Studs Move During Re-Torq - Problem?

[mgmshar]

I'm in the process of installing new head gaskets in-car. I used black RTV to seal the threads on the ARP head studs. As I loosened the nuts to do a re-torque on them, I noticed that about half of the studs turned with the nuts. This would make me think that the seal on the threads was broken.

For those of you who do re-torques on studs - have you ever seen this? Is this cause for concern?

Thanks,

 

[Scott87]

If the studs are turning with the nut it means that the torque holding the stud into the bottom hole is less than the nut on the top of the stud.

If you are concerned about the stud remove it and remove the nut if it is not gauled on the stud. You may need to soak the nut in penetrant to get it off the stud.

Far as the nut being stuck to the stud the idea with applying the torque is you are stretching the studs as you would any bolt or fastener. The amount of crush applied to the gasket is where your crucial seal is at.

If the nut is frozen to the stud and the length of it wont bottom out and possibly crack the block from bottoming then there shouldnt be an issue.

The downside of turning the nut frozen to the stud is that you may have questionable thread engagement in the hole in the block. This shouldnt be much of a concern if you only backed them off a small amount.

Sounds like you have removed them completly so you would have needed to number all the studs to make sure they go back to their proper locations.

 

[mgmshar]

I understand everything you are saying above. Maybe my question didn't get through...

I installed the heads last weekend. I used ARP studs. I cleaned the threads in the block, and I cleaned the stud ends that went into the block with brake clean. I then applied black RTV and threaded the studs into the block by hand until they bottomed. I then put the ARP "Ultra-Torque" on the top-side washers and nuts and torqued them down in steps. I let the heads sit for several days.

Because I had black RTV on the threads in the block, and ARP "Ultra Torque" lube on the nuts and washers, I would have assumed that there would be more friction at the block thread end than the nut thread end. So, when I went to loosen the nuts during the retorque process, I would have thought that the studs would not rotate in the block. Rather, I would have assumed that the nuts would rotate off the studs.

However, in at least half the cases, the nuts and studs rotated together as I was loosening them. As soon as the stretch was relieved, the nuts came off the studs just fine (no galling or anything like that, could turn them easily with my fingers). I would say that the studs backed out about a quarter turn or so before the nuts started turning on their own.

My question for those who do retorques - is this normal? Should I be worried about the RTV sealing the block threads because the studs moved during the re-torque? Is there some other sealant I should use besides black RTV?

Not to re-open the ongoing "re-torque vs. don't re-torque" debate, but this has me thinking that I should just torque down the nuts once and leave them alone. I don't want them to leak coolant because I did a re-torque on them.

Is that more clear?

Thanks,

 

[m233roller]

Mike,
Yes you have the possibility of it leaking coolant as the ones that have moved have broken the seal somewhat, how much ? Who knows? That's why on All the engines I build I have listened to my machinists (and he's one of the best out there) I install ALL the studs with lots of red lock tite. You hand twist them in til they stop, back them off 1/18 of a turn, get the head on now and torque to around 60lbs. Let them sit for at least 24 hours and then do your retorques. 2 or 3 whichever you like. I have yet to have any problem with stud movement on retorques and have NEVER had one leak. Now it's a different story if you ever want to take them out as I have to use a stud puller to do so.

PS. I also put 1 caddy pill in every new build or head gasket change.

 

[TR Custom Parts]

That's what I used on the supercharged 454 I built for my pro street 66 Chevelle. Red Loctite 271. Never had a problem.

 

[mgmshar]

...I generally will be doing engine work in the car, so I need to be able to pull the studs out in order to remove the heads. That's why I'm hesitant to use red loctite.

I'm sure that I'm not the only one who is using a non-loctite sealer (black RTV, Permatex) on my studs. What has been their experience?

Thanks,

 

[Nick Micale]

Just because someone had a different procedure or uses different stuff, does not make it right or wrong.

With that said, I will outline what I have found works best for me in this procedure.

When installing head bolt or studs I coat the threads going into the block with either teflon sealer or GM Gasket Sealing Compound. Both of these stay pliable and do not "set" like RTV, and have never had a sealing problem.

