Rear Main Seal Leak

[Coubra]

Installed "new" 428 block with Scat 4.25" stroke & stock bore in our '69.  1st run had some minor issues and oil leaking from rear of block.  Resolved issues, ran again with same leak that somehow, didn't fix itself...
Read all the other threads on rear main seal problems/install - good stuff.
Dropped K-member, suspended engine, and changed seal.  Original & replacement seal is Fel-Pro BS30138.  Was a little concerned when the new seal rotated easily into the block (crankshaft doesn't have sipes machined in seal surface area).  Did 3/8" seal rotation, put dabs of Permatex Optimum gasket maker on the end of the seal, and put small amounts on cap corners along with a few dollops in the side seal runs close to the block/cap intersection.  Installed cap without the side seals and torqued.  Sanded side seals, coated with gasket maker, applied a couple dollops to the side seal runs, then pushed the seal in until it wouldn't go any further and pushed out excess gasket maker - didn't use nails.  Trimmed side seals, spread some gasket maker on the inside cap/block seams, bolted up windage tray/oil pan (the bearing vent is exposed), reassembled engine/K-member, and let stand for 24 hours.  Cranked it up yesterday and it's got the same freakin' leak.  PCV valve is pulling air while running with 10" vacuum.  Ran it again today with UV dye in oil.
New plan: Drop the trans (TKO 600), take off bell housing, and check behind block plate to make sure the plugs and cam plug aren't leaking.  Assuming they're okay, then drop the K-member and pan again to retry seal.
Questions:
1) Is there a better seal out there?
2) Didn't put gasket maker on the seal where it contacts the block cap. Should I put a thin coating on the portion going into the cap? 
3) How will I get gasket maker on the portion rotated into the block without contaminating the surface of the crankshaft?
4) Plan on doing the same thing with the cap and side seals.  Should that change?
5) Thinking about changing to Permatex's Anaerobic gasket maker.  Anybody have any experience with this stuff?
Any help will be appreciated.

[PaulProe]

Roush makes a one-piece oil seal. Kind of pricey. Don't know the installation process. 

If interested contact James Kemp  (800) 597-6874 in the Roush Crate Motor department

Paul

[blykins]

It shouldn't be that hard to seal up, so I'm thinking it's possible you have a leak coming from somewhere else, maybe a gallery plug or similar.

One thing I did pick up on though, why didn't you use the nails?  If I do use side seals, the nails go in, because they are what push the seals outward against the block. 

FWIW, I haven't used side seals in years.  I use silicone and shove the tip of the tube into the hole and just pull the trigger on the caulk gun until I see silicone squirt out the seam on both the front and the back.  I wipe away the excess on both sides and call it a day. 

I always use the Felpro BS30138 seals.  Lip goes toward the front, seal halves get lubed up.  A very thin smear of silicone on the seal half ends and a very thin smear along the rear edge of the cap before it goes in. 

I've seen the Scat cranks be smooth and I've seen them have sipes.  Both seem to work ok.

I think I'd be pulling the trans, clutch, flywheel, etc. and taking a look.  You may get lucky and find a gallery plug that's not tight enough (it happens) or you may see a clear path from where the oil is coming down the rear of the block, which can tell you if it's a side seal or a seal half.

Also check to make sure the rear main cap bolts are not holding the oil pan up off the block. 

[My427stang]

I am with Brent, I'd pull the tranny, if for no other reason you can have more room to work.  I am not confident that a side seal, especially a hard Felpro one, would work without the compression the nail provides, however, having a completely unchanged leak makes me wonder if it was something else

As far as brands, Felpro seals are great, side seals and nails not so much.  Its very easy to drive the nail into the hard seal and then it doesn't compress well. If you get the nail in correctly you are good to go, but it can be a pain.   Because of that though, I have been buying Mahle/Clevite seals, they use a softer rubber side seal and a blunt nail. I have not tried to blunt a Felpro nail, that would likely work too, instead I bought a case of Clevite LOL

[Coubra]

Took your advice and yanked the transmission, bell housing, and flywheel. We (four mechanics) saw no evidence of the cam plug or threaded/sealed gallery plugs leaking at the back of the block.  We did notice oil coming down from the road draft tube fixture at the back of the intake manifold - fixed.  Saw oil running down the rear corners of the block that ends up on the starter and looks like it runs down the block to the block plate on the other side.  Did not see evidence of cap side seals leaking and front side of crankshaft & flywheel don't have oil slinging off them.  Bolted it back together, changed the valve cover gaskets, and ran it - still leaks. 

Suspended engine, dropped K-member, dropped oil pan and windage tray.  Still no oil visible on front side of crankshaft flywheel mounting flange.  See picture 6546 - oil running down front of block plate.  Changed oil seal with another Fel-Pro unit - this time putting light coat of Good Stuff on outside of seal and filling side seal grooves, along with 3/8" offset and small dabs at end of seals.  Installed cap, torqued, and pushed RTV-coated side seals as far as they would go pushing sealant out.  Cut off end of rubber side seals, pushed more sealant into cap/block intersection, put a dab of sealant at the cap/block point,  installed gasket-windage tray-gasket-oil pan, and torqued.  Let sit overnight, retorqued pan, put it all together with a new left valve cover gasket (just because the old one was suspect) and ran it this afternoon.  Still leaks down the front of the block plate and at both the lower rear head stud/nuts - see 6552 & 6556.  No valve cover leaks and can't see any intake manifold leaks. 

This is driving me crazy!  Was s'posed to have the car at Road America for the Optima event this month, but unless somebody's got a grand revelation, I'm going to give up my spot.

[jayb]

Sorry to see you are having so much trouble, it appears you are checking in all the right places.  I wouldn't let it keep you from going to the track though, you could always install an engine diaper to keep the oil off the track.

[RougeRiverForeman]

Wow! Really crazy you are having so much trouble.
 
One thing comes to mind that I would try is to pull the clutch & flywheel and all again,  pull the dizzy and spin the oil pump with an electric drill for a minute or so to really pressurize the oiling system.  then inspect all your gallery plugs and cam plug for leaks. 

Considering the number of times you have replaced the rear main seal it should have made difference if that was the problem,  It sounds like it's leaking from somewhere more obscure, Pressurize the system and see what happens.
   

[Cyclone03]

I fought a “rear main leak” for years.
I had another problem that had me tear the engine down .On reassembly I looked at the 3 surface junction of head block and intake. When I put the head gaskets on I put just a dab of TA31 on the top and bottom of the gasket at that junction ,then did the same with the intake install as well as using TA31 for the China walls. It seems to have worked no drips on floor going on 4 years now.