Remove and Torque crank bolt, finally an easy method.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Airborne

SHO Member
Joined
Oct 10, 2010
Messages
350
Reaction score
243
Location
Arizona
Well, at least you have to have one cylinder head on. I had been wanting to post this for a while, but wanted to try it first to make sure it worked. It works on my dirt bikes, just wanted to make sure it worked on my SHO motor. It is called an engine lock up tool and Steahly Off Road sells it. Here is a link.

http://www.steahlyoffroad.com/tools/engine-lock-up-tool.html

I drilled a hole in the tool and hammered an allen socket in the tool so that I could intall it in the spark plug hole. Use your hand only to install, no ratchet.
Connecttool
Use a coat hanger to find TDC of the cylinder you chose. I choose #4 in case something went wrong, it would be easier to remove the front cylinder head than the rear.
Installedinsparkplughole
To remove crank bolt: After tdc is found, rotate crank clockwise about 15 degrees and install lock up tool. then remove bolt with breaker bar. It is that easy!

To Torque: After tdc is found, rotate crank counter-clockwise about 15 degrees and install lock up tool. Then tighten crank bolt to proper torque. Agian, that easy.

Removedcranknut
 

LJRuddy

Pop lock n drop
Joined
Jun 2, 2005
Messages
3,143
Reaction score
1,870
Location
Poaceae fields
I would be worried that the aluminum threads would get fvcked up with this. They aren't exactly large threads and you gotta torque the ever living snot out of the crank bolt to prevent cancer...
 

Airborne

SHO Member
Joined
Oct 10, 2010
Messages
350
Reaction score
243
Location
Arizona
I would be worried that the aluminum threads would get fvcked up with this. They aren't exactly large threads and you gotta torque the ever living snot out of the crank bolt to prevent cancer...

The tool is plastic. I have been using this tool for about 7 years, the plastic tip is not even mushroomed.
 
Last edited:

auto.guru

Village Idiot
Joined
Jan 26, 2011
Messages
304
Reaction score
23
Location
Neenah WI
I would be worried that the aluminum threads would get fvcked up with this. They aren't exactly large threads and you gotta torque the ever living snot out of the crank bolt to prevent cancer...

why would torquing the crank bolt cause cancer? the bolt and harmonic balancer are added on to the crank, not part of it. So im failing to see how that bolt has to be super uber tight or youll get cancer...

dont look at the starlight to much stewie griffin, youll get cancer!
 

hawkeye18

Sorta cares
Joined
May 18, 2004
Messages
5,631
Reaction score
2,725
Location
Norfolk, VA
Village idiot is right. :p

Crank cancer is caused when the crank bolt is not tightened enough. Why? Because if it's not tightened enough, the crank keyway will start eating into the crank and timing belt pulley, as well as the accessory pulley. It happens all the time to people who just tighten it until the crank starts rotating. That's maybe about 80lb/ft.

The manual states that the crank bolt be tightened to somewhere in the neighborhood of 200lb/ft IIRC, and it's very difficult to do that - especially on an automatic where you can't lock the transmission in gear.
 

yamahaSHO

E85 whore
Joined
Jul 25, 2002
Messages
10,646
Reaction score
2,515
Location
Arkansas
I just put it in gear, have someone step on the brake and torque to 150+ ft-lbs with a very large torque wrench. I'd rather remove the starter and use a flywheel holding tool over the above (OP's) solution. Just my preference.
 
Last edited:

Airborne

SHO Member
Joined
Oct 10, 2010
Messages
350
Reaction score
243
Location
Arizona
Let’s talk about the forces on the spark plug threads. Normal production engines produce between 800-1000 psi during the compression stroke. High compression race engines produce about 1500 psi. Top Fuel produces well over 2000 psi on the same 14mm plug and aluminum threads. So how much force is exerted on the plug forcing out of the cylinder a hundred times a minute for hours?
Area of the plug:
A = Πr2 = 3.14(0.28) 2 = 0.2463 in2
Multiply 0.2463 in2 by 1500 psi and you get: 370 pounds of dynamic force exerted on the face of the plug trying to force it out of the cylinder.
How much force are we putting on the threads by using the Engine Lock-Up Tool?
Let’s assume you wanted to place 200 ft lbs of torque on your crank bolt. I used 85° because the Lock-Up Tool stopped the crank from moving at about 5° before TCD. That would equate to 133 lbs of static force exerted on the plug tool trying to force it out of the cylinder head. See diagram below.

