Let's talk oil

[Hatchet54]

What type of oil is everyone running? And where does everyone stand on the synthetic/conventional thing? I've heard opinions from both sides of the camp that seem equally as grounded.

At my altitude and temperature I've been using 5W30 ('77 350) with no issues. Just your basic NAPA/Wal-Mart conventional. Anyone have any preferred brands for these old trucks? I met somebody that swore by Royal Purple for his Blazer...but he also only changed it every 5 years.

Also, what are everyone's opinions on additives? Lucas, STP, etc. I've used that "Keep that engine alive" stuff in the white bottle whenever I remember to buy some. But I don't know enough to say if it's effective or not. A waste?

If this discussion already exists, my apologies. Tried using the search function but found zilch.

 

[73c20jim]

Mobil 1, no additives.

 

[4WDKC]

if your engine has a flat tappet cam you need to make sure it has the proper amount of zinc to keep from wiping the lobes.

 

[73c20jim]

Mobil 1 15-50 has zinc.

 

[Ronno6]

I own a different breed of truck which I purchased new on 1997. I have run Valvoline Full Synthetic since the 1000mile change. Never a hiccup in 270K miles........

For my '84 C10 355 engine, I may use full synthetic as well (roller cam) but it has been
recommended that I run 20w-50 but selection of synthetic in that weight is somewhat limited locally.

 

[yevgenievich]

For flat tappet old motor diesel oil conventional, for ls motor 0w40 mobile 1 synthetic. Decided to try mobile one on a one flat tappet engine as well, but added zink additive

 

[DoubleDingo]

Old flat tappet engines up to OBD I: Valvoline Conventional 10w30 or 10w40 with STP Oil Treatment added. No oil burning issues or lobes flattening in any of these engines. Occasionally I'll run some MMO for a few hundred miles before an oil change to clean out the passages.

Turbocharged Forester: Rotella T6 5w40 or Mobil1 0w40 depending on time of year.
I've read a lot of Subaru's have oil burning issues. The PO was pretty smart about oils and suspension and such. He didn't baby the car and used high quality oils and it has proved to work. Just logged >4,000 miles over 11 days and it didn't burn any while running 3k to 4k rpms almost the entire time to maintain 70 to 85 mph or get ran over.

 

[Honky Kong jr]

T4 Rotella

 

[Craig 85]

I just installed a new GM 454. I used Lucas Break-in oil and will make all other oil changes with this. I only put 1-2K miles on my truck a year, so this will only be once a year. 5 Qts is about $37.

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[richard A lindner]

Shell rotella has zinc i run it in everything incuding dirt bikes

 

[77 K20]

I like using Mobile 1 synthetic oil. It flows better when it is very cold vs conventional. And unlike other manufacturers where they don't post the specs of their oil or really know what you are buying at least they post their specs every year.

https://mobiloil.com/~/media/amer/us/pvl/files/pdfs/mobil-1-oil-product-specs-guide.pdf


When I had my flat tappet engine I used their high mileage oil because of the higher zinc content. Looks like it has dropped a bit- as I swear it used to be over 1000 ppm.

 

[73c20jim]

Mobil 1 15w-50 is designed for flat tappet cams.

 

[bedwards]

I used Rotella T4 and or Super Tech 15w40 Diesel oil up to the last oil change. No oil or burning and had a very minor drip in garage every now and then. Switched this last change to Rotella synthetic blend T5 10w30. Truck used some oil and the minor drip turned into an oil leak. I had always heard synthetics or synthetic blends could make an older engine use oil. While the oil use has slowed down the leak is still there.
When it comes time to change oil again I am going back to conventional diesel oil.

 

[Snoots]

T4 Rotella

 

[73c20jim]

See Mobil1 racing oils. Zinc up the wahoo!

https://mobiloil.com/~/media/amer/us/pvl/files/pdfs/mobil-1-racing-product-guide.pdf