Dude, you're a genius. A lot of people turn wrenches, but you clearly understand the principles, engineering, and physics that go into a vehicle. On top of that, you're very good at explaining them to a layman like me. Thank you for taking the time to plan, film, and upload this video.
Let's discuss. Torque can only be measured if there is an equal and opposite reaction. You are correct. Equilibrium must be achieved only if a force is applied. I think we are close on the definition. I enjoy the discussion. You are very astute.
DEEP INFO! Pete your the real deal, you remind me of my heavy line teacher (who was also a professor in automotive technology) when i was in automotive school. Thanks for breaking that down and keep on putting out the great content God Bless.
oldskool funk Thank you my friend. I really try to help with things that are important to understand. It's more than just a simple, 2 second explanation sometimes. God bless you too!
Thanks Junkman. I analyze torque and angle data every day. I am able to catch cross-threaded bolts, chips in a hole, dinged threads, worn sockets, and hundreds of other conditions that come up when a fastener is installed. Thank you for watching and your generous comments. I watched your videos and we both run on the same juice....wanting to teach what we know. Thanks again!
I learn something new every day. Sounds like a neat torque wrench. I know that feeling you get when you are sure you are getting ready to strip a thread and you just aren't reaching torque...and then strip! A little practice will give you that confidence back...Cheers!
My Karma is strong because I really want to teach and help people. The example you gave is one I hear often, which is why I made this video. A lesson to anyone who reads this, NEVER re-use a fastener that is torque to yield. Using that method stretches the fastener and puts it close to failure, Using it again is a guranteed failure. Thank you for sharing your experience Leigha...you Karma will help others.
Thank you my friend. I can tell you that every fastener on a vehicle has a rundown strategy that is electric. There is not a single impact wrench in any plant that will be used in assembly that runs forward. The are used for teardown only. Every fastener is installed with a computer controlled torque gun that has complex programs that monitor torque and angle data, and they are extremely accurate.
Thanks so much. Torque and angle is someting that is very important, but rew people understand it. It's great to hear good things from a professional such as yourself. Just wondering....what did you learn?
I agree and you are correct. However, the main purpose of this video was to emphasize the difference between torque and angle. Some people make the mistake of adding a few more pounds of torque to makeup the angle. This can be catastophic. I just want to make sure nobody gets hurt from an improperly tightened fastener.
One of the very best engine builder tutors. It's one thing to know your craft but also another to be able to explain so well. I hope you get some reasonable monetary return. You deserve it. Plus you like Fords.
Thank you very much Mark. to quote Einstein, if you can't explain it in 5 minutes, you don't understand it. I try to make things easy for everyone to understand.
Thank you for taking the time to execute this simplified explanation. My takeaway is that, in layman's terms: 1) You torque a bolt to a specific predetermined value and stop then, 2) You turn, torque or tighten the same bolt a little or a lot more using another tool called an angle gauge and stop. Questions: A- Should one presume that the torque value is necessarily set at the maximum torque point for a given fastener? and therefore the degrees values = the point at which the bolt begins to stretch? I am torqueing an aluminum cylinder head to an aluminum block. The bolt specs are: Cylinder Screw M11, Service Limit: 148.5 mm (5.846 in.). This is what the shop manual instructs: "First torque to 40 N*m (30 lbf*in). Then tighten screws turning an additional 120 degrees rotation with a torque angle gauge and finish tightening with a 90 degree rotation. Torque screws to 10 N*m (89lbf*in)." My understanding is: Step1: Torque to 40 N*M, then Step 2: Rotate 120 degrees, then Step 3: Rotate another 90 degrees, then Step 4: Torque again (another) 10 N*M Am I understanding this correct?
Yes. What you are doing is called "conditioning" the fastener. When you do this you must use new bolts. The purpose of this step is to get all of the threads on the bolt and in the hole "lined up" so to speak so the torque and angle step is secure. Go to 22 and then back off a couple turns. Then torque all to 14 in the specified order. The add the angle in the same order. If you don't have an angle gage turn the wrench from 12 to about 5 o'clock in one continuous motion. Nothing is dumb.
Hello. Very Complex video, great job :) I work as an engineer, daily calculate bolt connections for large industrial gearboxes acc to VDI 2230 german standard. There it is different: We never calculate bolts up to yield point, because due to yield you can loose pretension force in the bolt. Normally, we calculate 90% bolt utilization, that means 90% of yield stress. this is partially because there are many factors which are uncertain during calculation (torque wrench measure tolerance, friction coeficients between mating surfaces...) and because of that it is hard to determine exact final stress in the bolt, so there is an margin to avoid yield point.
Amazing video--I agree with Auto Body Everything! I've long known about torque angle specifications and that they are to be used in some applications but never understood why they're different from simple torque wrench settings. Pete's Garage makes this easy enough to grasp without delving into an entire course of study. I'm sure the thumbs down are from those who have nothing better to do than bash others or simply don't understand---which I don't understand but WTH huh? :) Thanks so much Pete's Garage!
Thanks my friend, I try to make things easy to understand. It's not helpful if all I did was try to impress everyone with fancy words. We're all here to learn.
Thank you very much for the good and clear explanations, as well as the explanation with kindness and interest, and for helping the advancement of science for the advancement of humanity.👏🙏🌹
3:25 By this point in the video, I'd already learned something very important, liked the video, saved it to a playlist and subscribed. Dude, you're awesome.
That is awesome...thank you my friend. This is one of the most commonly misunderstood things. I wanted to help people understand why angle is so important. I live with complex torque and angle programs every day. It is amazing how much you can get out of a properly installed fastener.
