Mechanics : Torque Wrench Question

[Wyzsard]

Will using a universal adaptor or wobble head extension throw the torque wrench setting off ?

I need to reinstall a throttle body w/ new gasket and it calls for about 6.5 ft lbs on the bolts/fasteners.

Don't want to over tighten them.

Also, I'm replacing the starter. I see the vendor shows shims. Should I replace them as well ?

Tia

 

[oregomike]

If you keep the wobble head at 90 degrees, it won't mess with the torque. If the head is off that axis, then yes.

This is a good example of effects using different extensions.

 

[Wyzsard]

If you keep the wobble head at 90 degrees, it won't mess with the torque. If the head is off that axis, then yes.

I 'm not sure I'll need a wobble head yet, just asking in case I do.

I suppose I could set the wrench at 5 lb and using the wobble, tighten the fasteners, increasing the setting until it doesn't break ?
Iow, attempt to see where I need to leave the wrench set to reinstall.

That even make sense ?

 

[Wyzsard]

This is a good example of effects using different extensions

Thanks, I'll give it a watch !

Eta : good demonstration in the video. With the universal, he tried it at a more extreme angle than I think I need.

Well worth a watch.

 

[The Zesus]

I conducted research on the use of “wobble head” extensions for use tightening hydraulic fittings on military aircraft about ten years ago during an internship. I tested Snap-on double cardan universal joint style extensions and Proto spline ball extensions. The extensions are needed to access many fittings, and there was a concern that the tightened fittings were not meeting the process specification. I tested a wide range of torque values between 10 in-lbf and 100 ft-lbf using calibrated torque wrenches and a calibrated torque cell.

What I found, and what’s in the video, is what is expected - that the misalignment extension simply reduces the lever arm acting on the fastener head creating an undertorqued condition. As the misalignment increases the lever arm shortens making this problem worse. My research was to identify the misalignment threshold such that the reduced torque at the fastener was still within the process specification. I found that if the misalignment was limited to 15 degrees we could set the wrench at the nominal torque and still tighten to the spec. I designed a tool that limited misalignment to no more than 15 degrees and ended up with a job offer so it was a good project for me personally.

I also discovered that clicker wrench accuracy is highly dependent on operator skill. You see this in the video when the guy puts on 30” of extensions and gets an overtorque at the sensor. This is because he didn’t let up when the wrench broke, and you can see this in the video. All the tool manufacturers are well aware of this, and back then were trying to sell electric wrenches with lights and haptic feedback that lets the operator know he is approaching the set torque value. They really do work well, but are very expensive and, at the time, could only be calibrated by the manufacturer.

This long post doesn’t really help you other than to say what’s already been said - limit the extensions to just the minimum to access the fastener and keep the wrench as in line with the fastener axis as possible. If you need the wobble extension try to keep the misalignment to less than 15 degrees and you’ll be fine setting the wrench to the nominal torque.

 

[ce24]

On the shims…if there are shims when you take it off, replace them…assuming you have the same starter as whats on there.

 

[Blrfl]

I suppose I could set the wrench at 5 lb ...

Unrelated tip: Adjustable clicker torque wrenches tend to be inaccurate in the bottom 20% of their ranges. If you've got one that does 5-80 lb-ft, don't use it for anything below 20.

 

[mycroftxxx]

I found that if the misalignment was limited to 15 degrees we could set the wrench at the nominal torque and still tighten to the spec.

Small-angle approximation for the win!

 

[Milspec]

Here is a little trick that Volkswagen used to teach mechanics back in the '60's. If you move the wrench with your index finger only....that is approx 5 lbs. Use 2 fingers....10 lbs., etc. on down the line. Keep your arm still, just pull with the fingers and you get pretty darn close.

I never get too wrapped up in torque wrenches anyway, you are not building a spaceship so you don't have to be exact. Truth be told, unless you just calibrated the wrench, you are likely off anyway. An old school beam style wrench is more accurate in truth anyway, but even then not perfect.

