As @AModelCat says, why are you trying to re-invent how to torque a fastener that already has a set torque? If the book says it gets torqued to x amount do it. If the book says x amount of torque and x amount of turn do it.
I would get my ### fired if I tried to make up a torque plus turn on a non torque plus turn fastener. To each his own but I hope its your own engine not a customers.
torquing main bearing caps
Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by stonefly4, Jan 18, 2020.
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Nobody is going to fire me. I'm a one-man trucking company. If anybody was going to fire me I'd have to fire myself.
I like the book, but also, there is the matter of experience.
I met the fellow many years ago at a neighbor's campfire party. We got to talking and I found out he was a trucker like me, but also that he was experienced in rebuilding Detroit engines, that he had done many of them. He is the one who told me about the method of torquing and then turning by degrees to a final torque.
I'm not inventing or reinventing anything. I'm remembering something told to me by a fellow who has rebuilt Detroit engines, but it's been so many years, I cannot remember the details, like the original partial torque or the number of flats turned to complete the torque. That's why I started this topic. I was hoping to find somebody who had this experience who knew the numbers, the details.
My neighbor moved away, and I have no way to contact the fellow I talked to sitting at the campfire.
Here is a video of somebody using the torque and turn method. It starts at 9 minutes into the video. It's an example, but it's on a Caterpillar engine. I take it that the guy in the video works in the shop, so it must be an accepted method.
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Isn't that a matter of experience?
That is why I started this thread. I was hoping to find somebody who had experience using this method who could supply me with the necessary details, namely the ft. lbs. to be used for the initial torquing with a half-inch drive torque wrench, and the number of degrees of turn necessary to finalize the torquing of the bolt.
In the Caterpillar video, the fellow makes an initial bolt torquing of 110 ft. lbs. and finalizes the torque by turning a further 60°.
I wonder what those numbers would be for a series 60. The same? More? Less?
Does anybody here have that information?Rideandrepair Thanks this. -
A lot of what we do in my shop is automatic transmission rebuilding and it requires an inch pound torque wrench so I’m not sure the torque to yield method would work in that application.
With that being said we do a fair amount of automotive cylinder heads using the torque to yield method.
You set the bolt to a specific torque and the I have a snap-on torque angle gauge I put on and then finish it to the desired angle specified.
To the OP
There is a shop about 5 miles from mine who does heavy diesel work and uses the very method you spoke about.
I had a conversation with the owner a few years ago and he said when he does main bearings he sets a specific torque with a torque wrench and then finishes them to the proper angle with an air impact.stonefly4, Dave_in_AZ and Rideandrepair Thank this. -
This all comes back to the service manual. I happen to know for fact (because I'm building an older 3406 right now) that CAT engineers specified the torque and turn method for my engine. They also specified a bit of an elaborate procedure as to the torque sequence for which cap bolts get torqued and turned. Will it matter if I just rattled them up with a big impact and put it to work? It'd probably be just fine but its not a chance I'd take with my engine or a customer's engine.
I'm sure if you really wanted to you could experiment and come up with a torque and turn value but that seems like a huge burden when you can just stick a 3/4" drive torque wrench on it and give it a pull. The spec listed earlier in this thread for those main bolts is less than a wheel lug nut or most u-bolt nuts.spsauerland, Dave_in_AZ, jamespmack and 4 others Thank this. -
Torque-to-Angle/Yield Threaded Fasteners
here is one article of many.
the reading states that the torque to yield method is superior to using the torque wrench method.Dave_in_AZ, stonefly4 and Rideandrepair Thank this. -
I don't have a 3/4" drive torque wrench, and it's more than a matter of "sticking it on there and givin' a pull." The engine is in the truck. I'll be underneath, with barely enough room to move. If the handle was 4' long, I'd have to pull nearly a hundred pounds while on my back and little room to maneuver, all the while holding the socket up with the other hand to prevent it from dropping.
I don't wanna experiment and come up with a torque and turn value. I'm asking for the values. I'm asking somebody who knows to please provide me with the values, the numbers, the info. That's what I'm here for.Rideandrepair Thanks this. -
Sorry we're not giving you the answer you want to hear.
I'll take my leave.Roberts450, spsauerland, blairandgretchen and 6 others Thank this. -
Not even close.
Information that I need is more like it.Rideandrepair Thanks this. -
Just the facts, please. Lol. It’s like when I go to the T/A and ask if they have a specific fitting or bolt, and they ask “ What exactly are you trying to do?”. Don’t matter, I know what I’m doing, just check for the part!!!!
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