Yeap, that would be me. Would not have guessed it could make that much difference.
It might be time to fire-up the AQ-1 again!
TBucket Engine Project (Dart SHP)
- Thread starter Indycars
- Start date
It might be time to fire-up the AQ-1 again!
Loves302Chevy
"One test is worth a thousand expert opinions."
Any updates Rick.
Don't tell me you did 112 pages of work to let the t-bucket collect dust.
Don't tell me you did 112 pages of work to let the t-bucket collect dust.
I sure hope it doesn't just collect dust. But I do worry about my kids inheriting the
car then having a catastrophic event because I can't be there to warm them of the
nuances of this beast. Believe me, I'm considering selling it when I can no longer
drive it. Neither my son or daughter has a clue about driving this car. Now both have
driven the car, but I still worry when I'm gone and they decide to test the performance.
It is in my Will, going to my son.
Ok, so today the weather was good and most likely it will go south or maybe I should say north actually.
I changed the oil to Royal Purple 10w30 Break-In oil, but it will be next spring before it's driven much.
While I was looking things over I noticed that the alternator pivot point bolt had fatigued and broke off.
I'm amazed that it was still charging [I have two belts driving the system], it was essentially just hanging on the
belts for support. The only other connection was the adjustment point. So I pulled the alternator out so I
could replace the bolt and it was too oily for me, the balancer seal must be leaking. Earlier this summer I
tried to turn the engine with the balancer bolt and it was stripped out. So I need to get in there and drill
and tap for the next larger size or put a heli-coil in. To do that I will need to drain the coolant and remove
the radiator to get a clean approach to the crank snout.Sounds like a winter project.
Now I wonder how many people would say just replace it with a grade 8 bolt and be done with it, never to
worry again. I don't have the bolt head that was there when it broke, but I have mixture of grade 5 and grade 8
bolts. But in this case I think I will go with a grade 5 and document it, then if it breaks again I will try a grade 8.
The point of the comments above are ..... don't just ASSUME that that a grade 8 is better in ALL applications.
http://www.industrialchassisinc.com/?p=622
What is the difference between the hardness, toughness, resilience, and stiffness of materials?
https://www.quora.com/What-is-the-d...ughness-resilience-and-stiffness-of-materials
car then having a catastrophic event because I can't be there to warm them of the
nuances of this beast. Believe me, I'm considering selling it when I can no longer
drive it. Neither my son or daughter has a clue about driving this car. Now both have
driven the car, but I still worry when I'm gone and they decide to test the performance.
It is in my Will, going to my son.
Ok, so today the weather was good and most likely it will go south or maybe I should say north actually.
I changed the oil to Royal Purple 10w30 Break-In oil, but it will be next spring before it's driven much.
While I was looking things over I noticed that the alternator pivot point bolt had fatigued and broke off.
I'm amazed that it was still charging [I have two belts driving the system], it was essentially just hanging on the
belts for support. The only other connection was the adjustment point. So I pulled the alternator out so I
could replace the bolt and it was too oily for me, the balancer seal must be leaking. Earlier this summer I
tried to turn the engine with the balancer bolt and it was stripped out. So I need to get in there and drill
and tap for the next larger size or put a heli-coil in. To do that I will need to drain the coolant and remove
the radiator to get a clean approach to the crank snout.Sounds like a winter project.
Now I wonder how many people would say just replace it with a grade 8 bolt and be done with it, never to
worry again. I don't have the bolt head that was there when it broke, but I have mixture of grade 5 and grade 8
bolts. But in this case I think I will go with a grade 5 and document it, then if it breaks again I will try a grade 8.
The point of the comments above are ..... don't just ASSUME that that a grade 8 is better in ALL applications.
http://www.industrialchassisinc.com/?p=622
What is the difference between the hardness, toughness, resilience, and stiffness of materials?
https://www.quora.com/What-is-the-d...ughness-resilience-and-stiffness-of-materials
Last edited:
thats one reason that use of grade 8 bolts , for most uses on a car ,are strongly suggested,
they may not be needed but they provide measurably longer fatigue life.
http://garage.grumpysperformance.co...orrect-bolt-length-and-type.13891/#post-71016
http://garage.grumpysperformance.com/index.php?threads/bolts-a-bit-of-useful-info.4868/#post-13372
http://garage.grumpysperformance.co...afety-wire-locking-fasteners.4306/#post-67565
http://garage.grumpysperformance.com/index.php?threads/cotter-pins.4733/#post-12852
http://garage.grumpysperformance.com/index.php?threads/parts-coming-loose.11008/#post-48646
they may not be needed but they provide measurably longer fatigue life.
http://garage.grumpysperformance.co...orrect-bolt-length-and-type.13891/#post-71016
http://garage.grumpysperformance.com/index.php?threads/bolts-a-bit-of-useful-info.4868/#post-13372
http://garage.grumpysperformance.co...afety-wire-locking-fasteners.4306/#post-67565
http://garage.grumpysperformance.com/index.php?threads/cotter-pins.4733/#post-12852
http://garage.grumpysperformance.com/index.php?threads/parts-coming-loose.11008/#post-48646
But would you agree that grade 8 are not always the best solution?
http://www.industrialchassisinc.com/?p=622
http://www.industrialchassisinc.com/?p=622
while thats technically true enough ,
(by now I.m sure you realize when I post answers its generally not directed to only one person, but too anyone reading the thread even years later)
(yes sitting through years of engineering classes , in stress and materials testing, makes me a bit crazy)
when was the last time you,ve seen a properly sized for the application, grade #8 suspension ,motor mount transmission mount, or accessory bracket bolt fail?
