If you’re driving a high performance vehicle — or really any vehicle, for that matter — the importance of oil temperature cannot be overstated.
Reaching and maintaining an optimal oil temperature is key for the long life and performance of an engine’s internal components, and while it’s certainly key for your daily driver, it’s absolutely vital for high performance vehicles with built engines, where RPM’s tend to be higher and the parts and pieces that comprise the rotating assembly are finished with tight tolerances. Now, of course we all know (or at least we all should know) that beating on an engine with cold oil in it is a bad idea any way you look at it, but what about the other end of the spectrum, where the oil has gone above and beyond the optimal operating range?
The need of effective oil cooling often comes into play with high horsepower, street-driven cars, where we not only want to achieve an optimum oil temperature, but keep it there under the rigors of the road.
Oil Oxidation And The Need For Oil Coolers
High horsepower, built engines are more and more commonplace in street cars these days, and our Project Biting The Bullitt 1965 Ford Mustang is a perfect example of such a vehicle. These types of cars are built and designed with the race track and ultimate performance in mind, all while still maintaining driveability on the street. And as you can imagine, driving in the perpetually warm climate of southern California or in the summer months elsewhere, in stop-and-go mode in town or on the freeway, the mercury on your oil temperature can rise fairly quickly — quicker than it has a chance to cool. And as Driven Racing Oil’s Lake Speed Jr. explained to us, this too, can have its damaging effects over the course of time.
“The most important rule of thumb is that, for every 10 degrees Celsius (or 18 degrees Fahrenheit) that you increase your oil temperature, you cut the oil’s useful life in half,” explains Speed. “And that’s basically in terms of the oil’s ability to withstand temperature and not break down.”
In the book of lubrication jargon, this is a simple way to describe what’s known as oxidation.
The most important rule of thumb is that, for every 18 degrees Fahrenheit that you increase your oil temperature, you cut the oil’s useful life in half. - Lake Speed Jr.
Speed continues, “This is just a fact of life when it comes to engine oil, and the solution sounds easy — you just keep the oil cold. But when your oil is below 212 degrees Fahrenheit — the boiling point of water — you’re building up moisture in your crankcase. In the combustion process, every time there’s a cycle, water vapor is produced. You then have blow-by, which all engines are victims of to some degree, thus you’re going to have some level of moisture built up inside the crankcase.”
As Speed explains, this vapor can be evacuated out of the crankcase fairly easily, but the issue is that when the engine only runs for a short amount of time and then cools down, the trapped vapor can condense, leaving moisture sitting in the crankcase. This isn’t a good thing to have, particularly if you’re using an iron block, which doesn’t play well with water and rusts easily.
To alleviate the creation of excessive moisture, the optimal operating range of engine oil is no less than 212 degrees, which is the point at which the water in the oil will evaporate. Vehicles with an oil temperature thermostat (which we’re going to discuss here shortly) are typically set right at or slightly above this mark. Conversely, you don’t want to run the oil above roughly 240 degrees, as Speed tells us, because you begin to significantly reduce the life and operating ability of the oil, as oil containing moisture doesn’t flow or lubricate properly. In a high performance engine with high dollar parts with tight clearances running at above-cruising-speed RPM’s, this is vitally important.
This is the complete setup that we’re installing on our Project Biting The Bullitt Mustang, including Canton’s thermostat, oil cooler, and sandwich plate, along with all of the plumbing hardware from Fragola.
This is where the aforementioned thermostat and the use of oil coolers come into play, and we’ve outfitted our Mustang with a setup from Canton that’s sole purpose is to keep the oil within this window of operating temperatures through a bevy of different driving environments.
“Oil coolers are a crucial component when you’re racing and hammering away on the engine,” says Canton’s Jeff Behuniak. “Most cars on the street don’t see the red line too often compared to a race car or really high performance street car.”
The thermostat is the ‘brains’ behind this entire operation. Utilizing an internal wax element, the thermostat reads the temperature of the incoming oil, and either diverts it to the cooler (if the oil is above 215 degrees it opens partially, and fully at 230) or sends it directly back to the oil filter and the engine to heat it up.
Behuniak continues, “For a powerful street car, traffic is the worst thing for oil temperatures, because you’re not getting the airflow that you need to cool the motor. The oil cooler gives the oil a place to go to keep it in check in situations like this.”
Canton’s Oil Cooling System
This particular oil cooling setup (like most on the market) is composed of three basic parts: the “sandwich plate” that allows for the use of a thermostat or oil pressure sensor and the oil cooler unit. Obviously, there are lines and fittings to this system, but those are the three main ingredients.
Canton’s oil cooler thermostat is a durable piece machined from a 3-1/4-inch square 6061 T-6 aluminum extrusion, and measures six inches in height. It comes with a black and clear anodized finish, with a stainless mounting clamp. The four oil inlet/outlet ports fit a 1-1/16-inch, -12 O-ring fitting. This thermostat can be mounted in any orientation you desire to cater the plumbing to your needs.
The Canton Thermostat
This diagram shows the general operation of the thermostat. The unit is designed to be user-friendly, as the bolts on the ends an be removed the sections “clocked” for easier plumbing under the hood.
The oil cooler itself is a 20,500 BTU unit measuring 8 x 11-inches and one-inch thick, and comes with all of the mounting hardware, 10 feet of stainless steel braided hose, and all of the required fittings. Canton offers six versions of the same cooling kit, with varying gasket sizes being the only difference.
