So Fix it

Tightening bolts to the proper torque is extremely important. Bolts that are not tightened enough can fail to provide the necessary support and stability, and bolts that are tightened too much can actually snap unexpectedly, particularly when you apply additional pressure. There are several factors to consider when calculating bolt torque specs, including the grade, size and purpose of the bolt, and the fastener that is catching it. If a bolt should be tightened to 2,000 inch-pounds of torque, but the fastener can only withstand 1,000 inch-pounds, there is a good chance the fastener will bend or break as the bolt is tightened.

Types of Stainless Steel

The two main types of steel used in stainless steel bolts are 18-8 stainless steel and 316 stainless steel. Stainless steel given an 18-8 designation consists of approximately 18 percent chromium and 8 percent nickel. The remainder of the steel comprises several other elements and compounds, including manganese, phosphorus, sulfur, silicon and chromium. Carbon is held to a maximum of 0.08 percent in both basic types of stainless steel. The term 18-8 applies to several similar grades of steel, including types 302, 303, 304, 305 and 384. These types of stainless steel represent the "basic alloy," and there is little difference between them in terms of strength or resistance to corrosion. Type 316 stainless steel is similar to 18-8 stainless steel except that it is more resistant to corrosion because there are higher levels of molybdenum in it. Type 316 stainless steel is often used in marine situations because it is particularly more resistant to corrosion caused by salt water.

Size, Thread Count and Other Factors

In addition to the grade of stainless steel the bolt is composed of, several other factors, such as the length of the bolt, the bolts thread count, the job that the bolt is being used for, the fastener the bolt is being applied to, any plating the bolt has been coated in and whether or not the bolt is clean, dry or lubricated can affect the the amount of torque that should be applied to a bolt. For instance, a 5/16 bolt with 24 threads per inch requires more torque than a 1/4 inch bolt with 28 threads per inch. The Rask Cycle website recommends lubricating motorcycle bolts with motor oil to reduce the torque by 15 percent to 25; to reduce torque by 50 percent, use a Teflon dry film or a Cetyl alcohol dry wax.

Bolt Torque Specs

Taking the above factors into consideration, the following specs provide a good ball-park range for the perred fastening torque of several bolts. The torque is given in inch-pounds and is intended for standard bolts (without plating) that are dry at the time of tightening.

You should tighten bolts that are 1/4 of an inch long and made of 18-8 stainless should to 75.2 inch-pounds if they have 20 threads per inch and to 94 inch-pounds if they have 28 threads per inch. Tighten bolts of the same size and thread count that are made of 316 stainless steel to 78.8 inch-pounds and 99.0 inch-pounds, respectively.

Tighten bolts that are 3/4 of an inch long and made of 18-8 stainless steel to 1,530 inch-pounds if they have 10 threads per inch and to 1,490 inch-pounds if they have 16 threads per inch. With bolts of the same size and thread count that are made of 316 stainless steel, tighten to 1,582 inch-pounds and 1,588 inch-pounds, respectively.

Tighten one inch long bolts that are made of 18-8 stainless steel to 3,440 inch-pounds if they have 8 threads per inch and to 3,110 inch-pounds if they have 14 threads per inch. Bolts of the same size and thread count that are made of 316 stainless steel should be tightened to 3,595 inch-pounds and 3,250 inch-pounds, respectively.

The Nissan Motor Company began importing the Datsun pickup truck to the United States in 1959. Automobile consumers in the United States were accustomed to large vehicles containing V8 engines, so the Datsun 1000, a compact truck with a 37-horse power four-cylinder engine, was a foreign concept to most American automobile consumers. Nissan soon dropped the Datsun name and continued to manufacture the truck under the Nissan name. Nissans sales continue to grow with continued innovations and standard features that include automatic transmissions and fuel injection. Installing a torque converter requires moderate automotive repair knowledge. The transmission should already be removed from the truck being serviced.

Instructions

1

Disconnect the negative battery cable from the trucks battery.

2

Raise the front of the truck off of the ground using a jack. Place one jack-stand behind each front wheel assembly, under the "A" arm. Lower the truck onto the jack-stands. Make sure the front of the truck is safely supported. Remove the jack.

3

Raise the rear of the tuck off of the ground using a jack. Place one jack-stand behind each rear wheel assembly, under the rear axle. Lower the truck onto the jack-stands. Make sure the rear of the vehicle is safely supported. Remove the jack.

