How to torque the flywheel bolt...without a torque wrench?

32251

Petty Officer 3rd Class
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Jul 14, 2009
Messages
85
Finished up a 5 HP Johnson today. All I need to do now is tighten up the flywheel bolt. I got it off using the hammer hitting the socket wrench handle method that I read about some guys use....worked fine.

Now I need to put the flywheel nut back on..so can I use the same method to tighten it back??

I only have a 150lb torque wrench...the manual says I need more than twice that!!! I also don't have a strap wrench.

What do you guys do? Many thanks for the advice.
 

bankerjohn

Chief Petty Officer
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Mar 21, 2008
Messages
444
Re: How to torque the flywheel bolt...without a torque wrench?

I only have a 150lb torque wrench...the manual says I need more than twice that!!!

There's NO WAY the specs call for 300+ foot pounds torque on a 5hp motor. You'd better go back and read the manual ... more likely the specs are in INCH POUNDS!
 

kenmyfam

Supreme Mariner
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Aug 10, 2006
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Re: How to torque the flywheel bolt...without a torque wrench?

Double check the torque !!!
 

jbjennings

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Jul 18, 2007
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Re: How to torque the flywheel bolt...without a torque wrench?

There's NO WAY the specs call for 300+ foot pounds torque on a 5hp motor. You'd better go back and read the manual ... more likely the specs are in INCH POUNDS!

Yepper!
It would be fun to watch someone trying to torque a motor to 300 foot-pounds. I'm visualizing a 6 foot cheater pipe and a strap wrench from Hades.:D
Sorry,
Couldn't resist......good luck. The inch-pounds thing threw me a loop once upon a time as well!:redface:
Good luck,
JBJ
 

32251

Petty Officer 3rd Class
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Jul 14, 2009
Messages
85
Re: How to torque the flywheel bolt...without a torque wrench?

INCH POUNDS....I must have mistaken for FT. Pounds!!! I will recheck the manual tomorrow. Duh!
 

Rick.

Captain
Joined
Jul 30, 2006
Messages
3,740
Re: How to torque the flywheel bolt...without a torque wrench?

Try 40 ft. lbs. That will do it just fine. Asking how to torque without a torque wrench is like asking how do you drive 35mph. without a speedometer. You can't. Best of luck. Rick.
 

trimoon

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Jul 23, 2009
Messages
16
Re: How to torque the flywheel bolt...without a torque wrench?

Although many wont like this answer as it wont give you an accurate torque/lbs... I used a air gun to take it off and put it on. It works just fine and i had no problems related to doing this. Im not saying its the right way, but it will get it off without damage and it seems to get it on tight enough.
 

billy4hp

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Jan 31, 2009
Messages
245
Re: How to torque the flywheel bolt...without a torque wrench?

Although many wont like this answer as it wont give you an accurate torque/lbs... I used a air gun to take it off and put it on. It works just fine and i had no problems related to doing this. Im not saying its the right way, but it will get it off without damage and it seems to get it on tight enough.


Yepper, doing that makes all sorts of people $$$ or adds to the landfills with ruined components...

:eek:
 

F_R

Supreme Mariner
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Jul 7, 2006
Messages
28,195
Re: How to torque the flywheel bolt...without a torque wrench?

Although many wont like this answer as it wont give you an accurate torque/lbs... I used a air gun to take it off and put it on. It works just fine and i had no problems related to doing this. Im not saying its the right way, but it will get it off without damage and it seems to get it on tight enough.

That is a great way to get it off, but a terrible way to put it back on. That is a great way to spread the flywheel hub. resulting in a ruined flywheel and a broken points cam when the spread flywheel goes down against it. It happens all the time. Then people wonder why their cam breaks.

There is a reason for the narrow 5 ft/lbs tolerance allowed in the torque.
 

wbeaton

Commander
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Messages
2,332
Re: How to torque the flywheel bolt...without a torque wrench?

The torque is 40-45 ft/lbs. I set them at 43.
 

trimoon

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Jul 23, 2009
Messages
16
Re: How to torque the flywheel bolt...without a torque wrench?

That is a great way to get it off, but a terrible way to put it back on. That is a great way to spread the flywheel hub. resulting in a ruined flywheel and a broken points cam when the spread flywheel goes down against it. It happens all the time. Then people wonder why their cam breaks.

There is a reason for the narrow 5 ft/lbs tolerance allowed in the torque.

Well if you go crazy and force it on beyond a reasonable amount. It worked fine for me but i made sure to only use about 80 psi to the air tool and stop as SOON as theres resistance. However, it is a bad way if you want exactly between 40 and 45 lbs
 

Cofe

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Apr 23, 2009
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Re: How to torque the flywheel bolt...without a torque wrench?

I have calibrated my right arm for torquing.......just took years of practice....just kiddin
 

jonesg

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Feb 22, 2008
Messages
7,174
Re: How to torque the flywheel bolt...without a torque wrench?

I use the air tools on my volvo crank pulley but its steel ( or iron) done it a bunch of times , never a problem.
But flywheels are alum and will distort.
It happens all the time with alum wheel rims when they use the impact wrench.
 

Cofe

Lieutenant Commander
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Apr 23, 2009
Messages
1,883
Re: How to torque the flywheel bolt...without a torque wrench?

Use torque wrenches. That is the only proper way to be a mechanic. (even a shade tree variety)
Bolts and nuts stretch every time they are torqued and stay stretched. That is why many manufactures suggest to replace bolts and nuts so they eventually won't break. Why take chances of being stranded because of fatigued (failed) bolts or nuts.
 

bktheking

Vice Admiral
Joined
Jul 29, 2008
Messages
5,057
Re: How to torque the flywheel bolt...without a torque wrench?

Go buy one, I bought 2 when they were on sale at Can Tire (don't laugh) inch and ft lbs for $45 each, have used them countless times since. Having the right tools to tighten is key when working on motors, head gaskets , flywheels, lots of different applications.
 

ridefst

Seaman Apprentice
Joined
Oct 23, 2008
Messages
34
Re: How to torque the flywheel bolt...without a torque wrench?

To find the torque without a torque wrench, use a fish scale :cool:

43 ft/lb means a force of 43 lbs on a 1' lever
Therefore, use a breaker bar, or cheater pipe if needed, to hook the scale onto the wrench/socket exactly 1' away from the bolt, then pull until you read 43lb on the scale.

If your scale doesn't read that high, try a 2' lever and 21.5lbs

If you're pulling up to do this, the weight of the wrench will affect the measurement, you'll have to note how many lbs it takes to take the slack out of the ratchet and add that to the total.
 

Cofe

Lieutenant Commander
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Apr 23, 2009
Messages
1,883
Re: How to torque the flywheel bolt...without a torque wrench?

Very good Ridefst. That took some good common sense thinking....
That would work out in the sticks in a pinch.
Did you consider writing McGuiver TV scripts? Just kiddin.....Thanks for your post! I will try to keep it in my magnificent magnifying mind somewhere.
 
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