I can,t remember one failing on any car I've owned so its not overly common.
if you take a wire coat hanger and bend it back and forth it will eventually break, and its not as strong an alloy steel, as even a grade 5 bolt, everything has an elastic limit , where it will bend but not break, until pushed repeatedly past that limit
the one place I generally don,t suggest grade #8 bolts is on exhaust manifolds , where a grade #K500 monel
https://www.extreme-bolt.com/produc...MIwuGB5q2Y1wIVCl6GCh1i2g_LEAAYAiAAEgLha_D_BwE
http://www.manasquanfasteners.com/hex_cap_screws_3_8
or at least stainless bolt, with anti-seize in the threads tends to last longer
http://garage.grumpysperformance.co...orrect-bolt-length-and-type.13891/#post-71016
it might help if you get out a stick of uncooked pasta ,
you will find you can bend it in your fingers back and forth ,without damaging it up to a certain limit, for a long period of time , past that limit of movement it snaps off, while thats no where near steel, its similar in that you can stress steel under its limit nearly endlessly, but pushed past its elastic limit it rapidly fails
if you select a bolt that does not have nicks or other stress risers , that concentrate stress in one small area, thats large enough in diameter and length, and use it where that the max stress is well below that bolts elastic limit
(YELLOW AREA IN GRAPH BELOW) its potential life span is almost limitless.
Ideally you want to stay well under the stress limitations
( between 0 (zero) and well below A in the area on the graph,s YELLOW AREA IN GRAPH BELOW)
thus one of the keys to durability is selecting a bolt large enough in size that youll never reach its elastic limit under the stress it will ever reasonably encounter, in the application its being used for.
(GRADE #8 allows a higher elastic limit on a given size bolt)
http://garage.grumpysperformance.com/index.php?threads/removing-rusted-broken-bolts.807/#post-43180
ARP posted these pictures of failed bolts
(by now I.m sure you realize when I post answers its generally not directed to only one person, but too anyone reading the thread even years later)
(yes sitting through years of engineering classes , in stress and materials testing, makes me a bit crazy)
when was the last time you,ve seen a properly sized for the application, grade #8 suspension ,motor mount transmission mount, or accessory bracket bolt fail?
I can,t remember one failing on any car I've owned so its not overly common.
if you take a wire coat hanger and bend it back and forth it will eventually break, and its not as strong an alloy steel, as even a grade 5 bolt, everything has an elastic limit , where it will bend but not break, until pushed repeatedly past that limit
the one place I generally don,t suggest grade #8 bolts is on exhaust manifolds , where a grade #K500 monel
https://www.extreme-bolt.com/produc...MIwuGB5q2Y1wIVCl6GCh1i2g_LEAAYAiAAEgLha_D_BwE
http://www.manasquanfasteners.com/hex_cap_screws_3_8
or at least stainless bolt, with anti-seize in the threads tends to last longer
http://garage.grumpysperformance.co...orrect-bolt-length-and-type.13891/#post-71016
it might help if you get out a stick of uncooked pasta ,
you will find you can bend it in your fingers back and forth ,without damaging it up to a certain limit, for a long period of time , past that limit of movement it snaps off, while thats no where near steel, its similar in that you can stress steel under its limit nearly endlessly, but pushed past its elastic limit it rapidly fails
if you select a bolt that does not have nicks or other stress risers , that concentrate stress in one small area, thats large enough in diameter and length, and use it where that the max stress is well below that bolts elastic limit
(YELLOW AREA IN GRAPH BELOW) its potential life span is almost limitless.
Ideally you want to stay well under the stress limitations
( between 0 (zero) and well below A in the area on the graph,s YELLOW AREA IN GRAPH BELOW)
thus one of the keys to durability is selecting a bolt large enough in size that youll never reach its elastic limit under the stress it will ever reasonably encounter, in the application its being used for.
(GRADE #8 allows a higher elastic limit on a given size bolt)
http://garage.grumpysperformance.com/index.php?threads/removing-rusted-broken-bolts.807/#post-43180
ARP posted these pictures of failed bolts
Last edited:
Grade 5 vs Grade 8 Fasteners
Which fastener grade should I use?
