Oil weight question

[Tony Hanna]

but, to thick of oil wont get through the engine like its supposed to, if you put gear oil in, it wouldnt get into the rod bearings as easily, and in turn they would wear more. my car with the damn cooling problem, when it heats up above half the stock guage drops off the op gets so low, im going to put in an oil cooler soon and fix my damn cooling problem, then after that and fixing the leak then i want to run synthetic, doesnt it not heat up and make the oil pressure go down as much?

The synthetic will thin out some as it heats up and you'll still see the oil pressure drop, just not as bad as conventional under higher temperatures. That and it doesn't break down as easily.

[turbovanman²]

http://www.amsoil.com/StoreFront/ima...llon_640px.jpg

Winter use in very cold climates,

[Greedy]

Yes, that is why you use a thicker oil. If that wasn't true, then you could run 10w30 in Diesels, right? you use the thicker oil so it doesn't SQUISH out, so to speak. Diesels use detonation to fire the engine so heavy rod bearing loads.

I believe this thread is about a td.

I believe the term is shear,and a 5w-50 won't shear like a 10w30 at operating temps and will cause higher temps on the bearings.
Since oil cools as well a lubricates just think of all that thick(at operating temperature)oil lubricating the turbo,as the oil pump (designed for 5w30)struggles to pump it.
No thanks!

[Tony Hanna]

I believe this thread is about a td.

I believe the term is shear,and a 5w-50 won't shear like a 10w30 at operating temps and will cause higher temps on the bearings.
Since oil cools as well a lubricates just think of all that thick(at operating temperature)oil lubricating the turbo,as the oil pump (designed for 5w30)struggles to pump it.
No thanks!

It is about a TD, but that doesn't make Simon's point any less valid.

If I'm allowed to borrow an example from another kind of vehicle, motorcycles (which rely heavily on the oil for cooling) can overheat if you run an oil that's too thin.
Also, the ammount of load the pump is seeing (which directly translates into oil pressure) is regulated by the bypass spring and bearing clearances (at operating temperature) not so much the thickness of the oil. In other words it's not going to struggle much if any more to pump 20w50 at operating temperature in a worn engine than it would to pump 10w30 at operating temperature in a fresh engine.

What I'm getting at is that oil thickness should be decided based on the oil pressure an engine carries at operating temperature. If you have an older engine that's carrying a little less pressure than what you'd like, then you'd probably benefit from a thicker oil. If you have a fresh engine with tight clearances and good oil pressure, then there's really no need for it.
This is all within reason though. No 80w90.

[turbovanman²]

I believe this thread is about a td.

I believe the term is shear,and a 5w-50 won't shear like a 10w30 at operating temps and will cause higher temps on the bearings.
Since oil cools as well a lubricates just think of all that thick(at operating temperature)oil lubricating the turbo,as the oil pump (designed for 5w30)struggles to pump it.
No thanks!

Your missing the point, the diesel was brought up to show WHY you use a thicker oil. Diesels are a great example.

Our engines weren't designed for 5W30 either and I am sure Mopar didn't have 20-30 pounds of boost in mind when they suggested 10w30. Either way, it comes down to what your comfortable in using. Me, I'll take a HP hit to save the bearings,

[MiniMopar]

Also, oil was a lot different in the 80s than it is today. I remember having to specifically look for the SG rated stuff so it could take the heat. I think you get a lot more protection with 10W-30 now than you did in 1985.

[BadFastGTC]

Our engines weren't designed for 5W30 either and I am sure Mopar didn't have 20-30 pounds of boost in mind when they suggested 10w30. Either way, it comes down to what your comfortable in using. Me, I'll take a HP hit to save the bearings,

I usually run a 10W-40 in the summer and a 5W-30 through winter. I have run Sledgehammer on 5W-30 at the track for years following the advice of the good folks at Red Line Oil. Dave at Red Line told me use of their 15W-50 was actually overkill if my oil temps weren't over 225. I've also run Royal Purple 5W-30 in the car when I was out of Red Line. The bearings in the car always have looked great after teardowns. I use Red Line in all the cars save for my SRT4 which developed an oil useage issue for some strange reason on Red Line. The bearings in the old GTC I had looked like new after a load of 20 psi passes and 172,000 miles. The bearings were actually reuseable. Sledgehammer recently was torn down and the bearing condition was also excellent. I do run an oil cooler on the car. Just a little FYI.

[puppet]

The film strength idea is a little misleading. Don't forget that the oil, whatever vis level it is, is placed in between the bearings under pressure. Trying to squeeze 70psi of air pressure together is tough .. even though air is compressible. Fluids aren't. As long as the bearing clearances are in spec, expecting to squeeze a constant flow of oil at 70psi from between them is next to impossible.

Heat is key. I've been told this too ... use as thin a (good) oil as possible ... as long as you can keep it cool.

Somebody posted in this thread about a race team using 17.5W50 ?? If I'm not mistaken, don't these guys usually run 0W5 to qualify and 0W20 to race? (Rusty Wallace article?) Either way, a race engine doesn't use stock oiling systems or keep that oil in the sump all season long. When I think of racing with our engines/cars I think of a fella autoXing with a stock oiling system in summer heat. A heavier oil is probably a real good idea for these guys.

