Bad torque wrench or bad luck (broken injector holder)?

I keep breaking things with my torque wrench . A few weeks ago I broke a tranny pan bolt, while torquing it to 9 ft/lbs.

This weekend I was upgrading my injector nozzles to .184mm ones and everything was good until I began installing the injectors back on the engine.

I did install three of them with no problem and torqued the holder bolts to 20 ft/lbs. The last one of them however, kept turning and luckily I stopped in time and only ended up with a stretched bolt. A broken bolt stuck in the head would've been worse.

I got a new bolt from Ace and began tightening it again. I was doing that very carefully now, increasing the torque a little bit at a time. As soon as I got to 15 ft/lbs I heard a pop - turns out the injector holder snapped in two.

The dealers around me don't stock the part, however, I should be able to get it tomorrow. Should I be looking for a new torque wrench or just hope for better luck? Is there something else that I could be doing wrong?

stancho said:

I keep breaking things with my torque wrench . A few weeks ago I broke a tranny pan bolt, while torquing it to 9 ft/lbs.

Click to expand...

What is the range on yoru wrench. for something liek 9 ft/lbs you should be using a wrench with a low er scale than one like you would use for tire lug bolts and such that require 80 and up ft/lbs. Mine i use for lug bolts gos as low as 25 ft/lbs. Even though it goes to 25 it is problaby not near acurete. Infact a friend of mine broke a valve cover bolt using it at its low end. From what i have read from other people is that they are most acuret in their middel range. I don't have anyway to calebrate it so i can't say for sure. But sometime in the next year i will problaby have it done. I will see if they can profide some kind of acureacy graph.

Also, if your torque wrench is one of the spring loaded types, it needs to be zeroed after every use, otherwise the accuracy will be lost. For such a low torque, you should be dealing with a light duty 3/8 or even a 1/4 inch drive torque wrench.

Many/most wrenches only claim accuracy from 20-100% of max torque. If you are significantly below 20% of max, you are doing guesswork.

I'm not sure I have a torque wrench that reads less than 20 foot pounds. I do have torque wrenches that measure less but are calibrated in inch pounds. Are you sure you know exactly which type you have ?

Thank you all for the replies. I was not not aware that these wrenches can be inacurate on the lower end of the scale. I have the click type wrench and it goes from 10 ft/lbs up to 150 ft/lbs. Most likely, my usage of the wrench is to blame. I have to go out and find a wrench for lower torque ranges.

I would sugest to get yourself a new tq wrench and one that only goes to 30 ft/lbs for the more sensetive bolts. And make sure that you wont get lb/lbs with nm mixed up.

I'd only tighten that bolt to about 13lbs. Based on it's size that's about the maximum it can handle.

I just hope I did not overtorque the injectors themselves when installing the nozzles. I used 33 ft/lbs as mentioned in the how-to guide. That seemed to be somewhat more than 30 degrees.

Tonight I should be able to get a new injector retainer at the dealer and button up the engine. We'll see.

I would stop using that torque wrench... they do become miscalibrated over time.

Torque is all well and good on new threads. But a torque value on old threads is not always good. If the threads are clean and no burrs then its not bad if they are other than that then you need to go a bit more on the torque. I have never had a compression leak on injector installations and I have never broken a strong back either and I don't use a torque wrench. The feel also comes with experience.

Greg

The injector bodies are fine. You can torque them REALLY hard without issue.