Home / Grade 5 vs Grade 8 Fasteners
It seems that everyone has an opinion on which grade is better but not many people can or will tell you why. Well, we’d like to explain the technical difference between a SAE Grade 8 (Grade 8) and a SAE Grade 5 (Grade 5) fastener.
http://tinelok.com/grade-5-vs-grade-8-fasteners/
Most people think a bolt is a bolt is a bolt. They see it as a machined chunk of metal that holds or attaches things. Fasteners (aka bolts or screws) are complex mechanically-engineered hardware. They are made using different materials, different thread types (i.e. coarse, fine, extra fine), various lengths, with grip or no grip (shank), different types (i.e. hex, 12 pt, carriage, etc.), different coatings (i.e. passivated, cadmium, dry film lube, etc.), various classes of fit (i.e. class 3), and multiple grades (i.e. grade 5, 8, etc.).
Bolts come with left or right hand threads, metric or SAE threads, different number of threads per inch (i.e. 20 or 28 for the same size fastener) and various versions of those (i.e. UNF versus UNJF). In addition, there are way too many military specs in existence to list them all here. So with all these differences, it’s no wonder most people don’t understand the difference between fasteners very well. Of all these differences, I’ll focus on the different grades since that is what most shade tree mechanics ask about.
First, you need to be able to identify bolts by the different grades when you go to the local hardware store. Grade 5 bolts have 3 marks or lines on the head that are in the shape of a “Y”. Grade 8 bolts have 6 marks on the head.
Second, the different grades have a meaning to them. It tells you how strong the fastener is. There are different types of strengths listed for each grade. Proof strength (about 90% of yield), ultimate tensile strength (bolt fails in stretch), yield strength (bolt begins to get a permanent set and changes cross-sectional area typically) and shear strength (bolt prevents parts from separating by using its shank or body as a stop).
Depending on how you are using the fastener, you would look at the appropriate and corresponding strength type. For example, bolts that attach a D-ring bracket to the bumper face of a vehicle would be critical in tension. So you would want to know what the tensile strength a particular bolt is. Bolts that attach winch-mounting plates are typically seeing mostly shear loads thus preventing the winch from departing from the vehicle during winching operations. In that case, shear strength is important to you.
Mark’s Standard Handbook for Mechanical Engineers lists Grade 5 fasteners as 120 ksi fasteners. This means the tensile strength is 120,000 lbs per square inch. It also lists Grade 8’s as 150 ksi fasteners meaning the tensile strength is 150,000 lbs per square inch. Also, the ultimate shear strength of a fastener is typically about 60% of its ultimate tension strength. So given a certain diameter (cross-sectional area) and strength rating, someone can figure out how much load that fastener can carry in both tension and shear.
Let’s look at an example of where grade 5 and grade 8 bolts are subjected to single shear loads (winch plate reference).
Using a .250-inch diameter grade 8 fastener gives you the following shear capability:
A = Cross-sectional area of the fastener size (since bolt bodies/shanks have circular cross-sections, use area of a circle) = Pi x r2 where R (radius) = .250/2 = .125, therefore A = Pi x (.125)2 = .0491 square inches (in2)
Capability in shear = 91,000 lbs / in2 x .0491 in2 = 4468 lbs
Using the same .250-inch diameter grade 5 fastener results in the following:
Capability in shear = 75,000 lbs / in2 x .0491 in2 = 3683 lbs
That’s a difference of over 750 lbs or over 1/3 ton. In this example you can clearly see that using a grade 8 fastener has a superior advantage over the grade 5. Therefore the result is if someone is using grade 5 bolts in a shear application like the winch plate example, they will fail almost 800 lbs earlier.
There’s an argument that grade 8’s are more brittle than grade 5’s and that’s why you shouldn’t use them. Well, first you need to understand what the term “brittle” really means. Brittleness in bolts is defined as failure at stresses apparently below the strength of the bolt material with little or no evidence of plastic deformation. Typically, fasteners are not brittle below 180 ksi ultimate tensile strength. Grade 5’s have an ultimate tensile strength of 120 ksi and a grade 8 fastener has an ultimate tensile strength of 150 ksi. This is why brittle is a relative term. Nearly all fasteners are considered ductile except some made from PH 15-6 Mo, 17-4 PH and 17-7 PH.
