Changing oil for the first time..,
Thread Starter
Obsessed
Joined: Apr 2019
Posts: 627
Likes: 394
From: Valencia, Spain
2025 C3 ('68-'73) of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
2019 C3 of Year Finalist (stock)
Changing oil for the first time..,
I’m going to change the oil for the first time. I have put around 2000 miles on my 71 since I’ve owned it. I’m down about a quart and I don’t know what oil is in it now, synthetic or mineral so I figure I’ll just go ahead and change the oil and filter. Looking at the stickies here on the forum is kind of confusing and some of the info very dated... I have a rebuilt, completely stock, 350/270hp. From what I gather I should use a high zinc synthetic oil so which do you guys use/suggest? One friend suggests Shell Rimula R4 X 15 W40... I know this has been super hashed out but would still like to hear some options...
Last edited by Daveinspain; Jan 22, 2020 at 05:55 AM.
Burning Brakes
Joined: Jan 2003
Posts: 961
Likes: 275
From: Frederick MD
A good 10w30 or 10w40 will suffice. If you plan to drive in some pretty warm weather I would put 10w40 in it.
Regular Dino oil or synthetic will be fine. Synthetic will flow alittle better at cooler temps plus have a little longer service life but I doubt you will mileage either oil type out.
Personally I would pickup something formulated for older cars with additional zinc already formulated into it. AMSOIL has a 10w40 formula just for this application. It’s alittle spendy at around $50 a gallon but it’s decent stuff. Champion Racing Oil also makes a similar oil as well. I’m certain there are dozens of other good choices too.
Don’t over think it. Minus the zinc additive just about all oil formulations are superior to what that old 350/454 were designed for back in the day. Find something designed for a flat tappet cam and you should be good regardless of brand.
Regular Dino oil or synthetic will be fine. Synthetic will flow alittle better at cooler temps plus have a little longer service life but I doubt you will mileage either oil type out.
Personally I would pickup something formulated for older cars with additional zinc already formulated into it. AMSOIL has a 10w40 formula just for this application. It’s alittle spendy at around $50 a gallon but it’s decent stuff. Champion Racing Oil also makes a similar oil as well. I’m certain there are dozens of other good choices too.
Don’t over think it. Minus the zinc additive just about all oil formulations are superior to what that old 350/454 were designed for back in the day. Find something designed for a flat tappet cam and you should be good regardless of brand.
Drifting
Joined: Apr 2008
Posts: 1,540
Likes: 51
From: Lexington Park Maryland
Mobil1 15w-50 has enough ZDDP for flat Tappet cam motors.... I've been using it in my '66 L79 since I rebuilt it in '90. 
https://mobiloil.com/~/media/amer/us...pecs-guide.pdf
https://mobiloil.com/~/media/amer/us...pecs-guide.pdf
Le Mans Master
Joined: Mar 2004
Posts: 7,500
Likes: 1,508
From: Little Rock AR
You need high zinc in a weight that is the same as stock, or close to it. Your bearing clearances were engineered to provide proper lubrication with the original weight. If you get away from that viscosity, you will change the oil pressure. I am not sure how to justify a change in viscosity without any change in the clearances.
I generally prefer conventional oil in original weights for older engines because the synthetics seem to leak past the "old tech" seals more. Your results may vary. If you go to a lighter weight synthetic and get new leaks at least you know why. My late model supercharged LS motor gets the synthetic it was designed for.
You will get a lot of opinions here.
I generally prefer conventional oil in original weights for older engines because the synthetics seem to leak past the "old tech" seals more. Your results may vary. If you go to a lighter weight synthetic and get new leaks at least you know why. My late model supercharged LS motor gets the synthetic it was designed for.
You will get a lot of opinions here.
Racer
Joined: Nov 2003
Posts: 430
Likes: 60
From: Central KY
SImple answer- Flat tappet engines need extra protection due to increased friction. Modern synthetics do not provide this protection. The general conscious is that for normal operation, diesel 15W40 CJ-4 provides all the necessary wear protection and the long term durability you need. Racing oils also provide the necessary wear ingredients, but lack long term durability (the are designed for short term high stress use).
Shell Rotella or Chevron Delo 400 oils are readily available and cheap.
Shell Rotella or Chevron Delo 400 oils are readily available and cheap.
