Harmonic Balancer bolt
12 Second Club
Joined: Aug 2014
Posts: 205
Likes: 26
From: Houston, Texas
What RPM you gonna turn it to? Probably be fine, in regard to the bolt the GM stock crank bolt is torque to yield bolt so you must get a new bolt. If you buy the arp bolt I believe it is reusable. Plus a stock replacement bolt is like 5 bucks or something. Send it.
I just buy a new bolt.i saw one come loose once when a guy here i work with didnt buy a new one. I guess you could blue loctite it in a pinch to get yourself going but id still replace it when you can. cheap insurance. i just use the arp for now on. I always keep and extra new one hanging on my wall.
On The Tree
Joined: Oct 2004
Posts: 98
Likes: 11
From: in a large steel structure
Hello! 30 year career aircraft mechanic here...…..TTY are garbage.... every chance I get I replace the tty bolts with quality fasteners... when you torque a fastener, the clamping force comes from "streching" the bolt... one time use TTY are one time, use because once they are streched they take a set... and wont strech again to maintain a proper clamping force.... and personally on any C5 If I have removed the stock Harmonic balancer....It does not go back on... the stock balancers have a reputation of certain failure... the rubber loses its bond... if your on a budget, powerbond is a good replacement... for a good quality unit you cant beat a ATI.
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not that you should I guess..... but I have NEVER replaced the bolt, I have NEVER had one come loose OR break.... And I use an impact to tighten them after the pulley is fully seated
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TECH Resident
Joined: Mar 2012
Posts: 871
Likes: 411
From: Texas
If you look at the list of fasteners on some of the newer GM engines that are supposedly TTY, you'd raise your eyebrows.
We're talking fasteners that only see about 35 lb/ft of torque, total.
Methinks GM is just trying to sell extra bolts.
Oh, and just for the record: I HATE TORQUE TO YIELD BOLTS. A bunch of wasteful bullshit, if you ask me.
TECH Resident
Joined: Mar 2012
Posts: 871
Likes: 411
From: Texas
OEMs used non-TTY bolts for decades; no problems.
The '90s roll around, and suddenly we start seeing these one-time-use bolts showing up.
ARP bolts can be reused many times.
TTY bolts are a budgetary choice for the OEMs.
The '90s roll around, and suddenly we start seeing these one-time-use bolts showing up.
ARP bolts can be reused many times.
TTY bolts are a budgetary choice for the OEMs.
TTY bolts are for when they want to make damn sure the bolted joint never loosens.
Bolts don't have just one possible torque value. There are different torque ranges depending on how the bolt is used. There are low torques, standard torques, high torques, and even other special torques. Tightening the bolt causes it to stretch so that the threads lock in on each other. The more torque, the more stretch, and the tighter the threads lock in.
"Low" torque produces the least amount of bolt stretch. It is used only in special circumstances when you want lower clamping force for some reason.
"Standard" torque stretches the bolt more and is the usual torque spec you see documented. Most parts on the engine are assembled with standard torque, and the bolt can be re-used.
"High" torque is even tighter (by a significant amount) and the threads are stretched even more yet. It is used when there are large forces on the bolted joint and you want to make damn sure the clamping load doesn't relax and nothing pulls apart. An example would be major structural members of a tractor frame.
The GM damper bolt is made of a material that allows a lot of stretch and locks in the threads really tight. ARP uses a different material that doesn't stretch as much and can be re-used. But ARP likely has other tweaks to the bolt and washer dimensions so that the joint is good and won't loosen. Bolted joints is a much deeper topic matter than most people realize!
Bolts don't have just one possible torque value. There are different torque ranges depending on how the bolt is used. There are low torques, standard torques, high torques, and even other special torques. Tightening the bolt causes it to stretch so that the threads lock in on each other. The more torque, the more stretch, and the tighter the threads lock in.
"Low" torque produces the least amount of bolt stretch. It is used only in special circumstances when you want lower clamping force for some reason.
"Standard" torque stretches the bolt more and is the usual torque spec you see documented. Most parts on the engine are assembled with standard torque, and the bolt can be re-used.
