Good reading for all of us Mike!
Thanks
GS -
> At 08:25 PM 1/20/2000 -0500, you wrote:
> >Mike Schwall wrote:
>
> I was edging to the discussion of synthetic versus dino juice, and what
> makes synthetic better, and what makes a synthetic oil better than another
> synthetic oil.
>
> In your case it's kind of simple once you get familiar with it. Synthetic
> oil, no matter what weight, will be more fluid at a wider range of
> temperatures than dino juice. Regular organic oil (dino juice) is refined
> to a certain base weight, then viscosity modifiers are added to create
> multi-weight oil and to maintain proper viscosity over a certain
> temperature range. I'm not a chemistry professor, so I won't go into
> details about the chemical makeup. What the difference is between the two
> are that dino juice has a very narrow range of fluidity. Dino juice is
> very sensitive to temperature changes. When cold, the dino juice flows
> very slowly. That is why for colder weather, you have 5W oil, the base
> stock is very thin. Then viscosity modifiers are added to make a
> multi-weight oil. As the oil heats up, the viscosity modifiers create
> molecular chains which make the oil thicker. Only problem with dino juice
> is the molecular bonds that create the chains are not strong. Heat and
> stress will cause the modifiers to break down and make the oil revert back
> to it's original base weight. Which is not good. Imagine running your
> truck down the highway at 75MPH doing 2000+ RPMs when it's 90+ degrees F
> outside pulling a heavy trailer and you've got 10 weight oil in your
> engine. (10W-30). So we change the oil every 3000 miles. For you northern
> folks, thin weight is desired. You don't have to worry about the oil
> breaking down because your not stressing your oil with high heat, and you
> get oil pressure and oil flow.
>
> Now to synthetic. There are two different types of synthetic oil
> bases. One is a synthesized hydrocarbon base, and the other is a
> diester/polyester base which is basically a plastic/polymer base
> oil. What's the difference? Synthesized hydrocarbon base is the same
> hydrocarbon base used in regular dino oil, except it was made in a lab not
> by nature. It's a copy of nature. This synthetic base is much stronger
> than the organic, and it doesn't break down as easily as the real stuff and
> it's more stable through a wider temperature range. This allows it to flow
> at very cold temperatures and flow really well at higher temperatures
> without thermal breakdown. Even though it's the same weight as dino, it
> will be much "thinner" at any given temperature. Mobil 1 uses a
> synthesized hydrocarbon base. Both in their engine oil and gear oils. The
> oil will still break down, just not as soon and as easily as organic. That
> is why the manufacturers say you can extent oil changes to 6000 miles or so.
>
> Your diester/polyester oil is the only true synthetic oil. It is a totally
> artificially made oil. It is basically a plastic oil. It will NEVER break
> down. Only reason this type of oil has to be changed is because there is
> no way to filter it enough to keep it as pure as it was before it was
> poured. Only manufacturers of true diester/polyester base oils that I know
> of are NEO, Torco, and Red Line. I tried to contact AMSOIL in the past,
> but I never received a reply with a direct answer about the base used in
> their oils. From their specs on pour point, flash point, and viscosity
> index it looks the same as Mobil 1. Food for though, NEO lubricants are
> used by the top NASCAR, CART, Formula I and NHRA teams as well as SCCA and
> PSR competitors. Cost? One quart of 10W-30 costs $10. That's for the
> absolute best stuff you can get. I actually have NEO 75W-90HD in the rear
> end of my old Ferd which has all new Timkin bearings, Genuine Gear 3.89:1
> gears and a Detroit TruTrac LSD differential. That cost me $10 a quart
> times four.
>
> Now to answer your original question, finally :) The reason you hear more
> gear noise is because the synthetic oil is thinner which allows the oil to
> splash around and run off the gears quick, but still provide excellent
> lubrication, because it's so thin. When gears are meshed together they
> will create harmonics which if not absorbed by something, will become
> audible. With dino juice, the oil is "thick" enough to absorb the
> harmonics created by the metal to metal contact of the meshed gears. With
> synthetic, the oil is much "thinner" and won't absorb the harmonics as well
> as the organic oil. If you went to a thicker weight synthetic, you will
> reduce the amount of audible gear noise. That is why they sell 80W-140 in
> both dino and synthetic. It's more for heavy duty situations where high
> ambient temperatures and heavy loaded vehicles will break down thinner dino
> juice pretty quick and cause gear failures.
>
> Off to another point. Aftermarket gear sets are not alike. Every
> manufacturer uses a different hardness of steel in their gear sets. The
> harder the steel, the louder the gear set will be when in operation. Most
> of your racing gears such as what you will get from Richmond Gear are very
> loud gears, even when set up properly. The harder steel used in these
> gears make them stronger and less prone to breakage when you transfer high
> torque loads such as in a drag race vehicle.
>
> I have researched, in the past, different synthetic oil manufacturers and
> their oils. I have a list of the manufacturers I mentioned with their web
> site urls and the technical info. Email me if you want a copy of it.
>
> Hope this helped,
>
> Mike
>
> __________________________
> mschwall@flash.net
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