10W30 vs 10W40

[nikita]

i've got good oil motul 10W40 for my rappy, but the instruction says 10W30.
so...is there any diffence if i'll use 10W40?

[Krandall]

nope you shouldn't notice any difference whatsoever. if it's warm the 10-40 will actually be a bit better and help keep things lubed better in the warm weather.

[nikita]

thank u

[Gunz]

nope you shouldn't notice any difference whatsoever. if it's warm the 10-40 will actually be a bit better and help keep things lubed better in the warm weather.

Word

I use 10w-30 in winter
        10w-40 in spring/fall
        20w-40 in the summer

[Ranger]

I use 20w50 but it never gets below freezing here...

[Colorado700R]

I use 20w50 but it never gets below freezing here...

Therefore your robbing yourself of power all year long.  I understand the want to protect your machine, but that's a bit much IMO

[RaptorRandy]

I ran Klotz racing 15-50W full synth in my 780 ever since I put the lockup on it and it never seemed to lack for any HP 

[Colorado700R]

I got this from AA1car.com, and it is consistant with what I was taught, but I will never discredit someone for using caution and protecting their investment.  It's just a little overkill IMO.

Besides, What 780  

Most vehicle manufacturers today specify 5W-20 or 5W-30 for newer vehicles for year-round driving. Some European car makes also specify 0W-30, 0W-40 or 5W-40 for their vehicles. Always refer to the vehicle owners manual for specific oil viscosity recommendations, or markings on the oil filler cap or dipstick.

As a rule, overhead cam (OHC) engines typically require thinner oils such as 5W-30 or 5W-20 to speed lubrication of the overhead cam(s) and valve-train when the engine is first started. Pushrod engines, by comparison, can use either 5W-30, 10W-30 or 10W-40.

As mileage adds up and internal engine wear increases bearing clearances, it may be wise to switch to a slightly higher viscosity rating to prolong engine life, reduce noise and oil consumption. For example, if an engine originally factory-filled with 5W-30 now has 90,000 miles on it, switching to a 10W-30 oil may provide better lubrication and protection. The thicker oil will maintain the strength of the oil film in the bearings better so the engine will have more oil pressure. This will also reduce engine noise and reduced bearing fatigue (which can lead to bearing failure in high mileage engines).

For sustained high temperature, high load operation, an even heavier oil may be used in some situations. Some racing engines use 20W-50, but this would only be recommended for an engine with increased bearing clearances. Increasing the viscosity of the oil also increases drag and friction, which can sap horsepower from the crankshaft. That's why 20W-50 racing oil would not be the best choice for everyday driving or cold weather operation for most vehicles. The latest trend in racing is to run tighter bearing clearances and use thinner oils such as 0W-30, 0W-40, 5W-20 or 5W-30 to reduce friction and drag.


Aaron

[Krandall]

It's easier to rebuild a quad vs. a honda civic though.

[RaptorRandy]

What can I say......I'm old school when it comes to Oil......but at least I don't run straight 50W racing oil anymore 
The full synthetic 15-50 has the consistency of water, it's just protects as good as 50 in extreme conditions is about the besst I can explain it and it didn't cost me any HP, in fact I picked up a little when I switched from the 20-40 dino I was running......when I had my 780 

[Ranger]

Well I CAN go to 10w40 on my next oil change, in fact that was what I wanted to run in the first place but a buddy of mine with a 700r runs 10w50 on his and he's not lacking in power for a stocker...I don't want to f-up my engine though...FL is pretty humid and rains a LOT but otherwise the coldest we ever had all year was 29 degrees during a cold snap and that only lasted a few hours...

[1badazz_700r]

im running 0w-40 amsoil synthetic. I was told by a few big builders thinner oil will actually help the engine run cooler.IDK for sure though

[Ranger]

I've noticed it really depends on the guy doing the advising what's the best oil to use...Some guys I know will practically run 20w on everything, others use like 70w in everything but the lawn mower (because the mower was too hard to pull start hahaha)...I got my advice from a guy who builds, maintains, and races those fast go-karts and so I thought he might actually know something about small engines...

[Kenny]

You guys know I have to write a big story here

Heavier oils and synthetics are good for oil "wedge" in engines that have standard cam, crank and rod bearings. The wedge is used to keep the bearing and whatever is spinning in them from making physical contact. Higher film strength in synthetics and heavier dino oils work better(usually) in higher temps.

Now we have the issue of never having enough film strength for close tolerance extreme load components like lifter to cam nose, rocker shafts and piston pins. So we have to have extreme pressure additive packages that would include something like ZDDP (zinc), calcium carbonate, molybdenum disulphide etc....... Because oil by itself will just simply fail.

Now we have to add anti-corrosion packages to protect the engine internals from the acids and such that are very destructive but unavoidable byproducts of combustion.

Detergents are also a necessity to keep all those parts sparkling clean for long term engines. Note that many race oils do not have detergents because race engines burn a fair amount of oil because we are always trying to run the lowest ring tension possible, and detergents have a tendency to cause detonation. Of course that is bad for power and durability.

So we have regular dino oil that has lots of impurities and waxes that will cause a film buildup but does really well with additive packages, full synthetics that don't do a very good job of holding extreme pressure additive packages in suspension, then there is the new breed of super clean cracked hydrocarbon (dino) oils that are usually labeled as synthetic that is the best of both worlds. It has consistent sized molecules, none of the impurities, and holds additive packages really well.

One of the biggest jobs of oil is to cool the engine components. The most critical being pistons and valve springs. Thinner oil dissipates heat more quickly, doesn't have as much tendency to cling to the hot parts, which can cause it to "coke". The resulting coked oil is abrasive, causing more harm than good. Anyone that has seen a seized (or well used) piston pin from a Raptor motor can attest to this. One of the oddities that Randy can attest to is the effects of film strength. When he was at the absolute limits of a factory style clutch, synthetic oil woul cause it to slip, then he could change out to dino oil and it would get better. This was not because synthetics are slicker(they aren't)..... it is because the oil wedge was so much stronger that it would not force the synthetic from between the clutch plates.

Where does that leave us? Well we have full roller bearings everywhere that don't require the strong wedge, but we have a few places that require EP additives for protection, and we really need to keep the piston and valvesprings cool. So we could actually run water if it would hold a good EP package. So this leaves us needing to run the lightest oil possible that has a really good EP package. The thinner oil is gonna dissipate heat quicker, is easier to scrape off the cylinder wall in turn allowing lower tension rings (which lowers temps even further and builds more power. It is also easier to pump and move the rotating assembly through (again, more power with less heat). Lighter is better. Using an oil cooler helps too

If we had different bearings or cam follower types, my recommendations would be different

[1badazz_700r]

 :thumbs:Im glad you got in on this kenny