Going back to the D-ring on the face of the bumper example, you would want to know its tensile carrying capability. Calculating the tensile capability is not as easy as shear since the thinnest portion of the bolt is at the minor diameter of the threads (bottom of the thread “V”). So you need to know the nominal minor diameter of that particular fastener. That’s where military specification MIL-S-8879C comes in. It is titled “Screw threads, controlled radius root with increased minor diameter, general specification for”. It lists that and a lot more for almost all possible fasteners. MIL-S-8879C lists the nominal minor diameter of a .2500-28-UNF at .2065 inches. We can now calculate the A (area) of the cross-section:
A = Pi x r2 = Pi x (.2065/2)2 = .03349 in2
Grade 8 bolt capability in yield (stretch) = 130,000 lbs / in2 x .03349 in2 = 4354 lbs minimum
Grade 8 bolt capability in tension (failure) = 150,000 lbs / in2 x .03349 in2 = 5024 lbs minimum
Grade 5 bolt capability in yield (stretch) = 92,000 lbs / in2 x .03349 in2 = 3081 lbs minimum
Grade 5 bolt capability in tension (failure) = 120,000 lbs / in2 x .03349 in2 = 4019 lbs minimum
Again, you can see that the grade 8 will support over 1000 lbs more or a 1/2-ton more. But there’s something more important to note. The grade 5 fastener has already reached its ultimate load and FAILED BEFORE the grade 8 starts to yield or stretch. Therefore, the argument that you should not use grade 8’s because they are more brittle than grade 5’s is not a true statement in most applications.
Toughness is an important feature of a fastener. It is the opposite of brittleness and gives you an idea of how it will handle abuse without being damaged and eventually weakening the fastener or can cause fatigue to appear much earlier than normal. One way to “measure” toughness is by looking at the hardness rating of a fastener. The higher the number (Brinell, Rockwell …) the harder the material is and the tougher it is to damage. According to Marks’ Standard Handbook for Mechanical Engineers, Grade 5’s typically have a core Rockwell hardness of C25-C34 whereas a grade 8 typically has a core Rockwell hardness of C33-C39. Based on this, grade 8’s are tougher than grade 5’s.
Fatigue usually doesn’t play a big part in grade 8 or grade 5 fasteners since most steels are good for 2 million to 10 million cycles. Far more than you will ever winch or pull on. Here is a quick point about fastener fatigue. Almost all fastener fatigue failures are the result of improper (almost always too low) torque. Too low a torque will cause the fastener to pick up more load more often and eventually cycle it to failure. Therefore, you want to make sure you torque your fasteners to the appropriate level using a torque wrench and make sure to torque dry, clean threads.
Lubricated threads significantly change the actual preload on the fastener and you risk over torqueing it.
Due to space and time limitations, here is a chart showing you the tension and shear minimum capabilities of different grade fasteners relative to their size.
These examples show how much of a load can be carried by the fastener BUT you need to make sure the parent material is strong enough to handle the loads, as well, otherwise it will fail. Industry practice is to apply a safety factor to address any unknowns and/or combined load cases to give you an adequate margin of safety.
Getting back to the original question, “which fastener grade should I use?” We hope it’s very clear by now that grade 8 fasteners are far superior to grade 5 fasteners. If this is so, then why do the automotive manufacturers use some grade 5 fasteners? The automotive OEM’s use what it needs to be safe and nothing more since there is a difference in cost between grade 5 and grade 8 (or metric 8.8 and 10.9). Since the OEM’s manufacture millions of vehicles each year, the difference in a few cents per fastener adds up to a lot for them.
http://garage.grumpysperformance.com/index.php?threads/physics-of-racing-series-info.372/
Which fastener grade should I use?
Home / Grade 5 vs Grade 8 Fasteners
It seems that everyone has an opinion on which grade is better but not many people can or will tell you why. Well, we’d like to explain the technical difference between a SAE Grade 8 (Grade 8) and a SAE Grade 5 (Grade 5) fastener.
http://tinelok.com/grade-5-vs-grade-8-fasteners/
Most people think a bolt is a bolt is a bolt. They see it as a machined chunk of metal that holds or attaches things. Fasteners (aka bolts or screws) are complex mechanically-engineered hardware. They are made using different materials, different thread types (i.e. coarse, fine, extra fine), various lengths, with grip or no grip (shank), different types (i.e. hex, 12 pt, carriage, etc.), different coatings (i.e. passivated, cadmium, dry film lube, etc.), various classes of fit (i.e. class 3), and multiple grades (i.e. grade 5, 8, etc.).
Bolts come with left or right hand threads, metric or SAE threads, different number of threads per inch (i.e. 20 or 28 for the same size fastener) and various versions of those (i.e. UNF versus UNJF). In addition, there are way too many military specs in existence to list them all here. So with all these differences, it’s no wonder most people don’t understand the difference between fasteners very well. Of all these differences, I’ll focus on the different grades since that is what most shade tree mechanics ask about.
First, you need to be able to identify bolts by the different grades when you go to the local hardware store. Grade 5 bolts have 3 marks or lines on the head that are in the shape of a “Y”. Grade 8 bolts have 6 marks on the head.
Second, the different grades have a meaning to them. It tells you how strong the fastener is. There are different types of strengths listed for each grade. Proof strength (about 90% of yield), ultimate tensile strength (bolt fails in stretch), yield strength (bolt begins to get a permanent set and changes cross-sectional area typically) and shear strength (bolt prevents parts from separating by using its shank or body as a stop).
