Diesel

Hi I'm having issues. When I install 268 cams & put chain on seems like there to much slack on the guid side & when assembling everything & tensioner back rotate crank 4 revaluation back to mark the cam looking tool wont go in. I have to rotate past the line on the crank then they go in. Looks to be half tooth off on the crank shaft side where the shaved tooth is. Any help would be grateful Thank you.