Tight crank gear

[matchlessman]

Is there a technical reason the crank gear that drives the cam gear has to be so tight on the crank? I got mine off using an impact gun on a beefy puller. I'm about to put the new one and it's equally tight. I've worked on plenty of engines over the years and never experienced a crank gear being so tight. Is there a technical reason for the tightness? I can't think of one.


Ken
Eastern Ontario

 

[nkaminar]

The crankshaft vibrates in torsion. The nose of the crankshaft vibrates more than the rest of the crankshaft. If the gear and pulley are not tight on the crankshaft they will fret and wear. Modern engines have vibration dampeners on the front of the crankshaft that dampens out a lot of the vibration. They need to be tight too. You can buy a vibration dampener for a Model A engine but stock engines don't need one as much as engines that rev higher.