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Location:
Canberra
Registered:
May 2002
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re-using 4AGE head bolts?
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Sun, 04 August 2002 10:29
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can you re-use 4AGE head bolts, or are they torque to yield (stretch bolts)???
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I supported Toymods
Location:
Adelaide
Registered:
May 2002
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Re: re-using 4AGE head bolts?
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Sun, 04 August 2002 11:23
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As you 'torque' bolts you make them yield and stretch a little. YOU can use them, many people do and have no problems. However, at about $8 a piece from Toyota, it's cheap insurance to replace them.
Jaz
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I supported Toymods
Location:
melbourne.victoria.austra...
Registered:
June 2002
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Re: re-using 4AGE head bolts?
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Sun, 04 August 2002 11:46
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prolly re-use once, then replace 
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I supported Toymods
Location:
Adelaide
Registered:
May 2002
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Re: re-using 4AGE head bolts?
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Sun, 04 August 2002 12:11
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In general I'd follow your advice but I believe TE72_turbo is building a highHP GZE so rather than be sorry for a trivial thing as 80 buck compared with blowing a head gasket, I'd use new ones.
Jaz
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Location:
Adelaide
Registered:
May 2002
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Re: re-using 4AGE head bolts?
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Sun, 04 August 2002 13:36
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Was just doing some thinking (rare, i know) but....
Ive never even lifted a torque wrench, but nonetheless as a hypothetical. Say you were to tension a bolt with a clamping force of say 50N. Regardless of how much the bolt had stretched wouldnt the clamping force still be 50N?
Or is it more the concern of a bolt stretching and then continuing to stretch, therefore diminishing clamping force?
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I supported Toymods
Location:
NE Melbourne
Registered:
May 2002
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Re: re-using 4AGE head bolts?
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Sun, 04 August 2002 14:40
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Phil
if you are serious about the engine rebuild, don't bother with those head bolts i gave you. new ones from toyota are better, but really, i suggest you go for an ARP head stud kit p/n 203-4203 RRP approx $300.
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I supported Toymods
Location:
melbourne.victoria.austra...
Registered:
June 2002
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Re: re-using 4AGE head bolts?
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Sun, 04 August 2002 22:04
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jaz.........ah - then $80 is cheap insurance dude - dorikins idea is much better tho...
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Location:
Canberra
Registered:
May 2002
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Re: re-using 4AGE head bolts?
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Mon, 05 August 2002 09:08
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thanks for the replies, at the least I will buy new bolts.
Phil
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Location:
Sydney
Registered:
April 2003
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Re: re-using 4AGE head bolts?
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Wed, 17 August 2005 12:08
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Today was the first time I used torque to yield bolts. This was on a 5SFE. The initial torque was about 50Nm (36ft lb). While turning the final 90 degrees, it felt like a few of the bolts stretched (like they had momentarily stripped their thread). After finishing I wanted to know if all the bolts were evenly torqued, so I set the torque wrench to where the bolts would just move and it was about 95Nm. I tried all the bolts at 95Nm and only 2 wouldn't go to that torque. I probably moved one about 30 more degrees, but it still wouldn't get to 95Nm. As I didn't want to break the bolt, I left it at that. So to me it appears that torque to yield appears to hold the gasket down really tight, but not entirely even across all bolts. I'm interested to know what other people have experienced with torque to yield bolts. Any comments?
Also after cleaning the old bolts and seeing how corroded/damaged they were on the threads, I decided to spend the $80 on new bolts. The ACL value regrind set also recommended to use new bolts.
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Location:
Sydney
Registered:
February 2003
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Re: re-using 4AGE head bolts?
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Wed, 17 August 2005 12:13
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| Nobody wrote on Wed, 17 August 2005 22:08 |
Today was the first time I used torque to yield bolts. This was on a 5SFE. The initial torque was about 50Nm (36ft lb). While turning the final 90 degrees, it felt like a few of the bolts stretched (like they had momentarily stripped their thread). After finishing I wanted to know if all the bolts were evenly torqued, so I set the torque wrench to where the bolts would just move and it was about 95Nm. I tried all the bolts at 95Nm and only 2 wouldn't go to that torque. I probably moved one about 30 more degrees, but it still wouldn't get to 95Nm. As I didn't want to break the bolt, I left it at that. So to me it appears that torque to yield appears to hold the gasket down really tight, but not entirely even across all bolts. I'm interested to know what other people have experienced with torque to yield bolts. Any comments?