On a fresh build, I do a re-torque w/o loosening the bolt or nut. I am just verifying that all fasteners were pulled properly, none stretched or threads have been stripped/damaged. This is done once before starting the engine, and once after a heat cycle.

Will never use loctite on a turbo block with studs after ruining threads, as well as breaking a tap trying to fix them.

 

[A2000RICH]

Just because someone had a different procedure or uses different stuff, does not make it right or wrong.

Will never use loctite on a turbo block with studs after ruining threads, as well as breaking a tap trying to fix them.

nick-----i have to agree with you-------i don't build the level of engines that you are doing but i do build several engines a month and have been doing so for many years-------- knowing virtually nothing before i built my first engine I worked a deal to hang around the engine shop at Ruggles back in the early 90's--------watched them build lots of engines and they used Permatex #2 on all bolts that went into water jackets--------been doing it ever since and never had a single leak------stays pliable/removes easy and is cheap-----one large tube is enough to do over a dozen motors------lots of fancy new high tech, high priced chemical sealers have come and gone over the years but i have never seen the need to change what seems to work just fine---------many motors and many years-------when i have my first problem or they quit making it i will make a change..............RC

 

[TurboBuRick]

Teflon sealant on bolts, blue loctite gel on studs but thats just me. Like Nick says, different strokes for different folks. What ever works for you.

 

[87action]

Head studs sealer

I've built many motors, not many buick motors. I use gasket sealing compound for certain areas I know will leak. I do inboards, outboards, all kinds of different engines especially in saltwater. The gasket sealer is a little messy but it ALWAYS holds and will NOT leak, hope this helps. Also no reason to use loc-tite unless you are really worried about something coming loose!

 

[S10xGN]

I'm in the process of installing new head gaskets in-car. I used black RTV to seal the threads on the ARP head studs. As I loosened the nuts to do a re-torque on them, I noticed that about half of the studs turned with the nuts. This would make me think that the seal on the threads was broken.

For those of you who do re-torques on studs - have you ever seen this? Is this cause for concern?

Thanks,

That is puzzling... I've only had this happen on "mock up" with no sealer in the block threads. Did you torque-cycle the nuts 5x's as per ARP procedure? The reason for this is to burnish in the mating surfaces and remove any potential burrs, because it sounds like some kind of hang up between the nut/washer/top-end threads.

 

[Nick Micale]

.......Not to re-open the ongoing "re-torque vs. don't re-torque" debate, but this has me thinking that I should just torque down the nuts once and leave them alone. I don't want them to leak coolant because I did a re-torque on them............Thanks,

Your situation also has me thinking as well, not just about re-torque or not, but also the debate to loosen, or not, when re-torquing.

The reason to loosen, then torque is the dynamics of movement is needed to pull accurately to the same value. Also, new bolts or stud kits need to "season" by use.

I use my own system, not sure if it is good or bad, but again works for me.

When I build an engine, or just install heads in the car, they get torqued in sequence the first time to a given value. They immediately get checked again at the same value to be sure none were missed. From 12-24 hours later they are pulled to the same given value.

After a heat cycle or 2 and cool down, I then pull them to 5 ft-lbs more which is now at the target torque value.

On my car, I will check also torque after a few weeks, or 15-20 passes, usually when I check valve adjustment.

This method may not be "normal", but since I personally have not had a head problem in years I will continue with this procedure.

 

[Chuck Leeper]

yep..

nick-----i have to agree with you-------i don't build the level of engines that you are doing but i do build several engines a month and have been doing so for many years-------- knowing virtually nothing before i built my first engine I worked a deal to hang around the engine shop at Ruggles back in the early 90's--------watched them build lots of engines and they used Permatex #2 on all bolts that went into water jackets--------been doing it ever since and never had a single leak------stays pliable/removes easy and is cheap-----one large tube is enough to do over a dozen motors------lots of fancy new high tech, high priced chemical sealers have come and gone over the years but i have never seen the need to change what seems to work just fine---------many motors and many years-------when i have my first problem or they quit making it i will make a change..............RC

What Richard said^^
My Ruggles engine had the same sealers applied to it.

