Torque wrench problem/issue
 

Well, I think I blew it.

I purchase a 1/4" torque wrench from Harbor Freight. I was using it to torque my valve covers. When I was using the wrench (set for 4 ft pounds to start) I noticed it did not appear to be working properly. I was having to tighten the nut to much and it was the clicking the way it should. I took it back and got another wrench. As I was using it, the same thing was happening again.

Now the bad news. As I was tightening one of the nuts, I noticed it just keep turning. The bolt was not turning just the nut. I think I over tighten it.

Now you can give me the bad news. If the bolt is not turning however the nut will not tighten up what do you think I have done and how should I approach fixing it.
It on the top valve cover.

You know the saying, "You get what you pay for". The torch wrench was on sale for $20 and I now think I know why. It is made by Pittsburgh. I took it to a auto shop and they tested it and said it was defective. That's 2 in a row. So, beware on Harbor Freight's Pittsburgh torque wrenches.

I feel dumb for keep tuning the nut.

Your feedback and comments are very appreciated.

Not really sure what you mean by the bolt not turning, my 911 has studs and nuts to hold the valve covers on. I'll put my money on the locknut being stripped and the very much stronger stud being just fine. Simply back off the stripped nut, bin it and use another. The valve gasket kit should have all new nuts and alloy washers, you did get a valve cover gasket kit didn't you?

The alloy washers take a crush so reusing old gaskets, locknuts and alloy washers is a recipe for oil leaks, eventually. Everyone has an opinion on which gaskets to use, the Porsche ones work fine for me.

If the nut is absolutely stripped you sometimes have to lever it with a screwdriver or similar tool as you undo it with a ratchet. All that said, I use the torque wrench in my wrist to judge how tight to do those valve cover nuts up, more important to tighten them in a sequence imo. (I start on the centre 4 nuts then work my way outward, torquing them up a little at a time, just like a cylinder head.)

Over Torque
 

You are absolutely correct. I am talking about the STUD not turning and the nut will not tighten up because I over tighten it with a bad torque wrench.

It's great to have this forum where you can get feedback from experienced people.
I just starting to do work on my car and taking slow and easy. So far, it's been a real learning experience and enjoyable.

I hope I just messed up the nut.

I would also like to get some feedback on a decent 1/4" torque wrench.

Thanks

being a mechanic, for such a low torque i use my wrist meter. there not that critical to get spot on the torque value, just snug. Keep the ratchet in your palm when tightening that should do it. but do go in order.
might have to cut that nut off or get a small flat screwdriver under the nyt and apply pressure while unscrewing.

Agree with James ^^^^^

It is very difficult for a torque wrench to go that low (especially Harbor Freight which are better for higher torque values).

I own a 1/4"drive, inch/lbs torque wrench from Sears, and it works very well. It's important to relieve the pressure on the internal spring when you're done, and if you have it for a while, and use it regularly, it should be re-calibrated. I have had both my larger Snap-On wrenches re-calibrated, but not my 1/4" drive from Sears. It sees very little use. Buy good tools. They will last a life time. You don't need to buy Snap-on, but I'd buy a Sears torque wrench over a Harbor Freight one. Don't get me wrong..There are tools I'd buy from Harbor, but when it comes to measuring... I don't have confidence in their stuff.

I have used HF or equivalent torque wrench many times with no issues, but you are expecting too much from the wrench you bought. You are probably at the very low end of the wrenches range.

Start with a new nut. You may have tripped the nut, the stud may be fine. If that doesn't work, the next step would be a small spacer (I would NOT use a a stack of washers, but you might be okay with that). That will allow you to get to some 'new threads' on the stud.

Your last option is to remove the stud and install a new one with loctite.

I certainly would not use HF tools in anything that is critical. A torque wrench is an precision instrument and you should buy it from someplace reputable.

are these new valve-cover nylocs?

try another nut.

I agree that you should calibrate your wrist, and choke up n your ratchet until you get a feel for it.

Accurate, low torque wrenches are used in electronics and precision assembly industries, but are not cheap.

Buying any torque wrench ( a precision instrument) FROM HARBOR FREIGHT IS ABOUT LIKE BUYING SURGICAL TOOLS OFF OF EBAY...

Torque wrench
 

I have learned my lesson on precision tools and Harbor Freight.

To their credit, I took the 2 torque wrenches back to them today and the gave me a refund no questions asked.

You can do a rough calibration at home well enough. Take a 1' bar, hang 4 lbs off it and see if it trips the torque wrench.

Or hang 4.2 lbs at 10" say and gradually slide the weights out until the wrench trips. Measure the distance and do the math.

here is some food for thought:

A Lock nut resists turning. Usually nuts are free spinning, but locknuts nuts have a plastic patch that causes resistance to nut turning. This resistance is called "prevailing torque". Prevailing torque is the torque required to turn the nut. None of the prevailing torque goes toward tightening the bolt.

Lock nuts nuts fall within a group of nuts called 'lock nuts" Lock nuts come in all types and sizes. Typically there are the "Nylock" or elastic stop nuts, and the "all-metal" lock nuts.

The rule of thumb is to add the prevailing torque to the torque value when torquing a lock nut. This is because the prevailing torque doesn't contribute to bolt tightening. It is just friction that needs to be overcome.

For example, a Grade 5 1/4-28 bolt in tension lubricated zinc plating, with a torque of 10.5 lb. ft. produces a clamping load of 2,511 pounds.

If we use a use a lock nut that takes 2 lb. ft. of torque to turn, then 2 lb. ft. of torque is used in turning the nut leaving only 8.5 lb. ft. for bolt tension. Our clamping load is reduced to 2,009 pounds.

If, however, we take our original torque of 10.5 and add the 2 that the Nylock requires and set our torque wrench to 12.5, our clamp load is 2,511 pounds. The same as it was without the nylock.

You can use your torque wrench to measure lock nut torque and then add this value to the bolt's required torque.

Prevailing torque calculation should be done with your nut and your bolt using your thread lubricant. Published prevailing torque charts may give you an idea of how much torque is used up by the nut's locking feature, but in actual conditions, the results will vary. There is an interaction between the bolt threads, nut locking feature, and the thread lubricant (whether liquid or plating) that makes each prevailing torque calculation unique.


--exceptions to this rule----

Usually you wouldn't add prevailing torque to the torque value published by the equipment manufacturer. The equipment manufacturer has already done this for you. For example, propeller bolts use elastic stop nuts (prevailing torque nut). The propeller manufacturer is aware of this. So just go ahead and use the published torque values.

If you use a different nut or a different thread lubricant than what the manufacturer specifies, then the proper torque is unknown.

For the small stuff I ended up ordering this one:

CDI Snap-On 2502LDIN Dial Torque Wrench Dual Scale 3/8 Dr 0-250 in-lb

http://www.protorquetools.com/DSN/ww...lg1_000812.jpg

139.91 shipped. But then, of course, found it a few bucks less else where later....

I have a Craftman Professional Series in 1/2" drive for the ft-lbs tasks.

For the small bolts you really need a quality torque wrench or, as other have said, use your wrist feel...

Good info above. To sum up:

DIY torque wrenches tend to be highly inaccurate and many factors contribute to clamping force. So use with caution.

For my valve covers I use my Mark 1 calibrated hand. I tighten all the nuts snug and then turn each one until I feel the crush washer deform. I start in the middle and cris cross to the outside. I have yet to have a leak.

FWIW I do the same for spark plugs and the like.

Me too :p