Torqueing Harmonic Balance Bolt

[jjrbus]

I was not doing well with the timing belt install so called a mobile mechanic that was highly recommended by the local NAPA. When talking to him I told him to bring a big torque wrench for the harmonic balancer bolt and repeated it later in a text.

I don't watch him for 2 minutes and he puts the bolt in with an impact wrench!

I do not like mechanics doing things with an impact gun and not a torque wrench especially wheels. Should I go get a big torque wrench and redo it?

Jim SW FL

[Back East Don]

I think most of us can relate horror stories of one sort or other when dealing with mechanics or any trade. It has on more than one occasion become a issue of me telling someone else how to do their job and most times someone ends up insulted. For years I've done most of my own work with exceptions. Exhaust work always seemed not worth the value proposition as the parts often cost almost what a cheap muffler shop does. I also left brake work for others back when doing it was cheap as it was just messy work and I didn't like breathing the stuff.

Now I'm older and I've had to just learn to accept that many trades are not going to be as invested as I am in the work. So I drive new vehicles and get them serviced at the dealer and view it as the convenience tax.

As to your dilemma. That impact is more likely to over torque as under depending on his vigor at it. I'd likely grab a breaker bar at minimum and gauge where it is at by feel first before passing condemning judgement. If you have a torque wrench, sure get a reading as to how tight it actually is.

I continue to become more zen as I age. It is to the point where I sometimes don't recognize myself anymore. I once was really difficult. It can still come out at times. I don't much like that person.

[zero]

If It was mine, I'd back off the bolt, then retighten with a torque-wrench and make sure the bolt wasn't ruined by over-tightening. If you have a manual trans - you can put the parking brake on, trans in 1st gear and then tighten the bolt. If automatic - not so easy to keep the crankshaft from moving. A bolt is just a spring and like most all springs - if it gets stretched too far -it yields and gets ruined. A high-power gun with 150 lbs. of PSI can break that bolt right off and at least that hasn't happened. I've seen many auto components get ruined with an impact gun in the hands of the wrong person. Crank-pulley bolts, pinion nuts on differentials, brake rotors, etc.

[WME]

Unless the engine was locked somehow, I doubt the bolt was over torqued because, even if the wrench was set on stun, the engine would move. Even with a proper torque wrench, its very hard to get 150 lb ft of torque on the bolt.

[zero]

_{I've done many with a torque-wrench. If the vehicle has a manual trans - just sticking it in 1st gear with the parking brake on is usually all it takes to hold the engine. If automatic - I usually take out the starter motor and lock the flywheel via the ring-gear teeth. A good hand-held 1/2" air-impact gun can make 300-400 lbs. of torque - even on a bolt on a crank with an engine that is not locked up. They work great for taking off stubborn bolts. I'd never use one to re-install one.}

[WME]

Your ideas and methods are good. But in this case the Toy is an automatic and there is no mention of removing starter or locking the engine. The torque required is over 180 lb ft. I would guess that the breakover torque is around 50-75 ft lb

[jjrbus]

Thanks for the input. I knew I would never be happy with this and was confirmed here. This could be depending on the condition of the impact and compressor anywhere from 30 lbs to 400lbs of torque.

So it was off to buy a big enough torque wrench, it was a choice between a Harbor Frieght 300 lb one and a Lowes 250 lb Cobalt. I opted for the Lowes. I had to go to three stores to find one that looked like it had not been used!

I wanted to use the wrench to loosen the bolt, but something is telling me torques are not to be used to brake loose bolts?

I tried a 1/2" breaker bar and could not budge the bolt, so added a pipe. At about 3 ft on the pipe and angle iron the bolt loosened. I would guess it was torqued under the 180 lbs.

Yes it is an automatic, I had made up a tool from angle iron to install the bolt with. Angle iron = used bed frame, my go to material.

I am an old guy in an awkward position so It took some effort to torque it to 181 lbs. But then how accurate is a under $100 torque wrench??

Thanks Jim

[Back East Don]

Too late now but a trick I learned doing a Honda is the starter bump method of loosening the bolt. Brace the breaker bar and socket in place and hit the starter momentarily to knock the bolt loose. Worked like a charm on that Honda.

[jjrbus]

I used the starter bump method to take it off the first time. 1 Ataboy to the person that thought that one up.. I barely touched the starter and the breaker bar fell off. As I was trying to figure out how to duct tape, bungee, bailing wire the bar in place I discovered the bolt was loose. Wow.

This time I was curious and wanted to get a feel for how much torque was on the bolt.

Jim SW FL

[5Toyota]

thanks to don for bring up that trick. I knew a Toyota dealer mechanic showed me that trick 25 years ago. I was shocked the first time I saw that.

[Maineah]

Never seen a pulley fall off because the bolt was not tight enough.. Many old engines did not have a bolt they were hammered on. First time I saw the starter being use to remove the crank bolt was in 1962 by a mechanic at the gas station I worked for as a teenager. An impact wrench will over tighten a bolt if you sit there and hammer away till it moves no more that is why tire shops use torque sticks now a days because the bozos just hammered them until they stopped.

[jjrbus]

I have had 2 lessons over the years with mechanics and impact wrenches. One I watched a mechanic put my tires on with an impact wrench. Later in the day I am on the Thruway and hear a funny noise, I pull over and the lug nuts on one wheel are loose. I am absolutely positive they put the nuts on with an impact wrench, I saw it done. Low air, wrench going bad, inexperienced mechanic??

2nd one I bought new tires for my motor home in Salem Oregon. They put the wheels on with a 1 inch impact. A year later I could not get one side off with a 3/4" breaker bar and a 10 ft pipe! I had to replace the lug studs and nuts at a cost of over $100. That was 15 years ago, likely $200 today

The only reason torque wrench's are in common use now at tire shops is because of lawsuits!

If you Google "crankshaft pulley falls off" you will get 143,000 hits.

Stay Away from my vehicle with impact guns!!

Jim SW FL

[zero]

Never seen a pulley fall off because the bolt was not tight enough.. Many old engines did not have a bolt they were hammered on.

Older engines with harmonic-balancer and pulleys that pressed on to the crankshaft end with no fastener were often a much tighter press-fit that what many newer engines have. Kind of an “apples to oranges” comparison.

[Back East Don]

First time I saw the starter being use to remove the crank bolt was in 1962

I get it, I'm always last to hear about these things.

[jjrbus]

I get it, I'm always last to hear about these things.

You heard about it before I did! So you are not last. Jim