Hi, can anyone help me. I replaced the timing chain successfully a month ago using a complete renovation kit including an oil seal however it has now started leaking. I plan to pull off the belt pulley and replace the the seal but don't understand whether I can?

When I did the complete chain kit replacement I found out the sprockets were keyless, pretty strange but easy enough once I locked cams and crank and replaced all the gear but what happens now I am doing just the seal, I have to undo the crank shaft bolt which will release the crank sprocket with the timing chain tensioner active.

What will happen?

Thanks for any ideas/logic

Paul