Usually you don't want to reuse 12mm head bolts, it's a different story with 16mm head bolts they use in heavy duty engines. The bolts are much less likely to overstretch when torqued. Those ~450 dollar studs can be retorqued many hundreds of times before you see any stretch at all in the threads. Head bolts on a heavy duty engine should be replaced after 2 overhauls, light/medium duty should be replaced every time you untorque them.
Batojiri1 actually on the topic of heavy duty engines it depends on the manufacturer. The head bolts for Cummins and their ISX for example are allowed to be reused several times as long as they’re within spec. Detroit’s on the other hand, not so much. Many times you can use a gauge to see if the bolt falls within tolerance. And like he said in the video, anything torque to yield is a one and done.
EGR is designed to decrease combustion temperatures, its in Wikipedia look it up. And fine thread has nothing to do with more clamping force - it provides less thread resistance under high torque and therefore less differences in actual clamping force between individual studs. Basically it minimizes the torque errors because of smaller thread resistance.
Nils Jakobson I would have to disagree. If you take a 6 inch string and wrap it around a 3 inch diameter cylinder from end to end you may only get 1 rotation. Now repeat this process with a 30 inch piece of string, you are able to get 10 times the rotation and 10 times the material was used. With this being said the longer string will have a finer thread pitch and much more material in contact so you get more clamping force....
@@bernardwarr4187 Wrong again. While it does increase the intake charge temperature the combustion temperature is lower because less oxygen is present for the combustion - that is the desired effect and the whole point of EGR - to reduce combustion temperature and thus - reduce NOx emissions!
@@NilsJakobson wrong again. Higher combustion temp, reduced emissions. That’s why, mass produced cars, run high temps. Competition cars running cooling, high power and emissions!
Head studs are a upgrade that you need to make if your driving style would even have you considering the condition of your head gasket! All trucks and drivers are different. Better to have them and not need them.
I’ve been debating just using regular head bolts on my lb7 head gasket job because I’m half ass broke, guess you just changed my mind, I’ll spen the xtra $600 on arp studs
If I have head bolts in now, can I just pull them out and replace them with studs or do I have to have machine work done? I have a low mile big block that I would like to beef up a little but if I have to tear it apart to have it machine for studs I'll just keep it together and use it!
We have several customers that replace bolts, one at a time, with studs and have success. If you have a head gasket issue now, then we suggest the head to be removed and sent to a machine shop.
Hi ihave a 1985 vw jetta1.6 na diesel..i notice head is leaking engine have bean rebuilt..i would like to buy set off studs for this vehicle if there avialable..thankyou very much....J.E..and i like the tutorial about de diference in the stud and head bolt.
So in my case since my Toyota Corolla block is stock but my head is ported polished and 5 angle valve job, i could use New Head Bolts instead of head studs since block is stock and it's all motor right?
ive been looking all over the internet and cant get a straight answer as to why the head studs are only Hand Tightened into the block? why is this? should they not be torqued to spec?
As you are tightening the nut this will tighten the stud itself to a certain extent. The tightening of the nut against whatever surface you are working on actually pulls the stud and creates the “clamping” force. By not bottoming out the stud, you allow for the stud to advance in the bore and not become tightened against the bottom of the bore which is a force that is unnecessary and can cause damage to the bore.
I’m buying a 6.0 with 240k. The seller said it’s got aftermarket head bolts instead of aftermarket studs. Is this good or bad? Does an aftermarket bolt “bulletproof” to some degree, at least better than stock? I realize studs are better. It also is deleted. Anyone throw me some info? This thing gonna blow up on me? I don’t hotrod vehicles.
Undercut studs, in very very very general terms have more elasticity. We are controlling the stretch even more with studs so that we don’t have the expansion/contraction of the fastener AND the gasket. In layman's terms, I'm laying my money on a low stretch stud and compression of the gasket via the mating surfaces being the lesser of the two evils to hold it all together. Would love to discuss if you would like to call in, ask for Wade.
@@thoroughbreddiesel so whichever kit you buy for your vehicle will have its instructions. Cause I’m going to college for diesel and I’m barley learning of these thoroughly so it’s new to me.
