I spent close to $100 on my torque wrench that I've been using for injector bolts. I've seen torque wrenches as high as $500, and I've seen torque adapters as high as $1300 - and I'm sure there's some ubertool that I've overlooked. Our friend with the cheap stuff (Harbor Freight) had a sale on 1/4", 3/8", and 1/2" torque wrenches at 20 bucks each - so I bought one of each of them for my engine project.

Just for funny-ha-ha, I linked the 1/4" and the 3/8" wrenches to my existing torque wrench, and the readings were all over the map. I could set each wrench to a specific setting, and link them face-to face. One wrench or the other would click first, and I would have to adjust one wrench or the other up or down as much as 10% After resetting each wrench to zero and going back to the same setting the results were anywhere from a match to 10% high or low from each other - but no consistency as to which was higher or lower. This might sound outrageous, but if the opposing wrench just so happen to be 5% high and the other 5% low - that could account for the differential... maybe.

I won't do "maybe" when it comes to putting this engine together. I found a reasonably-priced solution to the problem - a digital 3/8" torque adapter. It's the ACDelco ARM602-3. This has the range I have chosen to verify torque settings on things under the valve covers, and since it goes up to 59 ft/lbs - I can verify the torque setting on many of the smaller bolts on the engine.



I found a wide price range on this unit - depending on the web site, the vendor, and possibly the temperature of the coffee in my cup. I picked one up from Amazon for 60 bucks, and what I received for that price really surprised me. The quality of the protective case and the box alone is of the caliper you don't see coming from our friends in the far East - this is some solid stuff. There is a very complete manual inside with good instructions and of all things - a parts list to service it. There is also a calibration sheet inside, showing the torque tested and the readings given. I've seen sheets like this on delicate measuring devices at work, so I'm familiar with the procedures behind these tests. The worst deviation on the readings was 0.86%. That's pretty freaking tight.

I completely understand the technology in these devices, and I know from vast experience with load cells that if you get the right sensor and electronics - that level of accuracy is not an unsubstantiated claim. I deal with load cells that take measurements of moving objects weighing over 200 grams with a 50 ms read time with +/- 1.0% accuracy. That's a lot of numbers, so I'll translate: The object weights anywhere between 3 and 10 ounces, and we're flinging it across the scale at 200 feet per minute. We don't stop to weigh it, we weight it in motion. With that, the common accuracy is +/- 1.5% with the same technology used in the digital torque adapter.

So... to the point of this thread: I bought two torque wrenches at 40 bucks total, then I bought a $60 torque adapter. I will use the torque adapter to set the torque on the wrench, then I will use the wrench. With this arrangement, I get very accurate torque on all the smaller bolts, without the need to buy two very expensive wrenches. I don't want to use the torque adapter directly on the bolts for a few reasons:

• The less wear and tear on the adpater, the longer I trust it doesn't go out of calibration.
• Every time I use it, I risk dropping it - bad juju.
• It won't fit between the wrench and the socket in many places I need to get to.

 

Rich, does the calibration sheet you have look something like this?

 

Attachment failed to open.

 

I'll try posting again from a different link... let me know if it works. If not, I'll capture the pic and upload it back into my album, then repost.





Ok, image moved to FTE's file server, so it should load for you. Back to the original question... does the calibration sheet you have look something like this?

 

Very cool, Thanks for the info!

 

Similar to that, but with 6 readings.

 

The calibration sheet above is to a Harbor Freight equivalent which the owner reported purchasing for $23.00.

Apparently, there are a lot of iterations of the same product, dressed in different colors, button styles, and brand names.

It was suggested on a tool forum that many of them might even be made in the same factory, for different importers. Others include a manual, a calibration sheet, and a case as well.

One guy reported testing the HF unit at work (his job happened to be testing torque measuring instruments for the military) and was surprised to find the accuracy consistent with what was stated on the calibration sheet.

Other guys reported no problem with accuracy, but short battery life.

If it is at all true that many of these torque adapters have the same "guts" inside, then I would be inclined to look for one in the $30 range.

The discussion of these items on the tool forum concluded that there was no link between price paid and performance expected, despite the American sounding brand names on some versions of them.

 

I looked at the HF unit. The one in the store is a 1/2" drive with ranges nowhere near anything that would be measured in inch/pounds. I chose this unit specifically because it's a happy medium between injector bolts and some of the larger bolts.

 

I ordered one, I have a torque wrench tester at work and if I remember I'll test it.

I have always wanted one of these just for checking my own wrenches so it might be worth it.

As to the battery drain its probably like the chi-com calipers that don't actually power off, its best to remove the batteries from these devices.

 

So far so good, I actually really like this device.

Somethings I noticed.

Putting the drive in a vise and torquing against it makes for a very awkward reading/feeling. Much different than against a bolt.

Secondly I feel this is way more accurate than a click style torque wrench if we are comparing low end torque wrenches.

 

Just a reminder...

 

Gasp.....isn't it bad Voodoo to use AC Delco stuff on our Fords???

 

I'm a field jockey so it's gonna be a bit...

 

Yeah... it was a little weird at first. I did notice that every time I set the wrench, it was never exactly the same as last time I set it. I like how I can set the wrench to this every time I use it, and the wrench is consistent once set.

Naw.... They really need our stuff to work good - so we can give them a tow.

 

Interesting observation.

I torqued the new driver side injector bolts to 120 with oil on the washer face and threads. I also torqued the oil spout bolts to the same setting with the same wrench.

The next day when the digital adapter arrived I checked the injector bolts and I got a 1/4 to 1/3 of a turn on all of them. The oil spouts however did not move at all when checked with the digital adapter.

This is not a hot torque and the engine had not been ran in between these torqings.

I am going to finish today and I'll recheck the driver again and recheck the passenger, I forgot to put the oil spouts on before putting the valve cover on