2ndGearRubber

A long time coming, here's a UOA for Rotella T5 10w30 (Semi- Synthetic).






$16 a gallon at Wally World, approx $21 at your local auto-parts store. So, after approximately $5 for a brightly colored Purolater filter (to aid in finding it in the future), and the $0.99 for my dealer supplied crush washer, and this oil change costs me about $25.


About the car. It's my 94 R package, with 65,000 miles on its' stock 1.8L engine. I purchased the car, with 58,000 miles on it, and during the post-purchase oil change, I could smell ATF in the oil..... and then the lifter tick began. A few quick OCIs with cheap conventional, and a cleaning/refilling of the lifter gallies during the TB/WP job, the engine seems happy and healthy. A tiny amount of tick on start up, which dies down in 1-2 seconds.




The car sees daily driving use here in Pittsburgh, as well as auto-x use. My father co-drives the car (he doesn't like the FWD dynamics of his Civic Si), so within a given season, the car sees about 100 runs. This oil had about 80 runs on it, as well as 2,750 miles. Why the sub-3k interval? My emission test was coming up, and I was concerned about fuel-blow by causing issues. Well, the car passed with what the mechanic described as "incredibly low" PPM counts, and the Black-Stone report confirms blow-by is not an issue.


So, here's the data:






Everything looks good, and I'll likely stretch the winter oil-change out to 3500 miles, and re-test. Any comments are welcomed and appreciated. Funny, I spend more on the UOA, and the TBN test, than I did on the oil/filter.

18psi

iTrader: (76)

Good data. I wonder how this stacks up to the T6 full synth. I know we've had plenty of discussions on that before, time to search.

mgeoffriau

iTrader: (7)

Looks like pretty good stuff, has good ZDDP content like T6.

I'd still rather have a 0w or 5w, though.

2ndGearRubber

That has me wondering as well. The T6 is only about $7 per gallon more, and I'd get the improved flow characteristics of a full synthetic. The main reasons I'm likely sticking with T5 are:

1) I'm concerned the T6 would aggravate the only OE seal left on the car (the rear main). I have one sitting in the "mazda box", but I have no intention on removing the trans to change that seal.

2) Even with the improved flow of synthetic, I'm concerned the 40 weight hot viscosity may aggravate the HLAs.

3) 10w30 works just fine, so why experiment more?





Agreed. The 0w-30 T6 Rotella alluded to a few years ago for the Canadian market is still eating at me.


Still, based on the above data, and the usage if the car, I don't see the 10w being detrimental. The only "high" metals are AL, Cr, Fe, and Pb. None of which are above average. Yeah, I'd like a lower "cold" weight, but is there really much to be gained on our engines?






EDIT: Link to Hustlers track/street T6 UOA - https://www.miataturbo.net/engine-pe...t-miles-40230/

Fireindc

iTrader: (13)

rotella is gods lubricant.

Switching to t6 made my engine sound so much happier, especially when hot. Looks like the t5 is good for a na car though.

hornetball

iTrader: (4)

If I were NA, I'd do T5. My G8 gets T5.

Leafy

iTrader: (1)

How is switching to synthetic going to effect any of the seals? We dont have any cork or rope gaskets in the engine last time I checked.

I also wouldnt be too concerned with the 0w30 in this car. Its an NA engine, you need to run whatever viscosity makes the lifters not tick while running. I tried T6 in the normal 15w40, 10w30 mobile 1, 5w40 M1, and 15w50 M1, the only one on my car that didnt have the lifters ticking after the first run at auto-x was the 15w50. I never got around to trying the 0w20 European blend castrol, which was going to be the next oil in that engine to see if that still had the tick or not. But either way, the oil that works in one set of miata lifters wont necessarily work in another.

Fireindc

iTrader: (13)

I forget about those HLAs sometimes. Man my 1.6 liked to make a racket for a while on a hot restart. Like if id park it, run into the store for 5-10 mins max, and come back out and start it, it would tick pretty loudly for a good 5 mins of driving.

On my dyno day i had warmed the car up and shut it off, when it was ready to go on the dyno people were like WTF is wrong with your car. I'm just like, meh it does that. Then put down 240whp and everyone was super impressed. It was hilarious.

hornetball

iTrader: (4)

The ticking is just 1.6L masturbation.

petrolmed

iTrader: (8)

Ha, the exact same happened to me except less power. Even more annoying was that it hadn't ticked within like 2 months because T6... but of course it randomly decides to right then.

2ndGearRubber

Synthetic cleans more, has better flow rate. If a bit of crud is keeping my OE rear main seal alive, so be it.