Depending on how you are using the fastener, you would look at the appropriate and corresponding strength type. For example, bolts that attach a D-ring bracket to the bumper face of a vehicle would be critical in tension. So you would want to know what the tensile strength a particular bolt is. Bolts that attach winch-mounting plates are typically seeing mostly shear loads thus preventing the winch from departing from the vehicle during winching operations. In that case, shear strength is important to you.
Mark’s Standard Handbook for Mechanical Engineers lists Grade 5 fasteners as 120 ksi fasteners. This means the tensile strength is 120,000 lbs per square inch. It also lists Grade 8’s as 150 ksi fasteners meaning the tensile strength is 150,000 lbs per square inch. Also, the ultimate shear strength of a fastener is typically about 60% of its ultimate tension strength. So given a certain diameter (cross-sectional area) and strength rating, someone can figure out how much load that fastener can carry in both tension and shear.
Let’s look at an example of where grade 5 and grade 8 bolts are subjected to single shear loads (winch plate reference).
Using a .250-inch diameter grade 8 fastener gives you the following shear capability:
A = Cross-sectional area of the fastener size (since bolt bodies/shanks have circular cross-sections, use area of a circle) = Pi x r2 where R (radius) = .250/2 = .125, therefore A = Pi x (.125)2 = .0491 square inches (in2)
Capability in shear = 91,000 lbs / in2 x .0491 in2 = 4468 lbs
Using the same .250-inch diameter grade 5 fastener results in the following:
Capability in shear = 75,000 lbs / in2 x .0491 in2 = 3683 lbs
That’s a difference of over 750 lbs or over 1/3 ton. In this example you can clearly see that using a grade 8 fastener has a superior advantage over the grade 5. Therefore the result is if someone is using grade 5 bolts in a shear application like the winch plate example, they will fail almost 800 lbs earlier.
There’s an argument that grade 8’s are more brittle than grade 5’s and that’s why you shouldn’t use them. Well, first you need to understand what the term “brittle” really means. Brittleness in bolts is defined as failure at stresses apparently below the strength of the bolt material with little or no evidence of plastic deformation. Typically, fasteners are not brittle below 180 ksi ultimate tensile strength. Grade 5’s have an ultimate tensile strength of 120 ksi and a grade 8 fastener has an ultimate tensile strength of 150 ksi. This is why brittle is a relative term. Nearly all fasteners are considered ductile except some made from PH 15-6 Mo, 17-4 PH and 17-7 PH.
Going back to the D-ring on the face of the bumper example, you would want to know its tensile carrying capability. Calculating the tensile capability is not as easy as shear since the thinnest portion of the bolt is at the minor diameter of the threads (bottom of the thread “V”). So you need to know the nominal minor diameter of that particular fastener. That’s where military specification MIL-S-8879C comes in. It is titled “Screw threads, controlled radius root with increased minor diameter, general specification for”. It lists that and a lot more for almost all possible fasteners. MIL-S-8879C lists the nominal minor diameter of a .2500-28-UNF at .2065 inches. We can now calculate the A (area) of the cross-section:
A = Pi x r2 = Pi x (.2065/2)2 = .03349 in2
Grade 8 bolt capability in yield (stretch) = 130,000 lbs / in2 x .03349 in2 = 4354 lbs minimum
Grade 8 bolt capability in tension (failure) = 150,000 lbs / in2 x .03349 in2 = 5024 lbs minimum
Grade 5 bolt capability in yield (stretch) = 92,000 lbs / in2 x .03349 in2 = 3081 lbs minimum
Grade 5 bolt capability in tension (failure) = 120,000 lbs / in2 x .03349 in2 = 4019 lbs minimum
Again, you can see that the grade 8 will support over 1000 lbs more or a 1/2-ton more. But there’s something more important to note. The grade 5 fastener has already reached its ultimate load and FAILED BEFORE the grade 8 starts to yield or stretch. Therefore, the argument that you should not use grade 8’s because they are more brittle than grade 5’s is not a true statement in most applications.
Toughness is an important feature of a fastener. It is the opposite of brittleness and gives you an idea of how it will handle abuse without being damaged and eventually weakening the fastener or can cause fatigue to appear much earlier than normal. One way to “measure” toughness is by looking at the hardness rating of a fastener. The higher the number (Brinell, Rockwell …) the harder the material is and the tougher it is to damage. According to Marks’ Standard Handbook for Mechanical Engineers, Grade 5’s typically have a core Rockwell hardness of C25-C34 whereas a grade 8 typically has a core Rockwell hardness of C33-C39. Based on this, grade 8’s are tougher than grade 5’s.
Fatigue usually doesn’t play a big part in grade 8 or grade 5 fasteners since most steels are good for 2 million to 10 million cycles. Far more than you will ever winch or pull on. Here is a quick point about fastener fatigue. Almost all fastener fatigue failures are the result of improper (almost always too low) torque. Too low a torque will cause the fastener to pick up more load more often and eventually cycle it to failure. Therefore, you want to make sure you torque your fasteners to the appropriate level using a torque wrench and make sure to torque dry, clean threads.
