1931 Mod 90 bearing torque

[1wonton]

What would be the torque setting for the main and rod bearings on the '31 90 engine?

[trimacar]

This might help…

 

https://crower.com/rod_bolt_torque    

[keiser31]

32 minutes ago, 1wonton said:

What would be the torque setting for the main and rod bearings on the '31 90 engine?

 

[1wonton]

Thanks guys.  I looked this up in an old Motors manual bt those main bearing numbers seemed too high;  I guess that's what it's supposed to be.  Hope I don't break anything.

[1wonton]

Fifty years or turning wrenches, I should have gone with my gut instinct.  120 lbs on the main bolts seemed too much but I went with the charts instead of tightening these bolts to what I felt was sufficient.  Of course I snapped off the rear main bolt right away.  What a bitch trying to drill out, easy (Ha) out, pick out, rethread and find another stud.  I should have known better.  Experience is the best teacher, unless you're too dumb to pay attention.

[Jubilee]

Yeah, before I saw the charts posted I was going to say a grunt to a grunt and a half.

[Pete O]

In 1931, there were no torque wrenches- hadn't been invented yet.   When the cars were being assembled, they used wrenches of the appropriate length so that a man of average strength could tighten the fastener to the correct-ish tightness using the two grunt method (get it tight, then yank it two more times with a good grunt on each yank). 

[Larry Schramm]

On 10/8/2022 at 7:09 PM, 1wonton said:

Fifty years or turning wrenches, I should have gone with my gut instinct.  120 lbs on the main bolts seemed too much but I went with the charts instead of tightening these bolts to what I felt was sufficient.  Of course I snapped off the rear main bolt right away.  What a bitch trying to drill out, easy (Ha) out, pick out, rethread and find another stud.  I should have known better.  Experience is the best teacher, unless you're too dumb to pay attention.

 

Were you using the size of the bolt head for the torque?  Like 9/16" to get the 120 ft/lbs?  If you did, that might be your problem.  

I believe that the chart that states GENERAL STUD TORQUE means the diameter of the bolt shaft.  ??

[Mark Shaw]

Torque settings are also dependent on new or old (reused) fasteners. 

Reused fasteners are already stretched and will often fail before reaching their originally specified torque settings.

Torque is also affected by weather the fastener is lubricated or not.

Many old bolts do not have a raised machined mating surface that would qualify as a fastener for specific torque settings.

[Grimy]

That chart has numbers for Pierce-Arrow that are way too high--by half.  I would never run an iron Pierce 8 head beyond 55 but the chart calls for 83.  I mentioned in another thread that some charts published years after the cars mentioned have excessively high numbers and this is the best example.

[1wonton]

No torque numbers in the original "Specifications and adjustments" manual from 1931.  I went with an old (1940's) Motors manual for 1935 Buick, says 110 ft lbs. ; this can't be right.  I installed the rear mains caps with an 8" wrench, as tight as I could get them.