A handy little tool

As you can see I have changed the main photo at the top of the blog.  This is the ’66 Commander that will get the new engine.  It will also be getting new rear fenders and rockers, but that will be a later blog.

An old mechanic friend who is now in a nursing home (and sadly, suffering from alzheimers) gave me this tool when he helped me check  a 170 a number of years ago to see if the bore was over the limit top-to-bottom.  I finally remembered that this tool would also measure my actual bore size. It consists of the dial attached to an arm and plate to slide up and down the cylinder, various lengths of tips for the dial gauge, a tool to set the basic width to be measured and a set of feeler gauges.

This part of the tool is made up of plugs of various sizes which can combined give you a base width for setting the dial gauge.  I combined the plugs to come up with 1/16″ over3.5″ which just happens to be the exact size of a standard Studebaker V8 engine bore – 3.5625″.


I then added a rod length to the gauge which was just enough to allow for expansion beyond the standard cylinder diameter.  I then set the gauge on the measuring rod between the two uprights (the one of the left is hidden behind the gauge mount) and set the needle to zero.

I had earlier cleaned the bores out just enough to remove the majority of the surface rust. I slipped the tool into the bore and found that the cylinders are about .040″ oversize for a total cylinder diameter size of 3.6065″. The pistons are 3.6025″ which leaves a difference of  .004″ or .002″ all around between the piston and the bore – my tool and my actual measuring ability may result in some variance.  All the cylinders read the same and of course there was virtually no difference between the top and bottom of each one.

The Studebaker service manual says to check with a .002 feeler gauge. They use a long gauge that fits the full length between the piston and the cylinder wall.  I don’ have one so I made do with a standard one of about 4″.  The manual says it should take 8 – 12 lbs to pull the gauge out.  I don’t know what their gauges were made of but I doubt that my feeler could handle that amount of pull without breaking. When I did pull the feeler out it took a noticeable pull so I’m hoping things should be fine.  I still have to do a final hone which will clean out the last of the rust stains, but shouldn’t remove any significant metal from the walls.

Next will be cleaning out the lifter bores and checking the lifter fit.







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