Shovelhead 4 Speed Saga: Going Up Part 8

To put a helicoil in the case I need to drill out the hole straight and in the correct spot. I suppose some folks could hand drill it straight enough and hope the bit followed the old hole. I'm too anal, not brave enough, or not good enough to do it that way. I wanted to use my drill press, but it's not an easy shape to hold down, especially when the transmission is already built up. My first plan was to use my support box like this and use nuts on the primary studs to level the transmission.


The support box was too small for my little drill press table. So I called Columbus for idea support. He came through with a good one. 1X4 lumber built like this. Mainshaft through the hole and sprocket on the wood.



12 inches long and marked for 2 3/4 inside square.


I even have some cool clamps to use.(I didn't get a picture of the finished jig.)


I had temp installed the cover and gasket, so that's got to come apart.


Lots of blue tape to keep the chips out of the gear box and then find the hole.


Well the jig is not right yet. The rachet top is keeping it unlevel and off the sprocket on one end.


Remove the offending piece.


The jig is still in the way of getting the hole centered under the chuck.


More cutting of the jig and it's perfect.


Clamping everything down was a trick for sure.


I found a transfer punch that fit the hole and then centered the hole to the chuck.


Time to drill. (I'm nervous as a cat at this point.)


Not bad, I wonder if it's perpendicular to the correct datum plane and if its true position is within spec at maximum material condition.


I don't have a dead center so a center should do okay.


Taped and ready for the helicoil.


The bolt holds good.


Break off the tang of the helicoil. (If you have a craftsman screwdriver, then you have a punch, right?)


Good to go.


Back to building. My cover uses bolts not studs but I use 5/16-18 set screws as alignment pins.


Those hold the gasket for me and it won't slip.


Pull out the slinger and catch the crank gear behind it. Turn the the kicker shaft and put the stop where you need it.


Check the video.


Cover is on.


Add the bolts.


Pull the set screws. Add all the bolts and then torque them to spec. This sucker is ready to go back into the frame.