How do you torque?

[Nealcrenshaw]

Just wondering how my fellow members torque?Do you torque all the way to spec or do you step it up,as in torqueing a 75ft/lb bolt in 3 equal 25 ft/lb
rounds.For instance When torqueing Head Cylinder or a ball joints,How do you Torque?

 

[billymade]

I was just watching a video about how to "torque" they said to tighten with correct bolt sequence and start at 80% of torque value and then do sequence at 100% of torque value.... I had never heard this before but makes sense...

 

[Stanger]

I just take the first round by feel, not tightening too much. Then I go around at least twice more with the exact, 100% torque.

 

[Merkava_4]

If your final torque is 75ft.lbs., you'll make 3 passes - 25, 50, and then 75.

 

[Uncle Buck]

Just wondering how my fellow members torque?Do you torque all the way to spec or do you step it up,as in torqueing a 75ft/lb bolt in 3 equal 25 ft/lb
rounds.For instance When torqueing Head Cylinder or a ball joints,How do you Torque?

I was just watching a video about how to "torque" they said to tighten with correct bolt sequence and start at 80% of torque value and then do sequence at 100% of torque value.... I had never heard this before but makes sense...

I am sure billymade is likely right. I never read or saw anything but pop taught me to make several passes through the tightening sequence and sneak up on the final torque value. I have followed those directions for over 30 years and I have never had a problem.

 

[Elroy]

Don't torque me off buddy

Ok lets look at this

Lets say you have an assembly with a single fastener. What good is it to sneak up on it. Slam the full torque to it in one hit !

Now a multiple fastener assembly, like a cylinder head or any other "gasketed" joint needs to be pulled up even to prevent the gasket from being extruded or causing the covering component from getting cocked.

does that make sense?

 

[Uncle Buck]

Don't torque me off buddy

Ok lets look at this

Lets say you have an assembly with a single fastener. What good is it to sneak up on it. Slam the full torque to it in one hit !

Now a multiple fastener assembly, like a cylinder head or any other "gasketed" joint needs to be pulled up even to prevent the gasket from being extruded or causing the covering component from getting cocked.

does that make sense?

Yea, that was what I meant, I just did not clarify the issue as well as you did Elroy.

 

[Diesel-Mech]

I go by the manufactures recommendation when applicable and available, If I don't have any information other then the torque spec then I do it in equal steps, if it is multiple fasteners and I do not know the torque sequence then working from the center to the outside in a clockwise pattern is a pretty safe bet.

 

[Elroy]

Now a multiple fastener assembly, like a cylinder head or any other "gasketed" joint needs to be pulled up even to prevent the gasket from being extruded or causing the covering component from getting cocked

Also note that good technique would also call for this procedure to be utilized on dis-assembly as well.

 

[Uncle Buck]

I go by the manufactures recommendation when applicable and available, If I don't have any information other then the torque spec then I do it in equal steps, if it is multiple fasteners and I do not know the torque sequence then working from the center to the outside in a clockwise pattern is a pretty safe bet.

Nuther very good point there about what to do in the absence of knowing the sequence, been there a time ot two myself. Well said.

 

[Uncle Buck]

Also note that good technique would also call for this procedure to be utilized on dis-assembly as well.

I am sure you will make me pay for this, but I fail to see how this would really matter on the dis-assembly side. Go easy Elroy, I am not an engineer, just a decent backyard wrench.

 

[krusty the clown]

most aluminum engine parts sould be detourqued in order so the parts do not warp on dissasembly.

the proper way to touque an engine component is to follow the shop manual procedure. it will give you the order and the tourque value for each step.

 

[Uncle Buck]

most aluminum engine parts sould be detourqued in order so the parts do not warp on dissasembly.

the proper way to touque an engine component is to follow the shop manual procedure. it will give you the order and the tourque value for each step.

Perhaps that was what Elroy was making reference to.

 

[Nealcrenshaw]

I was watching a Engine rebuild video last night and the speaker was saying it's best,when dealing with cylinder heads to first oil the threads,then also a little under the bolt head, then to start from inner working your way in a circular pattern outward
Torqueing in three equal rounds,it did make alot of sense to me,since i would have thought about going full spec with each bolt.

 

[Stanger]

When loosening manifolds and such I usually just barely break each of the bolts loose, leaving some compression on the manifold. I then come back and remove them all. It should probably be done in more steps, but I haven't had any problems. If I did I would analyze the situation closer and create a more precise de-torquing sequence.