Thread Starter
Obsessed
Joined: Apr 2019
Posts: 627
Likes: 394
From: Valencia, Spain
2025 C3 ('68-'73) of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
2019 C3 of Year Finalist (stock)
A friend of mine who owns a shop told me to use a semi synthetic 10w40... What do you guys think?
Instructor
Joined: Aug 2012
Posts: 109
Likes: 21
From: Dripping Springs Texas
I've been using the Classic Hot Rod oil (synthetic or dino) in 10w-30 grade since my '73 motor's rebuild. It's high zinc content and you can get it from Jeg's. Kind of pricey at $10/quart, but with the low miles I put on the 'vette it's an annual oil change at most. IMHO, I'd stick with the recommended viscosity (10w-30) for your car and synthetic oil is much superior to conventional oil per a lubrication engineer I work with - but your choice.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Last edited by jackson; Jan 22, 2020 at 06:10 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Pro
Joined: May 2017
Posts: 583
Likes: 196
From: Wisconsin
SImple answer- Flat tappet engines need extra protection due to increased friction. Modern synthetics do not provide this protection. The general conscious is that for normal operation, diesel 15W40 CJ-4 provides all the necessary wear protection and the long term durability you need. Racing oils also provide the necessary wear ingredients, but lack long term durability (the are designed for short term high stress use).
Shell Rotella or Chevron Delo 400 oils are readily available and cheap.
Shell Rotella or Chevron Delo 400 oils are readily available and cheap.
The above is what I would use. Both for diesel motors and have the zinc in them.Synthetic is overkill for the cost and low miles you are driving and not racing. These should be available in Spain. In Spain Shell is sold under the brand name Shell Helix for diesel motors. Here is a link for info:
https://www.shell.es/en-ruta/lubrica...ix-diesel.html
I would recommend the Shell HX5 diesel. This one is non synthetic.
I could not find anything for Chevron in Spain.
Last edited by JETS C3-C4; Jan 23, 2020 at 02:34 AM.
Thread Starter
Obsessed
Joined: Apr 2019
Posts: 627
Likes: 394
From: Valencia, Spain
2025 C3 ('68-'73) of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
2019 C3 of Year Finalist (stock)
The above is what I would use. Both for diesel motors and have the zinc in them.Synthetic is overkill for the cost and low miles you are driving and not racing. These should be available in Spain. In Spain Shell is sold under the brand name Shell Helix for diesel motors. Here is a link for info:
https://www.shell.es/en-ruta/lubrica...ix-diesel.html
I would recommend the Shell HX5 diesel. This one is non synthetic.
I could not find anything for Chevron in Spain.
Burning Brakes
Joined: Nov 2012
Posts: 788
Likes: 100
From: Indianapolis IN
Diesel oils are higher in zinc than conventional gas engine/passenger car oils - BUT they contain much higher concentrations of detergents that diffuse a lot of the effectiveness of that zinc/phosphorus. Please everyone do more research ! The high detergent diesel oil will clean the engine internally very well, but they have also changed to formulations of diesel oil within the last few yrs and reduced favorable flat tappet additives. May not matter in a 350/270hp engine because of the low perf cam ramps and low spring pressure ! Everyone else BEWARE !!
Diesel oil used to be ok.
Just use a quality hot rod/classic car oil, or use any PCMO and HyPer Lube Zinc Replacement Additive with it.
But be cautious with ANY other type additive - such as add-on zinc/ZDDP.
The below additive (Hyper Lube Zinc Replacement), is a synthetic Polymer Ester and is used in synthetic high-end oils ($$$).
Don't believe it ? Do the research !!
$.02
Diesel oil used to be ok.
Just use a quality hot rod/classic car oil, or use any PCMO and HyPer Lube Zinc Replacement Additive with it.
But be cautious with ANY other type additive - such as add-on zinc/ZDDP.
The below additive (Hyper Lube Zinc Replacement), is a synthetic Polymer Ester and is used in synthetic high-end oils ($$$).
Don't believe it ? Do the research !!
$.02
Last edited by 68post; Jan 23, 2020 at 11:09 AM. Reason: Caps
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Seeing how you are in Spain its not likely you have big choices of brands. So, with all these suggestions of brand loyalty, it really doesn't matter who says what if its not on the shelves of stores in Spain.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Dunno about what's widely available outside North America.
But inside USA, API service category CJ4 has been superseded by API standard CK4.
Thus, CJ4 and previous standards have become more difficult to find on shelf.