Some posts from another forum:
Ultra Black RTV usage question re. ARP studs

Just like FOX NEWS...We report, you decide!

 

[mgmshar]

That is puzzling... I've only had this happen on "mock up" with no sealer in the block threads. Did you torque-cycle the nuts 5x's as per ARP procedure? The reason for this is to burnish in the mating surfaces and remove any potential burrs, because it sounds like some kind of hang up between the nut/washer/top-end threads.

I've had lots of people tell me about the torque cycling, and I understand the concept of conditioning the nuts, washers, and threads. I worked as an engineer in the auto industry, and I helped develop bolt torquing procedures for production engines at Chrysler. Bolt "conditioning" is something we had to consider in our procedures, particularly for head bolts.

HOWEVER: I have a relatively new ARP stud kit that includes a tube of their "Ultra-Torque" lube. In the box, they included data that supposedly shows that conditioning is NOT necessary when you use the Ultra-Torque stuff. The same information is on their web site: ARP-bolts.com | ARP Ultra-Torque? Fastener Assembly Lubricant

The bottom line is that ARP says if you use Ultra-Torque, you do not need to torque-cycle. Their claim is that ARP Ultra-Torque eliminates the need to condition the threads, washers, etc. by torque cycling. The graphs on their web page supposedly prove this.

I must say, when I removed the nuts, washers, and studs, there was practically no burnishing of the contacting surfaces. The parts pretty much looked like they had just come out of the box. So, it appears that the "Ultra-Lube" does a good job of preventing the burnishing and galling that we call "conditioning" of the mating surfaces.

So, I followed ARP's instructions exactly, which you can see here: http://arpinstructions.com/instructions/123-4003.pdf. This basically says to install the studs with ARP thread sealer, apply ARP Ultra-Torque to the threads, nuts, and washers (above the heads), and torque in three equal steps to 80 lb-ft.

The only things I did differently than the instructions:
1. I torqued in four steps: 40, 55, 70, then 80 lb-ft.
2. I used black RTV instead of the ARP thread sealer.

Hopefully this helps somebody.

As far as my second attempt, I'm probably going to try Permatex #2 and use Mr. McCale's re-torque check procedure rather than a full loosening and retorque. But, I'm still thinking about it.

Any other thoughts still welcome...

Thanks,

 

[mgmshar]

Your situation also has me thinking as well, not just about re-torque or not, but also the debate to loosen, or not, when re-torquing.

The reason to loosen, then torque is the dynamics of movement is needed to pull accurately to the same value. Also, new bolts or stud kits need to "season" by use.

I use my own system, not sure if it is good or bad, but again works for me.

When I build an engine, or just install heads in the car, they get torqued in sequence the first time to a given value. They immediately get checked again at the same value to be sure none were missed. From 12-24 hours later they are pulled to the same given value.

After a heat cycle or 2 and cool down, I then pull them to 5 ft-lbs more which is now at the target torque value.

On my car, I will check also torque after a few weeks, or 15-20 passes, usually when I check valve adjustment.

This method may not be "normal", but since I personally have not had a head problem in years I will continue with this procedure.

Hey Nick,

Just out of curiousity, how do you get around the header flanges when you recheck torque after heat cycling? Do you remove the headers? Or, did you remove the heat shields and grind off part of the flanges before you installed the headers?

Thanks,

 

[MSDGN]

I do what Nick does...don't loosen the nut for a retorque...just hit each nut in sequence with specified max torque...

 

[Nick Micale]

Hey Nick,
Just out of curiousity, how do you get around the header flanges when you recheck torque after heat cycling? Do you remove the headers? Or, did you remove the heat shields and grind off part of the flanges before you installed the headers? Thanks,

Depending on the headers, and this only applies to 8 bolts heads, clearance, grind or cut the flanges and gaskets as needed before install.

On the very close fit for the bolt or nut, I use a thin-wall 3/8" drive socket with an adapter for the 1/2" drive torque wrench. But use a good brand socket so if/when it cracks, the supplier will replace it!