I've replaced my rear main twice, both times it has started leaking after about a month, it leaks when the rpms are up (around 2500 or more) spills on the exhaust, and makes a huge amount of smoke. It doesn't leak when not running though. I've been told there is spacer to push the rear main out so that the seal doesn't lay on the ridge it has made in the crank, does anyone know of where I can obtain this spacer?

 

I have never heard of one. Since the seal is a snug fit, I don't now how you would fit a spacer in there. If your crank has a groove, sounds like it needs to be turned to remove it.
I know there are sleeves you can buy for hubs and balancers (in the front), but not sure if there is one for the rear main seal area.

I guess you are sure you are not putting the seal in backwards?

 

Never heard of a spacer,but they make a seal with a speedy sleeve that will fit over the crank for the seal to ride on comes complete with sleeve installer. Ya will have to remove your seal and go to a bearing and seal house to get one.
Have used them on heavy equipment and they work.

 

Are you 100% sure your not accidentally damaging them durring installation? It's very easy to do. Are you using a Rubber of Teflon seal?

 

I'm sure the seal isn't installed backwards. I had the spacer recommended to me by someone on another board. The crank does have a light ridge, my fingernail will catch on it.
I used a teflon seal the first time and then used a rubber one this time. Both times the seal appeared to be in good shape after install, no irregularities from a mashed tension spring in the seal, just a good snug seal around the back of the crank.
Both times I had no leaks at all for the first 3 or 4 weeks, then I started to see oil burning again on the exhaust along with a belly with a nice film of oil. It doesn't leak when sitting still, just when driving.

I don't really want to do another motor.

 

I'm going to vote for the ridge than. The rear main seal is tricky... I ran though teflons like an immigrant across the boarder. becasue I gouged the seal by accident with my Screw driver... but that was my trial and error...what I can tell you is that if the surfaces that the seal covers aren't clean and smooth... it's probably going to leak.