Hemi Test - 5w-20 to 0w-40

[1sttruck]

The following link has a Shell article on piston rings, with a chart showing the oil film thickness vs oil weight; the 20W has a higher film thickness than heavier oils. As long as the lower ends hold up with lighter oil, especially under hot, high low, low rpm conditions, then 20W seems like a good bet.

http://www.iantaylor.org.uk/papers/Additives2001.pdf

Note that I'm not a light oil fan.

 

[JohnBrowning]

Well I thought that the trucks do not use the variable displacement set up at all only the cars! Current cars prior to 2005 all had this system adn they did not have 5W20 recomendataion. SO I do not belive that 5W20 is needed for the lifters to activate and deactivate at all. GM's system is also lifter based and they do not use or recomend a 5W20 either.

I agree with one poster about useing dino instead of synthetic if you do not plan to keep it past 3 years! No need to increase your cost of ownership! The "bobistheoilguy" side of me say go for it!! Run the oils and do the used oil analysis!! I would start with the thickest and work my way down to the thinest. I would also do a used oil analysis right now to establish a base line!

 

[Steve S]

Use petro oil ,why waste money . The differences would be the same.

 

[Al]

quote:

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Originally posted by Motorbike:

quote:

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Originally posted by buster:

If anyone thinks this is a waste of time or I should modify it let me know.

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If your going to sell it in a couple years my thoughts would be to run dino ... w/o analysis to drive up operational costs for a vehicle you plan to trade off .

It will still be under warranty by time you trade and the dealers won't give you more money because you ran synlubes .

You asked

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Exactly
5W-20 Motorcraft..Set it and forget it.

 

[buster]

MC it is then. 3-4k mile drains. 5w-20, 5w30 then 10w-40.

 

[scout]

quote:

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Originally posted by 1sttruck:
The following link has a Shell article on piston rings, with a chart showing the oil film thickness vs oil weight; the 20W has a higher film thickness than heavier oils.
http://www.iantaylor.org.uk/papers/Additives2001.pdf[/qb]

http://www.iantaylor.org.uk/papers/Additives2001.pdf</strong><hr /></blockquote>

Yes, because more of the thinner oil gets pumped up there, which is very good to a point. But the same guy has *another* article in his collection that describes another wear study.

http://www.iantaylor.org.uk/papers/ITC95.pdf

To keep this brief, following measurements made on an actual engine, they derived the following formula for top-ring wear (in paragraph 5):

new wear = old wear * (old HTHS/new HTHS)**2.15

To illustrate, this would give
(3.6/2.6)**2.15 = 2 times more top ring wear using Mobil 1 0W-20 versus Mobil 1 0W-40.
[/QUOTE]

 

[TooSlick]

Buster,

I'd run the Synergyn 0w-20 in this motor if they allow a 20wt. I saw excellent performance and fuel efficiency with that stuff. It still looked almost like new oil after 6000 miles. Lots of ZDDP, Boron and Moly ....

Of course you could always stick with the Series 2000, 0w30 - but you'd probably wear out the motor after only 400k-500k miles...

TS

 

[buster]

quote:

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I'd run the Synergyn 0w-20 in this motor if they allow a 20wt. I saw excellent performance and fuel efficiency with that stuff. It still looked almost like new oil after 6000 miles. Lots of ZDDP, Boron and Moly ....

Of course you could always stick with the Series 2000, 0w30 - but you'd probably wear out the motor after only 400k-500k miles...

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They are now using 5w-20 in the 2005 Hemi's. Like I said before, I never planned on keeping the truck that long, I'm doing it just to compare the viscosity issue always talked about on BITOG. I might just run the S2k for awhile longer because I'm not looking forward to changing the oil that often. If I do decide to do this I'd run the Motorcraft bc it's cheaper and easier to buy. With 5k mile drains, any oil would do. Most additive packages are so similar anymore. I'll see if I feel like doing this when the time comes.

 

[1sttruck]

scout said: "To illustrate, this would give
(3.6/2.6)**2.15 = 2 times more top ring wear using Mobil 1 0W-20 versus Mobil 1 0W-40."

Which is why it was also mentioned that field testing took a couple of years for evluating a new oil, and why diesel makers are especially leery of thinner oil.

 

[Tones]

I agree with JB, you know the trend should be to decreasing wear as the engine breaks in. Start with the thickest and end with the thinnest. That way if the wear spikes up, you know you have something significant.