A week ago (last Tuesday night, actually), I found some old spark plugs that came out of my 99 Corolla and decided it was time for some testing. I pitted my used PU+MMO against my "leftovers" bottle that I use for top-off, straight canola oil, and a dry plug, soaking one plug in each oil for a week at room temperature. The results aren't what I had expected, honestly; here's what went on:
Sample 1: PU 5w20 run straight until 6.25% MMO was added at 2k. Oil was drained and stored at 2738 miles.
Sample 2: Just under 1qt each of PU 5w20, PP 0w20, Rotella T6 5w40, and Valvoline NextGen Maxlife 5w30, with 8oz of MMO and a small amount of ATF (thanks to my wife!). This is my emergency top-off jug; thankfully it doesn't get used much.
Sample 3: Pure canola oil, cooking grade.
Sample 4: Just a dry plug.
Each of the first 3 samples was soaked in its respective oil for a week, then all four samples we re "scrubbed" with plain, dry, brown paper napkins. Each plug was identical prior to the soaking ans "scrubbing"; here's what they look like now (images shot from 3 angles, one with flash and one without at each angle, camera in full manual mode to ensure that settings are consistent between shots, changing shutter speed only to compensate for flash):
Sample order: 1 2 3 4
Flash
No Flash
You can see that sample 1 (*used* PU+MMO) cleaned up most of the ashen deposits on the ground electrode, but also redeposited a fair but onto the insulator, which is forgivable for a used oil. It's hard to tell from this angle but samples 1 and 3 also cleaned up most of the carbon from the body of the plug; sample 2 didn't fare as well. Sample 2 redeposited the most dissolved solids onto the insulator of all 3 samples, actually leaving it dirtier than before the soak; worrisome considering that this was all fresh oil. sample 3 left the insulator the cleanest, possibly indicating that it carries dissolved solids better than the other samples. It also performed nearly as well as sample 2 in dissolving ashen deposits from the ground electrode (which admittedly isn't saying much), which will become more apparent from other angles.
Sample order: 1 2 3 4
Flash
No Flash
Here you can really see how much crud was redeposited onto the insulator by sample 2. Likewise, you can see how much cleaner sample 3 left the insulator than the other samples; it was the only sample to leave the insulator cleaner than before the test! Looking at tip electrodes, sample 1 is the dirtiest after the dry sample, with sample 2 being slightly cleaner than sample 2 and sample 3 being the cleanest, but not by much. Sample 3's cleaning of the ashen deposits from the ground electrode leaves something do be desired, but you can tell comparing it to the dry sample that it did soak into and soften those deposits. Samples 1 and 2 appear to have removes some of those deposits, with sample 1 having the cleanest ground electrode of the lot.
Sample order: 4 3 2 1
Flash
No Flash
From this angle, you can see that samples 1 and 3 both cleaned up the corona staining completely, while sample 2 appears to have hardened it, making it more difficult to remove than the staining on the dry sample! Also of note is the contact point on each plug; sample 1 left this point the cleanest, sample 2 left it the dirtiest, and sample 3 beat out the dry sample by a fair amount. Looking at the ground electrodes, the only other functional part of these plugs we can see from this angle, it is clear that sample 1 did the most cleaning, while samples 2 and 3 cleaned the "inside" surface of their electrodes more than adequately, leaving both shiny and silver.
What's striking, to me, about these results is that the plain canola in sample 3 cleaned as well as, or better than, the PU+MMO in sample 1, in all cases except that outer surface of the ground electrode and the contact point. That is to say that it handled carbon and varnish as well as PU+MMO, but with no detergents or dispersants (in fact, with no additive pack whatsoever). Sample 1 clearly did better than canola with regard to ashen deposits and corrosion, which is unsurprising given its stout additive pack (even after nearly 2750 miles of use).
It appears that I've chose the best possible use-case (short of polluting the local water supply) for the "leftovers" in sample 2: emergency top-off use ONLY! Despite being all fresh oil, it fared much worse than either the *used* PU+MMO in sample 1 or that COOKING OIL in sample 3!
This tells me all I really need to know about the cleaning properties of canola oil, and my current "top-off" testing, combined with a UOA at 3k and 5k, will tell me what I want to know about how it holds up under real-world use in a hard-driven engine that sees plenty of redline and WOT.
