Yet another oil thread

[spitfire]

Hey everyone. So, after searching this site, I've found that this topic has basically been beaten to death, but I wasn't able to find quite the right answer for me.

I've been debating different oils for the cars first-by-me oil change. I was thinking about using Rotella T1 30w from Tractor Supply company. My reasoning for this is the Zinc content of diesel oils. I have a few problems with this oil though.

First of all, they've lowered the Zinc additive in these oils very recently for emissions reasons. I read somewhere that after performing a test on a few oils, the Rotella T1 30W has about 900 ppm while the 15w-40 Rotella has closer to 1200 ppm. Is 900 ppm still enough if I do want to try the 30w? I don't really know much about it, other than that 1200 is a larger number than 900..... Anyway, I've also found through some research that all diesel oil zddp content has been significantly reduced within the last couple years. The generalization that I have sort of come to terms with is that most people experiencing issues with flattened cam lobes are people with cheap, Chinese made aftermarket cams and those with hipo motors, which a 250.6 ci flathead is not. The thing is, is that I wasn't around back when these motors were "newish", so I don't remember cam lobes being wiped off like some of you do, so I can't say for sure.

Greg g mentioned to me that Traveler oil is formulated similar to the old formulation of Rotella. I think I can order it in 30w as well, but that still brings me to my next issue.

The biggest worry I have is that diesel oils have a much higher amount of detergent in them. Some use diesel oils to flush old engines. I've read about diesel oils cleaning up the rings and motors losing compression. Granted, if your motor loses compression because the carbon was flushed away from them, you need a rebuild.

The reason why I'm asking this is that most people who reccomend diesel oil are running clean, rebuilt motors. I on the other hand am running a motor with 88K miles on it. It does have good compression (about 110 psi) and about 55 psi oil pressure on the freeway, so I figure it's in good shape, but of course I haven't seen behind the valve covers or in the oil pan.

The car sat since 1969. I do not know what oil the previous owner put in it to get it going, but it became pretty dirty looking within about 500 miles.

A couple people really helped me out on some of this subject in my original thread, and I really value their input, but I'd like to see if anyone else is in my shoes and what they are using in their vehicles. I would just grab some straight non-detergent 30w, but for one, it doesn't have any detergent (I'd imagine some detergent is way better than none, even in a used engine), and that oil doesn't seem to have much of a zinc content. How many people have introduced diesel oil into an old, high mileage engine and never had an issue? Any input will be greatly appreciated.

Thanks,

Dan

[austinsailor]

I've revived 2 trucks in the past few years, each had sat for 30 years or so. I put old formula Rotella in both, ran them for a time, and both quit smoking after a short while and run fine. The '48 B1B I drive frequently does not smoke, but does have oil burning smell and consumes some oil. However, it had about 30 lbs per cylinder compression before starting the first time. I was actually surprised it would start, and more surprised it runs rather well. I do not know what the compression is now. I will probably put rings and bearings in it in the near future, but I believe no other oil would have done any better.

I have a drum of old formula Rotella (about $7 a gallon) I'll use until I run out. I'm thinking of getting another drum to delay the problem.

My personal opinion is that you can't make it worse by getting the crud out of the rings and freeing them up.

[greg g]

Why is zinc necessary?

ZDDP is the most prominent ZDP (zinc dithiophosphate) used in motor oil. ZDP use in motor oil began in the 1940’s as a bearing corrosion inhibitor.

Later ZDP’s were used as “anti-wear agents for highly loaded rubbing surfaces”,

What highly stressed rubbing surfaces does a stock flathead 6 engine have??? Probably none, but primarily it is the camshaft lobe to lifter interface, but these engines do not have what would be considered a highly stressed as in super stiff valve springs and high rpm operation.

the recent concern includes the following

There are thousands of collector engines with flat tappets. The majority of these has been or will be rebuilt with ground camshafts or new after-market parts of widely varying metal quality.So, unless you have replaced your camshaft with a new one of unknown metalurgy or have installed increased resistance racing type valve springs and or new tappets of unknown metalurgy, or have recently had your camshaft reground to expose new metal, I believe you're good using any of the new oils.

If you are not comfortable, with that then use a modern oil with one of the may additives that have become available to replace the zic and phosporus.

[Don Coatney]

As you stated this topic has been beat to death. Pasted below is about as good an answer from Tod Fitch as you will find anywhere. Bottom line buy and use what makes you feel good as todays oil formulations will all work the same in Mopar flathead engines. I am still waiting for someone to produce pictures of a Mopar flathead camshaft (regrind or otherwise) that has failed due to no zinc or ZDDP or fizz additive. Remember the salesman will tell you anything you want to hear to sell you his product.