You don't sound like a noob....you can't know everything...Lord knows I don't. You are 100% correct. As long as you do not exceed the maximum torque for the fastener you will not enter the yield phase. As long as you know the fastener material, grade, and size you can look it up. Any fastener that has angle applied to it has gone past "A" and has started to yield and must be tossed out when removed. Great question!
56 Nm is not too high for a 10mm bolt, however, anything, especially grease, will shift the torque curve later in the tirghtening sequence and definitely cause a thread to strip. A fastener must be dry unless the manufacturer specifies a lubricant and different torque settings. Unless you have a unique deflecting beam torque wrench, you will not hear a click. You have to watch the needle and stop when it gets to the right torque. Clean threads and have faith in the wrench.
Hey Pete I have a Mazda 626 2.5L and the torque says 1. 17 ftlbs 2. 90 degrees 3. 90 degrees that seems really low for the head bolts does that mean the bolts are torque to yield?
Thanks so much. I get asked about the difference all the time so I made the video to help people understand. Saves a lot of broken bolts and stripped fasteners.
Thanks for the thorough explanation of the tightening force applied to a screw, and what happens in relation to the laws of physics. It is very well explained.
Yooooooooo!! thanks a lot for all this info, I was really really confuse with all this angle/torque situation many manuals say, I was wondering if it has to be with plastic and elastic deformation but I never knew about this graphic you explained, really helpful info and I'll make sure to measure those nuts every time I have to open a engine for first time and shows signs of being poorly assembled. I'll be explaining this info to more people and try to avoid this overtight situation, it's sooooooo common here in Latinamerica, I saw people assembling engines without a torque wrench or proper tools, them end up lasting a few thousand miles... Really good info, thanks a lot!
I agree with you. I have awesome electronic torque wrenches, but for the average guy using it once avery few years a Craftsman will suffice. Thanks for the comment my friend!
Nice. I have a car that I bought used that had the "torque to yield" crank pulley bolt (a $3.00 part) re-used by some numb-nut shade-tree mechanic that suddenly failed and cost me a $7000 engine.I find myself wishing that he'd taken the time to check out a good youtube vide or two like this one, beforehand. Your hard work didn't help me in this instance, but I am hoping that there is at least one other person in this world who can avert that nightmare. Your Karma is strong.
Always follow the manufacturers recommendations. If the instructions do not call for any prepping the bolts then none is needed. Sometimes a moly lube can be applied, but that will totally change the torque and angle specifications. The digital torque tools are cool, but a simple click wrench is suffucient. I use some really cool wireless, digital tools and a complex controller that allows me to write programs, but they are $15k. The deflective beams are fine, just take your time.
Very well explained video. I work in the Marine Business and all replace any tighten to angle bolts. You just can't walk back in case of failure of a bolt.
Any electronic tool is fine as long as it is calibrated at the recommended interval. I use some electronic torque wrenches and they are pretty neat..and yes they can accurately measure angle. A good one is very expensive but the manual method is just as good.
That is the most common question. It is tough to wrap your head around the fact that angle has no relation to torque. Angle is a different calculation for every fastener material / base material combination. Toque is a resistance to rotation, angle is a clamping force, two totally different things.
Thank you....this is actually a very simple concept, but not so easy to explain in a non-technical manner. I get many calls from my "Blown Head Gasket" video from folks asking about the angle on the head bolts. I had so many questions I decided to make this video to explain why angle is important and why new head bolts are required. Everything I do is to try to help and teach. I may not be a TV spokesperson...but I think I get the idea acrosss : > )
Any time you apply angle to a fastener it will stretch. You may need super mics to measure it, but some change will occur. If you pass the yield point you will always (depending of the material) see evidence. Shiny, bent, gaulled, or cracked threads are just a few things. Everything is material and application dependent.
thanks pete, should be right now ill get a angle gauge and figure it out; should i prep the bolts and holes in any special way. what do you think about those digital tourque attachments like a little box that you can use with any ratchet ,are these a good option to a tourque wrench, ihave a 1/4 drive and a 1/2 drive deflective beam tourque wrenches but im pretty sure the 1/2 inch needs callibration, they are quality tools? keep up the good work.
Well explained and much to think about . If your torque wrench is calibrated or if you use the degree tool and follow the chart on torque & stretch specifications you have other factors to consider . The quality of the threads on either the nut , bolt or machined part . We are left with trust of a manufacturer to produce a quality part . The metal , threads and heat treating process have to be consistently the same . This to give repeatable and consistent torque & stretch applied to each nut & bolt . If you are blue printing an engine that will be pushed to its limits , these are some of the many important things to consider .
Hey Pete good stuff thanks for sharing. I have a question though. I understand the theory of the stress & strain and where the temporary load or angle yield of the fastener from point A-B means what I'm trying to understand and maybe I sound like a noob but is how do you know when you get to point A? the beginning of the angle is it after the maximum torque specs? because you mentioned torque is a different calculation then the angle calculation.
The presenece of anything that acts as a lubricant will shift the torque window so it acts later on the curve. There are additional calculations to account for these circumstances. Usually threshold torque will be measured later in the rundown sequence.
Anti-seize compounds contain nickel to reduce galvanic corrosion. It will act as a lubricant as any other material would. There is no rule of thumb. Every fastener is different. The presence of anything acting as a lubricant causes the resultant torque to be lower. The threshold torque starts later so the angle can go past yield. I think you'd be safe with a 10% drop. Torque/angle applies maximum clamp load so loc tite is useless. Nothing should be applied unless the manufacturer recommends it.
Thanks for the really interesting video. My question is - if the angle after torquing is 90 degrees do i really need a gauge, can't I just go 90 degrees further with my torque wrench?
at first i was confused but it makes perfect sense. this explains why you need an angle to torque (because the equal opposite force changes as you get to point B and then to C) head bolts properly and why head bolts should always be replaced.