Wade, I got a question. I just picked up some APR Head studs for my F250. I do not have any head gasket leaks or loss of power and all the fluids look normal. I'm planning on throwing in some new gaskets, oil cooler, o-rings, stand pipes etc...Do you think this is wise to do for insurance? This is being done as preventative maintenance so I can avoid the trouble in the future. I also plan on towing a travel trailer(no more than 12k lbs). Please let me know what you think! Thanks in advance! -Joel
Absolutely. All of those things are going to help you to make the truck much more reliable. So many people right now just do a stud drop in and forget it. You truly need to have the heads removed and checked. Do not neglect to check the deck surface for flatness as well. Replacing the oil cooler and egr cooler are going to help keep their respective temperatures in the spec as well. Good luck with your install and if you have any questions please don’t hesitate to ask.
i have a triumph stag v 8 engine 74 model can I use the head studs and bolts again it has studs on top of head and bolts on bottom of head when doing head gasket as they are quite expensive new
Thank you for the video . I hope this is not too dumb of a question but can you replace 1 stud / bolt at a time or do you have to dis assemble the whole head ???
YW. We always suggest that the head be removed, checked, and a fresh gasket installed. If the truck is low mileage or you choose to do the studs 1 at a time, please remember to re-torque the studs after a heat cycle for proper seating.
Threads per mm in diesel engines. Usually a fine thread metric faster is between 1.5 to 2 threads per mm, much finer threads than standard per inch fasteners.
Cheaper and plus during the assembly process it would be too many extra steps on assembly line. If you ever look at a factory floor assembly heads it is with a machine that turns all the bolts at the same time to where it is torquing bolts fractions of a second behind the next.
Torque plus angle is automated equipment friendly. Torsion torque bar drivem by airnor electric impact for first torque step. Then a sleeve drops over the outside of the socket head, socket has external splines or hex, and then a gear reduction motorized drive turns the head bolts and is monitored by a position sensor. No backbreaking job for a human and tool life is long. Torquing to high value hammers the sockets and they wear and the friction of threads gives torque when the goal is consistent elongation of shank that sets the clamp force of fastener. Low torque in first stepnis low enough that friction is not factor but that steps a preload on gaskets so the angle is hust shank elongation.
Lol cylinder pressure maxes out the same, the max pressure just lasts longer because fuels burn at a rate…Corky Bell, John Lingenfelter and David Vizard know more about these things than anyone else and have tech manuals printed you can buy.
I have a 95 7.3 oil and antifreeze is mixing what could cause it replaced the oil cooler guy I brought it off of said that was what was wrong with it I’m think maybe the head gaskets and what would be a great head stud for my truck
Are you getting coolant in the oil or oil in the coolant? Could be the head gasket for sure. Do you notice any pressure on the coolant system after the truck has set for a few hours?
@@christophermooney2556 It probably at least needs head gaskets. Be sure to have your heads resurfaced so they are no surface imperfections. It could also be a cracked head. Either way they are both big jobs. I believe they make arp studs for those also.
A true torque to yield bolt will have TTY stamped on the head of the bolt. They are not reusable because they have been stretched to maximum working limits. Torque to angle bolts are stretch fasteners, but to a much lesser degree. On medium and heavy duty engines, you can get 2 or 3 head removals before you should start testing for thread stretch. Engines that have 12mm or smaller torque to angle bolts should be replaced every time they are untorqued, just for saftey reasons and because they are cheap enough.
Fair bit of mis information in this video. 1) there is not necessarily any difference in material, totally depends on particular bolt stud in question. 2) Bolts can penetrate deep enough into the head, and the load is only borne by a certain depth of thread anyway. 3) the stud has to resist the thread friction with the nut which is not necessarily any less than the bolt sees screwing into the head. Its called a reaction force. Ask Newton. There is a bit of an advantage using the fine thread, and its nice dropping a head onto studs. But that is where the advantages end
You forget one major advantage over angle torqued bolts that studs have, they exhibit far less stretch over a given cycle of torquing/untorquing than a bolt does. TTY and TTA bolts are essentially the same, only the TTY bolts have been stretched to maximum working limits. I honestly wouldn't reuse a TTA bolt that was 12mm or less in diameter. Due to the stretch caused by angle torquing. It's not much, but why take the chance? The one place where it doesn't make sense to have studs for purely mechanical advantage is 14mm, 16mm, 18mm, and above medium and heavy duty engine head bolts where fastener stretch is almost nonexistent.
