How do I get the crankshaft pulley bolt to the correct torque?
#1
How do I get the crankshaft pulley bolt to the correct torque?
I just replaced my timing belt and after reading the horror stories on here about crankshaft bolts coming off I want to make sure that I get it torqued right. I bought the biggest torque wrench I could find (up to 250 ft/lb if I remember correctly) so I can torque the crankshaft pulley bolt to the specified 217 ft/lb, but the wrench is only about 2ft long and there is no way I can get enough leverage to actually get the thing to torque down to 217 ft/lb and the wrench says not to use a cheater pipe on it to extend it's length. I don't have an air compressor. What do you guys do to get this right?
#2
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You make the crankshaft holding tool, put it against the frame, and push really hard on the Torque wrench. That's how I did mine...and I didn't have a cheater bar on it either. You have to make a tool, that's all there is to it.
Brett
Brett
#3
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Besides buying the SST or making a simile, you can use a large chain wrench (handle 24" or more) too, but you need to wrap the crank pulley in something so it won't be damaged. I use an old piece of bike tire which gives it grip and prevents damage at the same time.
217 ft-lbs is alot of torque so if you are pulling on a the end of a 24" torque wrench you'll still need to put almost 110 lbs of force on it to get near the required torque for the bolt to have proper preload.
217 ft-lbs is alot of torque so if you are pulling on a the end of a 24" torque wrench you'll still need to put almost 110 lbs of force on it to get near the required torque for the bolt to have proper preload.
Last edited by MTL_4runner; 06-29-2006 at 09:45 AM.
#4
Contributing Member
Yeah they really should put longer handles on a torque wrench that goes up to 250 ft-lbs (for those of us that don't have arms like the Terminator).
Maybe if you make a good holding tool with a long arm and get a buddy to help so you can use both arms on the torque wrench.
Maybe if you make a good holding tool with a long arm and get a buddy to help so you can use both arms on the torque wrench.
#5
Originally Posted by mt_goat
Yeah they really should put longer handles on a torque wrench that goes up to 250 ft-lbs (for those of us that don't have arms like the Terminator).
Maybe if you make a good holding tool with a long arm and get a buddy to help so you can use both arms on the torque wrench.
Maybe if you make a good holding tool with a long arm and get a buddy to help so you can use both arms on the torque wrench.
As the last one I did was a 5 speed, I put it in 4WD and in gear and just allowed the resistance of the vehicle and engine to hold the crank.
However, for the 98, I will make a tool ...
David
#6
Contributing Member
Originally Posted by nrgetic99
I borrowed a 30" torque wrench from work.
As the last one I did was a 5 speed, I put it in 4WD and in gear and just allowed the resistance of the vehicle and engine to hold the crank.
However, for the 98, I will make a tool ...
David
As the last one I did was a 5 speed, I put it in 4WD and in gear and just allowed the resistance of the vehicle and engine to hold the crank.
However, for the 98, I will make a tool ...
David
BTW the auto parts stores around here have loaner torque wrenches that go up to 250 ft-lbs. I'll probably borrow one when I do this, my Craftsmans wrench only goes to about 150 ft-lbs.
#7
Holding the pulley is not the problem. I already fabricated a pulley holder (2" x 1" rectangular steel tubing with the appropriate holes and bolts) to get the pulley off. The pulley isn't moving. The problem is getting enough force on the torque wrench to get it to the specified torque. If I remember my mechanical engineering correctly, for a 2ft long wrench I need over 100lbs of force on it to get the bolt cranked to the right torque. Problem is there is really nothing to brace yourself on when torqueing this thing down to put muscle into the torque wrench. A longer wrench might do the trick, but the one I have is longest one I could find anywhere and it says not to use a cheater pipe to lengthen it. Any ideas where I might be able to get a longer wrench or a different technique is appreciated. Also, which thread locker do people use on the crank bolt? My understanding is that the loctite high strength is for "permanent" bolts. Since the crankshaft bolt will need to removed again at some point should I use the medium strength?
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#9
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Originally Posted by toomanyedwards
Also, which thread locker do people use on the crank bolt? My understanding is that the loctite high strength is for "permanent" bolts. Since the crankshaft bolt will need to removed again at some point should I use the medium strength?
#10
Contributing Member
Originally Posted by mt_goat
That's a good question, wish I knew the answer. I'd probably use the medium. Also if you remember your ME classes, lubrication on the threads lowers the torque required to get the same amount of bolt preload. Remenber a torque wrench is just an approximation for measuring the preload on the bolt. I don't think Toyota factory specs say if their torque values are for lubricated threads or dry threads. But if the 217 ft-lbs is for dry threads and you put lock-tight all over the threads you will be puting more preload on the bolt unless you go down on the torque setting. You will have to calculate how much less, if you figure it out let us know.
Last edited by MTL_4runner; 06-29-2006 at 02:58 PM.
#13
Contributing Member
Originally Posted by MTL_4runner
The appoximation we used to use as a mechanic for Loctite is the same as you use for fasteners with machine oil. A value of 10-15% less is a pretty common adjustment, but in this case I don't think I'd adjust down less than 5-10% if at all because even at a full 15% over-torque value of 250 ft-lbs is not going to overstress nor even get close to yield on a bolt of that size (ie you'll have quite a bit of SF built in still and the consequences of too little preload are quite severe).
#14
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I haven't done my t-belt quite yet, but this is a good question. Not sure if there is room to fit your leg down there with or without removing the radiator, but maybe you can try standing on the torque wrench. Torque it with your foot?
#15
Contributing Member
Originally Posted by toomanyedwards
Also, which thread locker do people use on the crank bolt? My understanding is that the loctite high strength is for "permanent" bolts. Since the crankshaft bolt will need to removed again at some point should I use the medium strength?
Last edited by mt_goat; 07-08-2006 at 06:05 AM.
#20
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It won't work if your e-brake bellcrank is frozen on one side. You'll just turn that wheel. Ask me how I know.
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