MTFCA Forum

Does anyone have pictures of how they clearanced the crankcase for Model A crank and rods.

I’ve freehanded the dimples before… but carved a die for the last motor I did. Worked out very well! I also made up a hammer as no other hammer I owned or could find seemed to fit the shape I wanted. It was basically a piece of 1/2” round stock welded to the face of a hammer

Here’s a pic of the die. Not sure where the hammer went tho…?

A few vice grips to hold it tight, a bit of heat, and a bunch of carefully placed hammer strikes formed the pan into the die

Kevin, in your first picture, on both side of the dimple, there appears to be a weld. Did you slice the pan first?

Nope! Only heat and hammer on this pan. The die gave sumpin like 1/8”-3/16” of clearance (it’s been a while), but the 12 point nuts are the real secret. If you use the stock hex nuts you have to make the dimple much larger.

As Kevin said, use ARP 12 points nuts- they give you a lot more clearance. I like to horizontally split the pan wall with a small diameter cutoff wheel in a die grinder before forming the dimples as I've found the pan distorts less from the dimpling operation. Either way works, but with the split wall, the pan rail surface does not distort as much.