Thanks for your reply Pete,my wrenches are an aussie make ,i dont know if you know them , Warren and Brown, it has a beam which deflects on to as set value and clicks out a spring loaded pin which "clicks' and the pin never popped. I think ill have to experiment on some test fasteners to get a feel for it, but it sure shakes your confidence ,this was a pretty simple job and i stuffed it.Keep up the good work.
Not that I know of. There are so many different material / thread / variable combinations it would be a huge chart. That is why it is a calculation for each application.
what an amazing explanation! im thinking why not just angle torque from the start instead of using torque wrench? if thats passible, could you provide me an equation to convert ft-lb to angle or at least a link to a chart for that?
@@PetesGaragebut you know that a half turn (maybe full turn) of any size of metric fastener is a 1 mm going down, with that can't we bring a an equation to calculate who much force of that 1 mm going down?
Hey Pete ,got a problem here thats driving me nuts...over tourqued. I asked you a question a while back about the angle and you set me right .My problem is i got my tourque wrenches calibrated ,very technical certificates ,temperature test carried out and so on ,cost me over 200 bucks,results were very good.Im rebuilding susspension on a motocross bike , doing the top shock bolt up and ,i knew it looking back,but i stripped the bolt . Its a 10 mm bolt ,plain washer,u flange nut it had grease on
My one question is, if you're angle torquing and somehow you lose your torque by 5-10°, will that affect the whole torquing process to where the cylinder head will go bad?
I just had my first experience with Torque-to-yield bolts. ( Stretch bolts ) I figured out real quick, they are single-use. You never re-use them. I suppose you could if you could tell where it was starting to stretch and stopped right there... but I can't. I just dropped my 1/2" torque wrench at Alaska Matrology and Calibration Services where they do a lot of them for the Oil-patch on the North Slope. I drug them through the mud on this, and they said my Torque Wrench had to hold within 4% of it's setting, throughout it's range. That was important for me to know. So. 4% of 10 foot pounds, or 120 inch pounds... I thought the same as you said, but in the real world... Doesn't matter. Thanks! Mark
Hey great job on the the torque and angle topic, vary nice discription! I'm a license tech and I even learned a little something from that! Great job thanks for sharing.
The videos I make are driven by phone calls I receive. When I made the 3.4 head gasket video I had hundreds of calls & had to explain angle and torque-to-yield fasteners to most everyone. I analyze torque and angle data every day in an engine plant and it is immensely important to understand what it means. The data can tell me if there is a cross-threaded fastener, chips in a hole, or a bad part. It is an intricate science, I'm not an expert, but I tried to make it easy to understand. Thanks!
That is correct. The reason I made this video is because many people say " just add a little more torque to do the angle," but that is so wrong. As you are learning about the eloasticity modulus watch how the curves change with different materials. 20 degrees of angle on a 1020 steel bolt has a different curve than 316 stainless.
This could be the most important lesson in mechanics I have learned. Now, I came into a use for this information, but need more information before proceeding. I own a 2004 Cadillac CTS, 3.6 L engine. I must replace the bolt that holds the harmonic balancer to the mainshaft. The info I have is that I should torque to 37 ftlbs and then angle 120º (one site says 140º). How do I lock the engine so that it does not rotate while angleing and what is the correct angle, 120º or 140º? Thank you and keep a good work.
There is a tool that goes in the spark plug hold to hold the piston at top dead center. That would work. If you have info that says 120, I would trust that, unless you can get a different torque spec from a dealer.
it . The value was 56 Nm,as i was tightening it i could feel thet the fastener had taken up all the force but i kept going waiting for the click ,deflecting beam wrench.Do u think the grease on the bolt and maybe washer would make that much difference as to be wildly out .And 56Nm seems quit a lot on a 10 mm bolt, now i have no faith in my tourque values and i was planning on doing the crank bearings,but now it seems i got no chance.cool videos Pete.
Thanks, Question, Doing my heads on Durango and book says The cylinder head bolts are tightened using an angle torque procedure, however, the bolts are not a torque-to-yield design. Tighten bolts 1-10, 90 degrees. Tighten bolts 11-14, 30 Nm (22 ft. lbs.)Does that meen use the Torque Angle Gauge and bring it to 90 after the initial 22 ft lbs? Great video and easy learning .
Understanding the "why" is just as important as knowing the "how." Thanks for saying "HOLY CRAPOLA." Had you chosen a less intelligent explative I would have deleted the comment. I'm not a holy roller, but the use of profanity indicates lack of intelligence. I am just like you, I don't trust anyone to work on my stuff so I learned to do it myself. Everything is easy when it is broken down into simple English....Thanks for watching Junkman!
Thanks for the video. A question about lubricating cylinder tty bolts. Does that push the bolt beyond the elastic limit and hence have an impact on the start and end yield points
Hi Pete great video, just wanted to ask you a question to clear my confusion, I'm doing a head gasket replacement on my BMW E36 325i M52 B28 I have new stretch bolts the torque specs for the head bolts is 35nm at a angle of 90 then 90 again, my question to you sir do I torque the bolt to 35nm with my torque wrench first ? Then put my angle gauge on with my breaker bar do my first 90 degrees on all 14 bolts then do my second 90 ? I'm confused from the part of the video were you mention 80% of torque do I subtract 35nm by 20% ? I'm all the way from South Africa we use Nm instead of Lbs.
Hey, thanks for the video... very informative! Is there a way to calculate the number of rotations a bolt should make in order to exert 16 ft-lbs (21.57 Nm) of torque? Did some research and found there is a "Rotation Angle Method" - The tightening is managed by rotation angle which starts from the seating point of the bolt head.
