Another Oil question

A

ahshoe

Senior Member
Bought a used low mileage Y block. Previous owner says he has been running Shell Rotella 15-40 oil. He said it is used for diesel engines and is good because it has zinc already in it. I want to change oil and filter in the motor now and was wondering do I continue using what he did or use what I have been using which is not Shell Rotella oil formulated for diesels in a Y block?...Any pros or cons with the Shell Rotella 15-40?
 
Rotella 15-40 used to be an easy way to get the needed zinc & phosphorus (ZDDP) but motor oil rated for diesel engines is being reformulated so often these days it isn't a sure thing any more.
Zinc & phosphorus were removed from automotive motor oils with the advent of catalytic converters in emission systems.
It's my understanding that in the last few years more modern emission equipment is being added to large & small diesel powered vehicles, and presumably the oil spec'd for use in those engines.

Finding a motor oil with suitable levels of Zinc and Phosphorus (hopefully) listed in their ingredients or an oil marketed to 'Classic' cars is more important than the name on the container.
Some 'racing' motor oils may have the needed/better ingredients but I suspect they are made to be changed out on a more frequent time & mileage schedule than other motor oils.
In a classic vehicle that isn't driven 10k+ miles per year that may not be a concern.

.
 
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In the past I have used Shell Rotella 15W-40 or Valvoline Premium Blue 15W-40 diesel oil. A couple years ago I got hold of a chart that showed the comparison of ingredients in several diesel oil brands and found that the Valvoline had the more desirable levels of zinc.
The oil in all of them is good, but it is the zinc you want because Y-blocks have solid lifters. Another consideration is that you don't get detergent action in diesel oil that you do with motor oil grades for gasoline engines.
I had been in the habit of running diesel 15W-40 for two oil changes, then use 10W-30 motor oil for gasoline engines for the third oil change and then switch back to diesel and start all over again. I would only change to gasoline engine motor oil for use in winter months and change back to diesel before summer hit, but back then I was running the 292 everyday, 60 miles/day on the highway.
Main thing is to keep an eye on the oil jug labels for the zinc content before you buy oil.
 
Shell Rotella 15-40 oil
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15W -40 is an awfully heavy oil to run in a small displacement gasoline engine.

At one time, ROTELLA was the only answer but things have changed over the years.
 
ahshoe said:
Bought a used low mileage Y block. Previous owner says he has been running Shell Rotella 15-40 oil. He said it is used for diesel engines and is good because it has zinc already in it. I want to change oil and filter in the motor now and was wondering do I continue using what he did or use what I have been using which is not Shell Rotella oil formulated for diesels in a Y block?...Any pros or cons with the Shell Rotella 15-40?
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Older solid lifter engines like flatheads and Y-blocks using stock/near stock valve spring rates really don't need oil with high zddp content. My 32 year old Ranger 2.9 V6 with stock solids runs just fine on regular Valvoline 10W30, along with a several single/V-twin-powered lawn mowers and snow blowers. If springs rates are high, then Valvoline VR-1 is a much better alternative to diesel, imo. I have been running 10W30 VR-1 for well over 30 years, mainly in built FEs, a 460, and the high strung flathead in my '32 (probably overkill) But the near stock flatty in my '51 is fine with standard 10W30 Valvoline.
Oil viscosity should be kept to a minimum for good cold circulation and minimum pump and related wear and tear. Stepping to a higher grade oil is usually only needed because of low or poor oil pressure. A 15W40 diesel oil is not the best for gas engines, but many use, or have used and swear by it. Your choice. :)
 
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Just for s--ts and giggles I looked up mobile 1 for zinc. The add says mobile 1 racing oil has double the zinc and phosphorus to reduce engine wear and long life. I guess I'll switch to 0-30 next oil change.
 
39deluxecp said:
Kultuz, what does engine displacement have to do with oil viscosity
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V8 Bob said:
Oil viscosity should be kept to a minimum for good cold circulation and minimum pump and related wear and tear. Stepping to a higher grade oil is usually only needed because of low or poor oil pressure. A 15W40 diesel oil is not the best for gas engines, but many use, or have used and swear by it.
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What he said.

DIESEL OIL is manufactured for heavy diesel (855 CI). Research shear strength and additive packages needed for diesel.

Again, ROTELLA was once the go to as modern oils were then re-formulated for new emission laws. That has passed. You can now buy any type oil you want.

15W-40 is too heavy for a passenger car gasoline engine daily usage. As mentioned, VR-1 is a good oil for older engines/street HP. There is an oil offered above VR-1 for a true competition engine.

MOBIL 1 is a quality product. Again, you need to search their SPEC SHEETS to pick the correct one for your particular application.

Unless one has frequent oil analysis done and an occasional engine tear-down, there is no way to claim one oil is better than another. And extended oil drains in an early engine is a no-no because of the fuel system(s).

I am no expert. I barely made third grade. But there are so many products out there (and rightly so) that proper choice is difficult.

Now why we are here, can we open discussion on brake valving and hydraulic lifter adjustment ...
 
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A noted Y Block engine builder uses Valvoline 10-30 or 10-40 conventional oil in all his builds. Good enough for me. Says sufficient ZDDP as long as the oil is changed at least once a year - more if mileage requires it.


I run 20-50 in my small block Ford (warmed over 302) for many years with no apparent problems
 
While I think break in oil is critical on Y blocks, after that I'm not all that sure. One of my best friends, an old school retired professional mechanic always said that if you change oil regularly what you use is not nearly as important as keeping it full and changing it regularly. Personaly use Valvoline Racing oil in mine. I have a solid lifter 302 in my 65 Mustang that I'v used Rotella and currently run some old stock Valvolene 10/40 thats in paper cans. Swap meet stuff.
 
I run standard 10w30 oil and add ZDDP each oil change for my 64 ford and 39 flathead truck. ZDDP runs about 8-10 dollars and need to add with every oil change. I wouldn't trust today,s Diesel oil to have zinc. Obviously there are expensive high quality oils out there with zinc but the additive works with standard non-synthetic oils.
 
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