Again, these plugs were soaked at room temperature for a week, no heating was done to the samples at any time during this test. Before anyone jumps in and points out that spark plugs in an engine don't (typically) sit in oil, I understand this; however, a spark plug is one place you're sure to find soot, ash, carbon, corrosion, and varnish, all of which you will find elsewhere in an engine, all close to each other and on a variety of surfaces; this, combined with the fact that I had them laying around and they were free and convenient, made them ideal test subjects.
Would the results of this testing in any way make me comfortable running canola straight? Heck no! It lacks any wear-reducing additives whatsoever and isn't very effective against soot and ashen deposits, though its ester makeup does make it quite effective at dissolving carbon and varnish and, most importantly, holding on to it and not redepositing it on other engine surfaces! It fared better than PU in this respect (I wish I had a virgin sample of PU to test with; perhaps I'll pick up a quart and drop that 4th plug in it for a week), which really did surprise me.
At this point, I'm confident in canola's abilities as an additive to a stout oil like T6 or PU, but I'll be taking a cautious approach in the rest of my experimentation and only advancing the research past a given point if each OCI in my testing is able to safely be extended past 5k.
Currently, I'm testing canola as a top-off oil with Rotella T6; presently, I have 8oz in a 4qt (due to oversized filter) sump (6.25%). I expect to be able to run this for 7.5k or longer. I don't foresee needing to top off any more, as th 8oz top-off at 165 miles was due to an improperly installed valve cover gasket and with roughly 450 miles currently on this oil (an additional 285 miles since the top-off) the oil level has not changed. I'll be sending a sample of this oil to Blackstone at 3k, then again at 5k, 7.5k, and 10k, assuming I'm able to push it that far.
If I can push this OCI to or past 5k, I'll be running 3qt T6 and 1qt canola, with the same sampling at 3k, 5k, 7.5k, and 10k, assuming I can push it that far. When wear metals start increasing or the TBN drops near or below 1.0, the oil gets dumped.
If the 25% run make it to or past 5k, I intend to run 50/50 T6 and canola, with the same 3/5/7.5/10k sample schedule. I don't expect to get much past 5k before the TBN falls through the floor, but I do expect wear metals to be reasonable at that point.
At any rate, I'll keep my flak jacket on while posting these results, as I'm certain there will be plenty of naysayers. To them, I have only this to say: you're more than welcome to try it yourself and replicate my results. I'm more than happy to be proven wrong, if someone's willing to step forward with actual proof.
Sample 1: PU 5w20 run straight until 6.25% MMO was added at 2k. Oil was drained and stored at 2738 miles.
Sample 2: Just under 1qt each of PU 5w20, PP 0w20, Rotella T6 5w40, and Valvoline NextGen Maxlife 5w30, with 8oz of MMO and a small amount of ATF (thanks to my wife!). This is my emergency top-off jug; thankfully it doesn't get used much.
Sample 3: Pure canola oil, cooking grade.
Sample 4: Just a dry plug.
Each of the first 3 samples was soaked in its respective oil for a week, then all four samples we re "scrubbed" with plain, dry, brown paper napkins. Each plug was identical prior to the soaking ans "scrubbing"; here's what they look like now (images shot from 3 angles, one with flash and one without at each angle, camera in full manual mode to ensure that settings are consistent between shots, changing shutter speed only to compensate for flash):
Sample order: 1 2 3 4
Flash
No Flash
You can see that sample 1 (*used* PU+MMO) cleaned up most of the ashen deposits on the ground electrode, but also redeposited a fair but onto the insulator, which is forgivable for a used oil. It's hard to tell from this angle but samples 1 and 3 also cleaned up most of the carbon from the body of the plug; sample 2 didn't fare as well. Sample 2 redeposited the most dissolved solids onto the insulator of all 3 samples, actually leaving it dirtier than before the soak; worrisome considering that this was all fresh oil. sample 3 left the insulator the cleanest, possibly indicating that it carries dissolved solids better than the other samples. It also performed nearly as well as sample 2 in dissolving ashen deposits from the ground electrode (which admittedly isn't saying much), which will become more apparent from other angles.
Sample order: 1 2 3 4
Flash
No Flash
Here you can really see how much crud was redeposited onto the insulator by sample 2. Likewise, you can see how much cleaner sample 3 left the insulator than the other samples; it was the only sample to leave the insulator cleaner than before the test! Looking at tip electrodes, sample 1 is the dirtiest after the dry sample, with sample 2 being slightly cleaner than sample 2 and sample 3 being the cleanest, but not by much. Sample 3's cleaning of the ashen deposits from the ground electrode leaves something do be desired, but you can tell comparing it to the dry sample that it did soak into and soften those deposits. Samples 1 and 2 appear to have removes some of those deposits, with sample 1 having the cleanest ground electrode of the lot.