Savanna Smolinski...Manufactures are short term, for the most part it is all about them/ Cost, cost per vehicle x many vehicles and/or diesels/ engines. Wish they would just make these improvement up front and pass this cost onto me, everyone would be better off for it. although, manufactures and most people cannot see it, therefore it just doesn't work out very well! also, manufactures don't want anything lasting to long. take a look at what these aftermarket head studs cost the consumer plus labor for some who choose installation. this same stud cost to these manufactures would be a fraction of this cost. Myself, would prefer buying mine initially any day! They all love selling parts, Lots of parts!
Same material. The bolt has the strength of the miner diameter. The stud has the same strength of the miner. same diameter same strength. the difference is torsion of the bolt during torquing.
Very informative. Why isn’t this just done my the manufacturer?
Thank you. IDK good question.
cost, they are in the business of selling, producing vehicles with longevity is counter to profit.
Bottom line, it's cheaper
Jaguar used them in the 80s and possibly 90s not sure about now ?
@Don Olypopper what if im considering 15% over injectors?
30 dollars vs 440 dollars for oem vs arp. MY WALLET IS SUFFERING
Usually you don't want to reuse 12mm head bolts, it's a different story with 16mm head bolts they use in heavy duty engines. The bolts are much less likely to overstretch when torqued. Those ~450 dollar studs can be retorqued many hundreds of times before you see any stretch at all in the threads. Head bolts on a heavy duty engine should be replaced after 2 overhauls, light/medium duty should be replaced every time you untorque them.
Batojiri1 actually on the topic of heavy duty engines it depends on the manufacturer. The head bolts for Cummins and their ISX for example are allowed to be reused several times as long as they’re within spec. Detroit’s on the other hand, not so much. Many times you can use a gauge to see if the bolt falls within tolerance. And like he said in the video, anything torque to yield is a one and done.
Thank you. I just learned about stud fasteners. This explains a lot.
You're welcome. Happy to help.
Thank you!
You're welcome!
Ok got it Now what's the difference between lug nuts & hex nuts & lock nuts
Thanks for that vid i would .like head stud for my isuzu 4jb 1
Head bolts are made to stretch the head gasket is made to expand to compensate studs don't give but the engine block will
Thank you for this video.
Glad it was helpful!
How much horsepower are the arp 425s rated for? At what point should you spend $1200 instead and get arp 625s on a 6.7 Cummins?
Thank you for the very informative video
EGR is designed to decrease combustion temperatures, its in Wikipedia look it up. And fine thread has nothing to do with more clamping force - it provides less thread resistance under high torque and therefore less differences in actual clamping force between individual studs. Basically it minimizes the torque errors because of smaller thread resistance.
Nils Jakobson I would have to disagree. If you take a 6 inch string and wrap it around a 3 inch diameter cylinder from end to end you may only get 1 rotation. Now repeat this process with a 30 inch piece of string, you are able to get 10 times the rotation and 10 times the material was used. With this being said the longer string will have a finer thread pitch and much more material in contact so you get more clamping force....
Hot EGR: Exhaust gas is recirculated without being cooled, resulting in increased intake charge temperature.
EGR, takes exhaust combustion gases, and reuses them, there forever, increasing intakes charge temperature and combustion temperature
@@bernardwarr4187 Wrong again. While it does increase the intake charge temperature the combustion temperature is lower because less oxygen is present for the combustion - that is the desired effect and the whole point of EGR - to reduce combustion temperature and thus - reduce NOx emissions!
@@NilsJakobson wrong again. Higher combustion temp, reduced emissions. That’s why, mass produced cars, run high temps. Competition cars running cooling, high power and emissions!
Do you need these on a stock 5.9 3rd gen with a mild tow tune?? Seems like overkill if nothing is wrong
Head studs are a upgrade that you need to make if your driving style would even have you considering the condition of your head gasket! All trucks and drivers are different. Better to have them and not need them.
Great information, just wondering why the studs aren’t torqued to the block & fitted hand tight, what is the reason for this?
Hi, I found 2 bolts and two studs on my car's throttle body attached to the engine. Why not all 4 bolts or studs? Can you please explain
I don’t have an answers for that. I don’t think that it will be an issue of torque application.
I’ve been debating just using regular head bolts on my lb7 head gasket job because I’m half ass broke, guess you just changed my mind, I’ll spen the xtra $600 on arp studs
If I have head bolts in now, can I just pull them out and replace them with studs or do I have to have machine work done? I have a low mile big block that I would like to beef up a little but if I have to tear it apart to have it machine for studs I'll just keep it together and use it!
