J_J said:
Thanks JJ.
Since we've been discussing "shear", here's a section from the article you linked:
In choosing a variable temperature hydraulic oil, operators should ensure the fluid has a high shear stability (the polymers' resistance to stress, which can break the molecules and reduce the viscosity of an oil at operating temperature), as well as excellent hydrolytic stability, which reduces the impact of unavoidable water condensation in machinery after shutdown, helping to reduce wear and corrosion.
"The true test of a good variable temperature hydraulic oil is finding one which offers a wide temperature range as well as other key performance features such as excellent shear and hydrolytic stability," Tavcar said. "Only by choosing a product that performs well in all areas will you be able to reduce downtime and maximize productivity."
Good stuff. To maximize the time between hydraulic oil changes (assuming it is not getting too "dirty" from use), we should choose an oil with "excellent shear and hydrolytic stability", since it would combat viscosity break down and condenstation.
Was poking around and found a fairly long and detailed article regarding engine oil performance in Alberta Canada:
http://www.fireblades.org/forums/ho...emi-synthetic-oil-for-929rr-2.html#post439116
I didn't get through the whole thing, but the following may be interesting to all you Mobil 1 fans out there (text discusses the 5w30 product):
Group-IV/V Blended Basestock Engine Oils:
As a comparison, Group-IV/V Blended based engine oils categorically outperform Group-I solvent extracted lubricants by 150% but differ in their application for straight PAO and PE, and Di-Based Ester lubricants.
This is the only class of engine oils to fully meet the Central and Southern Alberta 70 deg C ambient temperature differential requirement, in a single viscosity grade better, in this respect any other engine oil subsequently, free of any seasonal temperature range planning.
The only product in this category is Mobil-1, a severe service lubricant approximately equal in performance with AmsOil and Redline - unlike these two products, it is not approved for extended drain intervals, and due to its lower kinamatic viscosity numbers, is suitable only for light duty applications. We advise against the use of Mobil-1 in light truck engines in medium duty applications Redline, Amsoil or selected HD Engine Oils are better choices.
Make no mistake - this is an exceptional product; fabricated completely without viscosity indexing polymers, from premium Polyalphaolefin, Di-Ester, and Alkalated Napthalene blendstocks. It has the highest stay-in-grade properties of any lubricant on the market, has step-out high temperature shear stability, and despite its relative light kinamatic viscosities; has been proven to deliver engines through the 350,000 km without ANY measurable wear - and tested to 1,000,000 km on European Engines without catastrophic or terminal engine failure!
This is our first choice in passenger and performance car engine oils it comes very close to being the universal application engine oil suitable all passenger vehicle and many light truck / SUV applications (where the duty cycle is light).
Mobil 1 5w50 might be a good solution in my PT422 for extended temperature range applications, but the "kinematic viscosity cSt @ 40º C" seems pretty high. Probably not a big deal, but I'm assuming this suggests its ability to flow at colder temps is more comparable to a "10w" oil. Not sure though. Actually, having a higher kinematic viscosity to start may ensure it remains high enough over extended drain intervals when exposed to shear stress and viscosity breakdown. (<- tried to use all the fancy terms I learned in one sentence...
) The right oil, coupled with an effective, low-cost and easy to build "filter cart" (designed by someone on this forum?), maybe we could extend hydraulic changes and reduce operating costs.
Either way, I'm still trying to get an answer on whether a hydraulic type additive package would make sense in this scenario. I'll post up if I find out anything interesting.
Thanks.
