is it ok to reuse factory head bolts
05-10-2018, 10:06 PM
#41
I've seen ALL KINDS of things being built, as well as designed building things. I can assure you, what you "see", isn't necessarily the same as what's actually being DONE.
All the angle thing does, is establish how far the bolts stretch. 90° = ¼ of the thread pitch for example. Tighten em that far, the part between the threads and the head gets that much elongation, at some point you reach the spot where they quit acting like metal rods and start acting like springs. Which is what they're intended, in the FACTORY design, to do.
For all you know watching those robots, they might very well be tightening each until it reaches the "tight" point (25 ft-lbs or whatever), then tighten em .x turns (fractions of a turn, aka "degrees", aka angle) farther.
How is that "fool you guys"?
All the angle thing does, is establish how far the bolts stretch. 90° = ¼ of the thread pitch for example. Tighten em that far, the part between the threads and the head gets that much elongation, at some point you reach the spot where they quit acting like metal rods and start acting like springs. Which is what they're intended, in the FACTORY design, to do.
For all you know watching those robots, they might very well be tightening each until it reaches the "tight" point (25 ft-lbs or whatever), then tighten em .x turns (fractions of a turn, aka "degrees", aka angle) farther.
How is that "fool you guys"?
05-10-2018, 10:52 PM
#44
TECH Senior Member
The bolt's metallurgy and shape determine torqueing procedure. You can "believe" what you want, hardware is made to be torqued a certain way. TTY IS an actual procedure, ignorance notwithstanding....
05-11-2018, 06:03 AM
#45
I’m sure RockinWs6 is the type of person that sees a “Wet Paint” sign on a park bench and doesn’t believe it and sits on it anyways.
When you watch the “robot” torque machines you can see them torque to a specific value then they will turn another quarter turn. And that you can see with your own eyes.
When you watch the “robot” torque machines you can see them torque to a specific value then they will turn another quarter turn. And that you can see with your own eyes.
05-11-2018, 07:30 AM
#46
Take old head bolts out, place new head bolts beside, that tells the story right there. The used bolts are at least 1/4" longer than new, the "stretch" is what gives them such great retaining power over the long haul. I have done this same test with rod bolts and there is no length change, so I have reused rod bolts numerous times now without issue. I have wanted to try re-using head bolts simply to see how it works out but havent had a big enough junk pile to risk that on yet
05-11-2018, 09:22 AM
#48
TECH Senior Member
05-11-2018, 09:45 AM
#49
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AARP LS Head Bolts = NEVER unless machined Hi ALL, the ARP company is GOD ???
THIS COMPANY does NOT Manufacture LS head bolts/studs correctly.
THIS COMPANY does manufacture bolts/studs for AL head racing engines.
VIEW their OWN TECH showing the "undercut" bolts/studs for use on OTHER AL head racing engines.
I have a method, very simple, to correct this DEFECT.
I place an ARP stud in my Hardinge Lath then machine (undercut) to the correct diameter to ALLOW correct STRETCH.
I then install, tighten, the studs AND can feel the correct stretch !
Lance
THIS COMPANY does NOT Manufacture LS head bolts/studs correctly.
THIS COMPANY does manufacture bolts/studs for AL head racing engines.
VIEW their OWN TECH showing the "undercut" bolts/studs for use on OTHER AL head racing engines.
I have a method, very simple, to correct this DEFECT.
I place an ARP stud in my Hardinge Lath then machine (undercut) to the correct diameter to ALLOW correct STRETCH.
I then install, tighten, the studs AND can feel the correct stretch !
Lance
05-11-2018, 12:43 PM
#50
No they don't, I seen them being built. where did you see them being built? Person loads the bolts onto the engine and uses a large robotic air tool. All the bolts were tightened at same to a torque spec. No angle BS involved. All that angle BS is to fool you guys into ooowww AHHHHH I gotta jump how high?
You're a moron.
