Inliners International Forums Thread Like Summary - 250 chev sounds like rod knock. Timing gears?

Rebuilding a basket case 250 Chev.
Fired up in stand, sounds like a rod knock.
So I tear it down, rods about .004 to .006, journals all look good just worn down to the copper.
So I tighten the bearings up to .002 to .003, figure it's good.
Fire it up, SAME NOISE. Bang-bang-bang one per crank rev.
Pull the fuel pump & belts, same noise.

Pull all the rods, piston pins all tight, all looks good.
Soin the crank all quiet. Spins easy.
Add the cam & spin it over with spinner wrench: THERE IT IS.
Either the cam gear or retainer plate or crank-cam gear mesh is making the noise, once per crank revolution.
Aluminum cam gear, steel crank gear, looks all factory.

Anybody ever hear a noise like that? What is it?

Interesting sound. It has to be the crank gear. You should be able to see if it has a bad tooth.

When watching the Vid I could hear the hit/noise at the same time I see the Keyway on the crank.SO with that being said The spot on the crank gear Hit the cam into different Places, So would look closely at the crank gear having a Miss aligned tooth maybe. And with that much Hit/noise I would think you could feel that Hit when you turned it over slow. Yes the crank gear is the same. But they are made as sets or to be as a sets I should say.