 

[Danglerb]

Torque isn't a simple subject, but generally the tolerance range is greater than the screw up factor.

Be careful.
Don't guess.
Follow the manufacturers instructions.

One of the most experienced engine builders I know still uses a piece of cardboard to check off each torquing stage, bolt by bolt.

 

[Elroy]

Elroy is easy as they come. Ya ready?

The phone rings at the Holmberg residence.

Hello.......

Hay Buck, This is your good buddy Elroy. I need you to come over here and help me change out the thermostat on my neglected Toyota with the aluminum manifold.

Sure Elroy I'll drop everything I'm doing and be right over.

So first off Elroy and Buck drink like 57 beers. Tell a bunch of lies and THEN we open the hood.

And Buck says: Why Hell Elroy this job is going to be a piece of cake. The bolts are right there. Hand me that big 1/2" breaker bar.

See I told ya this was going to be easy. Look Elroy the first bolt came right out. Now let me get this second bolt.........oh **** Elroy. I snapped it right off.

Well you dumb *** you should have listened to Elroy and left the beers at home. Give me that damn wrench.

So here is what happens. The total clamping in the joint is developed by both bolts. By removing the first one totally you transfer all the clamping force generated by the gasket into the single remaining fastener. This extra load causes the friction to go up and snaps the bolt when yo try to remove it. Now if you follow the Elroy method of beer drinking. You only partially loosen the first bolt THEN loosen the second bolt. That way everything come out in one piece.

Try the Elroy method next time and see if it doesn't make the beers a little more enjoyable.

 

[jay50]

Elroy is easy as they come. Ya ready?

The phone rings at the Holmberg residence.

Hello.......

Hay Buck, This is your good buddy Elroy. I need you to come over here and help me change out the thermostat on my neglected Toyota with the aluminum manifold.

Sure Elroy I'll drop everything I'm doing and be right over.

So first off Elroy and Buck drink like 57 beers. Tell a bunch of lies and THEN we open the hood.

And Buck says: Why Hell Elroy this job is going to be a piece of cake. The bolts are right there. Hand me that big 1/2" breaker bar.

See I told ya this was going to be easy. Look Elroy the first bolt came right out. Now let me get this second bolt.........oh **** Elroy. I snapped it right off.

Well you dumb *** you should have listened to Elroy and left the beers at home. Give me that damn wrench.

So here is what happens. The total clamping in the joint is developed by both bolts. By removing the first one totally you transfer all the clamping force generated by the gasket into the single remaining fastener. This extra load causes the friction to go up and snaps the bolt when yo try to remove it. Now if you follow the Elroy method of beer drinking. You only partially loosen the first bolt THEN loosen the second bolt. That way everything come out in one piece.

Try the Elroy method next time and see if it doesn't make the beers a little more enjoyable.

But if we use your method, we would all miss out on the experience of using those ez-outs just sitting in the tool box, begging to be used, along with the drilling, and broken bits...on yeah, and the cussing that goes along with this exercise.....

 

[garfunkle24]

I was watching a Engine rebuild video last night and the speaker was saying it's best,when dealing with cylinder heads to first oil the threads,then also a little under the bolt head, then to start from inner working your way in a circular pattern outward
Torqueing in three equal rounds,it did make alot of sense to me,since i would have thought about going full spec with each bolt.

In technical school, this is what we were taught to do in the abscence of the specified torque spec and torque pattern. Of course service documentation for the given work-piece is always preferable.

 

[nissan_crawler]

It depends on what it is. If there's a manual, I go by that. RTFM. If not, if it's a gasketed assembly, then I torque in steps. If it's a steel on steel assembly, I'll often go to final torque, then go back over it all again.

 

[Frank Elson]

I just take the first round by feel, not tightening too much. Then I go around at least twice more with the exact, 100% torque.

me too.
Of course going round in order if there are more than one bolt.

 

[wrenchr]

Billymade is correct.......It has something to do with proper stretching of the bolt or something like that, you also have to make sure you have the threads clean on the bolt and where it will thread into. You also have to use a thread oil or sealant so you do not get a wrong reading on the torque wrench.

 

[wrenchr]

http://www.small-block-chevy.com/assemblyspec.html

 

[Theo]

I do all the fasteners at the same time, in one rundown.

http://www.toolingtechnologies.net/assets/17 Spindle DC Multiple - Engine Assembly.jpg

Any other way and you're wasting your time.

 

[chammyman]

depends on application like nissan_crawler said.

