Buying a torque wrench

[willwal98]

I am in the market for a torque wrench but I don't really know what to look for. I am just a home (backyard) mechanic but this leads to various jobs on various motorbikes and cars for family and friends. I will need something that will do light torque (5ft-lbs) to heavy (150-200 ft-lbs for head bolts, crank bolts etc). From what I have seen there isn't too much that I can afford that will do that kind of range. I have used a cheap micrometer style one and it was almost the end of a freshly built mini engine so I don't want to waste my money on something that will be unreliable.

So what type is the best, micrometer, deflection bar, dial, old skool needle one, other?
What brands are better than others or ones to stay away from?
Would I be better of trying to get one good all rounder or two reasonable ones?
What is the minimum to spend so I get something that lasts and stays reasonably well calibrated?

I have done a lot of googling and toymods searching and havn't really found anything usefull apart from some care instructions such as don't drop or knock it, don't leave micrometer style ones tightened, don't loosen stuff with them etc etc.

[oldcorollas]

the click type are easy to use because you don7t have to balance the force vs watching some shitty dial.
even the cheaper ones you can get calibrated (or can calibrate yourself with various loads), and as long as they stay relatively constant and repeatable, is all you need.

for the light stuff, you might need a seperate smaller wrench, and then a larger one for general work. otherwise a big one will nto be accurate for the small stuff.. too big a range.

brands.. there are heaps of cheapy ones that are vaguely ok, but it depends how accurate you want it to be...

[Billzilla]

Get an Aussie-made Warren & Brown beam one. I got mine from Repco at a pretty reasonable price.
They don't go down to very lowe torque figures though.

[willwal98]

Thanks guys, I have had a look on the warren and brown site and they have a few local distributors including Repco and a wholesale place I use so I will get some prices.

[SuperDave]

I got a Kinchrome one from Bunnings, was half the price of all the auto shops

Those Warren and Brown torque wrenches look good.

[PlacentaJuan]

i would worry about the low end wrench.

you can usually do the job by feel, but its the big tourques like cranks and head bolts that are important

like bill said a warren and brown are good ones, make sure that you have plenty of reading above the maximum tourque you need.

ie if you need to do a bold ut that requires 200ft-pb then make sure the wrench can handle at least 300.

you dont want to max out the scale.

[Billzilla]

Also make sure that you prepare the bolt/nut properly, to make sure you get the correct torque setting, or it'll be under-torqued and you're wasting your time.

[willwal98]

What sort of preparation do you need billzilla? Just a dab of grease?

[Billzilla]

What sort of preparation do you need billzilla? Just a dab of grease?

I can't remember the figures off the top of my head, but if you simply dry-torque a typical bolt it'll be something like 30% - 40% under-torqued.
If you put some oil on the threads only then it'll be about 10% under-torqued.
If you lubricate the threads and under the head then you'll get the right torque.

A lot of people lube the threads but forget under the head of the bolt.


*Edit - To get those figures the test series that I saw put a load meter sandwiched under the bolt, etc.
There's other ways to torque-up things as well - One way is to run the bolt up to a relatively low torque then a set angle such as 90°. The more correct way is to measure the length of the bolt, and from the stretch gained you can work out just how much clamping pressure is being applied. Naturally this is hard to do with something like head bolts so either the straight torque or torque + angle is used.

[oldeskewltoy]

Hmmmmmm, don't forget multiple passes! early 4AG manuals said 44#s... too many "mechanics" just torqued them to 44#s... but not in passes! Newer 4AG manuals use 22# and then 90 degrees... this requires 2 passes!

(btw.. on a 4AG. although the torque method changed... the headbolts never did! Same part number from 84 through 92)

Also.... don't forget your tightening pattern!

for a 4AG loosening and tightening are NOT the same........



Another thing....... before you put the head on... run each oiled bolt into each bolt hole... I recommend running them all the way to the bottom...

this applies a thin coat of oil to both bolt and block alike. Running them all the way down first will also clean and deburr any debris in the threads that may cause an inaccurate reading

[lexsmaz]

Don't just willy nilly lubricate all bolts when torqueing them down, head bolts need to be lubricated, but a lot of other bolts around the car are clean thread dry torqued, you can over torque bolts by quite a bit if you oil the threads etc when they are mean't to be torqued up dry ..
Good workshop manuals will usually say wether to oil the threads etc on a certain bolt when torqueing it down ..

[PlacentaJuan]

^yes what that guy sais,

don't wet torque bolts unless specified by manuel

[petergoudie]

Be very careful with those torque methods that specify 90 degrees (or similar) after a specified torque.

Often this method takes the bolt above its elastic limit into the plastic region before it reaches its ultimate tensile strength (that is, it breaks).

Once used these bolts are throw away and can't be used again. My 2RZ Hiace engine is like this and a new set of head bolts must be used if the head gasket is replaced.

If you can find a manual, read it carefully to find out if the bolts need replacing.

[SilverRA23]

Please done't buy a Kincrome one if you can afford not to. I know lots of backyard guys recommend them, but I had a collection of them and wanted to get them calibrated. The calibration guy refused to touch them and he put them on his tester to show us why.. the difference between two supposedly same settings was remarkable...

[Smokey228]

I got a Total Tools one, its been pretty good and was only 95$ after some haggling... It only works inside 40-110nM, but i also have a sidchrome one for the smaller figures... I actualy prefer the TTI one

Cheers,
Jase