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Almost everything I work on is torque angle. After a bit you know what 22 ft lbs + 120 deg is for a particular bolt and just flat torque it. I have torque angle digital Snap-On wrenches for smaller stuff. Larger bolts I turn with an impact. I'm torquing down head bolts on a 15 liter Cummins in the AM. 150 ft lbs, 300 ft lbs then 90 deg for 26 bolts. I use a 35 pound 1" drive impact to turn the front ones and my 4' long 3/4" drive ratchet with a pipe on it for the ones under the cowl. When I'm done with that I get to go over to the collision shop and put some rods and mains back in a Mercedes 15 liter that have one time use bolts. The mains pop at 185 ft lbs then 180 deg. I don't have a 1" drive 12 pt 24mm socket as I don't normally work on them so get to do it by hand, pretty sure it will just blow my adapter up if I stick the big gun on it. For stuff that pops in the 1,800 ft lb range I have a 4 - 1 multiplier. | |||
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7.62mm Crusader |
So you are going through the Cummins torque pattern 3 times correct? And I cant even imagine what gets 1,800 foot pounds. Jeez..I have an idea but not sure about a multiplier? | |||
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7.62mm Crusader |
OK..I saw a torque multiplier on the tube. That is quite a nice tool for heavy work. | |||
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Member |
Heads are a 3 lap deal. 150 300 90 deg. Volvo heads are 75 ft lbs, 120 deg, then 90 deg. Steering and suspension bolts can go to 1,800 ft lbs. Mack camel back rear springs are one and they are upside down as well. My multiplier has a 3/4" drive input and 1" drive output. Gear drive and held in place with a handle. Like this one but bigger. https://www.hanessupply.com/williams-tm-290 | |||
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7.62mm Crusader |
That is a nice tool powermad. I only tonight learned if these. | |||
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Rumors of my death are greatly exaggerated |
The engineering with torque and stretching is outside of my knowledge. I am familiar with a Citabria aircraft that had one of the bolts stretch and fail causing a ground loop/gear failure. The folks that maintained it were aware of a service bulletin..recommended but not mandatory replacement of these bolts about 50 to 100 of use time prior to the failure. Sometimes it pays to heed advice. It was sad to see it totaled because they didn't replace the bolts that held the gear on. Glad it didn't happen when I was using it. "Someday I hope to be half the man my bird-dog thinks I am." FBLM LGB! | |||
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Banned |
As said, a torque to yield is a one time use bolt, and I note that a lot of those are spec'd for aluminum heads and blocks. I suspect one reason is that when aluminum is overheated it reduces the yield strength of the alloy and if you can't get it to spec it's because the block threads have gone soft. Goes to that being a one time assembly and done. Take it apart and it's junk. A certain Dodge motor was prone to having a bad t stat housing that would lead to overheating and blown head gaskets. Repair it and within 5,000 miles/six months, same problem again. The block had lost yield strength in the threads and no matter how often it was repaired the bolts would pull and the head gasket would blow again. Other makes are now seeing the issue, too. TTY + blown head gasket = install a used working assembly hoping it never overheated. In a lot of cases, it's also cheaper than a rebuild and a lower mileage engine than the vehicle. I note that lug nuts and studs are not TTY. The owner has to have the wheels removed for servicing tires, brakes, etc. but the head bolts being one time use is a clue the engine will not suffer well if they are, unlike the older cast iron motors. We have arrived at disposable motors and it wasn't made well known for reasons. | |||
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