Which oil would be better living in NC, 20w 50 or 10w 40? I am currently using 20w 50. It is a 72 454 400 trans. I also have an 82 camaro with a built up 450 hp 355 that i also use 20w50.

 

Your oil pressure when up to operating temp determines the correct weight of oil.

Really tight clearanced motors require lower viscosity.

 

On my opinion, 5/30 for power and 10/60 for safety. Both full sint, i prefer and use Motul, Valvoline or Castrol RS.

 

The thinnest oil that will still hold acceptable HOT oil pressure is best. Any thicker than that will cause more wear on start-up due to reduced flow, it will use up more power, and because of less flow at all temps, it will carry away less heat from vital engine internals. Remember that our engine's internals are directly oil cooled (think of the oil itself as a coolant), but only indirectly water cooled.

 

The biggest worry is whether or not the oil is compatible with a flat tappet camshaft, if that is what you are running. The ZDDP in most oils has been removed by the manufacturers to meet new standards set to prolong the catalytic converters on newer models. Ron B.

 

Agree with the others. Since your's is an older based engine, I'd stick with the 20W 50 in hot weather. Also, the new oils don't have the proper additives (like zinc), so you might want to look at some additives too.

 

I actually run 20w 50 all year around in both vechiles. I only drive the corvette in the winter (ocassionally in 40 degree weather). The camaro dosn't have a heater.

 

There's no advantage to thicker oils unless your tolerances are real loose or it's an older engine. Thicker oil will sap HP and can cause premature wear on the distributor/cam gears. I've noticed that more racing oils are now thinner viscosity.

For me, a good 10w-30 fits the bill.

FWIW

 

If you run it hard,use 20W-50

 

I think i will start using 10w 40 in the corvette (stock 454)since i just drive it easy and short distances. I will still use 20w 50 in the camaro (built 355) since i get on it quite a bit.

 

I have read that we should be using oil for diesel engines that still have the additives to lube the flat tappet cams. I use rotella 15W40 and have not had any problems, plus it works in air cooled harley's.

 

been using 10w-40 im 355 and 383 for 12 yrs now and no issues as of yet! beat on them both as often as possible,just change it regularly! 2500-3000 miles

 

As has been discussed many times on the forum and above, most of the oils on the market now have reduced ZDDP which is vital to older engines with flat tappet cams (lack of it will cause cam failure). In my opinion, any synthetic oil is superior to organics due to the uniform molecular structure and superior flow characteristics versus organics. I have been Mobil 1 synthetic since 1985 in my 78 L-82 4 speed. I had been using Mobil1 5W-30 for the reasons mentioned above but recently switched back to Mobil 1's 15W-50 Racing (recommended by Mobil for Flat tappet cam engines, by the way) since it contains 1200 PPM phosphorous versus 800 ppm for most of the other Mobil 1 weights. Mobil 1's 5W-40 Turbo Diesel oil has 1,300 ppm which may be a better alternative all around especially in cold weather. As long as you know what's in the oil concerning phosphorous/ZDDP, it really doesn't matter which oil you use. Most major oil manufacturers do not recommend that you add oil additives to their oil since it could potentially adversely effect the additives in the oil when it is produced. I think that you are better off using an oil that has the best lubricating characteristics for your engine without adding anything. My humble opinion based on my research and talking to "experts".

 

It has been my experience that synthetic oils offer no real cost effective benefits over petroleum based oils. They do come in much prettier packaging.
Synthetics do offer a slightly higher viscosity, but at a substantially increased cost.
Zinc and other additives have been reduced over the years to reduce emissions, and yet it is these additives that aid in the lubrication of key components like the cam lobes.
For a break-in oil, I use Shell Rotella Diesel engine oil.
For summer, I run 20-50.
For winter I run 10-40.
I've seen no internal wear differences on engines that have run either, synthetic or peteroleum based oils, in daily drivers. Race engines are a whole other situation.
Newer engines have tighter tolerances and benefit from the thinner oils. A hard worked engine will benefit from thicker oils.
If you change your oil every 3000 miles, with "standard" petroleum based oil, you will be fine and cost you $15.
If you run synthetic oil and change your oil every 6000 miles, it will cost you $30.
So what is the benefit?
Remember that the engine oil filter is a particulate filter, not a chemical filter. Do you want to leave corrosive chemicals in your oil for a longer time?
To each their own. Some like the pretty packaging; it makes them feel like that are getting something "better", after all it did cost more.
By-the-way, I run Wal-Mart 20w-50 in my pickup trucks; each at over 200K miles now. Same in my Kawasaki 1100. 10w-40 in my Jeep right now, and the Vette will be fed the same. Read the oil quart packaging for specific certifications of the oil.

 

I agree with the comments above about if you change your oil at least every 3,000 miles with organic oils that any engine should be fine as long as the oil has the appropriate amounts of ZDDP. However, as for no benefit to synthetic oils, I would disagree with comments about "pretty" packaging is the only benefit to synthetic oil. It is an undisputed fact from years of research and real world testing that a conventional oil versus a synthetic oil will definitely result in more wear in any engine run for many miles, not just racing engines. Racing engines accelerate the wear curve for the engine into a much shorter time cycle and will utimately mimic the wear one would experience in 100,000 miles of normal driving into 500 miles or less of racing. Tests conducted comparing 200,000 miles on engines with conventional oil versus organic oil results in very little wear for the synthetic versus a "junk" engine of the exact type of motor using organic oil. The reason for this difference is that synthetic oils have molecules that are exactly the same size resulting in even wear protection versus conventional oils that have molecules of different sizes, superior flow characteristics at low temperature for the synthetic and at start up, and much superior high temperature protection versus a conventional oil. Synthetic oils cost more for a reason and the price difference versus a good quality oil like Shell Rotella is very small at retail outlets like Wal Mart where Shell Rotella costs about $16 for 5 quarts versus Mobil 1's 15W-50 Racing or 5w-40 Turbo Diesel which costs <$22 for 5 quarts. For a $6 difference, I would recommend the these 2 Mobil 1's for Flat Tappet engines, these two Mobil 1 weights only, not the others with less ZDDP. A friend of mine who has PHD in chemistry form the University of Chicago told me that there is absolutely no comparison between synthetics and conventional oil. Some of the above information comes from him. Hope that this helps explain the diifference between the 2 types of oil. Lastly, I still change my oil every 3,000 miles with a synthetic even though you can go longer. Check out this article for more info:http://www.carcraft.com/techarticles...oil/index.html

 

Do you actually know your bearing clearances?

 

What is the difference between 00W40 and straight 40W? I saw it in the store the other day in synthetic form.

 

A staight 40 weight oil is relatively thick at colder temperatures and will thin out as the engine warms up which is not ideal since a majority of wear in engines occurs at start up when the oil does not flow well. A 0W-40 oil, on the other hand, will flow extremely well at cold temperatures but offers the protection of a straight weight 40 oil when hot, the best of both worlds which is why all cars use multi-viscosity oils as their recommedned lubrication. Please see my prior post on this thread and read the aCar Craft article on conventional oils versus synthetic where it talks about viscosity. Hope that this helps!

 

Is it recommended to run synthics in a brand new engine?

If not what is the best thing to use?

 

New as in rebuilt or brand spanking new from a manufacturer? If rebuilt, I would follow the advice of the builder for various reasons until broken in. If new like a GM crate engine, I would use a synthetic from day one. Many high performance cars today including corvettes (about 15 years now are filled with Mobil1 at the factory, Porches, BMW's etc, all are factory filled with a synthetic. If its good enough for them, it's good enough for me!