Lubricated threads significantly change the actual preload on the fastener and you risk over torqueing it.
Due to space and time limitations, here is a chart showing you the tension and shear minimum capabilities of different grade fasteners relative to their size.
These examples show how much of a load can be carried by the fastener BUT you need to make sure the parent material is strong enough to handle the loads, as well, otherwise it will fail. Industry practice is to apply a safety factor to address any unknowns and/or combined load cases to give you an adequate margin of safety.
Getting back to the original question, “which fastener grade should I use?” We hope it’s very clear by now that grade 8 fasteners are far superior to grade 5 fasteners. If this is so, then why do the automotive manufacturers use some grade 5 fasteners? The automotive OEM’s use what it needs to be safe and nothing more since there is a difference in cost between grade 5 and grade 8 (or metric 8.8 and 10.9). Since the OEM’s manufacture millions of vehicles each year, the difference in a few cents per fastener adds up to a lot for them.
http://garage.grumpysperformance.com/index.php?threads/physics-of-racing-series-info.372/
Last edited:
Loves302Chevy
"One test is worth a thousand expert opinions."
Suggestion: whether you have to drill & tap to the next larger size, or if there are enough threads left,
RED Loctite an ARP stud in there. Then you are no longer working the threads in the crank snout.
RED Loctite an ARP stud in there. Then you are no longer working the threads in the crank snout.
mathd
solid fixture here in the forum
I think that if the bolt is the correct size and torque for the application and grade it should not break,
It probably got loose and broke off.
I can usually remove any broken bolt without oversize and using heli-coil.
I just drill smaller then the thread, then use a carbide burr to enlarge if needed and use a tap to clean the thread. it take time but 99% of the time i can get the thread back to normal/stock state or very close to. I hate having 1 bolt thats not the same size then the rest or drilling larger is NEVER an option to me.
If you really mess up you can even weld the hole shut and re-machine and drill/tap.(welding on a cash iron block... thats a pita i know. but a good welder could manage it)
If the bolt is big enough just weld a nut to it and remove it while its hot. Thats what i did here in the aluminum crankcase of my dirtbike.(not a broken bolt but a stripped star screw)
It probably got loose and broke off.
I can usually remove any broken bolt without oversize and using heli-coil.
I just drill smaller then the thread, then use a carbide burr to enlarge if needed and use a tap to clean the thread. it take time but 99% of the time i can get the thread back to normal/stock state or very close to. I hate having 1 bolt thats not the same size then the rest or drilling larger is NEVER an option to me.
If you really mess up you can even weld the hole shut and re-machine and drill/tap.(welding on a cash iron block... thats a pita i know. but a good welder could manage it)
If the bolt is big enough just weld a nut to it and remove it while its hot. Thats what i did here in the aluminum crankcase of my dirtbike.(not a broken bolt but a stripped star screw)
Last edited:
mathd
solid fixture here in the forum
Even better.. i broke off the bolt for the balancer into the crankshaft...
since it was not bottomed out i just used a punch to turn it counter clockwisw and i successfully removed it, effortless.. If that was a brittle grade 8 then it may come out easily, if its a soft bolt that distorted or that is seized in then thats another story.
This summer i broke 2 of the 4 bolt on the differential yoke for holding the strap/driving shaft on the truck. And i did just what i said, i drilled(offcenter to make thing worst) and used the carbide burr(since my hole was off center...) then a tap to clean the remaining.
since it was not bottomed out i just used a punch to turn it counter clockwisw and i successfully removed it, effortless.. If that was a brittle grade 8 then it may come out easily, if its a soft bolt that distorted or that is seized in then thats another story.
This summer i broke 2 of the 4 bolt on the differential yoke for holding the strap/driving shaft on the truck. And i did just what i said, i drilled(offcenter to make thing worst) and used the carbide burr(since my hole was off center...) then a tap to clean the remaining.
Hey, that's a really good idea Loves302. Will have to check into that.
I'm with you there. In my case there is only one bolt whether it's the alternator bolt or the balancer bolt.
The alternator bolt was not in a blind hole, so I was able to unscrew it with my hand from the back side.
Will have to see about the crank snout when I get in there and get a good look at it. It's not broke off, but
just the threads are stripped. How does a thread insert compare to the original threads in a forged crankshaft?
Did you have a very small diameter burr to get in that small bolt hole? Every time I've used a burr in a hole
about the same size as the burr, it ends up rattling my teeth, when it starts going around hole at the 10,000 rpm.
I wondered about rolled threads vs cut threads and which one is stronger. A little research came up with this document.
Are Rolled Internal Threads as Good as Cut Threads?
Questions about internal rolled threads come up from time to time. Why do fastener manufacturers
want to provide internal threads using the rolling rather than cutting process? Are rolled threads as
strong as cut? How do you gage internal rolled threads verses internal cut threads. Why do screws
tend to cross-thread in internal rolled threads more than internal cut threads?