 

[dogmeat]

I have also tested wobblies except not the U-joint, I mean the kind of socket with the wobbly built in. and yeah, 15 degrees makes no substantial difference.

as for the starter shims... use as required. what worked on the last starter may not work on this one. if you can't find a procedure, you'll just have to try something, and if it grinds or won't engage add a shim. if the teeth skip, remove a shim

 

[telemnemonics]

Here is a little trick that Volkswagen used to teach mechanics back in the '60's. If you move the wrench with your index finger only....that is approx 5 lbs. Use 2 fingers....10 lbs., etc. on down the line. Keep your arm still, just pull with the fingers and you get pretty darn close.

I never get too wrapped up in torque wrenches anyway, you are not building a spaceship so you don't have to be exact. Truth be told, unless you just calibrated the wrench, you are likely off anyway. An old school beam style wrench is more accurate in truth anyway, but even then not perfect.

I didn't want to speak up but I agree in particular on a throttle body as opposed to say an aluminum cylinder head where it is much more critical.
Personally I might just see how firmly my hand tightens on the wrench on some random bolt, and remember that force, if stuck unable to get the torque wrench into a tight space for a throttle body.

 

[MarkieMark]

After many years in automotive service and precision machining of all kinds, I have accumulated a series of reliable torque measurement tools for when it matters...
From a few inch pounds to 450 Ft. Pounds, I have it covered.

The specification given- (5 foot-pounds) is honestly odd and not really a common close measurement.
By brain interprets a specification of 5ft-pounds something like "Plastic manifold, dont over tighten" as opposed to "torque to exactly 5 ft. lbs"

The torque wrenches would remain in the toolbox drawer.

IOW. Overthinking this?

Yes. Absolutely.

One develops a feel for when the gasket compresses, the bolt/screw is snug and the understanding that "this assembly doesn't hold the engine/transmission in"
Favorite lesson used to be a spark plug. The type with a compression gasket.
If the threads are clean, you should be able to feel the seat either by hand, or light tool use.
From there you can distinctly feel the gasket compress, then the resistance increase. Stop. Your done.

As an aside... Please people, just quit tightening the oil drain plug to the point of stretching it. And the oil filter? Doesn't need to be so friggin' tight. Trust me!

Throttle body-
Snug them all up a little until you feel the resistance increase, then a final light pass to verify. Done.

Seriously.
5 ft-Lbs. means " Don't kill it, these threads won't take it.
Thats it!

 

[pippoman]

After many years in automotive service and precision machining of all kinds, I have accumulated a series of reliable torque measurement tools for when it matters...
From a few inch pounds to 450 Ft. Pounds, I have it covered.

The specification given- (5 foot-pounds) is honestly odd and not really a common close measurement.
By brain interprets a specification of 5ft-pounds something like "Plastic manifold, dont over tighten" as opposed to "torque to exactly 5 ft. lbs"

The torque wrenches would remain in the toolbox drawer.

IOW. Overthinking this?

Yes. Absolutely.

One develops a feel for when the gasket compresses, the bolt/screw is snug and the understanding that "this assembly doesn't hold the engine/transmission in"
Favorite lesson used to be a spark plug. The type with a compression gasket.
If the threads are clean, you should be able to feel the seat either by hand, or light tool use.
From there you can distinctly feel the gasket compress, then the resistance increase. Stop. Your done.

As an aside... Please people, just quit tightening the oil drain plug to the point of stretching it. And the oil filter? Doesn't need to be so friggin' tight. Trust me!

Throttle body-
Snug them all up a little until you feel the resistance increase, then a final light pass to verify. Done.

Seriously.
5 ft-Lbs. means " Don't kill it, these threads won't take it.
Thats it!

I’m thinking the same thing. I would leave the torque wrench in the tool box, but that’s just me.