Re-torque question...your opinion please.

All,

I would like to know what others consider a re-torque.

I see it as getting a part up to temperature, loosening the fastener, and applying the documented torque, in increments.

Some say to apply documented torque after heating, and if nothing moves, al is well.

Sound off, smartly,

D.
 
Use never seize and red loctite torque to specs and it will stay there without re-torquing due to the red loctite.
 
I have never had one not to move on re torqueing. With fiber gaskets you can check the difference if you check rocker clearances before and after. Of course re set the rocker/valve clearance after re torqueing. You probly will not get much valve/rocker clearance using a solid copper gasket. You can never recheck details to often.
 
Hello Dennis mn,

It always amazes me when people ask torque question. I never questioned torque values. I don't know if you have the proper specifications, but really!, that is all you need,

Guido.
 
(quoted from post at 21:56:47 11/07/15) All,

I would like to know what others consider a re-torque.

I see it as getting a part up to temperature, loosening the fastener, and applying the documented torque, in increments.

Some say to apply documented torque after heating, and if nothing moves, al is well.

Sound off, smartly,

D.

What does the factory service manual state on the topic?
If rebuilders were not so cheap and used new fasteners instead of trying to reuse old stretched and fatigued bolts and studs. After running a tap through all the threads and cleaning everything up. Re-torquing and many failures after rebuild would be a non issue.
Does anybody re-torque a brand new machine after a few hours ?
 
Well what are you working on? When I worked for Dana Victor gasket said no retorque necessary. That was for automotive applications, Victor gaskets for heavy duty application said it was necessary to retorque. Also on the loosening, if the fastner did not move, put a pencil line on one of the hex corners and back it up about 1/4 turn and then torque it most would move. Also most torque valves have a slight range such as 120-125 pounds. Torque them to the low spec and then when you retorque go to the high number. Then you know they will all move.
 
Hello dr sportster,

You blanket statement is really not correct. Red locktite will not prevent the clamping force to stay as torqued. Cap screw/fastener stretching is one of the reasons among others. Some applications require new fasteners for that reason,

Guido.
 
Well like Buick and Deere said what does the engine mfg. say . For the most part a retorque is required . Now as for some gsk. mfg. they say there gskt does not need re torque ,yea wright that way down the road you get to do the job over again . BTDT . with over 55 years of engine building from mild to wild from little pony motor to really big diesels the first thing i do BEFORE i even start to put it together is i chase the threads with bottoming taps , then ALL the bolts are checked and chased . All holes are flushed out and compressed air dried then all fasteners are lightyly lubed . Head bolts rod bolts and main bearing bolts are torqued in a three step torque . to spec.'s when the engine is ready to be lit it is then started and checked for oil pressure and any leaks that may or may not start . If breaking in a new cam then the engine is set to run at rec. speed for the time frame . All the while watching oil pressure and temp. Then it is run till the engine is at OPERATING temp then it is shut down and re torqued and I DO NOT BACK off any bolts they get pulled down to the rec. spec.'s and run the valves once again . Head bolts and manifold bolts . Most times you will find that the center head bolts will be the ones that will get the loosest and same applys to the exhaust manifold-s. This past summer i worked on a Allis Challmers 5040 and that is the first engine that i came across that did NOT requier a retorque other then these new torque to yield head bolts . Those you throw away and put new bolts in.
 
Ah yes but you must select the proper tap or { in my opinion ] if chips are coming out your tap is too big . You are cleaning crud not cutting metal out. For the ARP fasteners the tap size is speced out [ as the smallest].
 
As far as retorquing hot, I've never heard of loosening the fastener. Somewhere in the 70's or 80's, AC sent out a service bulletin that said we could over torque the 301 head (180-190-etc.) 10%(165ft.lbs.) and not have to re-torque it.

I suppose there are too many variables for a blanket statement to apply. Type of head gasket, type and amount of fastener, etc.
 
After sitting, a bolt will take a set so I back them just enough to move ever so slightly, then pull up to specs. It takes a lot more to break that set when tightening.
 