FWIW, my engine sees it's share of hammering. It's driven over 600 miles a week too ... every week. Oil pressure is still 25psi hot idle (5W30).

Simon, I can appreciate your thinking on this. I'll bet you see a lot of people with tired, poorly maintained, engines. ... lot's of blowby, over fueled at WOT contaminating the oil thinning it further.

Oil is better these days ... even conventional oils can be good enough with regular changes in a healthy engine. Heh ... something I've been considering all along is putting in one of those bypass filters. I'm going to do it now. Extra clean oil will last even longer and I'll be money ahead on changes and engine wear. Plus, between that and the oil cooler, the system will have (6) quarts to work with.

[Greedy]

Your missing the point, the diesel was brought up to show WHY you use a thicker oil. Diesels are a great example.

Our engines weren't designed for 5W30 either and I am sure Mopar didn't have 20-30 pounds of boost in mind when they suggested 10w30. Either way, it comes down to what your comfortable in using. Me, I'll take a HP hit to save the bearings,

Simon,I understand the point you were trying to make.
I also understand the motorcycle reference but too thick of an oil can do the same thing the point is you need to find a medium.

I didn't mean to say Mopar recommended 5w-30,I did mean 10w30
I have yet to see any kind of testing to prove that a 5w-50 will protect better in fact I have seen a test where 10w-30 amsoil beats castrol syntec 5w-50 in a wear test.

Steve,
thanks for the input I know you have been using the Redline oil in Sledgehammer.

Also redline,royal purple and amsoil don't make a 5w-50 that should tell you something.
I just think 5w-50 is unneccesary,if you like it great but I don't think the thread starter will get any benefits from it.
As long as he uses a good synthetic 5w-30 or 10w30 would be fine.

[BadAssPerformance]

Either way, it comes down to what your comfortable in using. Me, I'll take a HP hit to save the bearings,

Right on, 10w40 for life!

[shelby zed]

we had to watch this video for class, they took a shadow, and then put some 5w30 in itand started it up, it was minus 20. but it took about 5 seconds for the oil to start coming out of the head and lubricating the valvetrain. compare this to when they tryed it with 20 w50. that poor shadow barely turned over, and then when it did it took over 30 seconds for the oil to come out, iirc and then after a while it started to smoking out of the vc (they had a clear one) because the oil was to thick and it just started to burn off, it seized in the movie too

[BadAssPerformance]

Yeah but thats at -20°F ...

[JDAWG]

just a fyi, Mobile1 is not a true syntetic anymore, this guy did some research
http://www.g35driver.com/forums/showthread.php?t=143074

[ShelbyZD]

we had to watch this video for class, they took a shadow, and then put some 5w30 in itand started it up, it was minus 20. but it took about 5 seconds for the oil to start coming out of the head and lubricating the valvetrain. compare this to when they tryed it with 20 w50. that poor shadow barely turned over, and then when it did it took over 30 seconds for the oil to come out, iirc and then after a while it started to smoking out of the vc (they had a clear one) because the oil was to thick and it just started to burn off, it seized in the movie too

I ran 5w-50 in my concorde all last winter and it always started fine.. even at -30 below. Naturally it was a bit slow turning over... but what car wouldnt be at that temp?


Anwyays. .I was just thinking that... our engines in stock form (T2 and according to mopar) have an internal pressure equal to a 450hp V8. Im jumping on the bandwagon that using anything less than 10w-30 is crazy. We aren't driving Honda's here folks. (aka we are making power).

Also thanks for the good read on the mobil 1.. I won't be buying that anymore.

[slasky]

I run mobil 1 10w 30 in my SC. Should I switch to 10w 40 since the car is mostly a track car that is only run in the summer?

[turbovanman²]

I run mobil 1 10w 30 in my SC. Should I switch to 10w 40 since the car is mostly a track car that is only run in the summer?

Synthetic has better properties so its a better oil than 10w30 dino oil. If you drive it hard and run lots of boost, I would switch to 10w40. If normal driving and low boost, stay with 10w30.

[slasky]

Synthetic has better properties so its a better oil than 10w30 dino oil. If you drive it hard and run lots of boost, I would switch to 10w40. If normal driving and low boost, stay with 10w30.

Since I have to change my oil anyway I went out and bought 6 qts of royal purple 10w40. The car spends most of its time at the track and I am running 27 psi now. I hope it is worth the $45 I spent on it.

[turbovanman²]

I have seen alot of articles and Royal Purple, Amsoil etc are a good brand. I had read that Mobil 1 took a dump awhile ago.

[MiniMopar]

Yes, after they lost they're lawsuit against Castrol who called their not-quite-synthetic oil a full synthetic in 02-03. So now M1 is a "hydrolocked Group III" oil like Castrol Syntec, instead of the true Group IV oil it once was. The thread linked to earlier in this thread has a lot of good info, such as the "Made in Germany" 0W-30 Castrol Syntec is a true Group IV oil.

[slasky]

So is mobile 1 not any better than conventional oil? What should I use in my srt4 that is a DD? I have been using mobile 1 since the first oil change.