Fermentation not starting

I did a continental pilsner kit on Saturday that used a lager yeast. The yeast packet said it was OK to ferment at ale temps, up to 72*. Since I don't have the setup for lagering, I stuck it in the basement where it's 64*, and 4 days into it there's no fermentation. No activity in the airlock and the gravity is the same as on Saturday. How long do I go while waiting for the fermentation to start? Is it OK to dump another package of yeast in?

BTW - I've never used a lager yeast before. When I opened the yeast package, it didn't smell like what yeast normally smells like. It had a somewhat sour odor to it with a light yeast odor underneath. Is that smell normal for lager yeast?

what kind / brand of lager yeast ? I dont think any lager yeast smells sour, I have used saflager mostly. All lager yeast requires cooler than 64 f. to ferment.  A good yeast starter will ensure you have live yeasts going into your brew, at least re-hydrate with water and look for foam and activity to be sure.

I always go by the Beersmith yeast temperature profiles;  as some suppliers tend to exaggerate their yeasts specs.

Once I had a lager fermenting and the temperature got out of control and went too high (72). The brew went bad.  sour, turbid and smelled like turpentine.  If your brew doesnt smell sour or look bad, you could repitch with proven yeast that will work at your fermentation temperature.

Most lager kits use an ale yeast to create a pseudo lager. If your kit included a small bag of yeast taped to the lid which you sprinkled on top of the beer then it may take four or more days to start especially at cool temperatures.
Kits often sit on the shelves for many months before being sold. It sounds like your yeast may have been well past it's shelf life.
Give it a good stir and if it still doesn't start within a few days add some good quality yeast. Any neutral ale yeast should do the trick.

Patience is a virtue. I finally got some airlock activity on the 5th day. This is the slowest fermentation I've ever seen. It's bubbling every 15 seconds or so. I smelled the aroma coming out of the airlock and it has a slight hint of the fruity esters you'd get in a Weizenbier or something like that, but otherwise everything smells fine.

I'm not sure the brand of yeast it was. It came in a Brewer's Best kit and had German on one side, English on the other. The basement's up to 66* or so with a cool down coming mid-week, so it should be good to finish. Thank you for your assistance RR and TW.