I have a short attention span. 5 to 7 minutes and I click to the next video.... I just watched the whole 14:50 and was bummed when it ended. Might just have to watch this again. After snapping bolts for the last 45 years ,I assumed I just didn't know my own strength. Thanks to "you" dammit ! I now realize I'm just an idiot. ;)
Torque to yield fastener specifications most common call for a torque and angle. Like 110 ft lbs with 95 degrees of angle. You can torque in sequence in stages, but the angle must be applied in one, continuous motion. I have never seen a 35°+5° spec, but I would do the 35° in sequence on all bolt and add the 5° as a second step.Thanks for watching!
I’m getting ready to put head gaskets on my duramax, I’m ordering new studs (amx, acr something like that), can I get away with just torquing them to the required torque, not doing the angle? I don’t have a torque wrench that does angle, thanks.
So, we just touched on this in my mechanics of materials class, though we're staying in the elastic region for now. Force per unit area is equal to young's modulus multiplied by the change in length divided by the unloaded length. With a little bit of algebra, and some knowledge of your bolt threads, you can make some neat things happen...
There is a LOT more to it than torque and stretch bolts as aluminium castings are usually porous. To get around this problem, castings that are subjected to pressure are Vacuum Varnish Impregnated. If the cylinder head is skimmed this VVI layer will be lost although there is a company in the Manchester area that will re-impregnate castings. Empirical results with the Peugeot 106 diesels indicate that the original head gasket will last for about 50,000 miles but replacement gaskets will only last about 30,000 miles. Of course the alloy in an old engine will be impregnated with oil. The small car to have in the Peugeot range was the now classic 205 with the iron engine as that was a horse of a different colour! 250,000 miles was quite possible and the extra weight on the driving wheels could be very useful!
hi Pete, I'm changing the hg on a bmw and the oem head bolts are m11 with instructions to tighten to 30nm +90º +90º, since I don't have a way to measure these angles accurately, I used the torque setting and then gave it 80nm instead of the angles, but now I see there's more to it regarding this angle thing and i'm afraid the clamping power is not optimal Is there a way to tighten the cyl head giving the approximate values intended through nm's only? thanks a lot and great video.
Ricardo Nunes There is a way, but it takes tons of math. You can estimate the angle. 90 degrees is simply a quarter turn of the fastener. That is pretty easy to do with a wrench. 80 Nm is almost 3 times the suggested torque. The resultant torque from two 90's may be a bit higher. If you're worried you can re-torque them. You can do this us to 3 times on a torque to yield fastener.
Sorry to be dumb. But why are manufactures using torque to yield fasteners now, why not 70 years ago in WW2 fighter engines or in GP engines in the 70-80s . Weight saving? Space saving? or just a nice Cash cow? 2nd question why does Mercedes allow the reuse of torque to yield fasteners so long as they are within length limits ?
TTY fasteners are used to achieve maximum clamp force. It is a more accurate way of installing the fastener. Mercedes does that because if the fastener has not stretched to the yield point it can be reused. That is measured by length.
+Petes Garage Yeah, it's essential as we're learning this stuff for wind turbine maintenance. Anyway, they never drew the simple graph you did which made it all make sense. Thanks again!
Dude, you're a genius. A lot of people turn wrenches, but you clearly understand the principles, engineering, and physics that go into a vehicle. On top of that, you're very good at explaining them to a layman like me. Thank you for taking the time to plan, film, and upload this video.
Thanks Ryan, I'm glad it helps
Let's discuss. Torque can only be measured if there is an equal and opposite reaction. You are correct. Equilibrium must be achieved only if a force is applied. I think we are close on the definition. I enjoy the discussion. You are very astute.
DEEP INFO! Pete your the real deal, you remind me of my heavy line teacher (who was also a professor in automotive technology) when i was in automotive school. Thanks for breaking that down and keep on putting out the great content God Bless.
oldskool funk Thank you my friend. I really try to help with things that are important to understand. It's more than just a simple, 2 second explanation sometimes. God bless you too!
Thanks Junkman. I analyze torque and angle data every day. I am able to catch cross-threaded bolts, chips in a hole, dinged threads, worn sockets, and hundreds of other conditions that come up when a fastener is installed. Thank you for watching and your generous comments. I watched your videos and we both run on the same juice....wanting to teach what we know. Thanks again!
These clips are among the best to watch simple accurate explanations love the channel
Thank you
I learn something new every day. Sounds like a neat torque wrench. I know that feeling you get when you are sure you are getting ready to strip a thread and you just aren't reaching torque...and then strip! A little practice will give you that confidence back...Cheers!
Outstanding. I have never really understood the torque to yield untill you explained it the way you did. Thanks for your efforts.
My Karma is strong because I really want to teach and help people. The example you gave is one I hear often, which is why I made this video. A lesson to anyone who reads this, NEVER re-use a fastener that is torque to yield. Using that method stretches the fastener and puts it close to failure, Using it again is a guranteed failure. Thank you for sharing your experience Leigha...you Karma will help others.
Thank you my friend. I can tell you that every fastener on a vehicle has a rundown strategy that is electric. There is not a single impact wrench in any plant that will be used in assembly that runs forward. The are used for teardown only. Every fastener is installed with a computer controlled torque gun that has complex programs that monitor torque and angle data, and they are extremely accurate.
finally somebody has explained how it works, thanks pete.
Thanks my friend, it's important to understand
This is awesome!!! How could anyone give a thumbs down unless they don’t understand. Thank you so much.
That's a great question, people just like to hate I guess.
I have an idea. Because the information being presented is incorrect. Thumbs down.
Thanks so much. Torque and angle is someting that is very important, but rew people understand it. It's great to hear good things from a professional such as yourself. Just wondering....what did you learn?
