Cool and Heat

• FAITHFUL TEMPERATURES

Cooling an engine is like walking a tightrope.  If the temperature is not kept in check, the radiator will boil over.  If the temperature is too low, the engine will not produce peak horsepower, as you would expect!

Can horsepower numbers be found in cooling down the engine?  Oh yes it can!  Temperatures commonly run in street applications are too low for the production of peak horsepower.  As a rule of thumb, the coolant temperature should be in a range between 200-210°F, while the internal pressure should be in the area of 20 lbs.  If the engine is run at a lower temperature (lets assume your temperature guage hovers around 175-180°F), you are wasting approximately two to three percent in the horsepower department.

It should be noted that a 21-pound pressure cap would automatically raise the boiling point of pure water from 212°F to 260°F.  The addition of a 50-percent solution of aftermarket “coolant” (almost always ethylene glycol or more commonly, “anti-freeze”) will then raise the boiling point to approximately 275°F.  Obviously, an internal combustion engine operating at these temperature extremes is out of the question with current technology.  Just consider the added temperature capacity as a “cushion”. All these points taken into account set you up in the rule of thumb division.

• ENGINE PULLEY POWERS

Perhaps easier than swapping impellers, changing pulley sizes gives you the opportunity to “tune” the cooling system for your application.  When the crank pulley is reduced in size, the actual speed of the water pump can be decreased from 25 to 50%, which in turn frees up a significant amount of power from the engine.  Obviously, a larger diameter water pump pulley will accomplish the same goal.

If you decide to play with pulleys (and we highly recommend that you do), there are several different options open to you.  Moroso Performance offers a wide array of cast, machined aluminum pulleys for a number of different applications.  By mixing and matching components, you can tailor the water pump speed to your application.  Take your pick in regards to methods of reducing the water pump speed, they all work, but playing with pulleys isn’t the easiest and most productive way out.

What about “deep groove pulleys?”  Deep groove pulleys are just that, pulleys with deeper than normal grooves.  Their sole purpose is to keep the belts affixed at high rpm and aside from correct pulley alignment, they are the only salvation when it comes to tossed belts following a high rpm blast down the strip with your street rod.  Most of the original equipment had the foresight to install this form of pulley on their hi-performance models during the heyday of the muscle ‘super’ car and because of this, the parts are “somewhat” available. It always takes some doing to ‘find’ the precise parts when looking4spares. You must use every avenue possible when trying to locate these out of date and elusive parts. Somebody, somewhere will have exactly what you are looking for when looking4spares. Keep on trying and never give up.

• AUTO COOL

The thermostat’s purpose is to control the cooling down and heating up of any engine.  It is an essential feature and should be considered as the cooling system’s ‘on and off’ switch.  The purpose is simple-it allows the engine to warm up quickly (by blocking the flow of coolant through the radiator), thus discouraging the buildup of sludge and internal acids.  When the thermostat is removed, the coolant circulation is constant and in some cases, way too fast to provide adequate cooling. In addition, the engine’s warm up time is increased if the thermostat is removed.  What this accomplishes is simply escalated engine wear.  The by-products of combustion condense on the cylinder walls and as a result, the chances of wear are multiplied. Engines are designed to run between certain varying temperatures to reduce wear. The powerplant will suffer the most wear during the cold start up period, (especially in winter), that is why the thermostat plays such an important role and should never be removed from a streetcar.

In the event that warm-ups are not critical to your application (i.e.: a warm weather street/strip car), you might consider the use of a water outlet restrictor plate.  These components available from Moroso) replace the thermostat in the engine water neck.  They are flat “discs” fitted with either a 5/8-icnh, ¾-inch or 1 – inch diameter hole.  Designed to reduce the coolant outlet flow from the engine, these components give the coolant an opportunity to absorb internal engine heat when compared to a non-thermostat example).  As expected, they do not provide any opening or closing action such as a thermostat (and in certain applications this may prove superior), but they do offer a method of regulating coolant flow.

If overheating in anyway is being suspected, remove the thermostat from it’s housing and place it in a kettle or pot of water on a stove keeping your eye on it as the water heats up and approaches near boiling point. If it hasn’t started opening or doesn’t open then your problem has been identified. Thermostats have been known to cause all sorts of failures and frustrations. Replace them with ‘quality’ products.