 

[dreaminbimmers]

I watched a snap-on video recently specifically on this subject. For applications with multiple fasteners the three stage method should be used (divide total torque value in thirds). This is particularly important when working with things like aluminum cylinder heads.

Following the manufacturer's torque sequence is of coarse a given but this should also be followed on disassembly to prevent warping and breaking of fasteners as Elroy pointed out.

One other thing that I learned from the video is that non-detergent oil should be used to lubricate the threads. Anything with detergent or friction modifiers may decrease the torque accuracy.

 

[SpiderGearsMan]

impact gun

 

[Moose-LandTran]

"It's good to torque"

If you're not a brit, you won't get that.

 

[russlaferrera]

I was thought the fastener had to move. If not, the correct torque could not be determined, because of static friction.

On a re-torque you loosed the fastener then re-torque to specs.

 

[garfunkle24]

One thing to note is that a simple torque spec is not that accurate anyway. The torque and turn method is far more accurate and of course means a multi-stage torquing process inherently.

 

[speed bump]

If you can get to both sides of the bolt a stretch gauge is the prefered method.

Personally, I use antisieze run them down in whatever method specified and then double check everything afterward.

 

[Elroy]

The torque and turn method is far more accurate

Ya with torque to yield fasteners. These aren't typically used on thermostat housings or water pumps.

 

[garfunkle24]

Ya with torque to yield fasteners. These aren't typically used on thermostat housings or water pumps.

The torque to yield method requires special fasteners? I wasn't aware of this. I thought it was just a different technique used by certain manafacturers.

CAT uses this method extensively and when I had some factory engine training they covered this technique, but there was no mention of specific fasteners.

Educate me Elroy!

 

[Fedwrench]

I just adjust my 3/8 impact wrench from low to high depending on the type of engine I'm working on and switch to 1/4 air ratchet for light duty items like upper intakes. Torquesticks handle the lugnuts.

 

[swgray]

The torque to yield method requires special fasteners? I wasn't aware of this. I thought it was just a different technique used by certain manafacturers.

CAT uses this method extensively and when I had some factory engine training they covered this technique, but there was no mention of specific fasteners.

Educate me Elroy!

I'm not Elroy, but Wayne hopes when you torqing those torque to yield bolts, that you've also replaced those bolts. They're designed to be replaced after each use.

 

[audi noroad]

How important is this with wheels? I work at a dealership and the way I was taught was to just take them all off in one go, and it looks like most of the employees do the same. I actually leave one loosened holding the wheel on until I know the wheel is loose from the hub. I have not seen them work on water pumps, cylinder heads, etc as much so I'm not sure what there method is for that.

When I put them on I was taught to screw the bolts on by hand and then use the impact wrench to tighten them at full torque, in a star pattern. I spoke with one tech some time after I started doing this job and he mentioned going around a second time to make sure the wheel was on straight. I can see how it could not be on there right or the first one may not be torqued the same as the last, so I always go a second time.

I've never had any trouble with this, but I'm wondering if it would be considered good practice.

 

[Nealcrenshaw]

I start mines by hand then tighten them till snug in star pattern,then once they're all snug i then torque them to full spec.

 

[Stanger]

I treat wheels the same way. I crack them loose while the car is on the ground. Lift the car then zip them off. Finger them back on and tighten with a ratchet. Put it back on the ground and torque to spec. Not sure if its right but thats what I do.

 

[KenS]

Don't torque me off buddy

Wow, mark this down boys: Elroy spoke in the first person!

 

[speed bump]

The torque to yield method requires special fasteners? I wasn't aware of this. I thought it was just a different technique used by certain manafacturers.

CAT uses this method extensively and when I had some factory engine training they covered this technique, but there was no mention of specific fasteners.

Educate me Elroy!

No torque to yeild just means you torque them to the yeild point of the metal, for A36 steel this is 29 or 30 KPSI and different for other metals.

For a fun with fasteners you can figure out your the yeild strength and ultimate strength of some fastener using a beam type torque wrench. Just clamp the fastener in a vise and start turning the fastener. At first the torque will increase nice and linearly. This is called the elastic region which is were the bolt will return to the same shape after your done with it. Once you hit the yeild strength you will see a temporary plateau in the increase in torque. Then you will be into the in-elastic region here you can actually see the fastener take on permanent deformation and you will need to apply more torque to get the same amount of movement. Finally you will reach the top of the curve or the ultimate strength, from here on the required torque to apply will decrease until failure. Chances are it will fail were you clamped it.