3.6 Pentastar viscosity done by clearance and temperature

[Camperguy]

Honestly I went strictly by bearing clearances and operating temperature. I'm just stating what I did and why. If you're still under warranty I would do whatever they want you to do but probably more often to be on the safe side. My Jeep is 10yrs old and way past Warranty and even if it wasn't they wouldn't cover it because of all the mods I've done.

 

[kschachn]

Also be aware that chart has a lot of nonsense in it, at least as far as it goes with the grades. It’s more of a sales tool.

 

[Camperguy]

Sales tools for what ?

 

[kschachn]

Sales tools for what ?

Driven. They like to designate their own grades as you see in the chart. I do not like them for that reason.

 

[Camperguy]

So bearing clearances pertain only to their oil?

 

[kschachn]

So bearing clearances pertain only to their oil?

That chart does. And some of those grade designations are only the imagination of that blender so they can make them out to whatever they want them to be.

Plus you don’t need thinner oils like that for those tighter clearances. It only means you can but it’s not required.

 

[Camperguy]

https://www.enginelabs.com/ They're an engine builder site

 

[kschachn]

https://www.enginelabs.com/ They're an engine builder site

Okay.

 

[Camperguy]

And

 

[kschachn]

And

I have no idea what you’re trying to say. That site has some nonsense on it as well. That “flow test” down the plastic ramps is not representative of what happens inside of an engine. It’s only representative of what happens when you try to flow oil down little plastic ramps.

Plus I see they are promoting a brand of oil as well.

 

[Camperguy]

1/8 & 1/4 mile is what the thin stuff is for. Guys looking to eek out a few more HP on a full power run. Though I've never seen repeatable results on a Dyno, considering fuel dilution and blow by I never would chance it unless I was sponsored.

 

[Camperguy]

Lake Speed JR was the original article where I actually found the clearance chart. It makes perfect sense having used Plastigauge a couple of times.

 

[kschachn]

1/8 & 1/4 mile is what the thin stuff is for. Guys looking to eke out a few more HP on a full power run. Though I've never seen repeatable results on a Dyno, considering fuel dilution and blow by I never would chance it unless I was sponsored.

Yes racing has different expectations, assumptions and objectives for sure.

 

[INTENSE]

I currently run 5w-40 Mobil 1 Euro spec API SP. So far so good. Much quieter. No noticeable loss in economy in my 21 Rubicon.

If I understand correctly, the 2012 Pentastar had 5w-30 recommended. Can someone point to a resource for main, and cam journal clearances, etc? I’d like to use that information along with cumulative knowledge of what viscosity works with those clearances/temps and put it all to bed.