• HORSE & HOSE POWER

Hoses are hoses.  You just bolt them on and have confidence in their design integrity.  Unfortunately, it isn’t that simple, especially when a high-performance vehicle enters the equation.  While braided lines make up the upper end of the spectrum, the cost seldom justifies the installation, particularly since the pressures found in cooling systems is not that great. The ‘correct” radiator hoses to use are the non-ribbed formed equipment that is commonly associated with OEM suppliers.

Many of these rad hoses are manufactured by the original vendors and as a result, the quality and fit is right on target.
When it comes to the hose clamps, the best setup we have examined is the line of “T-handled” clamps sold by Moroso.  These clamps feature a special “handle” that is complete with a 3/8-inch hex head and a simple screwdriver slot.  You can use either the T-handle, the hex or the screwdriver slot to tighten down the clamp.  T-handles are by far the better products and you can gain a better ‘feel’ when tightening the hose clamp.

Using the screwdriver type clamps is more than often cumbersome and tightening procedures are hard to ‘guage’ on how much tension is being needed or being applied to the clamp, (often ending up in an over-tightened or stripped clamp).

While seemingly insignificant, T-handled clamps can prove to be a marvelous addition if the car is drag raced (even minimally). The quick release feature of the clamps allows the radiator hoses to be removed quickly and instantly, providing immediate access to the engine for between rounds cooling.

If you have ever experienced a “missing” lower rad hose, you might consider double clamping the assembly.  An inexpensive set of stainless steel, worm gear hoses from Earl’s will solve the problem-especially if a pair of clamps are used on each end of the hose.  Credit this tip to the NASCAR crowd.  They take every precaution when it comes to reliability and hose clamps are no exception! Always keep a set of spare hoses in the trailer, just in case.

• FANBELT TENSIONS

Belts should be checked periodically for tension.  Low tension creates belt slippage, which in turn wears out the belt, creates heating problems and allows the battery to run down for obvious reasons.  On the other hand, excessive tension is hard on water bearings and in the case of certain aluminum pumps; it can destroy them in no time.

If you don’t have a belt tension guage in your possession, you can use this “old-timers method” of determining correct tension:  Select the longest unsupported span of belt.  Push on the belt with your thumb.  If it moves more that a quarter-inch its too loose.  If it doesn’t move, the belt is too tight.  You will get the feel and if it’s too loose you should hear it slipping, screaming for help as you accelerate. It’s as simple as that!

POWER TRAIN

• GEARED FOR RATIO

Selecting the correct rear axle ratio for your car is probably the most important decision you’ll have to make.  In this arena you can vary the amount of torque created on the back wheels (also depending in tyre size diameter), or make for the longer hauls giving a bit more top end speed. Let’s look at a pair of different street cars, one with the rear fenders stuffed full of Mickey Thompson Sportsman tyres and the other with wide, but short 17-inch radials For the sake of comparison, lets assume that both cars are powered by the above engine and are hooked up to an automatic transmission.  Both have 3.00:1 gears in the third member.  The following are the basic tire and gear ratio specs:

Corner Burner                           Pro Street
Axle Ratio                     3.00:1                                     3.00:1
Tire Diameter                26.00 inch                               33.50 inch
Final Drive Ratio             1.00:1                                     1.00:1

As you can see from the above figures, there is a huge difference in the speeds of cars at a given RPM level. The only mechanical difference between the pair is the height (or diameter) of the rear wheels. Obviously, the 3.00:1 gear isn’t close to being optimum for the pro street application. And if your corner burner has an overdrive, it too needs more gear. Given this set of circumstances, it would seem appropriate to stiffen up the gear in our paper Pro Streeter. An educated guess would be a gear in the range 4.10:1 ratio. Using the same engine speed 33.5 inch rear tyre height (diameter), here’s the final cruising speed calculation with the new ring-and-pinion gears:

As you can see, it’s certainly better than the earlier situation where the engine combination was barely off idle at a typical ‘highway legal’ cruise speed. Naturally, if the Pro Street vehicle had an overdrive automatic gearbox, the ring-and-pinion gear choice could be much stiffer, (a 5.38 gear coupled with the .70:1 overdrive and 33.5 inch tall tyres works out to a cruise speed of approximately 66 mph hour). Finding the best combination will be the deciding factor and this always boils down to one thing – ‘horsepower’. If you don’t have the ponies, your next best bet is to find the most compatible gear-tyre-ratio.

