Oil Type and Weight?

[will13fox]

Got a 79 CJ7 with 43,xxx (so either 143,xxx or 243,xxx), orignal engine the AMC 5.0. I live in NC and put about 20-25 miles a day on it for now (i know, i know, i know, a 79 CJ 9mpg daily driver your out of your mind). The question is what do you guys reccomend for oil? 5w-30? 10w-30? 10w-40? Synthetic?

 

[Torxhead]

Rotella T 15w-40.

 

[Saddle Tramp]

In the day 10-40 was the main stay; the other one was just straight 30 weight. However the book says at 40 degrees and above OK to use 30w or 40w in single viscosity but 10-30, 10-40, and 20-40 is also OK; down to 0 degrees 10-30 or 10-40. I always used 10-40

 

[will13fox]

Ok thanks I had a buddy tell my to use 20-40 and my Haynes doesn't have that in there I think it's time to get a new Haynes manual.

 

[thiswontbetooexpensive]

20-40 sounds like it might be a little to viscous for that tired engine. But on the other hand, it might slow the leaks down!


This won't be too expensive Dear! That's what I keep saying. Over and over again.

 

[Saddle Tramp]

Torxhead tossed out using Rotella 15-40 as it is diesel engine oil. The powers that be in the oil world have taken some of the additives out of the typical gas engine oils that affect the lubrication properties. Most likely not a problem for modern engines but not so sure about the effect on the more vintage iron; however the diesel rated oils basically have stayed the same. Others hear on the board may be able to give a better summation of the issue but in reality Torxhead’s call is probably the right call.

 

[will13fox]

So 15w-40 it is thanks guys

 

[johnnyreb]

diesel oil is a higher detergent oil than convential motor oil. diesels have alot of blow by and soot issues and the oil is designed for that. Make your motor clean.

 

[ftwflh]

These old engines like almost anything.I recommend a decent low priced 10w40.Like Carquest brand made by Valvoline and is half the price.Heck you are going to leak a lot of it so why leak pricey oil

 

[dalefan88]

I work at Oreilly auto and I use 10w-40 in our brand.


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[Jeep guy]

Rotella is good oil have used it before and it will clean your engine up nicely.
I run 10w40 casterol with a quart of Lucas to keep things smooth.

 

[ftwflh]

Lucas is a must!I knocked a hole in the filter and lost oil.Had Lucas in it and had no damage.But I shut it down as soon as presure dropped

 

[johnnyreb]

Funny Lucas sure does smell alot like STP oil trealment.

 

[Saddle Tramp]

diesel oil is a higher detergent oil than convential motor oil. diesels have alot of blow by and soot issues and the oil is designed for that. Make your motor clean.

I didn’t think it was just a detergent issue so here is what I found:

http://www.fifthaveinternetgarage.com/tech_tips/tech_tips_Modern_engineoil.html

Turns out the zinc was removed from the gas motor oils due to the cats which affects wear on the tappet/cam lobs. It looks like the zinc is starting to come out of the diesel motor oils too per this article.

 

[xena1]

Rotella has all the same properties as other oil but also is rated for diesel. I have driven AMC V8's over 250,000 miles using Rotella 15-40 since new.

 

[johnnyreb]

read the article on zinc additive. Good to know since i've also got severl antique tractors at the house.

 

[007]

I use Lucas Magnum 15/40. It has the elements of the stabilizer already in it, but you can add a quart if you prefer. I run this in everything I own except my wife's Jetta (Lucas 5/20 Synthetic). We also run it in 90 trucks at work.

 

[Tinman22]

My uncle used to work for Kendal as a chemical engineer as well as the company that pioneered white oils and synthetics talking to him is like listening to a Russian speak Latin with a German accent. Be that as it is his answer was a not so reassuring "sure" Basicly in older flat tappet motors IE 20 years ago not a problem,but here is the hitch OLDER flat tappet motors. newer ones maybe not . .Also in newer roller motors maybe not as lifter and rocker rollers require different lubricants.As he says 20 years ago a lifter was a lifter and engines lasted 60,000 miles as manufactures began to build engines that would go 100/200 thousand miles there internal parts metallurgy began to change ,requiring specific oil additive packages to the point where some oils were engineered for a specific car and adopted by others I.E. 0w30 wich I would never put in my motor. While diesel oils of yesterday had high levels of zinc and phosphorus todays don't. The need to control soot has been greatly reduced with the introduction of ultra low sulfur diesel. So what may have worked yesterday may not work today like using "diesel oil" in a gas engine it just depends on what is in YOUR engine and what those parts are made of. And to some extent when they were made.

 

[007]

My uncle used to work for Kendal as a chemical engineer as well as the company that pioneered white oils and synthetics talking to him is like listening to a Russian speak Latin with a German accent. Be that as it is his answer was a not so reassuring "sure" Basicly in older flat tappet motors IE 20 years ago not a problem,but here is the hitch OLDER flat tappet motors. newer ones maybe not . .Also in newer roller motors maybe not as lifter and rocker rollers require different lubricants.As he says 20 years ago a lifter was a lifter and engines lasted 60,000 miles as manufactures began to build engines that would go 100/200 thousand miles there internal parts metallurgy began to change ,requiring specific oil additive packages to the point where some oils were engineered for a specific car and adopted by others I.E. 0w30 wich I would never put in my motor. While diesel oils of yesterday had high levels of zinc and phosphorus todays don't. The need to control soot has been greatly reduced with the introduction of ultra low sulfur diesel. So what may have worked yesterday may not work today like using "diesel oil" in a gas engine it just depends on what is in YOUR engine and what those parts are made of. And to some extent when they were made.

I don't disagree with that at all... To that end, there are 2 types of the Lucas Magnum oil I speak of, one is the CI-4 the other is the CJ4 to address what you speak of.

The CI-4 is for everything 2006 and older, the CJ4 is for everything period (including 2007 and newer).

The nice thing about these oils is that they come blended with the key stabilizer chemicals already. This does NOT mean you can't add the stabilizer (as I do), just that most of the chemistry in it is blended in at the factory.

This is the difference between blending Lucas Oil Stabilizer with the Lucas Magnum oil and blending it with Rotella, or Kendall, or Castrol or whatever.

But oil is alot like pizza...we all have our favorites for one reason or another and nobody is completely right or totally wrong. Keep your oil fresh and full and most any will serve you well.

 

[Tinman22]

Exactly. As ultra low sulfur diesel was introduced in July of 2007 you also see the break in even the oil your referencing. Regardless newer shell rotella in an older design flat tappet motor could possibly cause some wear issues in the valvetrain area. But in a newer ls motor converted to carb with no cat sure, add a cat no, 8 quarts of 25 year old rotella in a new motor not a good idea. Like I said what's it made of and when was it made.