Plugcalcs
 

Airborne

SHO Member
Joined
Oct 10, 2010
Messages
350
Reaction score
243
Location
Arizona
I just put it in gear, have someone step on the brake and torque to 150+ ft-lbs with a very large torque wrench. I'd rather remove the starter and use a flywheel holding tool over the above (OP's) solution. Just my preference.

Flywheel lock up tools are great. I use them all the time. I have about 10 for different engines in my tool box and will use them when I have them. If I had one for this Yamaha engine, I would have used it. I have worked on motorcycles for decades. Every time I had a different engine to rebuild, I would buy another flywheel lock-up tool. I haven't bought another flywheel lock-up tool since I purchased this tool from Steahly. I take that back, I had to buy a lock-up tool for my CRF450 that is placed between the primary drive gear and clutch gear because the CRF450 uses a 12mm plug.
 

sdpatt

Sr. SHO Engr.
Joined
Dec 6, 2000
Messages
9,670
Reaction score
382
Location
Dallas, TX
A stout strap wrench on the damper works pretty good with no risk to any other parts or loosening the carbon crust on the piston top. I can easily get the required 113-126 lb-ft (or more) on the damper bolt.
 

auto.guru

Village Idiot
Joined
Jan 26, 2011
Messages
304
Reaction score
23
Location
Neenah WI
A stout strap wrench on the damper works pretty good with no risk to any other parts or loosening the carbon crust on the piston top. I can easily get the required 113-126 lb-ft (or more) on the damper bolt.

i hope you know that when the engine is running there is no physical outward force on the harmonic balancer. And the rotational forces and resistance all vary on the factors that act upon it - ie: belts. But if you knew how the balancer was made you wouldnt be using a strap wrench.

harmonic balancers are a 2 piece unit press fit together with a rubber gasket in between them. The 130+ forces youre putting on that balancer in a rotational direction could dislodge and make those 2 pieces slip on eachother. BALANCER.... not aligned correctly....

any of this making sense? the only thing you wanna touch is the crank bolt, and only the bolt.
 

yamahaSHO

E85 whore
Joined
Jul 25, 2002
Messages
10,646
Reaction score
2,515
Location
Arkansas
auto.guru - Pay attention to the mileage in sdpatt's sig and realize he's the original owner. ;)
 

sdpatt

Sr. SHO Engr.
Joined
Dec 6, 2000
Messages
9,670
Reaction score
382
Location
Dallas, TX
I have never found a crankshaft damper to slip on its rubber ring when doing this task. If the outer ring does slip, the damper was soon to fail and needed to be replaced anyway. The damper is much easier to swap that a piston. These parts are actually crankshaft dampers and not harmonic balancers. They also have the task of being a pulley for the accessory belt(s). The rotational force applied against the outer damper ring by the accessory belt during a quick engine rev in neutral would be quite great as the engine quickly spins the significant mass of the alternator at three times the crank speed (plus the A/C compressor pulley if engaged and not full throttle). Think of the strap wrench as a damper integrity tester.;)
 
Last edited:

auto.guru

Village Idiot
Joined
Jan 26, 2011
Messages
304
Reaction score
23
Location
Neenah WI
true true. i did not know he was the original owner....
i was just taught in school not to do such things for fears such as:
you break it, you buy it - and now you have to eat the cost of that part
 

pjtoledo

'ol man in the SHO
Joined
Nov 28, 2000
Messages
2,782
Reaction score
371
Location
toledo,ohio,usa
Airborne just freakin' pwned you with math.

actually, that math is so far off it isn't even funny.

look at the 1523 lbs of force being exerted at the rod journal. that part I'll agree with. now envision 2 items, poles, walls, verticle planes, or whatever that are 5.9" apart. now place a 6" long bar between them ('bout the size of a rod) , won't fit. one side is at the bottom, the other side is about 1/2" from the bottom. now step on that high side with a 1523 lb foot, smash it down to spread the ends. it's gonna put way more pressure against those poles, walls, etc than 1523 lbs.


Perry
 

Airborne

SHO Member
Joined
Oct 10, 2010
Messages
350
Reaction score
243
Location
Arizona
actually, that math is so far off it isn't even funny.



Perry

The math is 9th grade algebra.

You mean the force assumptions in my free body diagram are so far off it isn’t even funny. Now that you brought it to my attention, I am starting to understand what you are explaining, but I need a little more information. Imagine, with this revelation that you have, that we can turn the mechanical engineering world upside-down. Imagine the look on their faces when we tell them what they have accepted as basic engineering principals, for the last couple of centuries, is false. I can’t wait!
 
Back
Top