We have several customers that replace bolts, one at a time, with studs and have success. If you have a head gasket issue now, then we suggest the head to be removed and sent to a machine shop.
Hi ihave a 1985 vw jetta1.6 na diesel..i notice head is leaking engine have bean rebuilt..i would like to buy set off studs for this vehicle if there avialable..thankyou very much....J.E..and i like the tutorial about de diference in the stud and head bolt.
Good video, very informative. The way you say stuuuuuud is funny though!
Thank you. That's riiiiiggghhhtttt!
So in my case since my Toyota Corolla block is stock but my head is ported polished and 5 angle valve job, i could use New Head Bolts instead of head studs since block is stock and it's all motor right?
ive been looking all over the internet and cant get a straight answer as to why the head studs are only Hand Tightened into the block? why is this? should they not be torqued to spec?
As you are tightening the nut this will tighten the stud itself to a certain extent. The tightening of the nut against whatever surface you are working on actually pulls the stud and creates the “clamping” force. By not bottoming out the stud, you allow for the stud to advance in the bore and not become tightened against the bottom of the bore which is a force that is unnecessary and can cause damage to the bore.
Great video 👍🏼
I’m buying a 6.0 with 240k. The seller said it’s got aftermarket head bolts instead of aftermarket studs. Is this good or bad? Does an aftermarket bolt “bulletproof” to some degree, at least better than stock? I realize studs are better. It also is deleted.
Anyone throw me some info? This thing gonna blow up on me? I don’t hotrod vehicles.
Would you guys have any information on how to pull the cab and engine on a lb7
It maintain's head torque better than stretch to yeild factory bolt's? What about under-cut head studs?
Undercut studs, in very very very general terms have more elasticity. We are controlling the stretch even more with studs so that we don’t have the expansion/contraction of the fastener AND the gasket. In layman's terms, I'm laying my money on a low stretch stud and compression of the gasket via the mating surfaces being the lesser of the two evils to hold it all together. Would love to discuss if you would like to call in, ask for Wade.
How is the torquing procedure perform on these? Is it the same as the factory head bolts or are there different procedures?
Tq values are different but sequence will be the same.
@@thoroughbreddiesel so whichever kit you buy for your vehicle will have its instructions. Cause I’m going to college for diesel and I’m barley learning of these thoroughly so it’s new to me.
Wade, I got a question. I just picked up some APR Head studs for my F250. I do not have any head gasket leaks or loss of power and all the fluids look normal. I'm planning on throwing in some new gaskets, oil cooler, o-rings, stand pipes etc...Do you think this is wise to do for insurance? This is being done as preventative maintenance so I can avoid the trouble in the future. I also plan on towing a travel trailer(no more than 12k lbs). Please let me know what you think! Thanks in advance! -Joel
Absolutely. All of those things are going to help you to make the truck much more reliable. So many people right now just do a stud drop in and forget it. You truly need to have the heads removed and checked. Do not neglect to check the deck surface for flatness as well. Replacing the oil cooler and egr cooler are going to help keep their respective temperatures in the spec as well. Good luck with your install and if you have any questions please don’t hesitate to ask.
i have a triumph stag v 8 engine 74 model can I use the head studs and bolts again it has studs on top of head and bolts on bottom of head when doing head gasket as they are quite expensive new
And what about the down side for the studs?
In the performance world, the only downside that I know of is the extra time for installation.
Great class
Thanks!
Good video it sucks that those head studs are overpriced
Darrin Portell there’s some xotic headstuds that are half the price of ARP studs
Great vid👍
Thanks!
Good stuff, good explanation.
Thank you.
well explained Thank you s.r 👍
Thanks!
Thank you for the video . I hope this is not too dumb of a question but can you replace 1 stud / bolt at a time or do you have to dis assemble the whole head ???
YW. We always suggest that the head be removed, checked, and a fresh gasket installed. If the truck is low mileage or you choose to do the studs 1 at a time, please remember to re-torque the studs after a heat cycle for proper seating.
Fine vs coarse thread..more clamping because of threads per inch
Threads per mm in diesel engines. Usually a fine thread metric faster is between 1.5 to 2 threads per mm, much finer threads than standard per inch fasteners.
what about bore distortion?
