oil weight for hot climate

Author Topic: oil weight for hot climate  (Read 1124 times)

Offline ff6849

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oil weight for hot climate
« on: June 03, 2013 - 12:52:52 PM »
How or should you adjust your engine oil for regional climate conditions,  I live in the desert southwest where summer temps are in excess of 100' winter temp rarely get below 60'.   8)
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Offline EB3-GranCoupe

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Re: oil weight for hot climate
« Reply #1 on: June 03, 2013 - 01:14:40 PM »
Now that i am ready for my second oil change at 1000 miles, i think i am going to use Amsoil Z-Rod 10W-30:

http://www.amsoil.com/shop/by-product/motor-oil/gasoline/z-rod-10w-30-synthetic-motor-oil/?page=%2fstorefront%2fzrt.aspx

I'm in florida, and it's almost as hot here in the summer (mid-upper 90's), and with way more humidty.  I'm guessing that 10w-30 is right at the cusp of switching to the heavier 20w-50, but i don't know where the balance is with tighter tolerances in a rebuilt engine, versus the high heat of the climate and the motor.  i haven't figured it out jsut yet.

Compare the viscosities at 100deg C and 40deg C with the Z-Rod 20W-50:
http://www.amsoil.com/shop/by-product/motor-oil/gasoline/z-rod-20w-50-synthetic-motor-oil/


Viscosity Index:
http://en.wikipedia.org/wiki/Viscosity_index
« Last Edit: June 03, 2013 - 01:22:28 PM by EB3-GranCoupe »

Offline 73EStroker

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Re: oil weight for hot climate
« Reply #2 on: June 03, 2013 - 01:30:08 PM »
I use Diesel Shell rotella 15W-40 as it has the ZDDP stuff for the cam and the car is only run in the summer.
Barry (Salmon Arm)

Offline EB3-GranCoupe

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Re: oil weight for hot climate
« Reply #3 on: June 03, 2013 - 01:36:55 PM »
Found this online explaining variable viscosity:

Measuring Motor Oil Viscosity

The standard unit used to measure viscosity is the centistoke (cSt). According to the Automotive and Industrial Lubricants Glossary of Terms:

Viscosity is ordinarily expressed in terms of the time required for a st­andard quantity of the fluid at a certain temperature to flow through a standard orifice. The higher the value, the more viscous the fluid. Since viscosity varies inversely with temperature, its value is meaningless unless accompanied by the temperature at which it is determined. With petroleum oils, viscosity is now commonly reported in centistokes (cSt), measured at either 40°C or 100 °C (ASTM Method D445 - Kinematic Viscosity).

­The centistoke rating is converted into the SAE weight designation using a chart like the one shown on the Superior Lubricants Web site. http://www.superiorlubricants.com/classtable.html

Multi-weight oils (such as 10W-30) are a new invention made possible by adding polymers to oil. The polymers allow the oil to have different weights at different temperatures. The first number indicates the viscosity of the oil at a cold temperature, while the second number indicates the viscosity at operating temperature. This page from the Sci.Electronics.Repair FAQ offers the following very interesting description of how the polymers work:

At cold temperatures, the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up, the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C, the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot.

Quote
I use Diesel Shell rotella 15W-40

I noticed a lot of Diesel spec oils had the ZDDP amounts (1100-1400 ppm) needed for flat tappet cams.  15W-40 might be a good compromise.

Offline brads70

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Re: oil weight for hot climate
« Reply #4 on: June 03, 2013 - 03:33:56 PM »
I'm using 20W-50 but only use my car in the summer. (I'm in Canada)
Brad
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Offline cudabob496

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Re: oil weight for hot climate
« Reply #5 on: June 03, 2013 - 05:42:11 PM »
I have a 600+ horse 496. I use 0wt-30 full synthetic Mobil 1.  The 0wt is great because
it flows quickly at startup. Startup is where 90% of engine wear occurs.  When engine
warms up, the oil gives full 30wt protection.  I've been pounding on my engine for 12 years
now, and still running strong. If you use more than 30wt, that robs horsepower
by having your engine push a heavier weight oil.  Thats why in the engine masters competitioin
they use 0wt-20 synthetic motor oil.