Also after cleaning the old bolts and seeing how corroded/damaged they were on the threads, I decided to spend the $80 on new bolts. The ACL value regrind set also recommended to use new bolts.
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did you grease the bolts first?
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Location:
Sydney
Registered:
April 2003
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Re: re-using 4AGE head bolts?
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Wed, 17 August 2005 12:26
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I oiled the bolt threads and washers with motor oil. Should I have used grease?
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Location:
Sydney
Registered:
April 2003
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Torque to yield bolts
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Thu, 18 August 2005 08:13
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Well, I decided to retorque the head bolts this morning. This time everything went smoothly. Something might have needed time to settle.
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Location:
Bottom of the hill, Sydney
Registered:
April 2004
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Re: re-using 4AGE head bolts?
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Thu, 18 August 2005 09:34
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| Rex_Kelway wrote on Sun, 04 August 2002 23:36 |
Was just doing some thinking (rare, i know) but....
Ive never even lifted a torque wrench, but nonetheless as a hypothetical. Say you were to tension a bolt with a clamping force of say 50N. Regardless of how much the bolt had stretched wouldnt the clamping force still be 50N?
Or is it more the concern of a bolt stretching and then continuing to stretch, therefore diminishing clamping force?
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What happened to Rex and who's this "Ive". 
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Location:
cambo
Registered:
May 2002
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Re: re-using 4AGE head bolts?
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Thu, 18 August 2005 10:25
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bigport 4ages are not torque to yield, smallports are.
i do headgaskets at work on average probably once or twice a week, i only replace headbolts if they are torque to yield, unless the customer wants new ones or unless its a falcon.
i personally hate torque to yield bolts, cause even with new bolts, a VERY clean thread and a lightly greased bolt, when your doing the final 90 degree turn they dont all feel even which disturbs me a little and i hate the feeling they give, like they are about to break 
on my own personal engine id get new bolts, but i definately wouldnt spend $300 on ARP bolts.
also VRS stands for valve regrind set, not value regrind
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Location:
Sydney
Registered:
April 2003
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VRS - VALUE regrind
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Fri, 19 August 2005 13:40
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 Sorry for the typo. Funny though.
Thanks "EVOSTi" for your opinion on torque to yield head bolts.
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I supported Toymods
Location:
Ademelaide, SA
Registered:
July 2003
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Re: re-using 4AGE head bolts?
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Sat, 20 August 2005 08:03
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| Rex_Kelway wrote on Sun, 04 August 2002 23:06 |
Was just doing some thinking (rare, i know) but....
Ive never even lifted a torque wrench, but nonetheless as a hypothetical. Say you were to tension a bolt with a clamping force of say 50N. Regardless of how much the bolt had stretched wouldnt the clamping force still be 50N?
Or is it more the concern of a bolt stretching and then continuing to stretch, therefore diminishing clamping force?
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CAUGHT!!! first person 
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: re-using 4AGE head bolts?
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Sat, 20 August 2005 08:24
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just for the record,
normal head bolts, when torqued to their spec, will not plastically deform as ther strength is higher than the torque specs/clamping force. they may creep a little over time, but they should still be ok to re-use. for any serious motor you would always use new bolts.
torque to yield are exactly that. usually the main part of the bolt has a reduced diameter, so that when you torque to their spec, and then that little bit more, the bolts plastically deform, REDUCING the clamping force to that which the bolt can withstand without deforming.
the reason you can't re-use them as torque-to-yield is twofold..
one, when the bolts deform, they may work harden a little and gain strength, so that when you torque to the spec'd yield load, they will actually have higher clamping force.
or two, they workharden and do not gain strength, but they DO lose the ability to elongate (ie their %plastic deformation was used up last time), so that they will break when torqued to spec, as they ar eno stringer, and the plastic deformation caused results in failure...
or something like that...
[Updated on: Sat, 20 August 2005 08:25]
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Location:
Canberra
Registered:
May 2002
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Re: re-using 4AGE head bolts?
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Sat, 20 August 2005 12:20
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| Quote: |
bigport 4ages are not torque to yield, smallports are.
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based on what? from what I can see, the toyota EPC lists the same part number for both engines.... And they both have the same reduced shank diameter.