“Oil coolers are a relatively basic product, and the technological advances are few and far between. What we really focus on is quality, to deliver a product that does the job as well as it can and doesn’t break down for the customer.” Oil coolers are typically mounted in the front of the car, forward of the radiator, and this puts them in the crosshairs of dirt and debris on the track or parts from other cars, and according to Behuniak, “This is where the higher quality product comes into play, because it will last longer under those conditions.”
Also included in the kit is the billet aluminum sandwich plate. This plate mounts between the block and oil filter, directing the oil out to the thermostat and the oil cooler, then accepts the returning oil on its inlet side.
The thermostat operates using a standard, thermostatic wax element rated at 215-degrees that partially opens an internal valve to the cooler at 215 degrees and fully at 230 (about 1/4-inch of travel), with a reaction speed from partial to fully open ranging from 2.5 to seven minutes, depending on the type of oil and the temperature it’s at. Below 215 degrees, the valve remains closed, bypassing the oil from the cooler and directly back to the engine so that it can cycle through and heat up to the optimum range.
By using a thermostat paired with the cooler, you can get the oil heated up above the oxydation point quicker and, once there, keep it at the sweet spot of 212 to 240 degrees.
Two questions generally come to mind when discussing the addition of an oil cooler.
(Left) The sandwich plate, as it's known, is situated between the engine block and the oil filter, and allows for the oil to be directed to the thermostat and to the cooler, before returning via the opposing inlet and circulating through the filter. (Right) The cooler itself is a 20,500 BTU unit measuring 8.5 by 11-inches and an inch thick, making it relatively easy to find a place for.
The first is whether extra oil capacity is necessary to fill the oiling system that now comprises an external “loop” that wasn’t there before. This is somewhat dependent on how much of the -10 hose you’re using (how far the thermostat and cooler are located from the engine), but both Behuniak and Speed agree that it’s not likely to be more than one-fourth to half a quart. As always, this is determined by checking the oil dipstick after letting the engine run and cycle for a short time.
Oil coolers are a relatively basic product, and the technological advances are few and far between. What we really focus on is quality. - Jeff Behuniak
The other question is in regards to oil pressure drops, which Behuniak explained will result in a slight increase in drag on the oil pressure, in the neighborhood of 2-3 psi. Cold versus warm oil will naturally change the oil pressure, as well, so you can expect some differences as the oil heats up.
In the grand scheme of things, plumbing Canton’s oil cooler setup is relatively simple and straightforward. The sandwich plate is outfitted with the supplied O-rings and AN fittings and then screws onto the engine the oil port on the engine block, with the oil filter then screwing on on top of the sandwich plate. We the mounted the thermostat on the passenger framerail, and thanks to the “clockable” design of the blocks that comprise the unit, we were able to turn it to allow for easy plumbing of the AN fittings. We then positioned the oil cooler itself in the front of the car, just in front of the radiator, where it can get fresh air going down the road. From there, with all of our distances between the three components of the system set, we could trim our hoses down to size and plumb the system.
We're utilizing Fragola Peformance Systems' Premium Black Nylon Race Hose and their Series 2000 hose ends to create a leak-free, long-lasting, and great looking plumbing loop under the hood of our Mustang.
This was accomplished with the help of the team at Fragola Performance Systems, who supplied us with their -10AN Premium Black Nylon Race Hose and a plethora of their Series 2000 hose ends, includings 90’s, 45’s, straights, and 1/2-inch NPT to -10AN’s to complete the plumbing loop.
Their Series 2000 hose ends are what the company calls compression hose ends, and feature a one-piece design, with stainless steel lock wires and J-gauge threads for increased strength and leak-free performance.
It’s a tight fit, but here, the oil filter is screwed onto the sandwich plate, once the plate has been installed onto the block. We then route the Fragola lines from the plate to the thermostat.
“The compression style hose end is called a single nipple style and draws the hose over a long tapered single nipple. The sealing feature is the crush of the hose between the inside of the socket and the outside of the nipple,” explains Fragola’s Brian Downard. “This sealing method along with the black nylon hose will provide more than enough pressure protection for most automotive applications. In size 4 to size 10 it can withstand up to 500 psi and size 12 to 16 350 psi.”
The Race hose, meanwhile, has a synthetic rubber core and is full resistant to oils, fuels, coolants, and most forms of alcohol. As well, it has a reinforce single braid of corrosion-resistant type 302 stainless steel braiding, which makes it incredibly strong albeit very flexible. As Downard shared, most imported hoses don’t feature that stainless support and the don’t have the same bursting or bending abilities.
“The hose is an economical alternative to the light weight and expensive hoses out there. It’s half of the weight of traditional stainless hose and priced comparable,” says Downard.
Last but certainly not least is the cooler itself, which we've mounted in front of the radiator to gain access to cool, clean air. After the oil circulates through the cooler, it's returned to the engine through the thermostat and to the sandwich plate.
The end result of our project is a street-driven warrior packing plenty of ponies that can handle a warm day in traffic or even some hot laps at the track, with the oil temperature fine-tuned just where it needs to be for optimum performance and operation. What Canton has delivered is a simple, easy-to-understand product that get site job done, and with the help of Driven Oil and Fragola Performance Systems, it’s sure to have us running in top-top shape for years to come.