I have purchased a Gen one 4:88 to 1 gear set to install in to a Gen two third member. This was done to meet the ICSCC technical requirements for the RS (Radial Sedan) class in the Pacific Northwest area.

This was the procedure I used.

On the second Gen pinion shaft I took a grinder to remove the case harden pinion gear to the point of leaving about a 1/8 of an inch of material extra for final machining. On this shaft record the overall length so that when you put the Gen one gear on the end it will be with in .005” to .010”.

On the end of the Gen one pinion gear (Gear End) you will machine in from the end in to the center of the shaft a taper of 6 degrees. You will continue far enough in so that as you work your way outward from the inside you will cause the Gen one pinion gear to fall off. There will be a coarse edge were it separates, debure it by using an air die grinder flapper wheel, 120 grid is fine. At this point do not change the angle on the lathe because you will now put the preground Gen two shaft in the chuck and machine the out side to match the pinion gear ID angle you just separated. The trick here is to remove the material slowly and keep checking the overall length by sliding the Gen one pinion gear on to the Gen two shaft. What you want is an overall length .015” to long with a hand fit. At that point STOP. Now put a small 45 deg. Taper on the end of the shaft and a 3/16 hole ½ “in. This will accommodate the last step of Tig welding.

Take the pinion shaft and put it into a freezer for two hours. Take the Gen one pinion gear and put it in a toaster oven and set to 450 Deg. For 45 minutes. Hold the frozen shaft in a strong vice so that you can drop the heated gear on to the shaft and drive it down with a 2 lb hammer and a large 2 inch brass drift. Be sure that the gear is seated on to the shaft.

Let it cool to the touch the put it back in to the lathe and check it for run out. If you have a good lathe and proper tool bits you will have only .0010” of total run out. That is good and will not present a problem. In most cases it will come from your old Gen two shaft being off to start with.

The last step is to make a container to hold the shaft in water so the gear is sticking out on the top buy 1/8”. This is so that as you Tig weld you do not soften the Gen one gear with the transfer of heat. Also remember the hole on the end. This is so you can put a small bolt in to hook up your ground for welding. You do not want to have arc transfer between the shaft and your water container that will create pits in your final product.

If you are capable of performing this procedure then you will not have any problem with assembly.

Happy Racing, Good Luck