question.....torque-cycle????

[drive805]

i have read ina GM hy-tech article about rebuilding a buick motor replacing the head bolts and doing a torque-cycle.......i have emailed the motor builder and haven't got an answer so i decided to try this.... does anyone really know what a torque-cycle is and how its performed....i thought it would be torque 25-55-75 but it isn't explained in the article very well and i'm not sure what it means is this something that others have done how critical is it to do a torque-cycle?????this is a term that i haven't heard before and i just wanted to make sure that i'm setting this up correctly.... i have rebuilt small block chevys before and have not had problems but this is a little different so if anyone knwos please tell me thanks again

 

[UNGN]

Maybe this was what they were talking about.... read down at the bottom of this article about TTY procedures:

All About Torque

 

[The Radius Kid]

I read that myself,and that's the first time I've heard of that procedure.Sounds like what he's doing is torquing,releasing the bolt,then re-torquing,a few times in succession.That's the way I read it.Probably to make the bolt dimensionally stable.

 

[TurboDave]

Yes, that's it. I called the article's author. It's nothing more than, once you get up to your finish torque, just release and retorque several times. Not the whole sequence, just loosen a little and retorque several times.

 

[drive805]

thanks

after talking to a few mechanics "in the know" i was told that a torque-cycle is to "cycle" the new head bolts to stretch them so they become seasoned so to speak...what to do is to torque to final setting then loosen the bolt then tighten to final torque again four or five times...so i understand it now...thanks for your replies i had never heard of this before but i guess it is more common now with the different alloys in engines and hardware that it is something that is practiced more and more ....again thanks for the replies

 

[The Radius Kid]

I'm still wondering about the actual procedure.
Do you release them 90 degrees and retorque to spec?Totally release them,and retorque?Do them individually,or release them all and retorque in sequence?Would this help a head bolt,or just mains?Maybe Dave can chime back in here if he got that info?

 

[Intercooler]

What a crock of ****! Yea, put your thread sealer on then do that I don't see it in any manuf. of head gasket or bolts directions. I have seen big time racers not do this. Ever see a top fuel or in general any shop do this? Did or does GM do this? No! Are you talking about Merkel here? I think he must have been reading a bunch of Car Craft crap when he wrote that! My .002

 

[bob86gn]

I have the same concern as IC. What happens to the bolts in the water jacket? I have also heard to run the motor, get everything hot and then retorque. Do you think the bolts in the water jacket with the Teflon sealer will still be sealed after all this tightening, untightening and retightening? I would be nervous.

 

[TurboDave]

Originally posted by The Radius Kid
I'm still wondering about the actual procedure.
Do you release them 90 degrees and retorque to spec?Totally release them,and retorque?Do them individually,or release them all and retorque in sequence?Would this help a head bolt,or just mains?Maybe Dave can chime back in here if he got that info?

Just enough to release the torque and redo them individually.
The article I think was only refering to head bolts.

 

[TurboDave]

Originally posted by Intercooler
What a crock of ****! Yea, put your thread sealer on then do that I don't see it in any manuf. of head gasket or bolts directions. I have seen big time racers not do this. Ever see a top fuel or in general any shop do this? Did or does GM do this? No! Are you talking about Merkel here? I think he must have been reading a bunch of Car Craft crap when he wrote that! My .002

It was Merkel's article. And as for thread sealer he told me that they don't use any

I'm not sure I understand how they get away with it, but he swore up and down all they use on the head bolt threads is assembly lube. Honest. Not sure I have the nerve to try that.

 

[The Radius Kid]

Interesting topic,this one.If I was to try it,I would put the teflon thread sealer on the bolts,go through the procedure,pull all the bolts,clean the block threads and the bolt threads,then relube with the teflon sealer and do final assembly.Teflon sealer's primary function in a pipe thread application is to lube the threads for a tighter thread engagement allowing more intimate contact between threads and a better self seal[pipe threads,in theory,aren't supposed to need a sealer].Now ,before you chastize me for talking about pipe threads,the point I was making was that lower friction,and better torque accuracy can be achieved using teflon sealant on the threads than by other methods.

 

[gofstbuick]

If I recall right, the TTY head bolts from GM have some type of a sealer (reddish in color) applied from the manufacturer. All I did was clean the threads in the block, and installed the head bolts dry. Supposedly, the sealer on the threads have a lubricant in it. Also, I verified with a GM technician, and he confirmed, that a new set of factory TTY head bolts already have sealer on the threads

 

[gofstbuick]

Also, there is some of that same type of sealer on the base of the bolt that meets the cylinder head. I assume there is some lubricating properties with the factory applied sealer