popshumphrey

I just bought a hobby 74 L48. Body and interior are my strong suits. So the question. What oil would you recommend. 350 4 bbl. Engine is strong. Synthetic - or not. 5 w 30 or 10w 30. I have no idea what mileage is on the car. Got it cheap so I am going to play. My other one is a 97 and can't play with it. So weight and brand folks.

l88rocket

dino oil Quaker state 10w30

johnnyw

Well what a great question, these people in the FORUM all agree on the exact same oil to use in these old corvettes. I just can't recall which one it is. Best of luck with your new venture and you did well in saying it's a hobby.
Johnny Y

63mako

http://forums.corvetteforum.com/c3-t...ppet-oils.html Check the first post in this sticky. If you want a suggestion use Amsoil Z-rod 10W-30. It has everything your engine needs and long term is an inexpensive option. Be prepared, you just opened a can of worms.

Roughrider

mds3013

Correct answer. The recommended oil that is. F the worms. mike...

popshumphrey

I knew it would be a can of worms. I have heard many people rcommend amsoil. My goal is not to do any damage to what is already a project. I read the sticky and then read that some synthetics can do more damage to old engines. Hey, I don't even know how old it is. But it runs real smooth. I am just wanting to learn and you guys saved me with my 97 on a chassis issue. So I like worms!

540 RAT

Since you like worms, you came to the right place

Amsoil products are quite good in my experience. However, you may not be happy using a synthetic in that old engine. It won't actually hurt anything. But, in old engines you may experience oil leaks that were not there with conventional dino oil. Many people have reported that happening, and I've had it happen as well.

I've also experienced hydraulic lifters bleeding off in old engines when sitting for a length of time with synthetic oil, and then clacking badly for a good number of seconds when finally being fired up again. But, after going back to conventional dino oil, the problem was gone. And this was with the same viscosity. Your results may vary, but those are a couple of things to be aware of. As for the weight to use, I'd suggest using a 5W30. Consider the following:

THE BENEFITS OF USING THINNER OIL:

• Thinner oil flows quicker at cold start-up to begin lubricating critical engine components much more quickly than thicker oil can. Most engine wear takes place during cold start-up before oil flow can reach all the components. So, quicker flowing thinner oil will help reduce start-up engine wear, which is actually reducing wear overall.

• The more free flowing thinner oil at cold start-up, is also much less likely to cause the oil filter bypass to open up, compared to thicker oil. Of course if the bypass opened up, that would allow unfiltered oil to be pumped through the engine. The colder the ambient temperature, and the more rpm used when the engine is cold, the more important this becomes.

• Thinner oil also flows more at normal operating temperatures. And oil FLOW is lubrication, but oil pressure is NOT lubrication. Oil pressure is only a measurement of resistance to flow. Running thicker oil just to up the oil pressure is the wrong thing to do, because that only reduces oil flow/lubrication. Oil pressure in and of itself, is NOT what we are after.

• The more free flowing thinner oil will also drain back to the oil pan quicker than thicker oil. So, thinner oil can help maintain a higher oil level in the oil pan during operation, which keeps the oil pump pickup from possibly sucking air during braking and cornering.

• The old rule of thumb that we should have at least 10 psi for every 1,000 rpm is perfectly fine. Running thicker oil to achieve more pressure than that, will simply reduce oil flow for no good reason. It is best to run the thinnest oil we can, that will still maintain at least the rule of thumb oil pressure. And one of the benefits of running a high volume oil pump, is that it will allow us to enjoy all the benefits of running thinner oil, while still maintaining sufficient oil pressure. A high volume oil pump/thinner oil combo is preferred over running a standard volume oil pump/thicker oil combo. Because oil “flow” is our goal for ideal oiling, NOT simply high oil pressure.

• Oil flow is what carries heat away from internal engine components. Those engine components are DIRECTLY oil cooled, but only INdirectly water cooled. And better flowing thinner oil will keep critical engine components cooler because it carries heat away faster. If you run thicker oil than needed, you will be driving up engine component temps.

• Thinner oil will typically increase HP because of less viscous drag and reduced pumping losses, compared to thicker oils. That is why very serious Race efforts will generally use watery thin oils in their engines. But, an exception to this increase in HP would be in high rpm hydraulic lifter engines, where thinner oil can allow the lifters to bleed-off at higher rpm. In everyday street vehicles, where fuel consumption is a consideration, thinner oils will also typically increase fuel economy. The majority of new cars sold in the U.S. now call for 5W20 specifically for increased fuel economy. And now Diesel trucks are increasingly calling for 5W30, also for fuel economy improvement.

• With the exception of high rpm hydraulic lifter engines, almost no engine should ever need to run oil thicker than a multi-viscosity 30 weight. The lower the first number cold viscosity rating, the better the cold flow. For example, 0W30 flows WAY better cold than 20W50. And 0W30 flows WAY better cold than straight 30wt, which is horrible for cold start-up flow and should be avoided at all cost. And the lower the second number hot viscosity rating, the better the hot flow. For example, 0W30 flows WAY better hot than 20W50.

• Thicker oil DOES NOT automatically provide better wear protection than thinner oils. Extensive “dynamic wear testing under load” of dozens and dozens of motor oils, has shown that the base oil and its additive package “as a whole”, is what determines an oil’s wear protection capability, NOT its viscosity. For example, some 5W20 oils have proven to provide OUTSTANDING wear protection, while some 15W50 oils have only been able to provide MODEST wear protection. So, do not run thicker oil under the false assumption that it can provide better wear protection for our engines.

• BOTTOM LINE: Thinner oils are better for most engine lubrication needs.