Also, Rotella T3 has been supplanted by T4.
Sure there's probably some CJ/T3 here and there; YMMV.
I used to run Rotella Mineral T3 15W-40 in everything (including sbc circletrack race motors) until advent of Rotella FullSyn T6 and its reasonable pricing. The Rotella Mineral T4 15W-40 remains a Great oil!
There are hundreds of good oils both Mineral/Synthetic both cheap/pricey. IMO, what matters MOST is good vehicle maintenance and reasonable O&F change intervals.
FWIW, today ... in addition to Zinc & Phosphorus, refiners employ other extreme pressure additives in their wear packages. Also, if you're truly concerned about good oil choices, strongly suggest educate yourself in addition to mine and others' opinions and monkey-see monkey-do: make your own informed decisions. As a starting point, below are some links to helpful sites. Happy hunting!
https://www.api.org/products-and-ser...l-c-categories
http://pqiadata.org/Shell_Rotella_T4_15W40_4192017.html
https://www.bobistheoilguy.com/forum...40#Post5315970https://www.bobistheoilguy.com/forum...19#Post5253266
https://www.bobistheoilguy.com/forum...la_T6_May_2017
But inside USA, API service category CJ4 has been superseded by API standard CK4.
Thus, CJ4 and previous standards have become more difficult to find on shelf.
Also, Rotella T3 has been supplanted by T4.
Sure there's probably some CJ/T3 here and there; YMMV.
I used to run Rotella Mineral T3 15W-40 in everything (including sbc circletrack race motors) until advent of Rotella FullSyn T6 and its reasonable pricing. The Rotella Mineral T4 15W-40 remains a Great oil!
There are hundreds of good oils both Mineral/Synthetic both cheap/pricey. IMO, what matters MOST is good vehicle maintenance and reasonable O&F change intervals.
FWIW, today ... in addition to Zinc & Phosphorus, refiners employ other extreme pressure additives in their wear packages. Also, if you're truly concerned about good oil choices, strongly suggest educate yourself in addition to mine and others' opinions and monkey-see monkey-do: make your own informed decisions. As a starting point, below are some links to helpful sites. Happy hunting!
https://www.api.org/products-and-ser...l-c-categories
http://pqiadata.org/Shell_Rotella_T4_15W40_4192017.html
https://www.bobistheoilguy.com/forum...40#Post5315970https://www.bobistheoilguy.com/forum...19#Post5253266
https://www.bobistheoilguy.com/forum...la_T6_May_2017
Pro
Joined: May 2017
Posts: 583
Likes: 196
From: Wisconsin
I’m going to change the oil for the first time. I have put around 2000 miles on my 71 since I’ve owned it. I’m down about a quart and I don’t know what oil is in it now, synthetic or mineral so I figure I’ll just go ahead and change the oil and filter. Looking at the stickies here on the forum is kind of confusing and some of the info very dated... I have a rebuilt, completely stock, 350/270hp. From what I gather I should use a high zinc synthetic oil so which do you guys use/suggest? One friend suggests Shell Rimula R4 X 15 W40... I know this has been super hashed out but would still like to hear some options...
https://image.indotrading.com/co1153...15w-40-tds.pdf
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Found a spec sheet for the Rimula R4 X 15W40 oil. I think you would be fine using this oil.
https://image.indotrading.com/co1153...15w-40-tds.pdf
https://image.indotrading.com/co1153...15w-40-tds.pdf
https://www.bobistheoilguy.com/forum...pics/4825529/2
Does the same CI-4 formulation remain readily available in Spain ? If so, it (CI-4) looks plenty good to me.
Pro
Joined: May 2017
Posts: 583
Likes: 196
From: Wisconsin
Here's a VOA Zn & P for CI-4 Rimula R4X 15W-40
https://www.bobistheoilguy.com/forum...pics/4825529/2
Does the same CI-4 formulation remain readily available in Spain ? If so, it (CI-4) looks plenty good to me.
https://www.bobistheoilguy.com/forum...pics/4825529/2
Does the same CI-4 formulation remain readily available in Spain ? If so, it (CI-4) looks plenty good to me.
Good info and also reading thru it said that the ZDPP zinc content is 1120 PPM which is perfect for flat tappet motors
Daveinspain, you are good to use the Rimula R4X. Double verified.
Last edited by JETS C3-C4; Jan 30, 2020 at 12:20 PM.