The SAOCA Forum  

Go Back   The SAOCA Forum > Sunbeam Alpine Forums > Modified Alpine
FAQ Members List Calendar Mark Forums Read

Reply
 
Thread Tools Display Modes
  #1  
Old 10-12-2017
mamoose124's Avatar
mamoose124 mamoose124 is offline
Diamond Level Sponsor
 
Join Date: Jul 2014
Location: Gordonsville, VA
Posts: 363
Default Torque Spec for Crankshaft Nut

I found no reference in the Sunbeam Workshop manual to the torque spec for the crankshaft nut securing the balancer pulley to the crankshaft. Tim Raymond, in his paper describing his 1592 Sunbeam rebuild indicates he was told by a Sunbeam race driver to torque the nut to 180 ft/Lbs. He does comment, however, that this is an exceptionally high number.

My half-inch torque wrench only goes up to 150 ft/lbs. Even at that, I could only muster the heft to torque the crankshaft nut to 140 ft/lbs. I tried 145 ft/lbs but didn’t have the heft to manage it.

So, I’m wondering, gentlemen, is it absolutely necessary to reach 180 ft/lbs of torque on this nut? If it is mandatory, then I will need someone heftier than me to get the job done. Not to mention the purchase of a three-quarter inch torque wrench at considerable extra cost.

What say you gentlemen, is 140 ft/lbs sufficient for this nut?
__________________
Mike Youngblood

Last edited by mamoose124 : 10-12-2017 at 01:27 PM. Reason: Edited for clarity of meaning
Reply With Quote
  #2  
Old 10-12-2017
husky drvr's Avatar
husky drvr husky drvr is offline
Gold Level Sponsor
 
Join Date: Dec 2006
Location: NC, USA
Posts: 552
Default

Mike,

There is no torque value listed because Rootes specified the use of Churchill special tool RG.290, which is a "hammer tight" wrench. Hard to get a specified torque with a hammer.

Not sure if 140 lb./ft. is enough but can't say it's not either.

Just a wild guess, but I would say that the hammer wrench was more easily usable in the engine bay than an adequate torque wrench.

Found that tidbit on page 50, section B, WSM 124. Not sure why the tech section copy of WSM 124 Section B stops at page 48 and does not include this info.
__________________
Have fun, Don

"Even if the majority agrees on an idiotic idea, it is still an idiotic idea." Sam Levenson

"There is no worse tyranny than to force a man to pay for what he does not want merely because you think it would be good for him." Robert Heinlein
Reply With Quote
  #3  
Old 10-13-2017
mamoose124's Avatar
mamoose124 mamoose124 is offline
Diamond Level Sponsor
 
Join Date: Jul 2014
Location: Gordonsville, VA
Posts: 363
Default

Thanks, Don, for the information. I took a look at my WSM and sure enough, the information is there. Too bad they don't reference it in the section on torque specs. They also say " A new lockwasher must always be used when refitting the "jaw nut" Moreover, in the second paragraph above they indicate that a ". . . thick steel washer (Part No. 1208868) must be fitted between the pulley and the jaw nut lock washer." My engine had no steel washer or lock washer behind the jaw nut. So now I am worried that I need to find these two items which I am sure are no longer available. Do you have any idea where I might find these? I doubt that just using some common steel washer and lock nut would be advisable.
__________________
Mike Youngblood
Reply With Quote
  #4  
Old 10-13-2017
todd reid todd reid is offline
Gold Level Sponsor
 
Join Date: Jan 2007
Posts: 447
Default Torque Spec for crankshaft nut

A suggestion from the peanut gallery (I am not an engineer):

An appropriately sized grade 8 washer and lock washer should work fine.

Do you have room to slide a pipe over the end of you torque wrench to increase your leverage? If so take it up to 150ft/lb. and go with it.

If it is your nature to worry about these things, then perhaps you can borrow a 3/4' torque wrench?