4

Align the spines on the output shaft of the transmission to the grooves inside the torque converter

5

Push the torque converter onto the output shaft of the transmission by hand until the torque converter is fully seated.

6

Lift the transmission up using a transmission jack and align the flywheel studs on the torque converter to the holes in the flywheel. The flywheel is mounted on the rear of the engine, under the truck. Make sure the transmission is securely strapped or chained to the transmission jack before raising the transmission.

7

Push the transmission and jack assembly forward by hand until the torque converter studs come through the holes in the flywheel. Make sure the torque converter is sitting flush against the flywheel assembly and the bell housing is sitting flush against the rear of the engine.

8

Insert all six bell housing bolts through the bell housing into the rear of the engine block. Thread the bolts by hand to make sure there is no cross-threading. Tighten the bolts using a torque wrench and socket to the manufacturers recommended torque level. Make sure the bell housing is sitting flush on the rear of the engine block before tightening the bolts. Do not use the bell housing bolts to pull the two units together.

9

Locate the torque converter access cover on the bottom of the bell housing. Remove the two access cover bolts using a socket wrench and socket and pull the access cover off by hand. Set the access cover aside.

10

Locate the transmission gear selector switch on the drivers side of the transmission. Place the transmission in neutral. Check that the transmission is in neutral by rotating the flywheel and torque converter assembly by placing a pry bar through the access cover hole and turning the engine flywheel counterclockwise.

11

Thread all six of the torque converter nuts onto the torque converter studs by hand. Rotate the engine flywheel assembly counterclockwise using a pry bar to access each torque converter stud.

12

Tighten the torque converter nuts in a star pattern to the manufactures recommended torque level using a torque wrench and socket. Replace the bell housing access cover and tighten the two retaining bolts.

13

Replace the transmission cross-member and secure the cross-member to the truck frame using two bolts. Tighten the bolts using a torque wrench and socket to the manufacturers recommended torque level. Attach the transmission to the cross-member using two nuts. Tighten the nuts using a torque wrench and socket to the manufacturers recommended torque level.

14

Raise the starter mobile assembly up to the passenger side of the bell housing by hand. Insert the "gear end" of the starter motor assembly into the bell housing. Make sure the visible starter motor gears are facing the flywheel assembly and attach the starter motor assembly to the bell housing using two bolts. Tighten the two bolts using a torque wrench and socket to the manufacturers recommended torque level.

15

Attach the two transmission cooler lines to the passenger side of the transmission using a flare nut wrench.

16

Insert the drive shaft into the rear of the transmission. Lift the U-joint end of the drive shaft up to the rear axle of the vehicle and thread the four drive shaft retaining bolts through the U-joint into the rear end by hand. Tighten the four bolts to the manufactures recommended torque level using a torque wrench and a socket.

17

Attach the transmission shift linkage to the transmission gear selector switch on the driver side of the transmission and secure with a nut. Tighten the nut using a socket wrench and socket until the shift linkage is fully secure.

18

Locate the fluid filler tube hole on the front, driver side of the transmission. Insert the fluid filler tube into the transmission through the engine compartment. Secure the fluid filler tube onto the transmission using a bolt and tightening the bolt clockwise using a socket wrench and socket.

19

Raise the rear of the vehicle using a jack. Remove the two jack-stands. Lower the rear of the vehicle to the ground. Remove the jack.

20

Raise the front of the vehicle using a jack. Remove the two jack-stands. Lower the front of the vehicle to the ground. Remove the jack.

21

Connect the negative battery cable to the vehicles battery. Start the truck and let the engine idle until it reaches normal operating temperature. Shut off the trucks engine. Check the transmission fluid. Add fluid as needed until the transmission dip-stick reads full.

Stainless steel bolts are popular fasteners because of their strength and resistance to corrosion. While in many households bolts are tightened until they feel tight enough, industries and car mechanics require specific torque values for bolts to ensure that they are tightened enough. Depending on the bolt size, construction, fabric, and lubrication, torque specifications vary from bolt to bolt and situation to situation, and should be followed precisely.

Sizes and Threads

Bolts are identified by their sizes and threads. Screws can be as small as the number one screw, which is 1/16 of an inch or as large as the number 24, which is 3/8 of an inch for the most common screw sizes. Their threads are listed by distance between the threads and number per screw, and are listed like this: 1/4 x 20, meaning that the screw has a diameter of 1/4 of an inch and has 20 threads per inch.