Also, synthetics make your engine run cooler, due to less friction, and they help you make more power.
About 35% of all the power an engine makes just goes to overcoming internal engine friction.
Synthetics on a hot day are a big plus.
« Last Edit: June 04, 2013 - 02:17:49 PM by cudabob496 »
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

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Offline EB3-GranCoupe

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Re: oil weight for hot climate
« Reply #6 on: June 03, 2013 - 09:17:19 PM »
Quote
If you use more than 30wt, that robs horsepower
by having your engine push a heavier weight oil..

Also, synthetics make your engine run cooler, due to less friction, and they help you make more power.
About 35% of all the power an engine makes just goes to overcoming internal engine friction.
Synthetics on a hot day are a big plus.

I noticed that the Amsoil Z-Rod oils had viscosities of 157 & 163, both greater than 100.  What you said makes a lot of sense.

Offline cudabob496

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Re: oil weight for hot climate
« Reply #7 on: June 04, 2013 - 05:27:30 AM »

Also just read in the Finkbeiner book that if you had an engine that was cold, and it
was using 20w-50 conventional oil, going to wide open throttle would cause major engine
damage, because the oiling system would not be able to supply oil to all necessary
engine locations.
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline nqkjw

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Re: oil weight for hot climate
« Reply #8 on: June 04, 2013 - 06:40:17 AM »
I live in tropical North Queensland in Australia so we're always hot here.
Our winters are warmer than most of your summers.
I use a straight 30 weight.
Many around here use a 15W40
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Offline HP_Cuda

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Re: oil weight for hot climate
« Reply #9 on: June 04, 2013 - 01:41:22 PM »

Okay Bob, I have to ask as I've been reading up on this.

So what oil did you use for break-in and then when did you switch to synthetic?

I have a 600+ horse 496. I use 0wt-30 full synthetic Mobil 1.  The 0wt is great because
it flows quickly at startup. Startup is where 90% of engine wear occurs.  When engine
warms up, the oil gives full 30wt protection. If you use more than 30wt, that robs horsepower
by having your engine push a heavier weight oil.  Thats why in the engine masters competitioin
they use 0wt-20 motor oil.

Also, synthetics make your engine run cooler, due to less friction, and they help you make more power.
About 35% of all the power an engine makes just goes to overcoming internal engine friction.
Synthetics on a hot day are a big plus.
1970 Cuda Clone 440 4 speed - sublime green
1970 Cuda 383 4 speed - yellow - SOLD

Offline 73EStroker

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Re: oil weight for hot climate
« Reply #10 on: June 04, 2013 - 01:43:37 PM »
..... and to continue what I said earlier - even though I live in BC Canada the interior gets to 40ºC or 100F+ so the 15W-40 diesel is not such a big deal for cold starts. I do have a block heater that gets plugged in for the first start in spring (which may be summer as I am waiting for my Passon 5 speed - soon I hope))
Barry (Salmon Arm)

Offline cudabob496

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Re: oil weight for hot climate
« Reply #11 on: June 04, 2013 - 02:09:11 PM »
Okay Bob, I have to ask as I've been reading up on this.

So what oil did you use for break-in and then when did you switch to synthetic?

Conventional 10-30wt for the first 1500 miles, to set the rings, then switched to full synthetic.
Just got a new lawn mower. Gonna use the conventional oil Briggs and Stratton sent with it, for
one year, then switch to synthetic. Did this on my other mower, and its still going well
after 18 years.

The new Corvettes have been using synthetic oil for years, right from day one.

If you are using conventional oil, and the thought of using 0wt-30 is a little scary, try
a full synthetic 5wt 30 or 10wt-30. Your engine will love it! Its pretty cheap at Walmart
for Mobil 1. And your engine will last longer.

I remember an Accord I had, that when I put 10-40wt conventional in it, at startup, the
valves would rattle for about 3 seconds then become quiet. When I swithced to 5 -30wt
synthetic, the rattling was gone almost immediately. The conventional oil just did not get there
quick enough.
« Last Edit: June 04, 2013 - 06:29:47 PM by cudabob496 »
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000