Replace leaking rear main seal after new build

[fairlaniac]

So you may recall a few posts on my oil leak on my fresh built 427 (484 stroker, Scat 4.25). I've run through every potential oil leak location and verified or fixed them (valve cover gaskets, fuel pump block off, rear galley plugs, etc..) and I still have a significant leak dripping down the front surface of my scatter shield block plate. I'm convinced my rear main seal is the culprit. So when I installed the rear main seal I was confident I did it as well as possible. I followed many tips in "*THE* definitive guide to FE rear main seal installation" post found here:
http://fepower.net/simplemachinesforum/index.php?topic=758.0

As I re-read Jay's portion (which is what I followed mostly) I noticed one thing I did differently. I put some TA-31 in the side seal grooves and used the seals to push sealant into the groove and to the point some started to seep out the part line between the cap and block as the post mentioned to do. However what I did was use the seal and pushed the seal into the groove and below the deck. More sealant oozed out as the seal went in. I then applied the side nails and drove them below the surface. Filled the voids and cut them flush when the TA-31 cured. Jay didn't use the actual seal but filled the cavity entirely with sealant and no nails. I didn't see the harm doing what I did. Regardless, I have a significant leak. BTW I did have the one seal end about 3/8" clocked above the deck and the opposing end in the cap clocked 3/8" with a dab of TA-31 on the ends.

I plan to pull the engine in the next month or so to re-do my rear main seal. What is the best or preferred procedure to put a new seal in an assembled engine? Do I pull the crank? Do I loosen the crank? Do I not loosen the rank at at all? I'm not sure what went wrong on my first attempt but I don't want to repeat it. I don't know if anything will be evident when I pull it apart? I just don't want to be doing his a third time.

Too much fun was lost over the summer but chasing the leak and not getting to drive my Fairlane. 

Here is the dye in oil picture of my oil leak. It isn't leaking out the holes, it is coming from the back of the oil pan and going down and is following the hole edge and dripping at the bottom and then to one nice point on the bottom of the scatter shield.


I put a magnetic LED light on the scatter shield and again attached my camera to a tie-rod to capture the leak. After about 7-8 minutes is when the oil started to start running down the front of the scatter shield. I didn't upload the video. It shows what I already know.

Thanks,

[My427stang]

I think I do the same as you describe

1 - Install the cap and main seal, with the lip facing the right direction, torque it
2 - Fit the side seal so it goes in very easy but some resistance. 

FYI - With Felpro seals, the side seals and nails are HORRIBLE, they are hard, the nail is sharp, so I don't use them anymore.  Mahle or Victor (same) are soft and a blunt nail, and so far have not needed any sanding

3 - Push a good amount of RTV into the hole, I like the Black Ultra for heavy oil environments
4 - Coat the side seal, push it in and it squirts out, get it all the way in, usually ends up flush, if it doesn't I have a punch that I used to push it in
5 - Drive the nail in, in the groove, being careful not to damage the side seal (This is where Felpros fail, the nail cuts into the side seal and then binds, damages, you name it.  Junk....  At this point, the side seal is about 1/8-3/16 below the pan surface
6 - Clean up the RTV that pushed into the engine well and on the pan rail
7 - When you are ready for the pan, put a dab in each side seal at the top

Knock on wood, haven't had a leaker in a LONG time

I see Brent use some good stuff and just squirt down the hole, it works, I can't say a single bad thing about the stuff he uses.  He will likely chime in on the sealant he uses to do that

[blykins]

I haven’t used side seals or nails in a very long time.  I use Dow Corning 732.  I stagger the seal halves then shoot the cavities with silicone until it comes out the front of the cap and rear.

[BattlestarGalactic]

I have always trimmed the side seals until they slip in(used a bench grinder).  No forcing them.  Get the cap on them smear RTV on the side seals and a dab on top of the hole and slip them in.  Then the nails.  Never did anything else, never a leak.

[fairlaniac]

My number one question is, do I remove the crank, loosen it and lift slightly to remove top half of seal or don’t loosen at all and work the old seal out and new seal in?
Thanks!

[My427stang]

It’s easier if you loosen all the mains

[Nightmist66]

BTW I did have the one seal end about 3/8" clocked above the deck and the opposing end in the cap clocked 3/8" with a dab of TA-31 on the ends.

I would not put any sealer on the ends of the crank seal, that may have been what caused it. I also do not use any side seals. I fill the channels with TA-31 and install, torque the cap, and force more in until it squeezes out top to bottom. Make sure the cap and block are very clean(obviously), I like going over the surface a couple times with acetone.

[rockhouse66]

I have been putting a very thin smear of Ultra Grey sealer on the cap parting line on the inside face.  Seems like a little extra insurance and can't hurt.