Types

Stainless steel bolts come in numerous types, the most common of which are called 18-8 and 316. The 18-8 stainless steel bolt is composed of about 18 percent chromium and 8 percent nickel. These bolts are extremely corrosion resistant. The 316 stainless steel bolt, designed for industrial environments, has a higher nickel content and is austenitic (tempered for strength at low temperatures) and non-magnetic. These stainless steel bolts hold up under extreme stress and are used in heavy industry and as a part of surgical implants for humans and animals.

Torque Specifications

The 2-56 bolts are two inches in diameter with 56 threads per inch, torque to 2.5 inch-pounds for 18-8 stainless steel and to 2.6 inch-pounds for 316 stainless steel. Bolts that are 4 inches in diameter and have 40 threads per inch require 5.2 inch-pounds of torque if they are 18-8 stainless steel and 5.5 inch-pounds of torque if they are 316 stainless steel. For 18-8 stainless steel bolts with a size of 6-32, torque to 9.6 inch-pounds; for 316 stainless steel bolts of the same size, torque to 10.0 inch-pounds. The 1-14 bolts made of 18-8 stainless steel torque to 3110 inch-pounds, and those made of 316 stainless steel torque to 3250 inch-pounds.

Variations

These and other torque specifications for bolts are a starting point, but variation exists depending on the type and amount of lubrication used. If youd like to calculate your own torque, you can apply the following formula: Torque = 1.33 times the coefficient of friction times the diameter times the necessary preload, or T = K x U x D x P. Use 0.2 as the coefficient of friction for dry, or un-lubed fasteners and 0.09 for lubed ones. These are not precise values, but are acceptable averages.

To determine preload, take the established ultimate strength of your fastener (this information will be available at your hardware store), and multiply it by 2/3 to determine yield strength. Multiply the bolts thread area by the full yield strength and 2/3 to determine its preload. Once youve filled in these values, you can determine your bolts required torque.

The small-block Chevy is a compact eight-cylinder engine of cast-iron construction. Although Chevrolet used a V8 engine briefly in the 1920s, most of their cars from the late 1920s through the early 1950s were powered exclusively by inline six-cylinder engines. When virtually every other American car maker had an eight-cylinder engine to offer, the Chevy still had its six. All that changed in 1955 when the small-block V8 was introduced. This engine was designed with larger versions in mind, and several different displacements were manufactured until the 1990s, when the small-block was replaced with more modern engines. All parts of the small-block are fastened together and tightened to a specific torque, as this keeps everything together securely.

Internal Parts

The bearing cap retaining bolts on small-blocks with two-bolt 7/16-inch main bearing caps should be tightened to 70 foot-pounds. The outer bearing bolts on four-bolt 7/16-inch bearing caps should be tightened to 65 foot-pounds, while the inner bolts should be tightened to 70 foot-pounds. All four retaining bolts on four-bolt 3/8-inch bearing caps should be tightened to 40 foot-pounds. Connecting rod bolts with a measurement of 3/8 inch should be tightened to 45 foot-pounds, while 11/32-inch connecting rods should be tightened to 35 foot-pounds. Cylinder head bolts are tightened to 65 foot-pounds, while the screw-in rocker studs need to be torqued to 50 foot-pounds. The oil pump retaining bolts should be tightened to 65 foot-pounds.

External Parts

The threads on the exhaust manifold bolts should be coated with an anti-seize lubricant and tightened to 25 foot-pounds. The intake manifold gets tightened to 25 foot-pounds. The transmission bell housing bolts should be tightened to the block at 25 foot-pounds each. The center bolt on the harmonic balancer needs to be tightened to 60 foot-pounds. Spark plugs get torqued down to 20 foot-pounds. The flex plate on automatic transmission-equipped vehicles and the flywheel on manual transmission-equipped vehicles both get tightened to 60 foot-pounds.

Sheet Metal Parts

The small-block Chevys oil pan retaining bolts need to be tightened to 12 foot-pounds. The bolts attaching the timing cover to the front of the engine block get tightened to six foot-pounds, while the valve cover bolts require a torque of only three foot-pounds.

The exhaust manifold is a large metal block bolted to the side of the engine, and it connects the exhaust pipe to the main engine block. To locate the exhaust manifold, trace your exhaust pipe to where the round pipe bolts to a two-bolt connection near the engine. The solid structure to which the pipe is bolted is the exhaust manifold. Installing a manifold requires careful torquing of the bolts.

