Verify finish on starter motor

[Steve L.]

I'm guessing at the finish, This is for 72 SB:


Starter frame bolt bottom zinc bolt 6 inch long 1/4-20 thread
Starter frame bolt top zinc rod 6 inch+ long 1/4-20 thread both
ends flange head nut, lockwasher,
second nut
Solenoid to nose zinc pan head phillips 1/4-20
Shift lever pivot zinc 1 3/4long, 5/16-18, split lock, thin
nut
Starter to block black phosphate 3 5/8 long, 3/8-16, split lock
hash marks on shaft near thrds

What's the purpose of the hash marks on the mount bolts?

[Terry M.]

Re: Verify finish on starter motor

Those hash marks are called knurling and make the diameter of the bolt slightly larger in the area where they are. This is the interface between the starter and the cylinder case. They help keep the starter from moving against the torque of cranking the engine. I remember a post recently with a picture of the corner of the case broken off at one of the starter threaded holes. That happens if one uses bolts without this knurled segment or if one fails to use the starter support at the other end of the starter.

[Joe L.]

Re: Verify finish on starter motor

Those hash marks are called knurling and make the diameter of the bolt slightly larger in the area where they are. This is the interface between the starter and the cylinder case. They help keep the starter from moving against the torque of cranking the engine. I remember a post recently with a picture of the corner of the case broken off at one of the starter threaded holes. That happens if one uses bolts without this knurled segment or if one fails to use the starter support at the other end of the starter.

Terry------


.....and a block damaged in this way is, essentially, irreparable.

[John P.]

Re: Verify finish on starter motor

The solenoid to "nose" screw is a filister head.

[Steve L.]

Re: Verify finish on starter motor

Thanks John,
I checked it again and it is a fillister head rather than pan head.