No issues? Are you sure? Have you pulled the valve cover or dropped the oil pan and checked for any residue? Have you pulled the top cover off the injection pump to see how clean the quantity adjuster is?
Maybe you have been doing OK. I don't know what the ratio of oil to diesel is that you have been using. And chances are, the fryer oil that you have been filtering is soybean oil already anyway, so it is probably more of the same stock.
The only real differences in one veggie oil to another, for fueling purposes, is going to be the viscosity of the oil and what the gel point is. Chatsworth doesn't tell me where you are. So, if you don't get colder than freezing, you're probably OK on the gel side of things. For viscosity, just about any veggie oil you'd run into is going to be more viscous than #2 diesel. But I do not know if anyone has done any studies on the wear properties of veggie oil run through a distribution type injection pump. And by the time you get the engine heated up, at the injector, the fuel is probably heated sufficiently to make viscosity not an issue as far as injection quantities. For wear, most anyone is going to tell you that veggie oil has better lubricity than ultra-low sulfur diesel. So maybe wear isn't a problem. IDK what the added stress of pumping a more viscous fluid would be, and maybe it is inconsequential.
So basically, I seriously doubt you will find any differences in the oil you are planning to use versus the oil you are using now. Nobody's going to be using oil in a fryer sufficiently long to overheat it and polymerize it sufficiently to cause trouble going in. What happens after the engine runs it is another story. You may want to check in the oil pan, under the valve cover, and at the top of the injection pump. Just a suggestion; it would give you advance warning of problems so you'd know if you need to adjust the mix and/or do some cleaning.
Cheers,
PH
