Common practice is to replace the exhaust manifold bolts on ’94 – ’96 cars with Grade 8 hardware. They are hardened and will carry the highest tensile load, which seems to help them withstand the heat cycles the bolts are exposed to.
How strong is a Grade 8 bolt?
150 ksi
Grade 8 bolts are designated as a 150 ksi. This means its tensile strength or the resistance it has before it is subject to breaking under tension is equal to 150,000 lbs. per square inch. In comparison, a Grade 5 bolt is weaker as its tensile is 120 ksi, placing it at 120,000 lbs.
Are Grade 8 and Class 8 bolts the same?
Because there are so many different grades and fasteners all look about the same, medium carbon and alloy steel strength grades are marked for identification….Table 1.
| Grade/Class | Strength |
|---|---|
| Grade 2H Nuts | Strength is similar to Grade 5. Use with ASTM A325 structural bolts. |
| Grade 5 | Medium strength. |
| Grade 8 | High strength. |
What is the hardness of a Grade 8 bolt?
SAE Bolts / Sockets
| Grade | Material | Hardness |
|---|---|---|
| Grade 2 | Carbon Steel | B80-B100 |
| Grade 5 | Carbon Steel | C25-C34 |
| Grade 8 | Alloy Steel | C33-C39 |
| Sockets | Alloy Steel | C38-C45 |
Can I use regular bolts for exhaust manifolds?
Can you use regular bolts on exhaust? Exhausts are not high stress areas so the bolts can be 8.8 or even softer. We used to use brass nuts on exhaust manifolds so the nut could be easily cut off in the unlikely event it seized. Grade 4.6, 4.8 or 5.8 should be all be fine.
What are the different grades of bolts?
There are several grades of bolts but the three common grades for SAE are 2, 5 and 8. The common class (grades) for metric are 5.8, 8.8, 10.9 and 12.9. Each grade has a specific bolt strength. No matter the system used to grade the bolts, the higher number means the stronger the bolt.
What is the hardest bolt you can buy?
Commercial-grade 8 bolts are the strongest option available. They’re made from medium carbon alloy steel and have markings that include six raised dashes. The psi of the bolt is 150,000, meaning that it can withstand great deals of pressure because of the way it was quenched and tempered.
Is Grade 8 or 10.9 stronger?
Class 10.9 is stronger than class 8.8. It is commonly found in high strength automotive applications. Class 10.9 is similar to grade 8. A low carbon steel for general use.
What is the metric equivalent to Grade 8?
Metric Bolt Conversion
| Metric Nut Class | SAE J429 Normally Used | ASTM Grades |
|---|---|---|
| 5.8 | 5 | . |
| 8.8 | 8 | A325,A449 |
| 9.8 | 9 | A193,B7 and B16 |
| 10.9 | 10 or 12 | A490,A354, Grade 8D |
Can you replace exhaust studs with bolts?
Super Moderator. I agree, the bolts in place of studs and nuts would be okay. Be sure to observe the torque specs for the bolts, i.e. to be the same as the nuts on the studs. You dont want an exhaust manifold to be too tight – it interferes with the manifold expanding at a different rate than the head.
How is the tensile strength of Grade 8 bolts determined?
Determining the Load a Grade 8 Bolt Can Carry Tensile strengths and yield strengths are expressed in pounds per square inch in U.S. measurements. To determine the maximum load a bolt can carry, multiply the cross-sectional area of the bolt at the greatest thread depth by the tensile strength of its material.
Are there grade 8 bolts for exhaust manifold?
Quite a few people have broken grade 8’s as well. They’re better, yes, but not the best. Problem is the accelerated oxidation the steel undergoes as a result of heat cycling. Best is to go stainless. 316 class stainless best pairs to the load characteristics of the exhaust man bolts, but are difficult to find.
Which is Lug lug has the best tensile strength?
Proof Load Tensile Strength for Grade 2, 5, & 8 Lug-AllPermatexCabinetsScoop DrawersPolyboxes Associated Products Bolt GaugesCarriageCommon Head MarkingsCounter BoreElevatorFlangedHead PlowHeavy Hex HeadHeavy Hex Head SpecsHex Head CapHex TapL-AnchorProof Load TensileScraper BladeSquare HeadStepT-SlotTightening Torque About SSL Certificates
How many radial lines are on a Grade 8 bolt?
For example, a grade 8 bolt is marked with six radial lines around the face of the bolt head, and a grade 5 bolt has three radial lines, but a grade 2 bolt has no markings.
