Snap-on S-8663 Obstruction Wrench

[Y-Blockhead]

I saw two Snap-on S-8663 Model A Obstruction Head nut wrenches on e-bay today for good prices if anyone is interested. Not mine.

One looks really nice date coded 1959. https://www.ebay.com/itm/297388963592. The other has some wear, date coded 1954. https://www.ebay.com/itm/236141745480.

[Jim Brierley]

What's an obstruction wrench? I was a truck mechanic for 20 years and never heard that description before.

[Y-Blockhead]

It is a wrench that is bent to fit around obstructions so you can get the proper torque on the fastener. In this case the Model A distributor and carburetor.

I just looked it up in my 1980 Snap-on Catalog, Called a Cylinder Head Wrench/Torque Adaptor. "Designed for getting around obstructions and reaching into restricted areas when removing or torquing cylinder heads.


The nice one I referred to already sold.

[ModelA29]

I picked up one of these at an estate sale. Still sealed in the original package $5.
https://www.ebay.ca/itm/151574867052
I had been using my aircraft cylinder wrenches but they are pretty tall.



I also bought one of these little electronic torque wrenches at HF for the road tool kit.

[Y-Blockhead]

Another picture of a Snap-On S-8663-B Obstruction Wrench.

[nkaminar]

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I made my own. 11/16 box-end, open-end combination wrench, 1/2-inch drive to 3/8-inch drive reducer, square tube. I tried it first with just the bent wrench but it was too flimsy and I needed a longer version.

[mercman from oz]

Home made 11/16 box end open end combination wrench - nkaminar

[Bruce of MN]

Is that a piece of heavy angle between the wrench parts?

[Y-Blockhead]

Originally Posted by Bruce of MN

Is that a piece of heavy angle between the wrench parts?

I think he mentioned square tubing...

[JayJay]

Snap-On (especially old) stuff is lovely. I have a few. But as far as the head torque adapter, hard to beat the one Snyder's sells.

BTW, when I was growing up we knew these distributor wrenches, designed to get around the distributor body and to the bolt that was loosened to adjust timing.

[Brian SATX]

Just wondering- has anyone ever done a test to see if these angles affect the torque value at all?

[JayJay]

Originally Posted by Brian SATX

Just wondering- has anyone ever done a test to see if these angles affect the torque value at all?

The socket portion of the adapter is directly in line with the square hole for the torque wrench. No lateral displacement = no change in torque value.

[Keith True]

I have a few of those.We always called them torque adapters.Lots of farm and industrial equipment are built with a need for them.Continental and Perkins have head nuts tucked in between the pushrod tubes.Case had an odd casting overhang that required the use of them.On a John Deere engine mounted on an industrial stand you can't tighten the front main bolts without one of those.The smaller ones I kind of consider distributer and vacuum pump wrenches.The 11/16 through 1-1/8 are much beefier,and used for heads and mains.Instead of buying the whole set over 40 years ago,I bought one at a time as needed,and now I have the whole set.Probably cost me double that way.

[nkaminar]

Bruce, Square tubing. Any tubing will carry more torque than any angle iron. I had to bend the wrench parts to get everything in alignment because I was using it with a torque wrench. The wrench parts have to be heated to dull red to bend.

[Bruce of MN]

Originally Posted by Y-Blockhead

I think he mentioned square tubing...

ooops!

[larry harding]

i dug around in the junk and came up with some old broken sockets and some 5/16 x 1 flat bar and fabricated mine. you can pickup used sockets at a yard sale or flea market and make one cheap. i like fabricating my own A tools when i can, certain satisfaction in doing so. i even copied a rear brake drum puller a friend had made years ago. it is simple but does a good job.

[CarlG]

I've got several of the genuine Snap-On tools, $50 post paid to anywhere.

[rotorwrench]

Pretty much all of the aircraft engine manufacturers used the odd shapped tools such as these to remove various assemblies such as cylinders, tappet blocks , and even push rod tubes from the old radial engines as well as the opposed types. They were very common in aviation. Lycoming and Continental still use them.

[Fullraceflathead]

I have several snap on tools can somebody explain how you read the date on them.

[katy]

Originally Posted by Fullraceflathead

I have several snap on tools can somebody explain how you read the date on them.

Try this: https://www.google.com/search?q=snap...hrome&ie=UTF-8