I can't recall oil weight ever being the cause of an engine failure...


Just saying.

It's always side seal heat buildup that warps the springs until the seals break, or carbon buildup that unseats the apex seals or causes non-flush apex movement, wearing them, or overheating that warps a housing, or an oil control ring failure, or a coolant seal failure.


"Bearing wear" is the only thing that oil weight seems to have anything to do with, and even then, nearly every major rebuilder has only commented on it in passing, never with worry.


Oil has been a religious war. But probably for no reason at all.

 

^Warped the rotor tips from the heat in our last one, rest of engine was fine, seem to have nailed the side seals at last.

 

Curious, is this supporting or contradicting my opinion?

 

I do wonder if redline 5w-20 would be fine in renesis that is tracked, in another words is it's HTHS of 3.3 sufficient for bearing protection?

 

It should be fine, Redline oil has magic sprinkles in it that help with cooling the rotors.

 

Lol. The science I’ve read does give an indication that group Vs have a lower coefficient of friction yielding less heat production that can help improve cooling. Obviously with thinner oil you get more flow and more cooling too. I know M1 0w's have some group V in the form of AN and maybe some POE, but not enough to bump up the HTHS like the POE group Vs in Redline. I have also yet to read a report our from someone switching from M1 to a niche synthetic like RL, RP, Motul or NEO that hasn’t seen a temperature reduction but unless you are serious racer or really struggling from heat issues I doubt it will be anything meaningful. Then again it may allow you to get away with thinner oil if you were so motivated.

 

MAn, I Just love using 20w50 or 15w50.

bite me people. BITE ME !

 

And this pointless religious war will continue, until everyone looks at failed engines and realize that it's all about cooling and carbon build up. My oil temp has never gone above 200 since I replaced my cooling system except for one occasion and that was excessive reving in the drive way to make my oil leak, leak, so I could determine the location. My oil spike to 220 but my coolant never went over 200 and in no time it dropped right back down under 200.

Sorry for kicking this extremly dead horse but it is slow at work and I'm trying to stay awake

 

I used to think we got more oil flow with thinner oils but It was explained to me that oil pumps in vehicles are positive displacement and deliver the same amount of oil if it is 10 or 50 weight. I knew this as a mechanic of 35 years but lost the perspective that was again shown to me. You do not get more flow using thinner oils, end of story.

 

You do, end of story.

 

That is correct as Navier-Stokes equations specifically take into account a fluids viscosity. But, I think Phil can speak to this better than I can.

 

You do not get more flow using thinner oils, end of story.

That's funny - I hope you aren't an engineer!

 

You don't if the pump is a positive displacement pump like in the RX8 For every rotation of the impellor it delivers X CCs of oil. Not dependent on viscosity at all.

 

what you guys are forgetting is pressure release valve and oil filter bypass pressure..I wonder how much of 20w-50 if bypassed and returned to the sump at high rpms?

 

I'll put a vote down for either Redline or Royal Purple.

 

when i used royal purple it lost its viscosity very fast--say in 2K miles. I cant remember the exact milage. Redline keeps its viscosity ok. I did settle on the 5w/30.
I think the flow of the oil in this engine is the same regardless of the viscosity. The amount of flow in the closed part of the system is predetermined by the pump. Its going to pump the same volume no matter what. The viscosity of the fluid is what is determining the overall pressure--everything else being equal. Now the cooling ability of a thinner oil in the oil coolers is a no brainer. But cooling is only one part of the oils job. Lubrication is the other. That is where the oil film strenght becomes very important. Just remember the specs for the renny engine is the same as the 13B's and the oil film strenght needed for proper lubrication is well known.
If you really want to run a lower viscosity oil then look at engine metal treatments and coatings--i like MicroBlues approach.

 

Same, ran 3 different UOA's and all lost viscosity. Check UOA thread for more info.

 

Once a 50 oil is warm it really doesn't cause the bypass to open.

Having said that your oil presure will be higher with 50 than with 30 all other things being equal.

 

The filter bypass pressure is a pressure drop across the filter material itself. The engine oil pressure and the amount of oil rises in proportion to rpm until the system bypass opens. When the system bypass opens, no further increase in volume happens. Plus no one really knows if and when it is opening anyway so...........................

 

It's like listening to nerds arguing over which is better, Star Wars or Star Trek.

BTW Star Wars is better

 

so what is the psi rating of our stock engine bypass valve?

also for those with oil pressure gauge what is the observed oil pressure at:

1000 rpm
2000 rpm
3000 rpm
4000 rpm
5000 rpm
6000 rpm
7000 rpm
8000 rpm
9000 rpm

 

Are you saying that positive displacement pumps are not tested and specified in the same manner as is standard for other pumps? Not having hands on experience I have to ponder this too. Even if the pump pick up is constant regardless of viscosity what about resistance of flow from viscosity on the output and through the system? All given that viscosity by definition is a measure of resistance to flow.

 

Look in my single oil cooler install thread, I think I have some logs with oil pressure there. My car is down awaiting a new turbo otherwise I would get you the numbers. But I had the Mazmart oil pressure mod when those logs were taken. My new motor has basically the same thing from Pineapple Racing.

I can tell you that when I did not have the Mazmart mod and I went to the single Fluidyne oil cooler, my oil pressure increased to about 90psi max due to the larger more direct feed and return lines. With the Mazmart mod it went to about 125psi at redline. I have not redlined my new ported motor so I can't say what the max pressure is but at about 5,000RPM it is near 90psi.

 

Damn 125 PSI, my pressure gauge doesn't even go that high lol. With the engine warm my car idles around 20 psi, crusing around 45-75 psi depending on throttle and rpm, I think WOT at redline I'm around 80-90, not real sure I'm usually concentrating on trying to shift just at my rev limiter which I have set for 8950 rpms.

 

Max stock on a Series 1 should be around 75psi according to my oil pressure gauge. Of course each guage will vary and now I have a custom dual oil cooler setup so that will affect the readings as well.. I went with the Prosport because reads up to 150psi. I am also taking the reading at the oil filter adapter.