So I've looked around at some of the oil threads here, and I'll be honest, I don't understand much about shear, viscosity, or UOAs.

I have ~3000 miles on a new-to-me motor with ~150,000 miles that replaced the one that had a #4 crankshaft thrust bearing failure on it this spring. It is currently running the Rotella 10w30, and I'm pretty happy with it so far. It still looks very clean and I'm not burning or leaking anything driving around in this crazy FL heat.

I have my first track day with the new motor in a couple weeks, and with this heat I'm not used to, I'm wondering if the T6 (which I think is higher weight) would be better to run at the track? This car does get driven every day (but only 15 miles or so), and the other side of the question is would it be harmful for me to run the T6 every day? I understand that those with turbos would want to run it due (I think) to the added protection it provides - don't I wan't the same protection regardless of whether I'm N/A or not?

Just trying to make smart oil choices, I've got several track days lined up in the next 8-10 weeks, so I'll be keeping a very close eye on it.


Thanks!
Phil

 

I put T6 in every car I care about.

 

You should run both, get an analysis, and get back to us. That's what I did on the turbo car.

 

Do you have a pre-99 engine? If so you will want a heavier weight oil. I know even just after a 3 run heat of auto-x runs my car my car ticks with 10w30. And its because the oil is too thin being that hot. When I say ticks I mean even up in the revs not just at idle. 5w50 fixed that, still ticks at idle after the heat but not in the revs. If you have the solid lifters I still think you would be better going with a somethingW40 to better deal with the heat.

 

I also put T6 in every one of of my and my friend's cars.

 

My 1994 never ticks on 10w30 white bottle Rotella. Oils maintain viscosity differently with temp increases, you can't just say "all 30 weight oil is too thin", it doesn't work like that.

 

They're supposed to follow the viscosity chart from SAE at least somewhat. Since SAE does decide what a certain weight oil is supposed to react like to temperature.

 

Some sustain viscosity better at 250*f than others.

 

And 250F isnt on the graph of temperature vs viscosity that oils claiming to be a certain weight are supposed to follow?

 

Nevermind, all oils are exactly the same.

Please STFU and stop attempting to correct everyone on the forum. We're all tired of reading your ----. It's a disservice to all the people who've spent thousands upon thousands of dollars in what amounts to "research" that we share with people amenable to doing things right, the first time, based upon our collective experience.

Why don't you go spend a couple hundred bucks on fluids and UOA data and get back to us on how much we don't know? You can start by purchasing a subscription and be a site supporter.

 

Jeez, I'm not saying they exactly the same, or that they're even supposed to be. Just saying that they're all supposed to be generally kind of the same somewhat. I don't know the tolerance range on the SAE spec because, well, I dont feel like purchasing the entire SAE paper on oil viscosities just to get it. I do know that when new an oil needs to follow a certain temp vs viscosity curve within a certain tolerance in order to be sold as a certain SAE weight oil. What happens after the oil have been used (unless there is a spec for it) or its above the higher temp value on that curve isnt regulated so, yes they're all certainly different there.

 

Another fun variable is after the engine oil is used, and fuel shear becomes a problem. I found through a few UOAs that blue bottle Rotella was leaps and bounds above AMSoil, M1, and Valvoline 40wt oil in regard to fuel shear and ZDDP.

There are also documents out there that I've seen on BITOG where each weight is compared with virgin oil and they differ substantially.

 

I did find some data ranges at certain temps just kicking around lightly and the tolerance range looks HUGE.

 

Thanks for the input guys!

First off - Hustler your new avatar confuses and scares me. I didn't know who you were at first...

I think I'll change to the T6 before the track day and see how it goes. This oil will probably be in the car for 3-4 track days.

For those asking, sorry I didn't mention - I have a '99 NB1 with a '99 motor. Never had any lifter tick (in either motor), but I have heard that the valve springs are lighter rates in the 99 than an NA 1.8L's valve springs. Not sure if running a higher weight oil helps with that, but from what little I understand about oil I would think it does.

 

In the spec miata world; probably more similar a comparison for you, guys are running Schaeffer 5/20. Of course, this is in an attempt to get every last horse out of the engine, probably not a major consideration for you at this time.



Hustler, any data on Schaeffer?

 

I run T6 5-40 in my NB's. They have lots of zinc, which the solid lifters like, and it's inexpensive for synthetic.

 

Not that there is any correlation, but I was running M1 5/20 in my car when the engine finally let loose. Not sure if running a thicker oil would have helped the situation any as the bearing was on its way out anyways.

When I lived in MI, we just ran 5/20 year round because the theory is that it would get to all the internal components faster (at least that's what I'm told). I think with the heat down here, I'd have better piece of mind with the thicker stuff. Its tough to really compare, since this high milage motor runs way better than my lower milage one that blew. I'm just hesitant to run 5/20 on the track again lol.

EDIT: I am assuming 5/20 means 5w20 - are you talking about this? http://www.schaefferoil.com/supreme-...acing-oil.html

 

The multi-viscosity numbers relate an oil's flow behavior compared to straight-weight oil at two temperatures. The first number is at 0°C. The second number is at 100°C. And, that's all they mean.

All the other characteristics that matter aren't covered by those numbers. Film shear strength. Anti-wear additives. Detergents and dispersants. Ash control. How good the oil base stock is. Etc.

Bottom line, the diesel oils are great for our older cars. I've always run synthetics because of the heat the oil sees in the CHRA. But, I also used to have a lot of lifter tick. Started reading hustler's posts on Rotella T-6 (and those included oil analyses -- so there was some objectivity there). Switched to Rotella T-6 on my last oil change. It is less expensive than the synthetic I used to use, and the engine is utterly quiet with great oil pressures. So, that's what I'm using from now on, and I'm switching my other older cars to it as well.

Given that you are normally aspirated, you don't necessarily need synthetic. But the additive packages that are in the diesel oils will do you a lot of good.

 

T6 in my discovery, german castrol 0w30 in the miata and range rover. but im running low so it will probably get t6 next along with the range rover.

 

Thanks for the clarification on this. I'm going to read up on the Scheafer stuff on BITOG a bit, because I am curious.

This is enormously helpful, thank you! I have some reading to do to understand this in a more technical manner, but this was great to give me the "jist" of it.