I agree and you are correct. However, the main purpose of this video was to emphasize the difference between torque and angle. Some people make the mistake of adding a few more pounds of torque to makeup the angle. This can be catastophic. I just want to make sure nobody gets hurt from an improperly tightened fastener.
One of the very best engine builder tutors. It's one thing to know your craft but also another to be able to explain so well. I hope you get some reasonable monetary return. You deserve it.
Plus you like Fords.
Thank you very much Mark. to quote Einstein, if you can't explain it in 5 minutes, you don't understand it. I try to make things easy for everyone to understand.
Thank you for taking the time to execute this simplified explanation. My takeaway is that, in layman's terms: 1) You torque a bolt to a specific predetermined value and stop then, 2) You turn, torque or tighten the same bolt a little or a lot more using another tool called an angle gauge and stop. Questions:
A- Should one presume that the torque value is necessarily set at the maximum torque point for a given fastener? and therefore the degrees values = the point at which the bolt begins to stretch?
I am torqueing an aluminum cylinder head to an aluminum block. The bolt specs are:
Cylinder Screw M11, Service Limit: 148.5 mm (5.846 in.). This is what the shop manual instructs:
"First torque to 40 N*m (30 lbf*in).
Then tighten screws turning an additional 120 degrees rotation with a torque angle gauge and finish tightening with a 90 degree rotation. Torque screws to 10 N*m (89lbf*in)."
My understanding is:
Step1: Torque to 40 N*M, then
Step 2: Rotate 120 degrees, then
Step 3: Rotate another 90 degrees, then
Step 4: Torque again (another) 10 N*M
Am I understanding this correct?
That's the way it's written, but that does not sound right
Thank you a lot, Pete. With this information I can go ahead with my repair in confidence. Congrats on your solidarity.
Glad to help
Yes. What you are doing is called "conditioning" the fastener. When you do this you must use new bolts. The purpose of this step is to get all of the threads on the bolt and in the hole "lined up" so to speak so the torque and angle step is secure. Go to 22 and then back off a couple turns. Then torque all to 14 in the specified order. The add the angle in the same order. If you don't have an angle gage turn the wrench from 12 to about 5 o'clock in one continuous motion. Nothing is dumb.
Hello. Very Complex video, great job :) I work as an engineer, daily calculate bolt connections for large industrial gearboxes acc to VDI 2230 german standard. There it is different: We never calculate bolts up to yield point, because due to yield you can loose pretension force in the bolt. Normally, we calculate 90% bolt utilization, that means 90% of yield stress. this is partially because there are many factors which are uncertain during calculation (torque wrench measure tolerance, friction coeficients between mating surfaces...) and because of that it is hard to determine exact final stress in the bolt, so there is an margin to avoid yield point.
That makes sense. I would not want a large industrial bolt to be tightened to yield. Thank you for sharing that.
Amazing video--I agree with Auto Body Everything! I've long known about torque angle specifications and that they are to be used in some applications but never understood why they're different from simple torque wrench settings. Pete's Garage makes this easy enough to grasp without delving into an entire course of study.
I'm sure the thumbs down are from those who have nothing better to do than bash others or simply don't understand---which I don't understand but WTH huh? :)
Thanks so much Pete's Garage!
Thanks my friend, I try to make things easy to understand. It's not helpful if all I did was try to impress everyone with fancy words. We're all here to learn.
@@PetesGarage Always glad to thank or compliment those who take their time to help others!
Thank you very much for the good and clear explanations, as well as the explanation with kindness and interest, and for helping the advancement of science for the advancement of humanity.👏🙏🌹
3:25 By this point in the video, I'd already learned something very important, liked the video, saved it to a playlist and subscribed. Dude, you're awesome.
Awesome, thank you!
That is awesome...thank you my friend. This is one of the most commonly misunderstood things. I wanted to help people understand why angle is so important. I live with complex torque and angle programs every day. It is amazing how much you can get out of a properly installed fastener.
Thank you....it is very important to understand to make sure you put fasteners in correctly.
You don't sound like a noob....you can't know everything...Lord knows I don't. You are 100% correct. As long as you do not exceed the maximum torque for the fastener you will not enter the yield phase. As long as you know the fastener material, grade, and size you can look it up. Any fastener that has angle applied to it has gone past "A" and has started to yield and must be tossed out when removed. Great question!
56 Nm is not too high for a 10mm bolt, however, anything, especially grease, will shift the torque curve later in the tirghtening sequence and definitely cause a thread to strip. A fastener must be dry unless the manufacturer specifies a lubricant and different torque settings. Unless you have a unique deflecting beam torque wrench, you will not hear a click. You have to watch the needle and stop when it gets to the right torque. Clean threads and have faith in the wrench.
Hey Pete I have a Mazda 626 2.5L and the torque says
1. 17 ftlbs
2. 90 degrees
3. 90 degrees
that seems really low for the head bolts does that mean the bolts are torque to yield?
oldskool funk Yes...they are torque to yield. It may seem low, but the angle applies the additional clamp load.
Ok thank you Pete, I really appreciate the response. keep the great videos coming, Right on.
Thanks so much. I get asked about the difference all the time so I made the video to help people understand. Saves a lot of broken bolts and stripped fasteners.
Thanks for the thorough explanation of the tightening force applied to a screw, and what happens in relation to the laws of physics. It is very well explained.
Thanks my friend
Yooooooooo!! thanks a lot for all this info, I was really really confuse with all this angle/torque situation many manuals say, I was wondering if it has to be with plastic and elastic deformation but I never knew about this graphic you explained, really helpful info and I'll make sure to measure those nuts every time I have to open a engine for first time and shows signs of being poorly assembled. I'll be explaining this info to more people and try to avoid this overtight situation, it's sooooooo common here in Latinamerica, I saw people assembling engines without a torque wrench or proper tools, them end up lasting a few thousand miles... Really good info, thanks a lot!