I use ARP head studs now. Might be more than twice the cost, but at least they can be re-used, and in theory have more even clamp.
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Location:
Sydney
Registered:
September 2004
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Re: re-using 4AGE head bolts?
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Sun, 21 August 2005 00:21
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| TE72_Turbo wrote on Sat, 20 August 2005 22:20 |
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bigport 4ages are not torque to yield, smallports are.
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based on what? from what I can see, the toyota EPC lists the same part number for both engines.... And they both have the same reduced shank diameter.
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Based on the Toyota Rebuild Manuals. I have a copy of both the early bigport and the later smallport and the head torquing techinques are different as EVOsti said.
Doesn't mean the bolts are any different though... maybe they just changed the techniques???
Eddie.
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Location:
tallahassee FL usOFa
Registered:
May 2002
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Re: re-using 4AGE head bolts?
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Sun, 21 August 2005 03:24
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confusing two different things here - apples & oranges.
there are two different types of bolts, - reusable & non-reusable.
TTY(torque-to-yield) are usually non-reusable. all others are reusable forever, or until damaged - either threads or stretched & soft.
there are three different tightening techniques that may be used for the two types - torque only(the worst), measuring stretch(the best), and torque angle(a compromise).
there is nothing in any 4AG manual about replacing head bolts for any reason except damage.
these have a pretty decent writeup.
http://chevyhiperformance.com/techarticles/49258/
http://chevyhiperformance.com/techarticles/49258/i ndex1.html
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Banned by his request
Location:
moved to tamworth
Registered:
July 2002
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Re: re-using 4AGE head bolts?
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Sun, 21 August 2005 04:32
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| EVOSTi wrote on Thu, 18 August 2005 20:25 |
bigport 4ages are not torque to yield, smallports are.
i do headgaskets at work on average probably once or twice a week, i only replace headbolts if they are torque to yield, unless the customer wants new ones or unless its a falcon.
i personally hate torque to yield bolts, cause even with new bolts, a VERY clean thread and a lightly greased bolt, when your doing the final 90 degree turn they dont all feel even which disturbs me a little and i hate the feeling they give, like they are about to break
on my own personal engine id get new bolts, but i definately wouldnt spend $300 on ARP bolts.
also VRS stands for valve regrind set, not value regrind
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you shoud use the smallport bolts and technique as its the later one and the heads are very much identical exept for the ports etc. toyota changed the way they did the bolt because they found it was better.
mick
p.s it dosnt matter if there torque to yield or alloy studs if the engine has been done before you dont know what the hell the guy before has done to them.to do it properly you have to chase the threads etc etc.do it properly or get someone that knows what the are doing,and most mechanics dont know shit from clay in the engine building department.i only quoted the above to point out smallport,bigport, that is all not the work!
[Updated on: Sun, 21 August 2005 04:42]
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Location:
Canberra
Registered:
July 2005
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Re: re-using 4AGE head bolts?
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Sun, 21 August 2005 04:45
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I've been given the impression that you can measure the length of the bolt/threads and compare this to the standard length to give some idea of the plastic deformation the bolt has withstood. Of course, this would have shortcomings if the original bolts were a vague, inconsistent length.
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Location:
cambo
Registered:
May 2002
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Re: re-using 4AGE head bolts?
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Sun, 21 August 2005 09:55
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| kingmick wrote on Sun, 21 August 2005 14:32 |
[you shoud use the smallport bolts and technique as its the later one and the heads are very much identical exept for the ports etc. toyota changed the way they did the bolt because they found it was better.
mick
p.s it dosnt matter if there torque to yield or alloy studs if the engine has been done before you dont know what the hell the guy before has done to them.to do it properly you have to chase the threads etc etc.do it properly or get someone that knows what the are doing,and most mechanics dont know shit from clay in the engine building department.i only quoted the above to point out smallport,bigport, that is all not the work!
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i would think mechanics have a fair idea on rebuilding engines, sure we dont do it every day like an engine rebuilding specialist but for your average rebuilds its not too tough.
but i do agree with what you say about the bolts, they are basically the same engines so the different torque procedures are probably cause they found it better not cause they are diff requirements, but they still list them as different on the ACL VRS
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Banned by his request
Location:
moved to tamworth
Registered:
July 2002
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