from the looks of your signature, you have either a 95 or 96. Hopefully your car is a 96. if you have a 95, the tensioners that are currently supplied by Nissan require replacement of the timing chain guide with an updated model. this means you will have to take off the timing cover - the guide cannot be replaced through the small access cover.
if you have a 96, you don't have to worry about replacing the guide, the tensioner will be a direct swap.
if your car is in fact a 95, you can opt to 'rebuild' your current tensioner - buy the updated one from nissan, and use the spring and other parts from it to rebuild your old one. this way, you won't have to worry about changing out the guide.
whatever you decide to do, DO NOT let the tensioner explode and drop into the timing cover
Originally Posted by Xzecution'R
what's a rtv?
it's the silicone gasket-maker stuff that you can get at autozone. use it to re seal the access cover before you bolt it back on. i used permatex ultra copper for my rear valve cover gasket and it has not leaked.