Amount of Torque

Every vehicle has different levels of torque necessary to properly tighten its bolts. The standard is to use 20 to 30 foot-pounds of torque. Older engines often fall on the lighter side of the equation, so use 15 to 20 foot-pounds of torque if your engine is 15 years old or older. Some manifolds house different sensors and plugs, such as a check valve or exhaust plug. The different elements require less torque than the bolts on the manifold. Use between 10 and 17 foot-pounds of torque for those elements. The precise torque for your vehicle can be identified in the vehicle-specific repair manual, available from an auto parts retailer.

Torque Sequence

Clean off any used gasket material, and install a new gasket when you take the manifold off the vehicle. Torquing the bolts properly requires following a set pattern. The pattern helps the new gasket sit correctly against the engine blocking leaks. Hand-tighten all bolts initially. Torque the bolts in sequence to half the amount of torque necessary. Start with the middle bolts, and work your way toward the edges one bolt at a time. Repeat the process using the full torque necessary.

Additional Information

In most vehicles, the manifold is covered by a heat shroud, which is a simple piece of formed aluminum. The metal acts as a heat damper to prevent excessive heat from bouncing around in the engine. You must remove the heat shroud before working on the manifold. When installing the shroud, use 10 to 12 foot-pounds of torque. You also should inspect the length of the exhaust pipe for damage. When servicing the exhaust, you should disconnect each bolted connection, clean the surface of the connection and install new gaskets at each joint. You can unbolt each connection and separate the joint by several inches without removing the unit from the vehicle.

The Ford Taurus is a mid-sized family sedan first introduced in the early 1980s. The Taurus uses a conventional front suspension, with ball joints connecting the knuckle to the wheel hub. The ball joints carry the weight of the front of the vehicle and must meet specific torque specifications when replaced.

Testing and Inspection

Raise the vehicle until its wheels fall to full down position and are off the ground. Have an assistant grasp the lower edge of a tire and move the wheel assembly in and out. As the wheel is being moved in and out, observe the upper end of the wheel spindle and the rear suspension arm and bushing. Any movement will indicate abnormal joint wear.

Torque Specifications

The torque specification for the front lower and upper ball joint nut is 68 to 92 Nm, or 50 to 67 ft. lbs.

Part Replacement

The OEM part number for a ball joint for a 1999 Taurus is 5F1Z3050A. This part is supplied by Ford and available at dealerships.

A torque wrench provides a mechanic exact tightness capability when using the tool as a socket wrench. This feature is particularly important when working on engines and similar assemblies that must have factory-setting tightness on various nuts and bolts holding parts together. Too much and the threads in the engine casings could strip. Too little and the parts can come loose or cause leaks, deteriorating engine performance. Using a torque wrench ensures the assembly work is done right the first time. However, torque wrenches come in different types, some being better than others when it comes to exact measurements.

The Beam Type

Beam-type torque wrenches represent the bargain-bin version of the tool. Their cost is relatively low but the exact measurements are usually off or hard to keep correct.

The beam wrench uses a long lever that bends as the wrench is tightened. This bending triggers a mechanism in the tool that compares to another lever that stays the same regardless of the tool being used. As the first beam moves away from the second, the user can, in theory, measure the torque being applied.

The quality of the beam tool is questionable. Even if it works correctly, getting an exact tightness is hard since you have to eyeball the tightness on the lever display and guestimate when you are at the correct pressure.

The Dial Version

The dial version uses a mechanism similar to that in a beam wrench. However, with the dial version the pressure exerted is translated to a dial at the top of the wrench near the handle which displays the pressure relative to a dial chart. The tighter the wrench is pulled, the more the dial moves to reflect the torque measurement. This version also relies on a human eye to determine when to stop.

Electronic dial wrenches use the same approach but display the torque setting digitally. At least in these versions the human eye is taken out of the equation. The simple computer in the wrench displays the torque readings produced when using the wrench.

The Clicker Type

Long reputed as the correct torque wrench to use for engine applications, the click-type wrench has a mechanism that actually pops in the wrench when the correct tightness is applied. This click signals to the user to stop tightening.

Preset measurements are cast on the side of the handle to adjust the wrench for a desired tightness. Then the wrench is applied and the mechanism clicks when the preset torque is reached.

These tools are typically cast in all metal, similar to a normal socket wrench, and come in protective cases to avoid impact or banging which can disrupt the tools accuracy settings.