Google search tells me that ZDDP was first used as an oil additive years after my 1933 was built.

Wikipedia http://en.wikipedia.org/wiki/Motor_oil as this tidbit (with my bolding):

Since ZDDP was not in oil when the 190 cu.in. and 201 cu.in. engines were designed I can't see where the factory could require them. The 218 cu.in. and 230 cu.in. were introduced in the era when ZDDP was just starting to be added to oil. But Chrysler engineers had a reputation for attention to long engine life (witness exhaust valve inserts, full pressure lubrication, etc.) and I doubt that they relied on having oil with ZDDP in it to keep from having service problems.

You read your articles and do your Google searches. Then make up your own mind. My take is that specifications and testing indicate that oil that passes current standards should be okay for street driven cars. Your take could be different.

[spitfire]

Ok, thank you guys. I'll make my decision when I hit the oil isle. I won't worry about the detergent either, I guess. I'll just watch my oil pressure and maybe change my filter a bit more frequently for a while.

Austinsailor, that's pretty impressive that your engine ran with 30 psi of pressure. I guess if you didn't worry about it with that engine, I surely shouldn't worry about mine.

I apologize for cluttering the forum with another oil thread, I just hope to not screw my engine up by doing something that seems like a small thing wrong, because I wasn't thinking.

[oldodge41]

I would run what makes you feel good. I have run straight non-detergent 40w with a couple cans of STP in one old flathead that consumed anything lighter very quickly and it lasted till I swapped out the motor for another used one. It was run on non-detergent 30w for the first couple years. I then switched to 20w50 Castrol for awhile and then back to 30w for no particular reason other than I had some 30w left from before. The last I put in was 15w-40 Rotella, again because it is what was on sale. It has all worked ok. One better? Who knows, but none caused any problems I could see. Also I don't change oil very often. Even in my daily drivers I only change every 7500 miles. I know the lube joints recommend 3000 miles, and if I made my living changing oil I may also but I have never had an oil related engine failure. I think it is more important that there is "enough" oil rather than "what type" oil in an engine.............Tim

[spitfire]

Thanks Tim. I think you are correct. It's more important how much oil is in the system, rather than what kind (as long as it's somewhat acceptable in weight etc).

I ended up going with Castrol HD 30. The reasons are:

A. I use it in my 1980 Cadillac and it keeps everything happy. I use it because it has valve seal issues, so it tends to burn a little on start up when I use 10-30.

B. I found out that it has a fairly high zinc rating. Even if I don't need it, why not grab some if it's there?

C. I figured that it's a detergent oil, but not like diesel oil, so maybe it will be beneficial to the engines lifespan, rather than complete overkill.

Mainly, it's an oil that I trust.

During the oil change, I found that there was absolutely no sludge in the oil filter bypass canister. I read that many cars that do have a sludge issue have lots built up in the oil filter canister. I may pull down the oil pan and pull the valve covers off when I do my next change, just to see what I can find.

Thanks again guys. The engine may not notice a difference, but I feel good knowing what oil the old flathead is running. I have no clue as to what he put in it. Thanks for the peace of mind.

[55 Fargo]

I've revived 2 trucks in the past few years, each had sat for 30 years or so. I put old formula Rotella in both, ran them for a time, and both quit smoking after a short while and run fine. The '48 B1B I drive frequently does not smoke, but does have oil burning smell and consumes some oil. However, it had about 30 lbs per cylinder compression before starting the first time. I was actually surprised it would start, and more surprised it runs rather well. I do not know what the compression is now. I will probably put rings and bearings in it in the near future, but I believe no other oil would have done any better.

I have a drum of old formula Rotella (about $7 a gallon) I'll use until I run out. I'm thinking of getting another drum to delay the problem.

My personal opinion is that you can't make it worse by getting the crud out of the rings and freeing them up.

Shell Rotella T Heavy Duty engine oil has 1250 ppm of ZDDP in its formula.

As mentioned, the oil threads have been discussed at length, the consensus, is most modern engine oils ae far superior to 1940 50s engine oil, and will be adequate for most flat head 6s.

I am personally using Shell Rotella T 15W40, and am happy with it........

[oldodge41]

"Mainly, it's an oil that I trust." That is the best choice you could have made. If you aren't comfortable with your selection, all the data in the world won't make you sleep better............Tim