One of the most interesting & popular tools Lubrication Engineers have in their kit is the "Flowstick". It is primarily used to compare the viscosities between a new oil and its used oil constituent.
You will see the photo's below that illustrates the use of this simple apparatus. In the real world we put the new oil out of the container (Engine, Gear, Hydraulic, Compressor or Turbine oil) into one side (lower side in photo) and a sample of the used oil into the upper side. We wait till the oil temperatures are the same. We then tip the flowstick up to its predetermined angle and bring it back to the horizontal position when the new oil hits the mark about 3/4 way down the stick. On the used oil side you have other marks that mark a range where the oil is either suitable for further service or is beyond the viscosity limits rendering the oil unsuitable for further service and needs to changed. The oil can then be sent to the lab if desired for further testing (oxidation, particles, solids, contamination with water, fuels, glycols and dozens of other tests depending on the machinery it was used in).
In our case today we also used the flowstick to compare viscosities/flow rates of some popular 2T oils in the market. This follows my discussion early on in the thread when I mentioned viscosities of the oils. This relates to film thicknesses, ability of the oil to be mixed at greater concentrations, and oil migration rates.
I went out and bought some Motul 800 & 710, Bel-Ray Si7, Maxima 927 Castor/Synthetic and Castrol Power 1 TTS. I already had some Alisyn Pro-Power 21 Racing 2T oil that I import with our other US shipments for my own use and offload some of this once a year to prepaid orders from certain customers. (It is currently unheard of in Australia in the bike market except in the marine, PWC and Kart scene.)
I went out to look for Bel-Ray MC-1......couldnt find it anywhere as it was one prime product I needed for this comparison and when I get some I will post the flow tests with it. I went around to 6 bike shops, "Oh no we dont sell MC-1 anymore, most people have gone to using this (pointing to the 800)". "Nah we dont stock it, it was too heavy and hard to mix we have these other BR products if you want". "Why are you using the 710 in your bike it has been thinned down for injector use".............incorrect it hasnt been thinned down it just uses a lighter grade of Ester and perhaps a small concentration of PIB. Another shop I went to I said to the owner I cannot believe you dont have a full range of Maxima here on the stand, "Ahh, Our shop in Frankston sells heaps and always has but up here we dont move much of it" They only had Maxima 4T oils, gear oils, filter oil and Castor 927 as "some guys use it around here" and NO SuperM Injector or Premix!.
One shop where I bought the Si7 and 710 after enquiring what i am doing with the oils the sales assistant went on with a speal how I shouldnt be running 20:1 as you will get fouled spark plugs, deposits, carbon deposits and lots of smoke. Another dude buying parts for his bike heard this and said, "In me ole RM 125 I used Castrol TTS at 50:1 and it ran great, lots of power......if you want more power use less oil as you have more fuel to make power and with more oil you will loose power. I should have used 80:1 for more power." Common misconceptions carried over the decades. I was going to say why use oil at oil then??
Another observation I noticed was the vast differences in merchandising between oil suppliers. Castrol and Shell had very good stands (as the reps are always out on the road calling into servo's and convenience stores) with a complete range of all motorcycle products/cleaners etc. One shop didnt carry Castrol which surprised me. Another had some left over Silkolene Pro 2T (which is very good) and said they lacked support. (I will perhaps make him an offer to clear the last 2 x 4 litre packs)
Out of all the niche suppliers Motul had by far the best merchandising in every shop, then Motrex, ELF, Maxima. Not one shop had a complete range of Bel-Ray products, some had a few of their 4T range (Thumper) but no 2T oils, One had only one of their 2T oils (the Si7 I bought and nothing else), I wanted to actually buy the Bel-Ray H1R (that is slightly heavier than the Si7) but no one had it. One of the best penetrating oils I have ever used is their 6 in 1 All Purpose Lubricant in an aerosol and no-one had it.
Another thing is the prices of the products these days.(f--k......a slab of Vic costs as much as litre of 800/927/Si-7) I found the Shell Advance products to be the most realistic in price/ quality correlation (eg : Advance VSX-2). Castrol was between the niche players and Shell. I didnt go to a Honda dealer as they have also Mobil and KTM stock lots of Motrex due to tie ups with these motorcycle manufacturers. One shop had Castrol A747 for $49.95 a litre! The other leading grades were all 3-4 bucks either way a litre.
(I wont use all these products I purchased myself and will use them as giveaways at this weekends Vinduro with other sponsors items........I will use either the Si7 or TTS for my mixes this weekend at 20:1).
As the old saying goes a picture is worth a thousand words. The first pic shows the flow rates for Motul 800 (red), Motul 710 (Green), Bel-Ray Si-7 (light blue) and Castrol TTS (dark blue). The variation between 800 and 710 are obvious. Si7 and TTS are neck and neck. If we had the BR H1R it would be about a bit more than inch higher than the TTS/Si7 about the same length the 710 was lower than the TTS/Si7 combo but higher.
I wanted to have MC-1 next to 800 and from its specs it would be about half way further up the flowstick barely making it out of the starting gate.
The other photo's show 800 vs Maxima 927 vs Alisyn 21 (used as reference oil only). I had to let the 800 flow a bit longer for illustration purposes as the 927 Castor fortified oil was very thick in comparison. 927 is almost 50% slower flowing than 800. When looking at the data sheets between 800 and 927 they almost share the same viscosity (927 is slightly heavier @ 40c) but their Viscosity Indexes are quite different (Figures that measure an oils resistence in its viscosity/flow rate to temperature change). 135 vs 99. This means the 927 will not flow as easily at the same temperature. Its cold flow properties are not as good. As we discussed in the past a polar compound lke Castor is perhaps unequalled in lubrication film strength at high temps but being polar it has an opposite disadvantage in mixing, storage/shelf life and poorer lubrication reliability in colder operating conditions (ie : premix snowmobile applications).
It brings up the arguement that Castor fortified oils need to be mixed well and as it says on the label dont mix with fuels lower than Specific Gravities of 0.785 like Avgas 100 being the limit. This is because of rapid oil separation if left still as the high molecular weight of the oil will try to come out of suspension.
When cleaning out the flowsticks between tests I must say the 800 had very high adhesion properties to it which translates to its adherability to engine parts when in use. This has both advantages and disadvantages in a 2 cycle engine as the correct balance must be sought in order to allow oil migration through the engine. The high adhesive nature is also required for powervalves.
Once I get some MC-1 I will do a tri-comparison using 800 & 927. My guess from the specs it will be around the flow or perhaps a little slower than 927.
This has hopefully given the 2 stroke owner a greater appreciation for understanding more what is sitting on the shelf in the bottle and how it may impact (from earlier discussions) on the lubrication of his machine and rationale for recommended ratios by the maker.
