Diesel vs. conventional motor oil

[triracer67]

Purchased 3.5 gallons of Rotella T6 (https://rotella.shell.com/en_us/products/full-synthetic-and-blend-oil/t6-full-synthetic.html) for rv, and it doesn’t meet Mercedes spec, so, will this work in my Bronco? Stock 1969 351w 4v, stock internals, not rebuilt. Everything I read says follow engine specs, I don’t know what they are? Thanks in advance.

 

[68ford]

Short answer, yes.
Lots of older gas engines running rotella and delo including myself.

 

[needsmoarturbo]

I'd run the 5W40 or 0w40 weights no hesitation.

 

[Mark1911]

Not sure about Rotella synthetic oils but in the case of regular gasoline engine synthetic oils they do not have enough zinc to protect the metal on metal rubbing flat tappet camshafts.
Diesel engine oils contain a fair amount of zinc compared to little to no zinc in synthetics. So hence synthetics are really not good for older engines.
Mark.

 

[BUCKWILD]

i have a 289 with a 146000 om it now only running t6 shell synthetic 15-40 and have not had a problem ( changed a water pump) the diesel oil has more lubricants than standard oil because of there violent nature

 

[blubuckaroo]

No problem using a Diesel rated oil in your gasoline engine. Just as long as it has the gasoline "SN" rating in it's list.

 

[Broncobowsher]

SN rating is way above what the engine needs. Nothing wrong with that. For that vintage engine, all that is needed is about an SD rating.

The S in the rating is for spark ignited engines (gasoline)
The letter after that is the rating. A is the lowest. As the years go on and the auto manufacturers make more high strung engines that need better and better oils, the letter rating goes up and up. But reverse compatible.

Zinc is missing from the modern diesel oils as well. Not to worry. Flat tappet engines only need the zinc for the break in process. Once the cam and lifter are burnished together all that is needed is a regular oil. Zinc is a contaminate to the emissions controls that even diesels have today.

 

[jamesroney]

SN rating is way above what the engine needs. Nothing wrong with that. For that vintage engine, all that is needed is about an SD rating.

The S in the rating is for spark ignited engines (gasoline)
The letter after that is the rating. A is the lowest. As the years go on and the auto manufacturers make more high strung engines that need better and better oils, the letter rating goes up and up. But reverse compatible.

Zinc is missing from the modern diesel oils as well. Not to worry. Flat tappet engines only need the zinc for the break in process. Once the cam and lifter are burnished together all that is needed is a regular oil. Zinc is a contaminate to the emissions controls that even diesels have today.

Search for my earlier posts on engine oil elsewhere on this site. Higher ratings by the API are not "better." For a flat tappet camshaft, the SN rating is VASTLY INFERIOR to the SD rating.

Today's Rotella does not meet SN, and today's Delo does meet SN.

Google ZDDP.

I won't be replying to any more oil threads. Please don't take my disappearance as a lack of respect. I'm just going to be too busy for a while...

 

[WheelHorse]

ZDDP is just one of the factors, but not the sole determining factory for determining the film strength load carrying capacity.

I use a 50/50 blend of this: 5W30 Valvoline Full Synthetic High Mileage with MaxLife Technology, API SN, GM dexos 1 approved (silver bottle) = 123,470 psi

10W30 Valvoline VR1 Conventional Racing Oil (silver bottle) = 103,505 psi
zinc = 1472 ppm
phosphorus = 1544 ppm
moly = 3 ppm
calcium = 2,707 ppm
TBN = 7.6

I found that start up is quieter and I still maintain great oil pressure. You can do your own reading: don't let anyone put anything in your head that you have not researched on your own.

540 Rat Blog

 

[ransil]

find project farm on you tube, he has done multiple tests on oil.

 

[68ford]

The "need for zinc" is almost hear say especially pushed by companies like joe gibbs to sell overpriced oil.
Yes there is less zinc in modern oils but that is because they have more than made up for it with other additive packages. My work is a Cummins, Cat, Freightliner etc service dealership. I have spoken with engineers from Chevron, Shell and Valvoline. They all said the same about zinc " we made up for it elsewhere".
My engine is a perfect example, I run whatever regular non synthetic oil that I can get cheapest. Usually Delo at work. Flat tappet isky with .150 more lift than a stock cam and heavier dual valve springs. Definitely alot more pressure between the cam and lifter when the valve is open compared to stock. Probably closer to double the pressure. I cruise at 3000 to 3600 on the freeway and shift at 7000. In the desert running around in always above 3000 to be in the power band. Engine is 19 yrs old and has 80,000 miles on it.