I am planning to do engine repair work on this car, which will necessitate the use of a highly accurate torque angle gauge–not the crappy “OEM” brand one which I have, which is worse than worthless. Any ideas on which one to get, and if possible, a link to a website which sells it would be appreciated.
Are the fastener heads accessible? Can you put a paint mark on the bolt head and then use a protractor to measure 60 degrees or whatever?
Of course, the fastener heads are accessible. I used the “paint marker” trick when I replaced the cylinder head on my Caravan, but on that engine, the head bolt tightening sequence had only one step with an angle, and the angle was 90°. So it was not too difficult to put a dot with a paint marker on each head bolt at the 12:00 position, and a dot on the cylinder head at the 3:00 position, and then tighten slowly until the dots line up.
The Daewoo head bolt tightening sequence specifies a relatively low initial torque (18 LB-ft) followed by three angle tightening steps: 70°, 70°, 30°. These are not angles which I could possibly “guesstimate” visually, not easily at least. It is an interesting question if there is a different tightening sequence, which uses a torque value for the first three steps, and just one angle for the final step, which would give the same bolt loading tension, but that’s probably not an experiment that I’d be looking to perform.
They make torque wrenches that also measure angles.
Tester
Durofix also makes them.
It shouldn’t be too much work to mark off 170* total angle on the bolts and head, marking 10 degrees short of half a turn can be done with a protractor. The angle you reach for the first 2 steps isn’t life or death critical, that’s just so you stretch the bolts slowly and gradually. Some procedures actually have you wait a specified time between steps.
I don’t really shop for tools at harbor freight or online, but does a torque/angle wrench cost that much? Is there one for loan at Autozone, etc?
I am looking for a high-quality tool, comparable to what a professional mechanic would use to do this procedure. Of course, AutoZone, O’Reilly, etc. have cheaply made torque angle gauges for sale–I already own one. No need to buy or borrow another.
Because of the poor design, when I attempted to use it (on a different vehicle) the disk that shows the angle slipped, and I wasn’t confident that the head bolts were properly tightened, so I ended up absorbing the cost of another head gasket and set of bolts–that time I did the paint marker trick rather than using the “OEM” brand torque angle gauge.
How much are you willing to spend?
Tester
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I was thinking to spend about $300, but the MAC Tools digital torque wrench for about $600 with tax would not be a problem for me, as I assume this tool will last for a lifetime of home use. It is probably a lot more accurate than the beam-type torque wrenches I have been using.
Do you personally have experience with this specific tool? What exactly allows it to “reference” the angle of rotation, i.e. is there a part which anchors somehow to the non-movable surface around whatever fastener is being tightened? That was the Achilles heel of the “OEM Tools” torque angle gauge.
I was wondering if there’s a torque/angle wrench for loan, not a gauge. Those gauges are a joke and I would use paint marks before using them.
A professional would (or should) use a torque wrench with a gyroscope built into the head like Tester linked above. I use Snap-on, but there have got to be more economical choices out there.
I still think you’re overthinking this. If you need to be at 170 degrees final torque angle, mark your starting point, go less than a quarter turn twice, and then finish 10 degrees short of 180 from where you started. It’s not going to matter if you’re off a bit in your steps as long as the final is 170. This isn’t the space shuttle, it’s a crude car engine.
Then again, I have the right tools for this job. But if I didn’t, that’s what I would do.
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I used my torque angle gauge for years.
Because once the torque wrench is no longer required, you can use a breaker bar with a cheater pipe on the end, and you can pretty easily read the torque angle while tightening the bolt.
That’s why I don’t need an electronic torque wrench that can also read angles.
Tester
There’s a gyroscope built into the head of the wrench. You set it for 70 degrees and start turning. You can start and stop or change positions as many times as you want, it won’t beep or flash until it has seen 70 degrees of rotation while tightening. Mine is old enough that it won’t measure counter-clockwise, maybe newer ones do.
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Engineers include ridiculously troubling and costly procedures in an effort to give an appearance of highly technical, exclusive status. It’s often just a game of one-upsmanship in appearance.
Is anyone familiar with the ATD Tools 12550? This appears to be similar to torque angle wrenches made by MAC Tools and Snap-On, but for a much lower price. This model is currently out of production, but can be purchased new online for about $275. Is this a decent torque angle wrench for DIY use?
Educate me…why is an angle of twist any better than a twist measured in ft-lbs? I can see why they might not be exactly equivalent, but why is the angle preferred?
Tester
Great article…but dense enough that it will take some time to soak in.
Thanks!
To put it simply, using only ft-lbs, most of the torque is used to overcome friction. So, not all the fasteners may stretch properly to applying the proper clamping force.
With a final torque angle, friction isn’t a factor. So all the fasteners stretch the same to apply the proper clamping force.
Tester