05-11-2018, 01:06 PM
#52
Go to 4:10
https://www.youtube.com/watch?v=vsil_N5z6Kw
That same process has been used throughout the Gen III/IV/V builds along with nearly every other manufacturer's engines over the last couple decades.
You're a moron.
https://www.youtube.com/watch?v=vsil_N5z6Kw
That same process has been used throughout the Gen III/IV/V builds along with nearly every other manufacturer's engines over the last couple decades.
You're a moron.
05-11-2018, 02:23 PM
#55
Stock bolts are great. Re-use might work, it might not, i havent tried yet. They are inexpensive and its your engine so use whatever you want, however you want.
For all out race ARP makes a lot of sense simply due to tear downs and resisting head lifting. Once north of 1000hp head lifting becomes common and all those guys are always looking for ways to keep the heads down with upgrading head fasteners, 6 bolt block, etc. Worlds fastest cars all run ARP, including Top Fuel dragsters so they must be doing something right. Smokey swore by ARP, thats the only fasteners he would use. Great reputation for quality in that outfit. Not many here are planning over 1000hp though so for most of us stock bolts are fine. It is a pita to have to replace them each time apart, that I do dislike. Aint nothing perfect
For all out race ARP makes a lot of sense simply due to tear downs and resisting head lifting. Once north of 1000hp head lifting becomes common and all those guys are always looking for ways to keep the heads down with upgrading head fasteners, 6 bolt block, etc. Worlds fastest cars all run ARP, including Top Fuel dragsters so they must be doing something right. Smokey swore by ARP, thats the only fasteners he would use. Great reputation for quality in that outfit. Not many here are planning over 1000hp though so for most of us stock bolts are fine. It is a pita to have to replace them each time apart, that I do dislike. Aint nothing perfect
05-12-2018, 08:46 PM
#59
The only thing he's done successfully is look like an idiot. I made the mistake of arguing with him before. He acts like he knows all, uses big words, tells people they need to listen "when a professional tells them something" and then asks who can work on his car and how it's done.
05-13-2018, 12:24 AM
#60
TTY simply means the bolt was torqued to its yield point, stretching it permanently, as opposed to a standard fastener application which it is stretched only when torque is applied, and that returns to its original dimensions when removed. You can stretch any fastener to its yield.
When a TTY exceeds it's yield point, the clamping force will not increase. That energy is now put into permanent deformation of the bolt. Also, torque required to achieve a particular clamping force varies with thread friction. Using a torque angle method is much more accurate. LS TTY headbolds use a torque angle method of tightening to ensure they reach the yield point and deform permanently, so that the proper clamping force is delivered evenly across the entire head.
it isn't GM being cheap.
ARP uses a different process for their bolts. Because their bolts are much stronger, and iirc not really suitable for use as a TTY bolt, they use their own lubricant to ensure an accurate and repeatable amount of thread friction. This is why they have a ft-lb value on their specs and do not use torque angle.
Also, I have heard of people having to go back and re-tighten after some measure of heat cycling to ensure that the proper torque is maintained when using ARP studs/nuts. you don't hear of this with the stock TTY bolts. do it right once and you are done.
When a TTY exceeds it's yield point, the clamping force will not increase. That energy is now put into permanent deformation of the bolt. Also, torque required to achieve a particular clamping force varies with thread friction. Using a torque angle method is much more accurate. LS TTY headbolds use a torque angle method of tightening to ensure they reach the yield point and deform permanently, so that the proper clamping force is delivered evenly across the entire head.
it isn't GM being cheap.
ARP uses a different process for their bolts. Because their bolts are much stronger, and iirc not really suitable for use as a TTY bolt, they use their own lubricant to ensure an accurate and repeatable amount of thread friction. This is why they have a ft-lb value on their specs and do not use torque angle.
Also, I have heard of people having to go back and re-tighten after some measure of heat cycling to ensure that the proper torque is maintained when using ARP studs/nuts. you don't hear of this with the stock TTY bolts. do it right once and you are done.