new camsensor interupter magnet

ok i have to replace the cam sensor interupter magnet on my 1992 olds 88 3.8L. can i just pop the magnet in through the front of the sensor hole, or is it an absolute neccesity to have to the timing cover, chain and gear off?

I can't offer any advise on that one, but a word of advise, if you have to remove the timine chain/ belt, you should replace it, if it hasn't been done recently. No cure like prevention and it'll save the hassle of possibly having to tear it apart again in the future.

Got to get into the engine, good time to replace the chain as tri-power stated.