On engines that have a specified torque value.... I take them through a heat cycle up to operating temperature... then after it's cooled down retorque to spec. Sometimes they move. Sometimes not. I agree with others that the bolts need cleaned on a wire wheel, etc and ALL HOLES CHASED WITH A BOTTOM tap.
Where it could get interesting... is with engines that have a combination of basic torque values and finish with degree/turns rather than a specific value. I put a head on a 4BTA3.9 the other day and it's got different torque values for the long and short bolts with specific sequences for each... then a 90 degree twist on all of them in a conventional pattern. There's no going back to retorque that lid....

So bottom line is FOLLOW WHAT THE BOOK SAYS.

Rod
 
(quoted from post at 20:56:47 11/07/15) All,

I would like to know what others consider a re-torque.

I see it as getting a part up to temperature, loosening the fastener, and applying the documented torque, in increments.

Some say to apply documented torque after heating, and if nothing moves, al is well.

Sound off, smartly,

D.
Like RodinNS said when you are working with a torque to yield/strech there is no way to re-torque.
As far as using old head bolts I have done Cummins/Onan engines and they supply a gauge or measurements to check the old bolts with to determine if they need to be replaced or not.
Never had a problem using old bolts after following the instructions.
 
I did, and it clearly talks about why threaded assemblies loosen and how loctite will prevent that. However a gasket that starts out at one thickness and compresses down after clamping force is applied is a much different scenario. Yes loctite would prevent the bolts from ever becoming loose, yet the clamping force which is what makes the gasket work could diminish. I recently did a Toyota pickup head gasket and as since they are a pain to run then gettake valve cover off I did as others recommended and let it sit overnight, actually ended up 3 days, and retourqued and to my surprise they all turned a bit more
 
Hello market,

Finally some HARD facts! You found out by doing, most posting here is just not correct.
I have never worked on an engine made by locktite, have you? Maybe someone can post a link? Cummins, Detroit Diesel, Mack, International Harvested to name a few. Never so a head torque procedure requiring locktite. They must be all wrong! I had to always redo the valves and injectors after running any new overhauled engine. That was also done after torque when required,

Guido.
 
I agree,and have seen loctite or loctite patches on many oem assemblies but never a headbolt. I think a common misunderstanding is torque and clamping force, clamping force is what really matters in a gasket application. That can diminish obviously even if the bolt doesn't loosen, retorque is to maintain clamp force lost as parts settle in not from bolts backing off
 
Hello market,

As I stated in my first response to the post: All he needs is the manual. Some engines like DD it requires international compound #2 for head bolts, it is not used on Cummins which reqiures engine oil. I have used other oils including heavier ones.
How many know that most torque values are for clean and dry threads only? You add oil and now you have to reduce the torque value. Again......it's in the manual!

Guido.
 
Yup and right on the can of Caterpillar antiseeze it warns that lubricant changes the torque tension properties
 

The studs on older vehicle wheels get rusty, and I would put a couple drops of oil on them. Now it's said not to oil them, especially oh the E series chassis under most class C motor homes, It's a different system, and they need to be torqued. But what do you do if/when the studs get rusty?

Dusty
 
Wire brush... then spray with combustion chamber cleaner to dissolve the remaining rust.

Rod
 
(quoted from post at 00:27:30 11/09/15) Hello market,

As I stated in my first response to the post: All he needs is the manual. Some engines like DD it requires international compound #2 for head bolts, it is not used on Cummins which reqiures engine oil. I have used other oils including heavier ones.
How many know that most torque values are for clean and dry threads only? You add oil and now you have to reduce the torque value. Again......it's in the manual!

Guido.

But IH manuals state that their torque specs are for clean lightly oiled fasteners.

I learned the importance of re-torquing some head gaskets with the first JD 3010D I worked on. The directions were to run the engine to operating temperature and re-torque the head bolts. Then to re-torque again after 10 hours. Since the tractor had to be used I put off the 10 hour re-torque. The head gasket didn't make it to 20 hours before blowing out. After replacing the gasket I was surprised that most of the bolts turned about 1/2 a turn after 10 hours of use.

As far as new tractors requiring the heads to be re-torqued it was part of the post delivery service procedures at 100 hours if I remember correctly for an 86 series tractor. Re-torque the head, reset the valves, and a list of other things to be checked and adjusted. Since the owner had to pay for the after delivery service we saw very few tractors come back to the shop to have it done.
 

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