Thank you for the comment my friend
I agree with you. I have awesome electronic torque wrenches, but for the average guy using it once avery few years a Craftsman will suffice. Thanks for the comment my friend!
The extra 30 degrees applies an additional clamp load to get the fastener closer to the yield point and maximum holding pressure.
Pete, Great info. I'm about to do head gaskets for the first time and I found your video during my research. Keep up the good work!!
Awesome! Good luck
That thing is gonna blow.
What a great teacher your are. You made it very easy to understand the difference between the two. Thank you much.
Nice.
I have a car that I bought used that had the "torque to yield" crank pulley bolt (a $3.00 part) re-used by some numb-nut shade-tree mechanic that suddenly failed and cost me a $7000 engine.I find myself wishing that he'd taken the time to check out a good youtube vide or two like this one, beforehand.
Your hard work didn't help me in this instance, but I am hoping that there is at least one other person in this world who can avert that nightmare. Your Karma is strong.
Thanks for this extensive explanation. Will help me in getting the cylinder head job done right.
+Kaktus Jack Thank you
I can't believe I've never heard of this before. Thank you
I learn something new every day
Always follow the manufacturers recommendations. If the instructions do not call for any prepping the bolts then none is needed. Sometimes a moly lube can be applied, but that will totally change the torque and angle specifications. The digital torque tools are cool, but a simple click wrench is suffucient. I use some really cool wireless, digital tools and a complex controller that allows me to write programs, but they are $15k. The deflective beams are fine, just take your time.
Very well explained video. I work in the Marine Business and all replace any tighten to angle bolts. You just can't walk back in case of failure of a bolt.
+Charles Kettering Awesome. It's a long swim home
Any electronic tool is fine as long as it is calibrated at the recommended interval. I use some electronic torque wrenches and they are pretty neat..and yes they can accurately measure angle. A good one is very expensive but the manual method is just as good.
Glad to help. Thanks for watching and I hope you get things put together successfully.
I went to your page hoping to find some technical videos on the subject. Good stuff on lifting weights.
That is the most common question. It is tough to wrap your head around the fact that angle has no relation to torque. Angle is a different calculation for every fastener material / base material combination. Toque is a resistance to rotation, angle is a clamping force, two totally different things.
Thank you....this is actually a very simple concept, but not so easy to explain in a non-technical manner. I get many calls from my "Blown Head Gasket" video from folks asking about the angle on the head bolts. I had so many questions I decided to make this video to explain why angle is important and why new head bolts are required. Everything I do is to try to help and teach. I may not be a TV spokesperson...but I think I get the idea acrosss : > )
Thank you....it's all about helping each other my friend.
Any time you apply angle to a fastener it will stretch. You may need super mics to measure it, but some change will occur. If you pass the yield point you will always (depending of the material) see evidence. Shiny, bent, gaulled, or cracked threads are just a few things. Everything is material and application dependent.
thanks pete, should be right now ill get a angle gauge and figure it out; should i prep the bolts and holes in any special way. what do you think about those digital tourque attachments like a little box that you can use with any ratchet ,are these a good option to a tourque wrench, ihave a 1/4 drive and a 1/2 drive deflective beam tourque wrenches but im pretty sure the 1/2 inch needs callibration, they are quality tools? keep up the good work.
Great video, many thanks. At the age of 70 I thought that I knew all about torque settings!!!
+William Scurlock You can never know everything. I learn something every day. Thank you my friend
Well explained and much to think about .
If your torque wrench is calibrated or if you use the degree tool and follow the chart on torque & stretch specifications you have other factors to consider . The quality of the threads on either the nut , bolt or machined part . We are left with trust of a manufacturer to produce a quality part . The metal , threads and heat treating process have to be consistently the same . This to give repeatable and consistent torque & stretch applied to each nut & bolt .
If you are blue printing an engine that will be pushed to its limits , these are some of the many important things to consider .
It really doesn't matter if it's blueprinting or not. It applies to all fasteners
Hey Pete good stuff thanks for sharing. I have a question though. I understand the theory of the stress & strain and where the temporary load or angle yield of the fastener from point A-B means what I'm trying to understand and maybe I sound like a noob but is how do you know when you get to point A? the beginning of the angle is it after the maximum torque specs? because you mentioned torque is a different calculation then the angle calculation.
The presenece of anything that acts as a lubricant will shift the torque window so it acts later on the curve. There are additional calculations to account for these circumstances. Usually threshold torque will be measured later in the rundown sequence.
Anti-seize compounds contain nickel to reduce galvanic corrosion. It will act as a lubricant as any other material would. There is no rule of thumb. Every fastener is different. The presence of anything acting as a lubricant causes the resultant torque to be lower. The threshold torque starts later so the angle can go past yield. I think you'd be safe with a 10% drop. Torque/angle applies maximum clamp load so loc tite is useless. Nothing should be applied unless the manufacturer recommends it.
Thanks for the really interesting video. My question is - if the angle after torquing is 90 degrees do i really need a gauge, can't I just go 90 degrees further with my torque wrench?
Sure, you don't need a gauge. Just get as close as possible. Sometimes I see angles of like 135 or 160 degrees
Best ever explanation on subject of tightening.
at first i was confused but it makes perfect sense. this explains why you need an angle to torque (because the equal opposite force changes as you get to point B and then to C) head bolts properly and why head bolts should always be replaced.
Very good
Thanks for your reply Pete,my wrenches are an aussie make ,i dont know if you know them , Warren and Brown, it has a beam which deflects on to as set value and clicks out a spring loaded pin which "clicks' and the pin never popped. I think ill have to experiment on some test fasteners to get a feel for it, but it sure shakes your confidence ,this was a pretty simple job and i stuffed it.Keep up the good work.