My john deere b two cylinder tractor came with studs in it from factory and thats only like a 26 hp tractor
Ok
Why doesn’t the oem’s already Install studs wouldn’t that be better for everyone.
Cheaper and plus during the assembly process it would be too many extra steps on assembly line. If you ever look at a factory floor assembly heads it is with a machine that turns all the bolts at the same time to where it is torquing bolts fractions of a second behind the next.
Torque plus angle is automated equipment friendly. Torsion torque bar drivem by airnor electric impact for first torque step. Then a sleeve drops over the outside of the socket head, socket has external splines or hex, and then a gear reduction motorized drive turns the head bolts and is monitored by a position sensor. No backbreaking job for a human and tool life is long. Torquing to high value hammers the sockets and they wear and the friction of threads gives torque when the goal is consistent elongation of shank that sets the clamp force of fastener. Low torque in first stepnis low enough that friction is not factor but that steps a preload on gaskets so the angle is hust shank elongation.
Lol cylinder pressure maxes out the same, the max pressure just lasts longer because fuels burn at a rate…Corky Bell, John Lingenfelter and David Vizard know more about these things than anyone else and have tech manuals printed you can buy.
I have a 95 7.3 oil and antifreeze is mixing what could cause it replaced the oil cooler guy I brought it off of said that was what was wrong with it I’m think maybe the head gaskets and what would be a great head stud for my truck
Are you getting coolant in the oil or oil in the coolant? Could be the head gasket for sure. Do you notice any pressure on the coolant system after the truck has set for a few hours?
Thoroughbred Diesel I’m not sure I brought the truck like that
@@christophermooney2556 It probably at least needs head gaskets. Be sure to have your heads resurfaced so they are no surface imperfections. It could also be a cracked head. Either way they are both big jobs. I believe they make arp studs for those also.
Don't forget to have your head pressure checked at a machine shop.
You were right the first time I believe torque to yield on the head bolts , I’m guessing you changed it because that stupid 90 degree crap ?
A true torque to yield bolt will have TTY stamped on the head of the bolt. They are not reusable because they have been stretched to maximum working limits. Torque to angle bolts are stretch fasteners, but to a much lesser degree. On medium and heavy duty engines, you can get 2 or 3 head removals before you should start testing for thread stretch. Engines that have 12mm or smaller torque to angle bolts should be replaced every time they are untorqued, just for saftey reasons and because they are cheap enough.
Fair bit of mis information in this video. 1) there is not necessarily any difference in material, totally depends on particular bolt stud in question. 2) Bolts can penetrate deep enough into the head, and the load is only borne by a certain depth of thread anyway. 3) the stud has to resist the thread friction with the nut which is not necessarily any less than the bolt sees screwing into the head. Its called a reaction force. Ask Newton. There is a bit of an advantage using the fine thread, and its nice dropping a head onto studs. But that is where the advantages end
You forget one major advantage over angle torqued bolts that studs have, they exhibit far less stretch over a given cycle of torquing/untorquing than a bolt does. TTY and TTA bolts are essentially the same, only the TTY bolts have been stretched to maximum working limits. I honestly wouldn't reuse a TTA bolt that was 12mm or less in diameter. Due to the stretch caused by angle torquing. It's not much, but why take the chance? The one place where it doesn't make sense to have studs for purely mechanical advantage is 14mm, 16mm, 18mm, and above medium and heavy duty engine head bolts where fastener stretch is almost nonexistent.
Why don't newer diesels just come factory with studs??
Savanna Smolinski...Manufactures are short term, for the most part it is all about them/ Cost, cost per vehicle x many vehicles and/or diesels/ engines. Wish they would just make these improvement up front and pass this cost onto me, everyone would be better off for it. although, manufactures and most people cannot see it, therefore it just doesn't work out very well! also, manufactures don't want anything lasting to long. take a look at what these aftermarket head studs cost the consumer plus labor for some who choose installation. this same stud cost to these manufactures would be a fraction of this cost. Myself, would prefer buying mine initially any day! They all love selling parts, Lots of parts!
Head bbbBBBB-BOWLT.
Same material. The bolt has the strength of the miner diameter. The stud has the same strength of the miner. same diameter same strength. the difference is torsion of the bolt during torquing.
A bolt is a screw with a nut attached to it.
You showed a screw there,not a bolt.
michaelovitch clueless