These are good questions. Following are the answers:
Q1. Why do fastener manufacturers want to provide internal threads using the rolling rather
than cutting process?
A1. Rolling internal threads provide exactly the same benefits to the manufacturer that rolling external
threads do.
1. Rolling internal threads displaces material instead of creating scrap in the form of chips. This
can result in raw material savings.
2. Rolling internal threads can be performed at a faster rate than cutting threads, thus yielding
more parts per hour.
Q2. Are rolled threads as strong as cut?
A2. Yes, rolled threads are at least as strong as cut threads.
1. If the internally threaded fastener is not hardened by heat treatment the rolled thread is
stronger than the cut thread because of the work hardening that occurs as a result of the
process. This provides a part more resistant to thread stripping.
2. If the internally threaded product is hardened by heat treatment then the internal rolled threads
and the cut threads have equal strength.
Q3. How do you gage internal rolled threads verses internal cut threads:
A3. The dimensional and inspection requirements for internal rolled threads are identical to those for
cut threads. Internal threads must be inspected with threaded plug gages and cylindrical plug gages
to evaluate the pitch diameter and minor diameter.
The only difference is that internal rolled threads require a larger hole in the work pieces than do work
pieces intended for cut threads. The reason is that when rolling internal threads, the pre-tap hole size
in the work piece is approximately pitch diameter size. The material that is displaced by the crests of
the tap’s major diameter flows inward toward the center of the part to create the minor diameter.
When creating an internal cut thread in a work piece, the pre-tap hole size is at the nut’s minor
diameter. The flute in the tap cuts the thread into the material instead of flowing the material to create
the thread form.
Q4. Why do screws tend to cross-thread in internal rolled threads more than internal cut
threads?
A4. When an internal thread is cut into a work piece the minor diameter of the internal thread is flat
between each thread. When an internal thread is rolled, the material displaces in the work piece so
the material is being pushed outward to conform to the major diameter of the tap. The material flows
up the flanks on both the leading and trailing flanks of the tap to form the minor diameter of the
internally threaded fastener. When the material approaches the interior of the fastener a small open
valley is created at the root of the thread.
The size of the valleys vary with the material being tapped and the pre-tap hole size in the work piece.
Harder materials do not flow as readily as do softer materials. Using the same starting hole size the
harder material is likely to leave a much larger valley than will the softer material.
When the valleys are too large they cause screws to cross thread because the external thread
engages the valley on the minor diameter instead of engaging in the actual thread form.
The size of these valleys is the result of how well the manufacturer selects the starting hole size
based on the hardness of the material being tapped. Many people mistaken think that the starting
hole size for all 5/16-24 rolled internal threads are the same regardless of the material being tapped.
This is not true. To make good quality internal rolled threads the manufacturer needs to develop the
ideal starting hole based on the material being tapped and the length of engagement. Done properly
the valleys between threads can be maintained at a minimum size thus preventing screws from cross-
threading.
This same principle is involved when rolling external threads. If the starting blank diameter size is too
small large valleys will occur on the major diameter of the individual threads.
There are many good reasons for considering the
use of rolled threads in internally threaded
fasteners. Many users balk at the idea of accepting rolled internal threads only because they are not
familiar with them. When asked to consider the acceptance of a rolled thread also consider the points
made above in determining if it can be applicable to your project.
Are Rolled Internal Threads as Good as Cut Threads?
Questions about internal rolled threads come up from time to time. Why do fastener manufacturers
want to provide internal threads using the rolling rather than cutting process? Are rolled threads as
strong as cut? How do you gage internal rolled threads verses internal cut threads. Why do screws
tend to cross-thread in internal rolled threads more than internal cut threads?
These are good questions. Following are the answers:
Q1. Why do fastener manufacturers want to provide internal threads using the rolling rather
than cutting process?
A1. Rolling internal threads provide exactly the same benefits to the manufacturer that rolling external
threads do.
1. Rolling internal threads displaces material instead of creating scrap in the form of chips. This
can result in raw material savings.
2. Rolling internal threads can be performed at a faster rate than cutting threads, thus yielding
more parts per hour.
Q2. Are rolled threads as strong as cut?
A2. Yes, rolled threads are at least as strong as cut threads.
1. If the internally threaded fastener is not hardened by heat treatment the rolled thread is
stronger than the cut thread because of the work hardening that occurs as a result of the
process. This provides a part more resistant to thread stripping.
2. If the internally threaded product is hardened by heat treatment then the internal rolled threads
and the cut threads have equal strength.
Q3. How do you gage internal rolled threads verses internal cut threads:
A3. The dimensional and inspection requirements for internal rolled threads are identical to those for
cut threads. Internal threads must be inspected with threaded plug gages and cylindrical plug gages
to evaluate the pitch diameter and minor diameter.