Not that I know of. There are so many different material / thread / variable combinations it would be a huge chart. That is why it is a calculation for each application.
Cool....what class?
awsome explanation MR.PETE....thanks for that info and putting on video for the world to understand ....great graph and calculations ......!!!
Mechanical engineer here...I love it when guys get technical when talking cars.
I worked as an engineer for GM Powertrain for a long time. You may enjoy this video ua-cam.com/video/qV41SNntPxo/v-deo.html
Head bolts are the most common. Other engine bolts that may be torqued to yield are cam phaser bolts, rod bolts, and some intake plenum bolts.
This video is priceless! Thank you
You're very welcome!
Thanks for the great explanation! Enjoyed it!
Thanks my friend
what an amazing explanation! im thinking why not just angle torque from the start instead of using torque wrench? if thats passible, could you provide me an equation to convert ft-lb to angle or at least a link to a chart for that?
Angle is a different calculation based on many factors. It is intended to yield the fastener after a certain torque is reached. They are not the same.
@@PetesGaragebut you know that a half turn (maybe full turn) of any size of metric fastener is a 1 mm going down, with that can't we bring a an equation to calculate who much force of that 1 mm going down?
Hey Pete ,got a problem here thats driving me nuts...over tourqued. I asked you a question a while back about the angle and you set me right .My problem is i got my tourque wrenches calibrated ,very technical certificates ,temperature test carried out and so on ,cost me over 200 bucks,results were very good.Im rebuilding susspension on a motocross bike , doing the top shock bolt up and ,i knew it looking back,but i stripped the bolt . Its a 10 mm bolt ,plain washer,u flange nut it had grease on
My one question is, if you're angle torquing and somehow you lose your torque by 5-10°, will that affect the whole torquing process to where the cylinder head will go bad?
Awesome explanation!!! Congratulations !!! Gonna show it to my students
Awesome! Thank you!
I just had my first experience with Torque-to-yield bolts.
( Stretch bolts )
I figured out real quick, they are single-use.
You never re-use them. I suppose you could if you could tell where it was starting to stretch and stopped right there... but I can't.
I just dropped my 1/2" torque wrench at Alaska Matrology and Calibration Services where they do a lot of them for the Oil-patch on the North Slope. I drug them through the mud on this, and they said my Torque Wrench had to hold within 4% of it's setting, throughout it's range.
That was important for me to know.
So. 4% of 10 foot pounds, or 120 inch pounds...
I thought the same as you said, but in the real world...
Doesn't matter.
Thanks!
Mark
Interesting, thanks for sharing
Hey great job on the the torque and angle topic, vary nice discription! I'm a license tech and I even learned a little something from that! Great job thanks for sharing.
Great video thanks for taking your time to explain this it was a great help
+Alfredo Luciano Thank you my friend
Thanks a lot, I knew the operation but had no idea what was the purpose to add angle after torque tightening.
Super explanation. Thanks so much.
You are welcome!
The videos I make are driven by phone calls I receive. When I made the 3.4 head gasket video I had hundreds of calls & had to explain angle and torque-to-yield fasteners to most everyone. I analyze torque and angle data every day in an engine plant and it is immensely important to understand what it means. The data can tell me if there is a cross-threaded fastener, chips in a hole, or a bad part. It is an intricate science, I'm not an expert, but I tried to make it easy to understand. Thanks!
I could have made it a bit simpler...but I think I got the point across...thanks!
Great explanation, thanks.
Thanks my friend
Great to hear this simplified explanation. Very well explained! Ü
This is a great video. Thank you very much.
That is correct. The reason I made this video is because many people say " just add a little more torque to do the angle," but that is so wrong. As you are learning about the eloasticity modulus watch how the curves change with different materials. 20 degrees of angle on a 1020 steel bolt has a different curve than 316 stainless.
This could be the most important lesson in mechanics I have learned. Now, I came into a use for this information, but need more information before proceeding. I own a 2004 Cadillac CTS, 3.6 L engine. I must replace the bolt that holds the harmonic balancer to the mainshaft. The info I have is that I should torque to 37 ftlbs and then angle 120º (one site says 140º). How do I lock the engine so that it does not rotate while angleing and what is the correct angle, 120º or 140º? Thank you and keep a good work.
There is a tool that goes in the spark plug hold to hold the piston at top dead center. That would work. If you have info that says 120, I would trust that, unless you can get a different torque spec from a dealer.
it . The value was 56 Nm,as i was tightening it i could feel thet the fastener had taken up all the force but i kept going waiting for the click ,deflecting beam wrench.Do u think the grease on the bolt and maybe washer would make that much difference as to be wildly out .And 56Nm seems quit a lot on a 10 mm bolt, now i have no faith in my tourque values and i was planning on doing the crank bearings,but now it seems i got no chance.cool videos Pete.
I am going to use this in my class on Monday!! As Always, great stuff!
Thanks, Question, Doing my heads on Durango and book says The cylinder head bolts are tightened using an angle torque procedure, however, the bolts are not a torque-to-yield design.
Tighten bolts 1-10, 90 degrees. Tighten bolts 11-14, 30 Nm (22 ft. lbs.)Does that meen use the Torque Angle Gauge and bring it to 90 after the initial 22 ft lbs? Great video and easy learning .
Yes, angle is always added after torque. Even if the bolts are not TTY I would buy new ones, they're cheap.