Good Luck!
Reply With Quote
  #5  
Old 10-13-2017
hartmandm hartmandm is offline
Platinum Level Sponsor
 
Join Date: Aug 2013
Location: Wilmington, DE
Posts: 744
Default

There are 1/2" torque wrenches that go to 250. Anyways, many auto parts stores have free loaner tools, which includes torque wrenches.

Mike
Reply With Quote
  #6  
Old 10-14-2017
mamoose124's Avatar
mamoose124 mamoose124 is offline
Diamond Level Sponsor
 
Join Date: Jul 2014
Location: Gordonsville, VA
Posts: 363
Default

Thanks, Todd, for the suggestion about the grade 8 washer and lock washer. I was thinking along those lines but need a bit of support. I can put a pipe on the end of my torque wrench and should be able to get 150 ft/lbs out of it. This is my plan.
__________________
Mike Youngblood
Reply With Quote
  #7  
Old 10-14-2017
mamoose124's Avatar
mamoose124 mamoose124 is offline
Diamond Level Sponsor
 
Join Date: Jul 2014
Location: Gordonsville, VA
Posts: 363
Default

Good point, Mike. I think I will take Todd's point and use a length of pipe to give me some mechanical advantage.
__________________
Mike Youngblood
Reply With Quote
  #8  
Old 10-14-2017
Alpine 1789 Alpine 1789 is offline
Platinum Level Sponsor
 
Join Date: Dec 2006
Location: Southampton, NY
Posts: 2,927
Default

Just a thought: using a pipe to force the wrench past it's maximum torque might not be good for the wrench's accuracy. You might be better off putting the pipe on a standard wrench.
__________________
Jim
Alpine 1789
1966 SV, with 1789 Chevy rod engine
1965 SIV BW35, a future V6 conversion
1963 S3, future TBD
Reply With Quote
  #9  
Old 10-14-2017
Ken Ellis's Avatar
Ken Ellis Ken Ellis is offline
Platinum Level Sponsor
 
Join Date: Dec 2006
Location: Columbus, OH
Posts: 1,707
Default

Here's a plan:

Use enough extensions on the socket to get the wrench out the crank-start hole in the valence, and away from the rest of the car.

Get a jack stand, and adjust it to support the extensions so they are level.

Attach the ratchet/breaker bar so it, too, is level with the ground.

Measure 24" out on the breaker bar, and mark with tape.

Get the scale out of your bathroom.

Stand on scale, note the weight.

Still standing on scale, press down on breaker bar at tape-marked location, exerting enough force so that scale measures 75lbs less than your previously-noted weight. That will be 150 ft lbs. torque on the bolt in question, since you have a 2' lever arm.

Other values can be proportionally derived; working with 2' keeps the math easy and the forces reasonable:
200 ft lb would be 100 lb reduction in weight
250 ft lb would be 125 lb reduction in weight, etc.

If you're shooting for 180 ft lbs, scale weight reduction would be 90 lbs.

2.5 or 3 ft. extensions are left as an exercise for the reader...

Note that as you tighten the bolt, you'll need to re-adjust to keep the breaker bar/lever arm fairly level so your measurement stays accurate.

Never put all your weight on the lever, because when (not if) it breaks you'll bust your chin on your NOS hood flash molding.
__________________
Ken
SV B395013950 (OD) LRX
Weber 32/36 Pertronix
Reply With Quote
  #10  
Old 10-15-2017
mamoose124's Avatar
mamoose124 mamoose124 is offline
Diamond Level Sponsor
 
Join Date: Jul 2014
Location: Gordonsville, VA
Posts: 363
Default

You have a point, Jim. I think I will just get a hefty friend to lay on the end of my torque wrench and get the bolt torqued to 150 ft/Lbs.
__________________
Mike Youngblood
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -4. The time now is 06:02 PM.


Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright SAOCA 2017 Website powered by Subdreamer CMS & Designed by indiqo.media