"High" torque is even tighter (by a significant amount) and the threads are stretched even more yet. It is used when there are large forces on the bolted joint and you want to make damn sure the clamping load doesn't relax and nothing pulls apart. An example would be major structural members of a tractor frame.
The GM damper bolt is made of a material that allows a lot of stretch and locks in the threads really tight. ARP uses a different material that doesn't stretch as much and can be re-used. But ARP likely has other tweaks to the bolt and washer dimensions so that the joint is good and won't loosen. Bolted joints is a much deeper topic matter than most people realize!
Last edited by QwkTrip; Oct 28, 2019 at 10:55 PM.
From what I have been told and it may be completely ******* wrong is.
It's better for the OEM's to use a low initial torque value and degrees instead of JUST a flat final torque value.
It has a whole of lot things taken into consideration like prep, temp, lube, etc. It's easier to replicate a consistent clamp load based off a low initial TQ number and degrees because they know the elasticity of the bolt and the stretch of it's clamp force.
For anyone that says that stock TTY bolts are junk and should be changed out....well i guess all the people that are making ridiculous power on stock bolts are wrong.
It's better for the OEM's to use a low initial torque value and degrees instead of JUST a flat final torque value.
It has a whole of lot things taken into consideration like prep, temp, lube, etc. It's easier to replicate a consistent clamp load based off a low initial TQ number and degrees because they know the elasticity of the bolt and the stretch of it's clamp force.
For anyone that says that stock TTY bolts are junk and should be changed out....well i guess all the people that are making ridiculous power on stock bolts are wrong.
TTY bolts are for when they want to make damn sure the bolted joint never loosens.
Bolts don't have just one possible torque value. There are different torque ranges depending on how the bolt is used. There are low torques, standard torques, high torques, and even other special torques. Tightening the bolt causes it to stretch so that the threads lock in on each other. The more torque, the more stretch, and the tighter the threads lock in.
"Low" torque produces the least amount of bolt stretch. It is used only in special circumstances when you want lower clamping force for some reason.
"Standard" torque stretches the bolt more and is the usual torque spec you see documented. Most parts on the engine are assembled with standard torque, and the bolt can be re-used.
"High" torque is even tighter (by a significant amount) and the threads are stretched even more yet. It is used when there are large forces on the bolted joint and you want to make damn sure nothing pulls apart. An example would be major structural members of a tractor frame.
The GM damper bolt is made of a material that allows a lot of stretch and locks in the threads really tight. ARP uses a different material that doesn't stretch as much and can be re-used. But ARP likely has other tweaks to the bolt and washer dimensions so that the joint is good and won't loosen. Bolted joints is a much deeper topic matter than most people realize!
Bolts don't have just one possible torque value. There are different torque ranges depending on how the bolt is used. There are low torques, standard torques, high torques, and even other special torques. Tightening the bolt causes it to stretch so that the threads lock in on each other. The more torque, the more stretch, and the tighter the threads lock in.
"Low" torque produces the least amount of bolt stretch. It is used only in special circumstances when you want lower clamping force for some reason.
"Standard" torque stretches the bolt more and is the usual torque spec you see documented. Most parts on the engine are assembled with standard torque, and the bolt can be re-used.
"High" torque is even tighter (by a significant amount) and the threads are stretched even more yet. It is used when there are large forces on the bolted joint and you want to make damn sure nothing pulls apart. An example would be major structural members of a tractor frame.
The GM damper bolt is made of a material that allows a lot of stretch and locks in the threads really tight. ARP uses a different material that doesn't stretch as much and can be re-used. But ARP likely has other tweaks to the bolt and washer dimensions so that the joint is good and won't loosen. Bolted joints is a much deeper topic matter than most people realize!
Ya, torque wrenches in a production environment are waaaaaaay beyond what you have at home. They have to come up with fool proof methods. The tool senses torque and counts number of turns to catch problems and give really consistent results. So an example of a problem that would pass a torque spec is a cross-threaded bolt, but it won't pass the number of turns spec.