hbom

Putting bolts into the freezer is the best way to torque a crankshaft harmonic balance assembly, camshaft and various hard to reach high torque bolts.

Putting the bolt into the freezer effectively shrinks the size. This allows for a greater amount of torque to be used than just tightening.


For extra torque, heat up the engine first:
I had a loose crankshaft bolt and couldn't get enough torque on it. So, I put it in relatively tight and heated up the engine. Once warm, I pulled the crank bolt (being careful not to dislodge the harmonic balance), chuck the bolt into the freezer (bag of ice works too) and then reassembled it. It is still locked in today.

I know many of you, like me, are back yard mechanics and don't have a fancy air impact gun to get to those tight spaces. This method will help.


Heating up an engine is also a good way to remove pesky bolts. This assumes that the part you are working on is accessible (without getting near the exhaust pipes) and the engine is still relatively together. Don't go heating up an engine without oil!


Hope that helps someone save some bloody knuckles.

Cheers.

wyoming9

iTrader: (1)

At what temperature ??

How long do you maintain the temperature ??

scope103

Greater than what? The FSM specified torque? That will end your engine in a hurry.

Or is the problem that you don't have a 1/2" torque wrench, are pretty sure you're not reaching the correct torque, and don't care? Is the goal to just make it "tighter" and just guess at the torque you end up with? I don't doubt that you could try something like that, and end up with it "tight enough" that it would work for a few miles. But you'd have to be pretty lucky, and what do you save? Harbor Freight often has 1/2" torque wrenches on sale for $12!

You don't (EVER) torque bolts with an impact gun. I assume that reference was for the "heat the bolt to get it out" suggestion.

Thanks for the tip, but for my truck, it's just not that hard to torque the bolts correctly. Even the 181ft-lb 3VZE crank bolt.

MudHippy

It's a good hypothesis. But it's wrong. Plain and simple.

wyoming9

iTrader: (1)

I wanted the OP to explain with real live technical Data to back up his theory

scope103

The tip is "backwards" anyway. The reason you torque a bolt is to elastically STRETCH it a precise amount. Then the bolt acts like a very stiff spring, and the force of the stretched spring holds the bolt head to the surface to keep it from turning.

If you pack your crank bolt in ice, you'll reduce it's temperature by maybe 30°F, which will potentially SHRINK it by about 6%. If you could immediately tighten it to your desired torque, once it warmed back up it would EXPAND. That reduces the amount of stretch you were trying to put into it, so it is now at about 6% LESS torque than you just put on it! (Of course, steel conducts heat really well, and if you put a 40°F crank bolt into a 70°F crank, the bolt will warm up to the temperature of the surrounding crank before you could even get the wrench on it.)

Using heat to loosen stuck fasteners only relies on expansion and contraction indirectly. The reason it is stuck is not because it was tightened too well, but because something between the fastener and the surround (dirt? burrs? ) is keeping your force from turning the fastener. Random expansion and contraction can sometimes break that dirt layer enough for you to get it out. That's why sometimes TIGHTENING a stuck fastener will break it free enough to reverse the wrench and get it out; something between the fastener and surround "broke" when you tried to tighten it.

wyoming9

iTrader: (1)

If your going to cool something use liquid Nitrogen !!

scope103

-196°C; good working-man's coolant.

But real nerds use liquid helium. -270°C! (about 4°Kelvin)

wyoming9

iTrader: (1)

The thing is Nitrogen is much Cheaper!!

I only used liquid Helium once that I recall and it was a real pain to get .

This has to be at least 30 years ago

millball

I guess us hillbillys will have to stick with an inferior bastard refrigerant like dry ice.

Only -78.5C