• CLEAN N’ POLISH

Before commencing work on the rear axle housing, try this on for size: An excellent method for cleaning the housing is to have it dipped in your local chrome shops cleaning vat. All lubricant is removed making it easier to work on. If a tank is out of the question get down and dirty. A high pressure hose, lots of Prepsol degreaser and hot water and an array of brushes should get the job done.

• DA’  COCONUT

When welding the axle housing tubes to the coconut (centre section of the diff housing), grind down the area you are going to weld on first, and then spot-weld the factory tubes to the coconut via the heliarc weld. Naturally the work can be accomplished with another form of welder, but a heliarc welder proves much cleaner (no weld splatter or ‘spitting’) and offers better penetration than other formats when properly accomplished. It’s more labour intensive but welds are superior. Weld in an open-air environment and keep your eyes protected at all time by using quality equipment. I cannot recommend the use of a dust mask more than this. Don’t skimp here; you only have one life – take care.

• SWEATING OUT

In stock form, many axle tubes are attached to the coconut with a couple of spot welds per axle tube. In most cases these spot welds are not sound and in most cases pinholes in the welds are clear. This really doesn’t compromise strength in a housing that has been totally welded to the coconut, but there is still one major problem: The factory welds often seep lubricant. Because of this, more than one axle hosing has seen major seal, gasket and drain plug work, only to find the leak or sweat was a factory fault weld pinhole). The solution is simple but difficult and time consuming to accomplish. To fix the problem once and for all, grind off all the factory welds, (using your mask and eye protection). Next, using a plug weld or ‘rosette’ process, replace the factory weld with a bead of heliarc weld. It’s a messy process, but the result is a clean, leak-free, differential housing.

• SPRING PERCHES

Factory spring perches are strong enough for mild street use, but they can crack and work loose under severe loads imposed by high-performance engines and all-out drag racing applications. In order to brace-up the spring perches: Cut out small plates of metal (gussets) that will eventually brace the perch on both sides of the spring carrier. The housing is cleaned and the plates are cut with a V-shape and edges chamfered to allow for total weld penetration. After the plates are tacked into place, weld them. With the plates installed, the spring perch is now fortified for fore and aft movement to deal with the twisting and squirming that will be experienced when hammering down on the button. With the job now done you can tackle your next project.

• THROWING OUT THE CAPS

The rear bearing caps found on axles such as on the Chevy twelve bolt main and Dana 60 are cast iron and aren’t renown for their strength as would be found with a Ford 9-inch rear. The torque forces on the engine will try to push the carrier out the back of the housing – placing additional strain on the drivers side bearing cap. The shear forces of toque twisting and jerking have their impact.

As the car accelerates, the ring gear tries to climb out of the diff case or housing. To solve this problem aftermarket machined steel bearing caps can be fitted. In order to custom fit the steel bearing cap to the housing, the bottom of the cap is milled. (Align boring of the housing is not required). In most cases, installation of the cap is completed via a set of extra-long Grade 8 Allen head cap screws.

• SEVERE DIFF DUTY

The heavy duty 12-bolt diff features a thicker-webbed, reinforced flange on the diff casing, which reduces ring gear deflection under the x-treme loads experienced in drag racing. Spider gears are machined from high grade forged tool steel (approx. 40% stronger than the standard Chevy produced packages). Four more friction discs were included (A total of 22 discs), which allows for more even-distribution of shock loads to the side gears. The added friction gears help improve the torque split ratio that occurs in differentials.

Spring plate size, as well as springs them selves, are substantially larger than in the stock Chevy diff. The mod provides for an even bias ratio between the rear wheels and the outcome is improved on strait line traction, without breaking out and loosing valuable time. Most importantly, the U.S Gear units are designed for use with huge 33-spline axles, a huge improvement over the factory produced 30-spline axles. Although custom axles are required for this U.S. Gear-posi traction assembly, it is virtually bullet proof. Finally the U.S Gear-posi traction packages are designed for use with ring and pinions ranging from 4.10:1  to  6.14:1 and more ratios’s to come as we were informed.

