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The Delvac 1300 Super (15W-40) is compatible with gasoline engines. This might be my new oil pick as I've been looking to find something readily available in a big pail!
So I took another look. The Shell Rotella T 15w40 that is currently on the shelf at my local Walmart has the SN rating listed so it is currently gasoline rated again. That said the semi-synthetic T5 and Synthetic T6 did not have the SN or any other gasoline rating on them(probably shouldn't be using them in a rotary if still using the OMP anyway).
To me the question for use in a rotary is. If still using the OMP and the engine oil in it, does the detergents and other additives that may be different in a diesel oil leave any deposits behind when burned that may be harmful to apex seals? The same reason Mazda originally didn't recommend synthetics. I rolled the dice and switched to Rotella last oil change. I may switch back to Havoline 10w40 on the next one. Haven't decided yet. I've been meaning to get the Rotary Aviation OMP adapter so I can run only premix, then residue left behind when burned won't matter as much.
I did my 5 minuets of on-line research and decided to use a zinc additive to my choice of 10W-40 conventional motor oil!
People in the know recommend 1200 ppm of ZDDP in the oil.
I looked up the oil treatment MSDS and the chemicals in this product are "trade secrets".
Instructions are to add the 15 oz bottle when you do your oil change.
Since I have no idea how much ZDDP is in the 15 ozs it is impossible to determine if I have the 1200 ppm I want.
I will try to contact the manufacturer and see if they can provide this info.
Found another MSDS sheet that lists the Zinc Alkyl Dithiophosphate level between 1 to 4.9%!.
This zinc compound is not ZDDP, I do not think this is what I want. Even if it was a uniform 5% it would come out after adding it to 3.5 quarts of oil to 1.4%.
The oils with zinc in them are 1% to 1.5% zinc.
I will see what the other zinc oil treatments have, want the ZDDP, not the ZADP!
I really don't have much to say on this. This is something that I have been curious about people experiences. I switched after the second oil change to 20w-50. To me... the engine felt much more solid at higher RPM's. I will continue to use it, how about anyone elese and their experiences?
I was not aware of the Zinc in oil or not as of now. With an extremely brief search I learned that it was removed to lenghten the life of catylitic concerters. Also, Valvoline racing oil has the Zinc still, at $10 a quart....
The VR-1 non synthetic I choose to run still has high levels of zddp. (Around 1200 if I recall) The Synthetic version is slightly lower. I also Emailed Castrol a few years back regarding their Zddp ppm levels and they mentioned most of their oils were lowered substantially to lengthen the life of catalytic converters. The Castrol Edge variant still retains around 1200 ppm.
Since we do not have a flat tappet cam, do we need the ZDDP?
Probably not. But almost all oils had 1000+ zinc and phosphorus prior to most company's removal of it for EPA and catalytic converter lifespan I guess it cannot hurt.
Probably not. But almost all oils had 1000+ zinc and phosphorus prior to most company's removal of it for EPA and catalytic converter lifespan I guess it cannot hurt.
-M
My main reason that I want to have ZDDP in my conventional oil is that leaves a thin coating on the engine parts which remains after the engine is turned off.
On cold starting (which causes the most engine wear) this zinc coating helps prevent metal to metal contact before the oil has time to reach the parts.
I noticed several "Break-in" oils that have various levels of ZDDP and Phosphors. Does anyone recommend their use for breaking in my rebuilt engine?
Sounds like it might start coating the parts as they break-in.
Anything to help the lifespan of this engine is worth the extra cost, after two engines that only lasted 75k each I don't want a third repeat!
Hi everyone,
When I mentioned to the Mazda dealership service manager that my 88 GXL did not lose any oil between oil changes, he stated that I have a tight engine!
Hindsight is that my OMP was not functioning correctly!
I attribute the malfunction to why my original engine threw a apex seal at 75k miles.
Take the time to confirm that the OMP is working correctly if you want to get the maximum life for your motor.
Hi everyone,
When I mentioned to the Mazda dealership service manager that my 88 GXL did not lose any oil between oil changes, he stated that I have a tight engine!
Hindsight is that my OMP was not functioning correctly!
I attribute the malfunction to why my original engine threw a apex seal at 75k miles.
Take the time to confirm that the OMP is working correctly if you want to get the maximum life for your motor.
Fun fact: on my last engine I found that even with a working OMP, my oil level never decreased simply because of blowby. So much fuel was bypassing the seals and making it's way into the oil that the dipstick level just remained constant.
Now when I finally opened up that engine and looked inside literally everything was worn well past reusability. It's kind of crazy, it was probably putting around a liter of fuel into the oil every 1000km.
Fun fact: on my last engine I found that even with a working OMP, my oil level never decreased simply because of blowby. So much fuel was bypassing the seals and making it's way into the oil that the dipstick level just remained constant.
Now when I finally opened up that engine and looked inside literally everything was worn well past reusability. It's kind of crazy, it was probably putting around a liter of fuel into the oil every 1000km.
Great information about blowby and oil dilution, thanks!
This was on a brand new engine with 56 miles on it, was the blowby that much on a new car?
What in the blowby gases dilute the oil with, gasoline from the air/fuel mixture? That would evaporate out as soon as the oil gets hot!
What fluid would build up in the oil over time that compensates for what is used by the OMP?
This sounds like a very good reason to send a sample of my oil for analysis.
03-27-24, 11:50 AM
