factory head bolts

[87-TURBO-T]

anybody have luck re-using factory head bolts on a stock build? thanks

 

[bmackinnon]

They are 'torque-to-yield".... re-use is a big no-no....

 

[pajo]

I understand it is an issue with them but my last rebuild 6 years go I reused them with stock graphite gaskets and I have no issues . I am also not pushing more then 18-19 psi boost..

 

[turbo nasty]

Yeah well you did it wrong. Not worth flirting with disaster IMO. Do it right the first time and be done

 

[ALVAROG1983]

You can use them i've done it before no issues but its always good to put new head bolts.

 

[SS/GN]

You should NEVER re-use torque to yield head bolts

Kevin

 

[SPOOLN]

gm head bolts

I reused some and did not have any problems either. That was with graphite stock gaskets. I think head studs are a much better route, as far as clamping the head to the block...

 

[Just a Six??]

I reused some and did not have any problems either. That was with graphite stock gaskets. I think head studs are a much better route, as far as clamping the head to the block...

Buy studs once & your good for life unless it comes apart 10 times a season.

 

[eric_1984ttype]

I've tried to reuse a set in a newer sbc and broke off one of bolts trying to get it "torqued." Learned my lesson. One time use. Always replace them.

On a side note I did a cummins head gasket and the new kit came with a stretch gauge to determine wether the bolts had been stretched beyond use. I replaced them anyway.....

 

[bmackinnon]

Anyone who re-uses TTY headbolts has zero mechanical material properties knowledge... might they torque without breaking? yes..... is the clamping force at suggested torque proper? absolutely not.... TTY = torque-to-YIELD... yield meaning the bolts have YIELDED (stretched a prescribed/calculated amount).... retorqueing = further stretching = less tensile clamping force and further 'necking down' of the bolt OD = approaching the 'absolute' yield point = broken bolt = stupid

Mechanical Engineering 101..... stress vs strain relationship... strain = stretch in engineering terms...

 

[KL Mallender]

TTY bolts are amazing, but I've never been comfortable with anything considered a "Rubber Band", I've tested both stretch vs clamp loading in years past, you "might" get lucky to re-use TTY bolts once from factory issue, I'll almost guarrentee they never pass after the first re-use, if not broken during second disassembly, if you can't afford ARP, I suggest using a grade 8 capscrew/washer assembly available from "Most" local fastener suppliers that will satisfy the needs at hand. Just remember, not much sense having anymore clamping force when the material in question "Yeilds" at lower psi values.
Good luck,

Kevin.

 

[87-TURBO-T]

OK, just wanted to get some work done, but I guess I'll wait on the ARP's to show up. thanks

 

[A2000RICH]

Anyone who re-uses TTY headbolts has zero mechanical material properties knowledge... might they torque without breaking? yes..... is the clamping force at suggested torque proper? absolutely not.... TTY = torque-to-YIELD... yield meaning the bolts have YIELDED (stretched a prescribed/calculated amount).... retorqueing = further stretching = less tensile clamping force and further 'necking down' of the bolt OD = approaching the 'absolute' yield point = broken bolt = stupid

Mechanical Engineering 101..... stress vs strain relationship... strain = stretch in engineering terms...

contrary to what most everyone believes the original application of the TTY bolt on the 86/87 did not actually stretch the bolt to the actual yield point-------the spec did not exceed the modulus of elasticity of the bolt and even though stretched slightly it would return to the original length when removed-------if it was actually installed correctly the bolts could be used again as was spelled out in the GM tech papers-------most other applications of the TTY bolts in GM engines makes them NOT reuseable----------the length of these bolts was very exact and all it takes to determine if they have been stretched is to measure them carefully---------the factory engines were torqued very exacting and when removed from a factory assembled engine the bolts are very consistent---------they are no different than any other "spring" and as long as they are not stretched beyond a certain limit they can be used over and over.............RC

 

[turbofabricator]

I agree with Rich. There was a service bulliten years ago that states the bolts were NOT torque to yeild and could be re-used. I still use ARP, but some feel that ARP is not a very good bolt. Do a Google search and see for yourself. I use them all the time and have no complaints. I did read somewhere that a guy that runs a turbo Ford 2300 had BIG problems with ARP studs and went back to stock Ford bolts and his problems went away. That's not to say he figured out his tune-up problem at the same time.?

 

[KL Mallender]

I give up, you guy's are right, the factory didn't have a clue to what they had, any of us that ever re-used factory head bolts were just idiots and taking chances. I'd have thought I would have never seen a broken headbolt in my lifetime, but oh well, I suppose the ones I have seen broken (snapped in half) were over stressed from the factory, Hell, I dont really care if someone re-uses 1 time use only fasteners, it is their car after all, best of luck to them.
I'll have to send my son here to re-read all the posts reguarding head clamping, it will confuse the **** out of him after all the preaching I've instilled of how/why not to do what the populus does, as long as he pays for the broken hardware, I will sit back and laugh like the old fart I am.
And you people wonder....why?

Kevin.

 

[gunslinger]

Why take the chance?
A new set of Fel-pro head bolts are only $25.

 

[87-TURBO-T]

OK, just wanted to get some work done, but I guess I'll wait on the ARP's to show up. thanks

Why take the chance?
A new set of Fel-pro head bolts are only $25.

