Question: Motor Oil

[berry1133@bellsouth.net]

What type of motor oil do you guys use, synthetic or not? I was talking with a corvette mechanic and he made me aware that since the engine block is not aluminum, synthetic oil is not necessary. In fact he stated mechanically, it could be a disadvantage.
Your thoughts?

BBerry

 

[Vettehead Mikey]

I think I'd find a new mechanic. Oil type has nothing to do with whether the block is cast from aluminum or not. Oil is probably the most hotly debated subject on any car forum, there's usually little bits of facts mixed in with tons of BS.

 

[berry1133@bellsouth.net]

The mechanic's position was in relation to how the engine blocks heat up and cool down. He stated that the aluminum engine holds significantly more heat than the older engine blocks and that the older blocks cool down a lot faster.

 

[froggy47]

Ask him why almost all the cars in the world have aluminum radiators if it's so good at holding heat compared to cast irom.

I'm sure he'll have some answer.

I would love for you to post his answer here.

Seriously, I don't believe any "corvette mechanic" ever said that, this is a joke, right?

Bye.

 

[Hib Halverson]

That mechanic is quite misinformed.

Aluminum block engines heat up and cool down quicker than the older, iron block engines.

Block material is a not a major consideration in whether or not an engine requires synthetic oil. Duty cycle and oil temperature history are the key factors.

 

[Vettehead Mikey]

Aluminum block engines heat up and cool down quicker than the older, iron block engines.

Exactly- and even if it were true (the engine held heat longer after shutdown) why would synthetic oil be required? Engines can run continuously for hours/days/months without the oil overheating, what's so special about cooldown times?

 

[bill81vette]

I use Castrol GTX 10w-40 in my vette

 

[SVO]

Just for the sake of discussion, I think the oil filter you use is more important than if you use a synthetic or or not.

 

[Hib Halverson]

Just for the sake of discussion, I think the oil filter you use is more important than if you use a synthetic or or not.

In that statement, are you including engines for which use of synthetic oil is recommended by the engine maker?

 

[Peer81]

I'm not that much into the engine oils but I think you would like to first find out if you have a original/aftermarket/roller camshaft. After that lookup Hib's article on engine oil in relation to camshafts in the tech section. That is what I did and my choise isn't anywhere near synthetic.

Greetings Peter

 

[SVO]

Hib- No, I'm not. If you have a late model Corvette in which GM recommends using synthetic, then that's what one should use. I believe thqt the '89 model Corvette was the first year that GM recommended using a synthetic. Sine this is a 68-82 forum, best of my knowledge, GM never recommended anything other than a conventional oil. I base my statement on I see people dithering about whether they should use a synthetic or continue to use a conventional oil and never give a thought to the oil filter that they use. An oil filter is an oil filter right?

Maybe not. According to this guy, there is a difference, and if you accept his testing method, you may be surprised at how your favorite brand of oil filter stacks up.

GM Truck Central Oil Filter Comparison Study

I think that a majority of 68-82 Corvettes owners will never see a difference between a conventional oil and synthetic oil. For those with modified engines, yes, synthetic oil could be beneficial. But extra money spent on a good oil filter will pay dividends over the life of an engine, no matter which type of oil one chooses to use.

 

[berry1133@bellsouth.net]

As it goes, motor oil continues to be one of the most debated issues. Seems as if it boils down to personal preference, how much you're willing to pay, and how often you're willing to change your oil.

Thanks for everyone's input.

BBerry

 

[Hib Halverson]

Hib- No, I'm not. If you have a late model Corvette in which GM recommends using synthetic, then that's what one should use. I believe thqt the '89 model Corvette was the first year that GM recommended using a synthetic.

92 LT1 was the first.

Sine this is a 68-82 forum, best of my knowledge, GM never recommended anything other than a conventional oil.

Good point. When I posted to this thread, I did not, first, look at to which forum it was in. My bad.

I base my statement on I see people dithering about whether they should use a synthetic or continue to use a conventional oil and never give a thought to the oil filter that they use. An oil filter is an oil filter right?

Maybe not. According to this guy, there is a difference, and if you accept his testing method, you may be surprised at how your favorite brand of oil filter stacks up.

GM Truck Central Oil Filter Comparison Study

I think that a majority of 68-82 Corvettes owners will never see a difference between a conventional oil and synthetic oil. For those with modified engines, yes, synthetic oil could be beneficial. But extra money spent on a good oil filter will pay dividends over the life of an engine, no matter which type of oil one chooses to use.

If we are talking about stock or near stock 68-82s which are not driven in a aggressive high-performance or racing duty cycle, I agree wholeheartedly.

On the other hand if the engine is significantly modified and/or is driven hard on the race track, a synthetic may offer a durability advantage.

 

[RC81]

I run Royal Purple 5w-30 synthetic.

 

[Tim81]

I run a conventional 10w30 with a zinc additive.....

 

[bill81vette]

I started putting a zinc additive in mine as well.

 

[berry1133@bellsouth.net]

What value does the zinc provide?

 

[Hib Halverson]

The most common EP additive in automotive engine oils is zinc dialkyldithiophosphate (ZDDP), a family of coordination compounds of zinc and dithiophosphoric acid which, in longer-chain, molecular derivatives, easily dissolve in engine oils. Known more commonly as "zinc dithiophosphate" (ZDP), "zinc phosphate" or, quite incorrectly, just "zinc".

ZDDP's main purpose is as a high-pressure lubricant for the interface between the lobes on a flat-tappet camshaft and the face of the valve lifter.

Folks need to be careful with "zinc additives". The companies that bottle that stuff want you to believe you need lots of it. Most people don't even know what the stuff is.

If you insist on using a ZDDP additive, it needs to be used sparingly and mixed properly. Too high a concentration of ZDDP in the oil can cause as much damage as not enough.

A far better way to deal with the the ZDDP issue is to use the right engine oil.

For more information on engine oil and ZDDP, see the CAC's Technical "Deep Dive" article on the subject.
Corvette Action Center | Tech | Engine Oil Deep Dive - CAC's Comprehensive Look at Engine Oil and Flat-Tappet Camshaft Durability

As for what oil do I use?

Red Line Synthetic Engine Oil...usually 10W30, but in my Big-Block I use 10W40. Red Line Engine Oils have a nominal 1200 ppm phosphate content, more than enough for flat tappet cams...even ones with racing profiles and racing valve springs.

 

[Tommy Almond]

Amsoil for me now

Had a cam lobe to go so changed engine with GM crate stock 350 and my mechanic said to use only Amsoil so now 10w-30 Z-Rod for my new engine.

 

[black_81_vette]

Ive been using Brad Penn 10w30 and K&N filters