The only difference is that internal rolled threads require a larger hole in the work pieces than do work
pieces intended for cut threads. The reason is that when rolling internal threads, the pre-tap hole size
in the work piece is approximately pitch diameter size. The material that is displaced by the crests of
the tap’s major diameter flows inward toward the center of the part to create the minor diameter.
When creating an internal cut thread in a work piece, the pre-tap hole size is at the nut’s minor
diameter. The flute in the tap cuts the thread into the material instead of flowing the material to create
the thread form.
Q4. Why do screws tend to cross-thread in internal rolled threads more than internal cut
threads?
A4. When an internal thread is cut into a work piece the minor diameter of the internal thread is flat
between each thread. When an internal thread is rolled, the material displaces in the work piece so
the material is being pushed outward to conform to the major diameter of the tap. The material flows
up the flanks on both the leading and trailing flanks of the tap to form the minor diameter of the
internally threaded fastener. When the material approaches the interior of the fastener a small open
valley is created at the root of the thread.
The size of the valleys vary with the material being tapped and the pre-tap hole size in the work piece.
Harder materials do not flow as readily as do softer materials. Using the same starting hole size the
harder material is likely to leave a much larger valley than will the softer material.
When the valleys are too large they cause screws to cross thread because the external thread
engages the valley on the minor diameter instead of engaging in the actual thread form.
The size of these valleys is the result of how well the manufacturer selects the starting hole size
based on the hardness of the material being tapped. Many people mistaken think that the starting
hole size for all 5/16-24 rolled internal threads are the same regardless of the material being tapped.
This is not true. To make good quality internal rolled threads the manufacturer needs to develop the
ideal starting hole based on the material being tapped and the length of engagement. Done properly
the valleys between threads can be maintained at a minimum size thus preventing screws from cross-
threading.
This same principle is involved when rolling external threads. If the starting blank diameter size is too
small large valleys will occur on the major diameter of the individual threads.
There are many good reasons for considering the
use of rolled threads in internally threaded
fasteners. Many users balk at the idea of accepting rolled internal threads only because they are not
familiar with them. When asked to consider the acceptance of a rolled thread also consider the points
made above in determining if it can be applicable to your project.
Last edited:
You just might be correct, I never use a torque wrench for these type of applications.
The failure does look like it could be a fatigue failure, which would happen if the bolt
is NOT torqued to the required specs.
I changed oil in preparation for the winter season. I used Royal Purple Break-In Oil, but it
will next spring before I drive the car again.
Not sure what to make of the sludge in the bottom of the Wix 51061 filter. I checked something
like 30 pleats in the filter and they all looked like the one in the photo. Don't see any metal
in the filter.
I put a magnet on the bottom of the filter case, then laid it on it's side to see if maybe there
is metal. Will try to follow up in a few days with more info.
will next spring before I drive the car again.
Not sure what to make of the sludge in the bottom of the Wix 51061 filter. I checked something
like 30 pleats in the filter and they all looked like the one in the photo. Don't see any metal
in the filter.
I put a magnet on the bottom of the filter case, then laid it on it's side to see if maybe there
is metal. Will try to follow up in a few days with more info.
Last edited:
the filter pletes look good , theres always some fine metallic trace/crud in any engine after 10K miles, and yes it helps a great deal to check filters and use magnets to limit potential damage.
http://garage.grumpysperformance.com/index.php?threads/metal-in-oil.10875/#post-47688
http://garage.grumpysperformance.com/index.php?threads/oil-filters.11189/#post-54673
http://garage.grumpysperformance.co...ellect-does-make-a-differance.117/#post-34589
http://garage.grumpysperformance.com/index.php?threads/inspecting-filter.4611/#post-12336
http://garage.grumpysperformance.co...cam-lobe-rod-or-bearings-fail.2919/#post-7625
http://garage.grumpysperformance.co...wear-articles-you-need-to-read.282/#post-2022
http://garage.grumpysperformance.co...tal-flakes-particles-in-oil.13330/#post-69394
http://garage.grumpysperformance.com/index.php?threads/metal-in-oil.10875/#post-47688
http://garage.grumpysperformance.com/index.php?threads/oil-filters.11189/#post-54673
http://garage.grumpysperformance.co...ellect-does-make-a-differance.117/#post-34589
http://garage.grumpysperformance.com/index.php?threads/inspecting-filter.4611/#post-12336
http://garage.grumpysperformance.co...cam-lobe-rod-or-bearings-fail.2919/#post-7625
http://garage.grumpysperformance.co...wear-articles-you-need-to-read.282/#post-2022
http://garage.grumpysperformance.co...tal-flakes-particles-in-oil.13330/#post-69394
Well I guess it's been a few days now.
The magnet is still in the same place. I've used several solvents to remove the oily component
and leave any metal that might be in the bottom of the filter.
I don't see anything to be worried about, how about you ???
Loves302Chevy
"One test is worth a thousand expert opinions."
Looks good to me.
Be sure to run break-in oil again to make sure your rings are seated.
Be sure to run break-in oil again to make sure your rings are seated.