ARP's were ordered last week, had a few days off work and wanted to get something done.

 

[A2000RICH]

I give up, you guy's are right, the factory didn't have a clue to what they had, any of us that ever re-used factory head bolts were just idiots and taking chances. I'd have thought I would have never seen a broken headbolt in my lifetime, but oh well, I suppose the ones I have seen broken (snapped in half) were over stressed from the factory, Hell, I dont really care if someone re-uses 1 time use only fasteners, it is their car after all, best of luck to them.
I'll have to send my son here to re-read all the posts reguarding head clamping, it will confuse the **** out of him after all the preaching I've instilled of how/why not to do what the populus does, as long as he pays for the broken hardware, I will sit back and laugh like the old fart I am.
And you people wonder....why?

Kevin.

no one is calling anyone an idiot--------even the guys at Gm state that in certain applications that the bolts were used not in a torque to "yield" point but actually torque to tension--------my experience with using the GM TTY bolts specified for the GN is that they always reach a torque spec limit (60 ftlbs) long before they reach the specified angle spec (90+90)--------- any bolt that is going to stay put is always used under tension and stretched to some degree-------thats how they work--------look at the rod bolts from arp-------they suggest a torque spec but strongly prefer a stretch gauge be used and they say that as long as the bolt returns to the original length it is ok-------i have attached a portion of a Buick factory tech paper that covers this subject very clearly-------the entire misunderstanding about not reusing the factory bolts is a loosly based belief based on what can only be called bad information-------it is easy to see if these bolts are ruined due to incorrect installation-------the length is increased and even easier to see is to hold one of them against a new bolt to see if the threads mate exactly-------if they are streched they will not -------from what i have seen the stretch is always in the threads and not in the shank.................RC

 

[KL Mallender]

My appoligies Rich, to you and others.
You have the info and knowledge to look at the bolts in your hands to know if re-use is a possibility, you are spot on about looking at the upper threaded areas to find location of stretch.
My post was out of line, probably ventured to non-user friendly, but if you or I tried to describe how to determine re-use, guarrenteed that someone might interpet us incorrectly on a "judgement" call, and then flame our butts because we posted what "WE" have seen, and possibly done.
Saving a dollar is great, but not if it cost's us more than that down the road.
Who here doesen't "Want" to re-furbish their cars to be the best around???
I'll bet not many hands in the air on that idea.
You guy's have created probably the best informed "Site" around, Buicks or otherwise, it's all about the passion, the drive, the want, the reason any one of us bother to pick-up a wrench to fix instead of a pen to sign our savings away.
Today is probably more important than years ago, to help each other along the way, Bowling Green used to be the promised land to converge on in the first part of may,(just to keep the Vette owners in line, LOL). dates and locations may vary, the backbone won't.
(Just us old farts complaining will forever remain)
Best of luck to all,

Kevin.

 

[A2000RICH]

My appoligies Rich, to you and others.
You have the info and knowledge to look at the bolts in your hands to know if re-use is a possibility, you are spot on about looking at the upper threaded areas to find location of stretch.
My post was out of line, probably ventured to non-user friendly, but if you or I tried to describe how to determine re-use, guarrenteed that someone might interpet us incorrectly on a "judgement" call, and then flame our butts because we posted what "WE" have seen, and possibly done.
Saving a dollar is great, but not if it cost's us more than that down the road.
Who here doesen't "Want" to re-furbish their cars to be the best around???
I'll bet not many hands in the air on that idea.
You guy's have created probably the best informed "Site" around, Buicks or otherwise, it's all about the passion, the drive, the want, the reason any one of us bother to pick-up a wrench to fix instead of a pen to sign our savings away.
Today is probably more important than years ago, to help each other along the way, Bowling Green used to be the promised land to converge on in the first part of may,(just to keep the Vette owners in line, LOL). dates and locations may vary, the backbone won't.
(Just us old farts complaining will forever remain)
Best of luck to all,

Kevin.

I totally agree about the "lose a dollar to save a dime" thinking---------if i do much work at all to an engine i replace the timing chain, water pump, head bolts etc etc just because it makes sense while its apart---------and i know discussion about reusing head bolts seems just plain dumb-------BUT sometimes there is a good reason-------at times i work on really nice cars------lots of nice GNX's-------redone the engines in several low mileage GNX's--------and by low miles i mean well under 2000mi------usually those owners want the car to look 100% original--------that is not so easy if the inspector really knows his TR's--------thats when you have to know that original head bolts were marked SPS except for the two center top ones marked C, the front cover had an asbestos gasket, valve cover gaskets were cork painted silver, the pan gasket was black rubber and several hundred other details that make the difference between what looks like a worked over car and a perfect car---------little details can make tens of thousands of dollars in value difference---------i have rebuilt engines in a few really nice cars that I challenge anybody to tell they have ever been touched let alone taken apart---------thats when you go searching through your old parts to find a really good set of original head bolts that can safely be reused-------since GM changed vendors in the early 90's for the head bolts resulting in different head stamps an original set is MUCH too valuable to reuse on a normal car to save the cost of a set of ARP bolts---------i know some people don't understand this but either they get it or they don't----------this is why i challenged the reuse of the bolts--------if you know what you are doing it can be done but for the average person they should not ever consider it....................RC