• ALL AROUND THEY GOES

According to the guys at Summers Bro’s, axles have to endure two kinds of loads, tortional loads which are the twisting loads and bending loads which are the loads that try to bend anything possible if not retained and maintained, so to speak. The larger the diameter of the axle, the greater the ability it has to endure and withstand these violent forces. If the diameter of the axle is doubled from 1.0 inch to 2.0 inches, the tortional strength is increased ‘eight’ times.

Naturally it’s almost impossible to double the diameter of an axle, but in many cases it’s possible to increase both the size of the axle and the number of splines machined into the axle shaft. There is only one aim and that’s to improve strength and to ‘handle’ what is dished out in the horsepower to tarmac department. A good example of this is a 12 bolt rear main equipped with U.S Gear posi-traction unit, the axle spline count increases from 30 splines to 33 spline count, increasing strength by 32% over a stock axle spline configuration. These are essential steps when bidding for more horsepower that must be adhered to, and if ignored the fun comes to an abrupt end.

• “C”- CLIP SIDESHAFT

Not only are the factory C-clips a pain in the but; they’re also illegal in most drag race classes. In a stock application the splined end of an axle is machined with a special small end diameter groove to accept a C-clip. This groove not only weakens the axle by a significant margin but it can prove troublesome to remove and replace, (no matter what anyone says). With a C-clip system in place, the axle is retained from the inside rather than the outside. If the axle breaks anywhere the wheel/tyre combo can and (will), quickly depart from the vehicle. The use of a C-clip eliminator kit makes it possible to remove the axles from the vehicle without draining the diff lubricant. Finally, the old drill of grinding the ring gear teeth to clear the spider gear shaft is simply not required with the C-clip eliminator kit.

• STUDDED AXLES

Original equipment manufacturers, 7/16-inch wheel stud simply isn’t adequate enough for any vehicle that will be powered down the drag strip or see even any mild bracket competition. All modified cars or trucks should have the wheel studs replaced with minimum half inch studs. Heavy duty studs are fashioned from grade 8 materials and are threaded all the way to the head, (more like a fully threaded bolt), and can be fully engaged into the backside of the axle flange. If your street racer or full- blown drag car or truck that has a lot of heat under the bonnet, can benefit from the use of ‘axle studs’.

In most cases, these axles have massive studs that measure a massive 11/16 inch in O.D. Drive studs are designed to fit the holes in thick centre aluminum race type wheels like Cragar Race Rims. These studs feature a colossal ¾-inch axle thread, (the part of the stud that screws into the axle). Without these modifications to the drive shaft axles, your ride will become a danger to everyone especially if used for public road use. Every turn will weaken inferior axle configurations and eventually they will break off. Take the initiative to protect yourself and others from certain calamity!

Most custom axle manufacturers offer several choices for wheel bolt circle patterns. According to the pro’s, pick the largest possible bolt circle pattern that fits the application. When the pattern size is increased the unit load per stud is reduced. The larger the bolt pattern diameter the, the lower the force imposed on the stud. It is often possible (and relatively easy) to re-drill the brake drums so that axles with a larger-than stock bolt pattern can be used. Obviously, if stock wheels are planned for your ride, this method of increasing the bolt pattern circle is limited. Keep in mind that the Chevrolet pattern of 4-3/4-inches is larger than stock FoMoCo or Mopar passenger car patterns, (and the conventional truck pattern of 5x5.0 inches is larger still). Because of this, the unit load on each stud is less.

• OVER THE SEAS IMPORTS

Locating quality bearings can be a bit of a nightmare on a local level and can take frustration levels to the maximum. Companies such as Richmond Gear, G&G Specialties and Mark William Enterprises identified the problem and introduced ‘ring-and-pinion’ kits to the market place, throughout the world. These installation kits feature ‘top quality’, ‘made in the States’ Timken Bearings throughout. High grade 8 bolts (ARP models in the M-W kit) for the ring gear, a crush sleeve, a new pinion seal, thread locking compound, gear marking compound and brush, a cover gasket and a cross section of pinion and carrier shims are included in the ring-and-pinion kits.

If you are “looking4spares”, “Part Find” will assist you by finding the new spares or used parts. Simply fill in the parts-request-form on our home page and ‘submit’ your order.  Your parts request will be circulated to all leading “parts dealers” and “scrap yards” in Southern Africa. You deal directly with the parts supplier – No Middleman -