Castrol's Recommendations for Engine Warmup

[Lee]

This from Castrol:

From an article in Motorcyclist Magazine: "Riders who warm up their motorcycles for extended periods risk engine damage."

From David Jilbert, head of Castrol's English motorcycle research department: "The anti-wear components of engine oil do not work properly until the oil is heated to 140 degrees Fahrenheit to 158 degrees Fahrenheit." He went on to say that to warm up the engine and oil properly, the bike must be ridden.

[Mac020]

Yep. Start it up. Ride it easy for a mile or so.

[~Barn~]

So what did the article say about warming up the bike for too long? What did they say was excessive? Also, did they give any usable figures like number of minutes to warm it or something? I pretty much just warm mine, till it actually registers a temp, rather than just saying "Lo".

I obviously understand the need to make sure and get up to temp first before riding, but the article giving only oil temp. figures doesn't really help, cause riders can't tell what their oil temperature is anyway, unless you have some aftermarket gauge.

[rforsythe]

Well, this depends.

Take the 05 GSXR1000 for example - because of piston to bore clearances, they're actually too tight until the bike reaches operating temp. Riding it before that point (which includes waiting for the thermostat to open and heat the water) will result in premature engine wear and an increased chance of catastrophic failure, no matter what Castrol says. And by "operating temp" I mean 200 degrees, so it's going to have to sit there a while.

Your oil may not protect as well until it gets to temp, but it's still going to protect. And I think given the chance of serious damage if you get on a cold engine and start romping on it, I'll stick with my regimen of warming it up.

Do you know that most racers (at least, the ones who "know") warm up their bikes completely before getting on them? Now granted we get on the bike and flirt with redline almost immediately, but it is common practice and knowledge that to keep things working and prevent major component failure, things need to be operated in the temp they were designed for. Some (including myself) even go so far as to warm up the bike, and shut it off for a little while. This lets the heat completely soak through the motor, so that when you get on it and go race everything is ready to go.

But again, do what you like. Go by research, go by experience, go by the advice of a dozen highly experienced engine builders, or whatever you want. But if you intend to ride a cold bike, go easy on that thing until it gets completely warm. Don't rev above 5-6k, and take your time getting there so as to avoid stressing components which aren't yet working at the tolerances they were designed to perform at.

[I`m Batman]

i just start it up and bang in on the rev limitter for about a minute or so. it get's up to the operating temp REAL QUICK!!!

[Lee]

So what did the article say about warming up the bike for too long? What did they say was excessive? Also, did they give any usable figures like number of minutes to warm it or something? I pretty much just warm mine, till it actually registers a temp, rather than just saying "Lo".

I obviously understand the need to make sure and get up to temp first before riding, but the article giving only oil temp. Figures doesn't really help, cause riders can't tell what their oil temperature is anyway, unless you have some aftermarket gauge.

The very brief article on the words of the Castrol spokesman didn't say much more than I quoted. It didn't make recommendations or say what was excessive.


(I am going to qualify what I am about to say in this post:
I have owned 9 motorcycles and put about 70,000+ miles on them. One of those bikes was air cooled, a Honda CBR-750. I bought it used and neglected, and I rode the hell out of it for 20,000 miles. I have NEVER worn out an engine or even had to have one worked on for anything other than normal maintenance. I can tell you what I have always done to warm up motorcycle engines and maybe that can be factored into your knowledge base.)

I apologize for my response being so long but there is a lot to say on this subject. I have divided it up into named sections.

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My engine warm-up procedure:
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I have always warmed up bikes for about 2 minutes before riding them. I start them, keep the rpms under 2K for about 15-20 seconds to get oil into the upper reaches of the engine, then take them up to 2.2K-2.5K rpms and hold that until 120 seconds has elapsed. Then, I ride them at about 4K rpms for 3-5 more minutes, then 4K-5K for another 5-7 minutes. Then, I ride them pretty much normally.

I have done exactly that on both air and liquid cooled bikes before I begin to push the rpms higher. But I will not redline an engine or even come close to it until about 20 minutes has elapsed and I see a coolant temperature of 200+ degrees F. Here’s why:

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The fundamental process of engine warm-up described:
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(This knowledge was learned by a considerable amount of reading

It takes a little while for the oil to rise to the upper reaches of most engines, so the initial rpms are to be kept low. Once oil is fully circulating, the next goal is to heat the engine up to an acceptable operating temperature so that it will run correctly and not backfire or hesitate.

The engine coolant gives the first indication of engine warm-up. (I now have a bike with a coolant temperature gauge. It turns out that about 2 minutes of running a cold engine produces a coolant temperature of about 120 degrees F. This can take longer on really cold days.)

But, the oil does not keep pace. Oil temperature is normally 40-50 degrees F behind coolant temperature and in fact some of the engine parts are much hotter than the oil for a considerable amount of time. This phenomenon is caused by the fact that oil is a tremendous heat sink. A lot of heat can be stored in oil and a lot of heat has to be added to oil to raise its temperature.

That last point is very important because oil does not reach its full lubricity until it is hot. One of the roles of the additives in oil is to provide lubrication until the oil itself gets hot. So, one of the most important goals of engine warm-up is to heat the oil to at least 140-150 degrees F. so full lubricity can begin. And that is just a starting point. Ideally, the oil needs to be much hotter to do its best job of lubricating.

What generates the heat in an engine? Several things:
> Compression of the air fuel mixture
> Combustion of the air fuel mixture
> Exhaustion of hot gasses through the exhaust valves (1700-1800 degrees F)
> Friction of engine parts
> Friction of transmission parts

That last point is often overlooked and it is a crucial one in engine warm-up. The shear forces of the transmission gears produce a tremendous amount of heat and that is why you have to ride your bike to get it really hot. Riding your bike heats it up faster for many reasons, but the heat transferred to the oil from the transmission components is significant. So, ride it.

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Other factors in the engine warm-up process:
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The engine’s rheostat remains closed when the engine is cold. The rheostat is a little heat sensitive valve that impedes or allows coolant to flow through the engine and radiator. It is desirable to quickly heat an engine, so until the coolant reaches a pre-defined temperature, the rheostat remains closed. When the desired temperature is reached, it begins to open. This lets cold coolant in the radiator into the engine, and soon the rheostat closes again until the pre-defined temperature is reached.

I see this over and over on my bike as I ride it. The coolant temperature will reach the 190’s, then drop to the 160’s. This rise and fall of coolant temperature occurs several times and then stops when all of the coolant is finally hot.

The moment when all of the engine’s coolant is finally hot is a very important milestone in the engine warm-up process. When all of the coolant is hot, this means that the engine is nearing optimum operating temperature and that the oil is finally starting to heat up.

On my bike, the coolant temperature will stop fluctuating and stabilize in the 170+ degree range for a while. If I take my bike out on the highway, it will stay there, no matter how long I ride. But, if I stay in town, in the lower gears, the temperature will steadily climb to 200+ degrees.

It is at this point that I know for certain that my oil is hot enough to safely high rev my engine.

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If this process seems like a nuisance, I agree, it is. Just like you, I just want to ride my bike. But, to maximize engine longevity and good performance, it is VERY important to have hot oil. Only when your oil is hot can it do the job it was designed to do.

Lee

P.S. My mechanic, Jeff Behmer, has warned me about letting a motorcycle engine idle while the bike is on its side stand. He says that the right most set of main bearings in the engine will wear because of poor lubrication, especially when the oil is cold.