Technical Actual torque with extension & crows foot?

I need to torque some SBC four bolt main bearing cap bolts and can't get a straight shot on them. I'll need to use my 1/2" drive torque wrench with a 1/2" to 3/8" adapter, a 3" extension, and a 5/8" crowsfoot.
Torque specs are 67" lbs & 77" lbs.
What do the math experts say I should be reading on the wrench?

 

This doesn't answer your question but what's in the way?

 

Odd. Can you post a pic of your issue?
No help on the math, but I do know the crows feet ones I use will spread out.
I’m just curious as why you cnt get a straight shot at them.

 

The offset of a 5/8" crowsfoot is so small I wouldn't worry about it. Or you could measure from the center of the drive to center of the crowsfoot and the length of the wrench from pivot to the center of the drive. The increase in torque is dependent on the relationship between those numbers.

Or just offset the crowsfoot 90deg to the axis of the wrench. That cancels the length change.

The adapter and extension have no effect.

 

Is the engine still in the car?

 

I was of the impression that any extension from the torque wrench added some amount of deflection and affected the measured torque. No?

John

 

Always compute, if your tool does not do it for you: https://www.tekton.com/blog/how-to-accurately-use-a-torque-wrench-with-a-crowfoot-wrench

Yes, an extension and an adapter will have some torsional twist, so they should be avoided, if possible. Computing that twist will be very difficult to compute. It will be minimal, but it does exist.

 

The block I'm using for the 39 Poncho came with a splash tray held by three of the bearing cap bolts that have and extra couple inches of shaft added.. hence the issue. I plan on using the splash tray... cuz..it must be there for a reason...
First pic is current situation.
Second pic is how I found it.

 

Deep scocket,vs all ,that extra stuff,really. No BS math needed.


Opsssssss I type too slow

 

That may be a plan. Mig welder, scrap pipe, and a donor socket.

 

This^

 

Problem solved! All my "good" sockets won't drop all the way down over the stud. My junk drawer yielded an old 5/8 socket that drops all the way on, but the stud sticks up onto the drive 3/8 hole. But I also found a scrap 1/2 drive socket which I can weld to the back end which gives me length and drive needed.
Screw the math! Thanx guys.

 

And this proves that with the proper motivation you were a lot smarter than you thought you were ! Congrats!!

 

I'm thinking that there is a special socket or tool that somewhat resembles that crowfoot with extension with another offset at the top to center the torque wrench back over the bolt.
Quick revision:
This is a 5/8 Super deep socket for some spark plugs https://www.amazon.com/CTA-Tools-2375-8-Inch-Extra-Long/dp/B009VI9NLO/ref=sr_1_6?gclid=EAIaIQobChMI8J6RlIvr-AIVLSCtBh21SwxiEAAYASAAEgKrVvD_BwE&hvadid=232591061227&hvdev=c&hvlocphy=9059112&hvnetw=g&hvqmt=e&hvrand=8037293672416972237&hvtargid=kwd-384608767589&hydadcr=29035_10165969&keywords=5/8+extra+deep+socket&qid=1657345027&sr=8-6

This one is supposed to be 5 inches long. https://www.amazon.com/Sunex-2-Inch...s=5/8+extra+deep+socket&qid=1657345454&sr=8-2

 

I just came back to this thread. My earlier comment about the effect of extensions is often questioned. Really hard to prove or disprove without and expensive instrument so I was glad to see the posted video of said instrument and the test. Thanks Grimpala!

 

Can you explain why that would make a difference?

 

Yep...sometimes we get into a brain lock going down one path. Seemed like a simple solution to use the tools on hand..

 

It seems like there should be, but that might make for more opportunity for torsional twist, rendering the reading inaccurate, unless it is very well made.

It takes just a few seconds to use the online calculator, or to do the math, to figure the correction.

Since I need to use open end, crowfoots and tube nut crowfoots a few times a week, I learned to use the feature on my Snap-On digital torque wrenches.

A couple of button pushes does the trick.

 

You could put double nuts on the ends there and just grip on those with the regular socket. Then un do them with a couple hand wrenches. Mark the bolt and socket to make sure you dont see any slipping.