Head Bolt Torque Specs Briggs and Stratton 20HP. Model #331777

(25 Nm).

With the engine cold, tighten the cylinder head bolts, in sequence in 2–3 steps. Final torque on bolts 1–10 should be 65–72 ft. lbs. (88–98 Nm) and on bolts 11 and 12, 11–16 ft.

Yes, only hand tight for head studs. Just your fingers or an Allen wrench (when there`s a hex broached into the end of the stud). You also want to make sure the studs are completely bottomed out in the hole and not hung up on some debris or a burr.

Briggs and Stratton 1X140MA Bolt, Hex – 7/16-20 x 1-1/2.

DETERMINING TORQUE

The general equation for bolt load based on applied torque is T = KF_iD_b where K = torque coefficient. K is a function of the coefficients of friction and collar friction in the joint, and these are based on variables such as surface finish, coatings, and so on.

We recommend you use torque values specified below: For bolts with a 6mm Thread Diameter: 20Nm. For bolts with a 8mm Thread Diameter: 22Nm. For bolts with a 10mm Thread Diameter: 25Nm.

Engines in mainstream cars and trucks typically generate 100 to 400 lb. -ft of torque. That torque is created by the pistons within an engine as they reciprocate up and down on the engine`s crankshaft, causing it to rotate (or twist), continuously.

Because the minor diameter (root) of the threads is significantly less than the full-size diameter of the unthreaded shank on a headed bolt, the rod with nut often breaks at a much lower strength than a headed bolt.

We suggest you tighten the nut, bolt, or machine screw by hand until it makes contact with the washer or the surface of the workpiece. Then, using an adjustable wrench or a socket wrench, make a consistent number of turns to ensure that all the bolts have the same torque.

Briggs & Stratton Metric engines require metric fasteners and drivers for the assembly and disassembly of engine components. Unless specified, the crankshaft features and crankcase cover mounting flange remain as SAE threads.

To determine bolt diameter, measure the distance from the outer thread on one side to the outer thread on the other side. This is called major diameter. Alternatively, you can measure the bolt shank diameter. The shank is known as the body or sometimes, the shoulder.

The widely recognized engineering formula, T= K x D x P (to be explained later in this article), was used to provide the chart`s values, but it must be understood that every bolted joint is unique and the optimum tightening torque should be determined for each application by careful experimentation.

The larger the bolt, the more torque is needed to achieve the necessary clamping force.

Torque is a twisting force measuring force multiplied by distance. It is the application of force acting at a radial distance to create tension in threaded fasteners. When the nut and bolt are tightened, the thread converts the applied torque into tension, which is converted into a clamping force.

Metric Bolt Head Markings

Common metric classes are 5.8, 8.8, 10.9, and 12.9. The higher the numbers are, the stronger the material of the fastener is. The number that appears before the decimal, when multiplied by 100, will provide the approximate minimum tensile strength of the bolt.

What is considered good torque in a car changes with technology. But realistically, any normal car or SUV with 500Nm or more is going to be considered pretty torquey. But it`s also increasingly common to see cars with more than 600Nm torque, at which point, the thing is pretty potent.

Well, if you just want to go fast and hit 140 mph, then horsepower would be more effective for you. However, if you want a strong car that can pull boulders and take off quickly, a high torque might be more important to you. In short, torque makes your vehicle quick. Horsepower makes it fast.

A grade 8 bolt is the highest grade SAE bolt. Grade 8 bolts have a minimum tensile strength of 150,000 PSI. As a comparison, the ASTM A325 bolt is roughly equivalent to the SAE grade 5. A grade 8 bolt would be one that meets ASTM A490 standards.

Yes, bolts provide greater holding strength than screws. This is partly due to the presence of the washer, which spreads out the load over a larger surface area. Because bolts offer increased strength, they work well for heavy-duty, load-bearing applications.

Typically, an under torqued bolt will deform and be unable to provide as much clamping force as needed. An over torqued bolt will break.

A bolt will stretch slightly as it is tightened. If you tighten the bolt too much, it will stretch beyond its elastic limit. If you measure a bolt`s overall length before you overtighten it, then again when you release the preload, the bolt will be slightly longer. This is similar to overstretching a coil spring.

The rule is that the grade of the nut should always be the same as the bolt grade or one grade higher so: a grade 8.8 bolt should be fitted with a grade 8 or grade 9 nut.

Torque is the work power generated by the engine that keeps the blade spinning on your mower, drives the pump on your pressure washer, and turns the alternator on your portable generator. More torque means improved performance.