Sample order: 4 3 2 1
Flash
No Flash
From this angle, you can see that samples 1 and 3 both cleaned up the corona staining completely, while sample 2 appears to have hardened it, making it more difficult to remove than the staining on the dry sample! Also of note is the contact point on each plug; sample 1 left this point the cleanest, sample 2 left it the dirtiest, and sample 3 beat out the dry sample by a fair amount. Looking at the ground electrodes, the only other functional part of these plugs we can see from this angle, it is clear that sample 1 did the most cleaning, while samples 2 and 3 cleaned the "inside" surface of their electrodes more than adequately, leaving both shiny and silver.
What's striking, to me, about these results is that the plain canola in sample 3 cleaned as well as, or better than, the PU+MMO in sample 1, in all cases except that outer surface of the ground electrode and the contact point. That is to say that it handled carbon and varnish as well as PU+MMO, but with no detergents or dispersants (in fact, with no additive pack whatsoever). Sample 1 clearly did better than canola with regard to ashen deposits and corrosion, which is unsurprising given its stout additive pack (even after nearly 2750 miles of use).
It appears that I've chose the best possible use-case (short of polluting the local water supply) for the "leftovers" in sample 2: emergency top-off use ONLY! Despite being all fresh oil, it fared much worse than either the *used* PU+MMO in sample 1 or that COOKING OIL in sample 3!
This tells me all I really need to know about the cleaning properties of canola oil, and my current "top-off" testing, combined with a UOA at 3k and 5k, will tell me what I want to know about how it holds up under real-world use in a hard-driven engine that sees plenty of redline and WOT.
Again, these plugs were soaked at room temperature for a week, no heating was done to the samples at any time during this test. Before anyone jumps in and points out that spark plugs in an engine don't (typically) sit in oil, I understand this; however, a spark plug is one place you're sure to find soot, ash, carbon, corrosion, and varnish, all of which you will find elsewhere in an engine, all close to each other and on a variety of surfaces; this, combined with the fact that I had them laying around and they were free and convenient, made them ideal test subjects.
Would the results of this testing in any way make me comfortable running canola straight? Heck no! It lacks any wear-reducing additives whatsoever and isn't very effective against soot and ashen deposits, though its ester makeup does make it quite effective at dissolving carbon and varnish and, most importantly, holding on to it and not redepositing it on other engine surfaces! It fared better than PU in this respect (I wish I had a virgin sample of PU to test with; perhaps I'll pick up a quart and drop that 4th plug in it for a week), which really did surprise me.
At this point, I'm confident in canola's abilities as an additive to a stout oil like T6 or PU, but I'll be taking a cautious approach in the rest of my experimentation and only advancing the research past a given point if each OCI in my testing is able to safely be extended past 5k.
Currently, I'm testing canola as a top-off oil with Rotella T6; presently, I have 8oz in a 4qt (due to oversized filter) sump (6.25%). I expect to be able to run this for 7.5k or longer. I don't foresee needing to top off any more, as th 8oz top-off at 165 miles was due to an improperly installed valve cover gasket and with roughly 450 miles currently on this oil (an additional 285 miles since the top-off) the oil level has not changed. I'll be sending a sample of this oil to Blackstone at 3k, then again at 5k, 7.5k, and 10k, assuming I'm able to push it that far.
If I can push this OCI to or past 5k, I'll be running 3qt T6 and 1qt canola, with the same sampling at 3k, 5k, 7.5k, and 10k, assuming I can push it that far. When wear metals start increasing or the TBN drops near or below 1.0, the oil gets dumped.
If the 25% run make it to or past 5k, I intend to run 50/50 T6 and canola, with the same 3/5/7.5/10k sample schedule. I don't expect to get much past 5k before the TBN falls through the floor, but I do expect wear metals to be reasonable at that point.
At any rate, I'll keep my flak jacket on while posting these results, as I'm certain there will be plenty of naysayers. To them, I have only this to say: you're more than welcome to try it yourself and replicate my results. I'm more than happy to be proven wrong, if someone's willing to step forward with actual proof.