Understanding the "why" is just as important as knowing the "how." Thanks for saying "HOLY CRAPOLA." Had you chosen a less intelligent explative I would have deleted the comment. I'm not a holy roller, but the use of profanity indicates lack of intelligence. I am just like you, I don't trust anyone to work on my stuff so I learned to do it myself. Everything is easy when it is broken down into simple English....Thanks for watching Junkman!
Thanks for the video. A question about lubricating cylinder tty bolts. Does that push the bolt beyond the elastic limit and hence have an impact on the start and end yield points
It could depending on the fastener, it will not likely lead to ultimate failure
Hi Pete great video, just wanted to ask you a question to clear my confusion, I'm doing a head gasket replacement on my BMW E36 325i M52 B28 I have new stretch bolts the torque specs for the head bolts is 35nm at a angle of 90 then 90 again, my question to you sir do I torque the bolt to 35nm with my torque wrench first ? Then put my angle gauge on with my breaker bar do my first 90 degrees on all 14 bolts then do my second 90 ? I'm confused from the part of the video were you mention 80% of torque do I subtract 35nm by 20% ? I'm all the way from South Africa we use Nm instead of Lbs.
Torque all of them in sequence to 35 nm, then add 90 degrees to all of them in sequence, then add another 90 in sequence.
Hi Pete's Garage thanks for the reply buddy.
No wonder those bolts broke. Thank you for the explanation.
I suppose that the material the bolt is fastened to is also past it's yield stress point?
The base material usually has a higher yield than the fastener, but in most cases it can be repaired with a helicoil
Ok you got me.....what are XP points?
very well explained, clear and precise
Thanks John
Hey, thanks for the video... very informative!
Is there a way to calculate the number of rotations a bolt should make in order to exert 16 ft-lbs (21.57 Nm) of torque?
Did some research and found there is a "Rotation Angle Method" - The tightening is managed by rotation angle which starts from the seating point of the bolt head.
Yes there is, angle monitoring with torque control
I have a short attention span. 5 to 7 minutes and I click to the next video.... I just watched the whole 14:50 and was bummed when it ended. Might just have to watch this again. After snapping bolts for the last 45 years ,I assumed I just didn't know my own strength. Thanks to "you" dammit ! I now realize I'm just an idiot. ;)
See if you can double your time and watch this one ua-cam.com/video/qV41SNntPxo/v-deo.html
Nice video!
But is there som kind of diagram to get the right angle?
Thank you....glad it was understandable
Torque to yield fastener specifications most common call for a torque and angle. Like 110 ft lbs with 95 degrees of angle. You can torque in sequence in stages, but the angle must be applied in one, continuous motion. I have never seen a 35°+5° spec, but I would do the 35° in sequence on all bolt and add the 5° as a second step.Thanks for watching!
I’m getting ready to put head gaskets on my duramax, I’m ordering new studs (amx, acr something like that), can I get away with just torquing them to the required torque, not doing the angle? I don’t have a torque wrench that does angle, thanks.
No, you have to add angle. A torque wrench does not measure angle. Torque it down and estimate the angle as close as you can.
So, we just touched on this in my mechanics of materials class, though we're staying in the elastic region for now. Force per unit area is equal to young's modulus multiplied by the change in length divided by the unloaded length. With a little bit of algebra, and some knowledge of your bolt threads, you can make some neat things happen...
Great video and incredible explanation! I had no idea of the science behind it all. Subscribed :D
+CrimsonBradders There's much more to it. Watch this video about fastening
ua-cam.com/video/qV41SNntPxo/v-deo.html
There is a LOT more to it than torque and stretch bolts as aluminium castings are usually porous. To get around this problem, castings that are subjected to pressure are Vacuum Varnish Impregnated. If the cylinder head is skimmed this VVI layer will be lost although there is a company in the Manchester area that will re-impregnate castings. Empirical results with the Peugeot 106 diesels indicate that the original head gasket will last for about 50,000 miles but replacement gaskets will only last about 30,000 miles. Of course the alloy in an old engine will be impregnated with oil. The small car to have in the Peugeot range was the now classic 205 with the iron engine as that was a horse of a different colour! 250,000 miles was quite possible and the extra weight on the driving wheels could be very useful!
Excellent explanation, many thanks.
+Falk Guthert Thank you my friend
Very well explained & thought out. Great job & thank you!
hi Pete, I'm changing the hg on a bmw and the oem head bolts are m11 with instructions to tighten to 30nm +90º +90º, since I don't have a way to measure these angles accurately, I used the torque setting and then gave it 80nm instead of the angles, but now I see there's more to it regarding this angle thing and i'm afraid the clamping power is not optimal Is there a way to tighten the cyl head giving the approximate values intended through nm's only? thanks a lot and great video.
Ricardo Nunes There is a way, but it takes tons of math. You can estimate the angle. 90 degrees is simply a quarter turn of the fastener. That is pretty easy to do with a wrench. 80 Nm is almost 3 times the suggested torque. The resultant torque from two 90's may be a bit higher. If you're worried you can re-torque them. You can do this us to 3 times on a torque to yield fastener.
Sorry to be dumb. But why are manufactures using torque to yield fasteners now, why not 70 years ago in WW2 fighter engines or in GP engines in the 70-80s . Weight saving? Space saving? or just a nice Cash cow? 2nd question why does Mercedes allow the reuse of torque to yield fasteners so long as they are within length limits ?
TTY fasteners are used to achieve maximum clamp force. It is a more accurate way of installing the fastener. Mercedes does that because if the fastener has not stretched to the yield point it can be reused. That is measured by length.
Thanks! Really helped me to understand yield and will apply in the field!
+Logan O It's very important to understand when you are using torque and angle. Fastening is a science
+Petes Garage Yeah, it's essential as we're learning this stuff for wind turbine maintenance. Anyway, they never drew the simple graph you did which made it all make sense. Thanks again!