winter plugs and gear oil

[ThomasMagna]

I was in California where I saw bikers every day and I was jonesing for a ride. I was able to get out on Betty a couple days ago, the day after I returned to Michigan. I let work wait another day. It was 52 degrees and partly sunny, what a treat. No snow or slush on the roads and not much traffic either. It's gonna be nice for a little while but colder.

The manual calls for changing plugs and gear oil for temps below 41 degrees. The highs for the upcoming days will be hovering around that magic mark. Do I really have to change them if say the temp is 38? What are the consequences if I don't?

Thanks.

[magnagregcan]

There are no winter plugs; think of your car.
What year is your bike? With shaft drive, thus gear oil?
I would think a few degrees +/- would not matter. Don't know many ppl that change gear oil at all, tho they should.
Hope this helps!

[ThomasMagna]

I have an '82 V45 with the shaft drive.

In the manual it calls for different plugs for temps above and below 41 degrees, I wasn't just making it up. Well, I made up the term "winter plugs."  I thought the plugs for below that would maybe burn hotter or something.

I don't think a few degrees would matter either, but thought that I would go to THE SOURCE and see what the forum thought. I just want to do the right thing or at the very least, not do a wrong thing.

And thanks, that does help.

[Greg Cothern]

I am going to assume you keep your Magna in a garage?  Is it heated?  If so then I would not worry about changing things for those temps. Cause the gear lube and such will be warm enough to lubricate the gears and such.  
Basically as you already know the viscosity of oil and such is at its thickest when cold and thinnest when very hot.  In your case when it is very cold you run the risk of it not being thin enough to lubricate in all the small places it needs too.
Hope that helps some, and I hope you are able to get out and ride some Enjoy!

[silveradocowboy]

I don't think a few degrees would matter either, if the bike is running fine I would not worry about it. My V65 has been in 100+ temp.s to 17 degrees and it ran just fine. Found the following on a web page that might be worth reading...

A spark plug's heat range has no relationship on the actual voltage transferred through the spark plug. Rather, the heat range is a measure of the spark plug's ability to remove heat from the combustion chamber. The heat range measurement is determined by several factors:

The length of the ceramic center insulator nose,
The insulator nose's ability to absorb and transfer combustion heat,
The material composition of the insulator,
The material composition of the center electrode.

The longer the insulator nose gives you a larger surface area exposed to combustion gasses and heat is dissipated slowly. This also means the firing end heats up more quickly. We are talking about exposed ceramic length, not extended tip length.

The insulator nose length is the distance from the firing tip of the insulator to the point where the insulator meets the metal shell. Since the insulator tip is the hottest part of the spark plug, the tip temperature is a primary factor in pre-ignition and fouling. No matter what the plugs are installed in, be it a lawnmower, a boat, your daily driver or your race car, the spark plug tip temperature must remain between 450°C to 850°C. If the tip temperature is lower than 450°C, the insulator area surrounding the center electrode will not be hot enough to deter fouling and carbon deposit build-ups, thus causing misfires. If the tip temperature exceeds 850°C, the spark plug will overheat which can cause the ceramic around the the center electrode to blister as well as the electrodes will begin to melt. This may lead to pre-ignition/detonation and expensive engine damage. (see the plug pictures that are part of this article)

In identical spark plugs, the differences from one heat range to the next is the ability to remove approximately 70°C to 100°C from the combustion chamber. A projected style spark plug firing temperature is increased by 10°C to 20°C.

The firing end appearance also depends on the spark plug tip temperature. There are three basic diagnostic criteria for spark plugs: good, fouled, and overheated. The borderline between the fouling and optimum operating regions (450°C) is called the spark plug self-cleaning temperature. This is the temperature point where the accumulated carbon and combustion deposits are burned off automatically.

Bearing in mind that the insulator nose length is a determining factor in the heat range of a spark plug, the longer the insulator nose, the less heat is absorbed, and the further the heat must travel into the cylinder head water journals. This means that the plug has a higher internal temperature, and is said to be a "Hot" plug. A hot spark plug maintains a higher internal operating temperature to burn off oil and carbon deposits, and has no relationship to spark quality or intensity.

