 in everything for awhile, 10w30 in my truck and lawn equipment, 15w50 in my diesel car and motorcycle.
The standout is my old While LT111 that would barely run before and now runs okay. Its still beat but I think the rings had carboned up before I started using Mobil 1, its got alot more power now and starts alot better.
Mobil 1 is also great for engines run in cold weather, my Cub Cadet 70 starts much easier in the cold with Mobil 1 in it. It also smokes alot less now that its been run with Mobil 1 for a few months. I think it might also have had some carbon build up in the rings. I'm not sure that the Mobil 1 is pure magic on the rings or if I could have helped the problem just by changing the oil alot, you can't ever tell what a previous owner did for maintenance

I would take a good look at the API rating on any oil you plan on using, conventional or synthetic. Most of them have gone to the reduced anti scuff package required to get SM rating. Although this is the latest rating and claimed to be backward compatible, there have been a lot of problems showing up in the hotrod community when using SM oils. The problems are with flat tappet cams, non roller rockers, pushrods and valve tips. Newer cars are OK because they are all rollerized, and use improved materials.

Small engines are almost always flat tappet and non roller engines, so they would have many of the same issues, although it may take longer with the lower valve spring pressures.

Even the diesel oils are going to SM rating (yes Rotella) so that option is going away, and synthetics that are SM will not protect significantly better as this is a scuffing/galling additive issue.

Currently, I am using motorcycle oils in my hotrod and in all the small engine stuff (some dino, some synthetic). It is rated SG or SJ depending on the brand, and carries the full additive package (and then some) that the older car engine oils had. The other option would be Brad Penn oils, which I think are also SG rated, and are getting rave reviews from the circle track engine builders around here.

Im tempted to get some of the Royal purple gear oil as well for my racing tractor, and see what happens. Since i bot the thing for $50, i cant see any harm, plus the fact is the trans is spinning alot faster then stock. Before i tinkered on it, i dropped the trans and filled it with Lucas oil treatment- so far so good. Any lil bit helps.

I wasnt aware that new motors were using almost standard oil now, its possible because of the oil pressure, oddly enough my old 11/36 Dynamark states:SAE 30 for winter, 10w30 for summer. I just run one of the other- i dont switch between seasons.

Kidd

Booster is exactly correct. This is the reason Amsoil has introduced a dedicated small engine oil (ASE 10W-30/SAE 30).

What about using a syn in a brand new engine? Any benefit? Does there need to be a break in period with regular oil first?

Some factory cars come with synthetic installed.

Macguy-

Many small engine manufacturers do not recommend switching to synthetics until after the first 50 hours of operation. Consult with the manufacturer if you want to know for sure.

"Many small engine manufacturers do not recommend switching to synthetics until after the first 50 hours of operation."

Since there are "MANY", can you name just one of them?

Kohler, for one...

From one of their engine user manuals (2005 19 HP Courage):

" NOTE: Synthetic oils meeting the listed classifications
may be used with oil changes performed at
the recommended intervals. However to allow
piston rings to properly seat, a new or rebuilt
engine should be operated for at least 50
hours using standard petroleum based oil
before switching to synthetic oil."

John Deere has a synthetic oil. Change interval can be extended 50% when using a JD filter in a JD engine and it is guaranteed according to the 2007 JD parts cataloge they send me. They also note fuel savings of up to 2.7 percent.

That said I use Mobil One in all my engines. Only oil in my garage these days... one jug for new and one for old. Switched to Mobil synthetic in my truck transmission with good results. Even the weed whipper is 4 cycle so it get Mobil One 5w-30.

Things run smoother and start better with a good synthetic oil.

Cheez--that if very interesting about the Amsoil for small engines. A year ago when I was looking for a good oil for the small engines (due to the SM rating thing) the local Amsoil guys were all saying that their SM rated oil was just fine for small engines because of all the special improvements that it had. I didn't bite on that, as I had just spent a lot of money on new pushrods and rockers for my hotrod, which ate them right after a change to SM rated Amsoil from Rotella.

It is almost impossible to find oil that is not SM rated these days. The 5W30 synthetic that Briggs and Stratton sells is not SM, and the special Amsoil 10W30/30W is not SM. I was searching the oils at Autozone the other day, and I noticed a Castrol Syntec 5W40 oil that had ratings of SL, SJ, and CF. It said it was specially formulated for Mercedes Benz, BMW, and Volkswagen, and that it was "approved" by Porsche. I wonder how this oil would do in our OPE engines?

I knew I should have said 2 before I hit the send button:-)

That 5W-40 Castrol would do a fine job if you need/want a 40 weight oil.