And as for what brand to use, that is where the real can of worms comes in. There is more than one way to skin a cat, so I suggest you pull up a chair, grab a sandwich, and read my write-up on motor oil. You can see it here:

To see my entire 100+ motor oil “Wear Protection Ranking List”, along with additional motor oil tech FACTS (with over 11,000 “views” worldwide), here’s a link:

http://540ratblog.wordpress.com/

540 RAT

U.S. Patent Holder

Member SAE (Society of Automotive Engineers)

'82 Corvette

I had a neighbor that treated his late '80's something Chevy truck with synthetic oil at the 100,000 mile mark. It was the worst thing he did to the engine. Oil began leaking out from the gaskets in the engine. Ruined his paved driveway. A GM mechanic told him something like "if you start with synthetic, stay with synthetic. If you start with mineral, stay with mineral". He has 113,000 miles on his Chevy now and is back using mineral oil again. The truck is still leaking oil. With your new investment I would use a mineral 10W-30 with an AC Delco filter, and change both every 2,000 miles. Hope this helped.

68post

They've greatly improved the gasket sealing in newer engines, but an eighties engine needs new gaskets @100,000, or by 10 years old.
Neighbor should just buy a gasket kit to install then use whatever oil.

Pay no heed to the mechanic, the engine needed gaskets !

popshumphrey

You guys are great even if you don't agree. I have heard the synthetic story several times. The car will not be driven too far and needs lots and lots of tlc. But hey, its another vette! I will try staying at 10w 30 here in Oklahoma. Never too cold. Probably will end up staying with dino. thanks folks. But all comments will be read. Great stuff!

jb78L-82

There are many good dino oils you can use and even better synthetic oils, if you choose-lots of comments and thoughts on both the forum and else where.

However, as others have noted above, I have to reply to the constant myths about synthetic versus conventional oils, in both older cars like the C3's-my 78 L82, more recent newer cars-my 1994 Mustang GT and 2001 Pontiac Grand Prix, and even newer cars using synthetic oil-my 2008 Chrysler 300 3.5L DOHC. Please note that everyone of the aforementioned vehicles currently uses synthetic oil (I use Mobil 1) and everyone started out using conventional oil and I switched to Mobil 1 at some point as detailed below. As noted many times from others-synthetic oil does NOT cause leaks, WEAK/BAD gaskets cause oil leaks! A little chemistry here-one of the biggest reasons synthetic oil protects critical moving parts better than conventional oil is that all the oil molecules are the SAME size which is NOT the case with conventional oil. A weak/bad gasket could potentially allow more synthetic oil to leak past the bad gasket since there are no irregular larger shaped molecules in the oil like a conventional oil. I have not experienced this phenomenon! So here is my real life experience using a synthetic in various cars all of which I still own over 28 years now.

1. 78 L-82 4 speed C3-66,000 miles-converted to Mobil 1 in 1985 with 25,000 miles on motor-yes-1985. OEM rear main seal and OEM oil pan gasket both have slight leaks. NO OTHER LEAKS!! Both were leaking in 1985 and the leaks have pretty much been stable for 25 years. NOT caused by the synthetic oil-old/weak/ poorly designed gaskets. Run Mobil 1 15W-50 today-1,200/1,300 ZDDP

2. 1994 Mustang GT Convertible-30,000 miles today. Converted to Mobil 1 in 1998 with 20,000 miles on the engine running dino oil previously-ZERO LEAKS today!5W-30 Mobil 1. Converting to Euro Formula Mobile 1 0W-40.

3. 2001 Pontiac Grand Prix-3.1L V6-150,000 miles today. Converted to Mobil 1 5W-30 at 50,000 miles-previously used Conventional oil. Oil Pan gasket slight leak BEFORE the conversion to Mobil1 synthetic. No change for the last 100,000 miles using Mobil 1. The leak is really very very slight-oil moisture on the oil pan sides. No actual leaks. Car uses ZERO oil between 5,000 miles oil changes. Consistent high speed travel-80+MPH.

4. 2008 Chrysler 300 3.5L DOHC V6-Converted from conventional oil to Mobil 1 0W-40 Euro formula at 60,000 miles. Currently the engine has 100,000 miles. ZERO LEAKS anywhere.

These are my facts from my experience using a synthetic on various cars, various ages, various engines over 28 years!

I hope that my experience gives some perspective on the speculation often touted about using/converting to synthetic oils.

63mako

Synthetic oils 30-40 years ago didn't cause leaks but the uniform molecule size and minimal additives did make them more noticeable. Modern synthetics have additives like seal swellers and seal conditioners added as do dyno oils. Statements saying "Synthetic oil caused my engine to leak oil" are not true statements. Gaskets or seals that were bad cause your engine to leak oil and should be replaced as needed.

CheezMoe

Will this never end!?!?!

Valvoline VR-1 10w30 Silver bottle...~5.99 qt at Napa! Dino! All you need!

TedH

Since the cam and lifters are long since broken in, you don't have to worry about break-in. I'd say, use garden variety 10W-30 that you can afford and add a bottle of (zinc) additive from your local autoparts store or Summit.

I stopped chasing the oil solution when I converted to roller cam. I sleep better now knowing I'm not at risk to wipe a cam lobe. Now, I just buy 10W-30 in whatever is on sale as long as it is name brand and i don't bother with the additives.

REELAV8R

If you want to straddle all the fences You can get Mobil one 0W40 synthetic European formula at walmart.
It has 1000 ppm zinc
It is synthetic
It has excellent cold starting flow due to 0w
It has good hot temp protection due to 40W

63mako

That is also a good choice for a mild, stock valvetrain and readily available.

briankeery

Amen brother.

dochorsepower

Here we go again!