i have a 1983 z28 with a 305. it has an oil leak and i could never figure out where it was coming from, i changed the timing cover and the gaskets and oil pan gaskets and still has a leak. it does NOT leak at idle or lower rpm's but when you drive it and it hits higher rpm's it leaks and the harmonic balancer slings it everywhere. now here is the question!!! i pulled the balancer off after i saw an oil trail coming out of the timing cover seal that rides around the balancer shaft! it is NOT completely smooth it has a small ridge where it is kinda wore out you could say. would that cause it to make the seal leak at higher rpm's? and if so what would be better replacing the balancer or just buying a repair sleeve?

I'm more of a fan of replacing the balancer.

+1 here aswell, i dont like speedisleeves, they are just a bandaid to the problem IMO.

Replace the balancer and put a little blob of RTV on the woodruff key that indexes the balancer to the crank. Some engines you can get a slight oil leak past the keyway groove. A little RTV is how the factory handles that problem.

When you changed the timing chain cover did you also change the seal on the cover or did the new cover come with a new seal already installed? If not, did you re-use the seal off the old timing chain cover?

This "ridge" you're referring to, is it around the damper snout or the crankshaft snout? It's fairly common for wear to develop in those areas after many thousands of miles.

Jake

on the damper. i replaced the balancer and now no leak!!! thanks guys!!!