Conversely, a "Cold" spark plug has a shorter insulator nose and absorbs more combustion chamber heat. This heat travels a shorter distance, and allows the plug to operate at a lower internal temperature. A colder heat range can be necessary when an engine is modified for performance, subjected to heavy loads, or it is run at high RPMs for significant periods of time. The higher cylinder pressures developed by high compression, large camshafts, blowers and nitrous oxide, not to mention the RPM ranges we run our engines at while racing, make colder plugs mandatory to eliminate plug overheating and engine damage. The colder type plug removes heat more quickly, and will reduce the chance of pre-ignition/detonation and burn-out of the firing end. (Engine temperatures can affect the spark plug's operating temperature, but not the spark plug's heat range).

As air temperature falls, air density volume increases, resulting in leaner air/fuel mixtures. This creates higher cylinder pressures and temperatures that causes an an increase in the spark plug's tip temperature. Fuel delivery should be increased.

As temperature increases, air density decreases, as does intake volume, and fuel delivery should be decreased.

[silveradocowboy]

80w gear oil has a "pour point" of -13.0 degrees, 85w is -5.0. When I changed the final drive oil I could only find 80/90w so that should be well within operating limits. Below is some info. from an engineers webpage.


Gear lubricant must possess the following characteristics:

Good viscosity is essential to ensure cushioning and quiet operation. An oil viscosity that is too high will result in excess friction and degradation of oil properties associated with high oil operating temperature. In cold climates gear lubricants should flow easily at low temperature. Gear oils should have a minimum pour point of 5° C (9° F) lower than the lowest expected temperature. The pour point for mineral gear oil is typically -7° C (20° F). When lower pour points are required, synthetic gear oils with pour points of -40° C (-40° F) may be necessary.

Film strength: Good film strength helps prevent metal contact and scoring between the gear teeth.

Lubricity (oiliness): Lubricity is necessary to reduce friction.

Adhesion. Helps prevent loss of lubrication due to throw-off associated with gravity or centrifugal force especially at high speeds.

Gear speed. The now superseded Industrial Gear Lubrication Standards, AGMA 250.04, used center distance as the primary criterion for gear lubricant selection. The new version of this standard, designated AGMA 9005-D94 Industrial Gear Lubrication, has adopted pitch line velocity as the primary selection criterion. As noted above, gear speed is a factor in the selection of proper oil viscosity. The pitch line velocity determines the contact time between gear teeth. High velocities are generally associated with light loads and very short contact times. For these applications, low-viscosity oils are usually adequate. In contrast, low speeds are associated with high loads and long contact times. These conditions require higher-viscosity oils. EP additives may be required if the loads are very high.

Temperature. Ambient and operating temperatures also determine the selection of gear lubricants. Normal gear oil operating temperature ranges from 50 to 55° C (90 to 100 °F) above ambient. Oils operating at high temperature require good viscosity and high resistance to oxidation and foaming. Caution should be exercised whenever abnormally high temperatures are experienced. High operating temperatures are indicative of oils that are too viscous for the application, excess oil in the housing, or an overloaded condition. All of these conditions should be investigated to determine the cause and correct the condition. Oil for gears operating at low ambient temperatures must be able to flow easily and provide adequate viscosity. Therefore these gear oils must possess high viscosity indices and low pour points.

Enclosed gears. In addition to the general requirements, lubrication for enclosed gears must meet the following requirements:
  Chemical stability and oxidation resistance. Prevents thickening and formation of varnish or sludge. This requirement is especially significant in high-speed gears because the oil is subjected to high operating oil and air temperatures.
  Extreme pressure protection. Provides additional galling and welding protection for heavily loaded gears when the lubricant film thickness fails. Extreme pressure lubricants are available for mild and severe (hypoid) lubricant applications.

[ThomasMagna]

I thank you for the effort and the information for sure.  Ya know, for the 12 or 14 bucks, I should just get a set of the other plugs. At the very least, I should look at the two different ones side by side to see the difference and compare it to the info you sent. That will give me a reason to go to the cycle shop too. I doubt that I will ride at temps much lower than 39 or 40 anyway. I don't have warm enough clothes. Can't afford any either.

[magnagregcan]

Silveradocowboy-you sure know your stuff & how to explain it logically! great info for me too!
Cheers!
Greg

[silveradocowboy]

Silveradocowboy-you sure know your stuff & how to explain it logically! great info for me too!
Cheers!
Greg

You are welcome. Luckily I learned how to cut and paste!

[Gloveberg]

You are welcome. Luckily I learned how to cut and paste!

BUZZKILLER !!!!!!!