[fairlaniac]

It’s easier if you loosen all the mains

When you say "loosen" should I remove my cross bolt spacers or just loosen everything?

Thanks,

[My427stang]

It’s easier if you loosen all the mains

When you say "loosen" should I remove my cross bolt spacers or just loosen everything?

Thanks,

I think there likely is enough clearance if you just back them out a bit, to be honest, I have never done a seal swap in the car with a 427.  Certainly have with every other engine under the sun, but not a 427

I think it's very important that you see what is leaking though before you make decisions though.  If I understand it correctly, you know it's coming from the back, but not sure if seal or otherwise?

Any chance you could pull the tranny and flywheel?  or bite the bullet and pull the engine to see your die marks better?

[Cyclone03]

After years of chasing a “ rear main leak” I finally fixed it after my camshafts broke,did no go flat,it broke.

Two things different this time.
I Ultra Greyed the back of the oil pan on both sides of the gaskets, with canton wind age tray.

I also switched to Cometic valve cover gaskets. Expensive for sure I doubled them ,sealing the engine side with Ultra Grey and also the valve cover side of the other gasket. Then I torqued them to 15 ft pounds.

Into the second year and no drips on the floor.

In the previous years I always had a sipe around the valve covers as well a little run around the spark plugs. This is gone now as well.

Another area the sort of sweet was around the intake bolts,a little sealant under the washers and that area is dry as well.

[fairlaniac]

It’s easier if you loosen all the mains

When you say "loosen" should I remove my cross bolt spacers or just loosen everything?

Thanks,

I think there likely is enough clearance if you just back them out a bit, to be honest, I have never done a seal swap in the car with a 427.  Certainly have with every other engine under the sun, but not a 427

I think it's very important that you see what is leaking though before you make decisions though.  If I understand it correctly, you know it's coming from the back, but not sure if seal or otherwise?

Any chance you could pull the tranny and flywheel?  or bite the bullet and pull the engine to see your die marks better?

Ross, I had pulled the tranny a few weeks ago and fixed a leaking oil plug. I plan on pulling the engine and when I do re-pill the trans I will look for tell-tale signs.

[fairlaniac]

After years of chasing a “ rear main leak” I finally fixed it after my camshafts broke,did no go flat,it broke.

Two things different this time.
I Ultra Greyed the back of the oil pan on both sides of the gaskets, with canton wind age tray.

I also switched to Cometic valve cover gaskets. Expensive for sure I doubled them ,sealing the engine side with Ultra Grey and also the valve cover side of the other gasket. Then I torqued them to 15 ft pounds.

Into the second year and no drips on the floor.

In the previous years I always had a sipe around the valve covers as well a little run around the spark plugs. This is gone now as well.

Another area the sort of sweet was around the intake bolts,a little sealant under the washers and that area is dry as well.

Using the dye in the oil and a blacklight I have no indication of external leaks other than what is shown in the picture above.

[jayb]

I have to laugh, the "definitive guide" to FE rear main seal installation was 8 years ago.  I've learned a few things since then...

One of them (which isn't going to help you Doug, but I thought I'd throw it out there), is that with the engine on the stand upside down, these days I always install the crank and then the rear main cap first.  Once that is all done and sealed up, I fill the little breather hole for the seal in the rear main cap with oil.  Then I let it sit overnight.  Some of the oil can leak by the main bearing, but what you are really looking for is oil that leaks by the seal, and comes out at the rear of the block.  If you get a little puddle on the floor that came from outside the block, you have to tear the #5 cap off and do it again.  Kurt Neighbor turned me on to this method, and it really seems to help.  Kurt told me he's about 50% on this one; about half the time they leak the first time, and they have to be redone.

A couple years ago when I was assembly the dyno mule to test my intake adapters, I had to do this three times and still had a minor drip after the test.  I was pretty tired of tearing apart the #5 cap at that point, scraping away all the sealer and reinstalling, etc., so the last time I did it I smeared TA-31 on the outside of the rear main seal.  The way the seal fits in the groove in the block and the cap, I don't think oil should be getting around it, but I thought it may be possible so I put some sealer on the outside of the seal and tried one more time.  No leaks that time.  I don't know if this was due to a sub standard seal, or a block or cap that had the groove machined a little big, or what, but for whatever reason sealer on the back side of the seal solved the problem.  I imagine other people may do this on a regular basis, but I never did up to that time.  Now I do it on every engine...

[C6AE]

Ok, I have seen this once...
A 427 crankshaft from a CC rotation marine engine has the wee hash marks facing the wrong direction for an automotive engine. The only thing for it was to polish them right off the crank...