Is this an overcrushed rear seal?

A few weeks into running my new 545 it started weeping at the rear of the engine. I knew it wasn't the rear seal at the crank because the inside of the bellhousing was clean and assumed it was the pan but it turns out oil was weeping past the outside of the seal,alot. The rubber sealing surface that seats in the cap/block is almost all gone and the metal support rail inside seal is exposed. Curious what caused this to avoid round 2 after a repair. I'm trying to attach a couple pics.

One more.

This is the half out of the block and the cap half had the same symptom but only about a 1/3 of the way. The other 2/3 had sealed correctly and wasn't chewed.

A friend with a Boss 302 has a similar problem. When one side is flush the other side sticks UP almost .200! The cap will not even fully seat under full torque.

I'm assuming that's the issue. Unfortunately,I didn't get enlightened to the problem of oversized seals prior to assembly. First time I read about crush was after I had the progressive weep and did some research. Oh well,nothing like first hand experience to sharpen you up.

Is that a "high performance" fel-pro?

I think it's the Viton but I don't recall. Is the Viton blue? I'll be using a Viton this go round regardless,assuming it's available here.

Always apply a thin film of black silicone to the back of the seal. Be sure to rotate the seal so the parting lines dont match up with the main caps parting lines.

I would like to say I have always custom fit mine, but it took a couple before I wised up. Push it in hard with your thumb till one end is flush and mark the other flush with the block or cap. Grind with a bench grinder (slowly, as not to melt the vitron) down to the line. Grind both halves and seal with silicone. I have seen them as much as 1/8" too long.

That's interesting you grind flush. There was a figure here a while ago to leave seal protruding.
Not knocking your suggestion at all but any info is good .
The one piece seals from Kaase would be interesting to try

Keep the end square to the block or cap.  Also only grind one end, it will seal better to the other halves' unground end.   I usually leave about .025 pre side.  Not familiar with Kasse's, but put a couple in BBC's that were one piece with a split (to get over the flange) and an O-ring around the OD.  They were in pulling trucks and we were looking for something tougher that the clutch dust wouldn't eat up as bad.   Don't remember the brand.

FDB wrote:Keep the end square to the block or cap.  Also only grind one end, it will seal better to the other halves' unground end.   I usually leave about .025 pre side.  Not familiar with Kasse's, but put a couple in BBC's that were one piece with a split (to get over the flange) and an O-ring around the OD.  They were in pulling trucks and we were looking for something tougher that the clutch dust wouldn't eat up as bad.   Don't remember the brand.

Yep ... only grind the side other than where the tiny lip sticks up above the flat; proud about .010" when inserted.

This becomes a big issue with blocks that have been line bored or honed.

Thanks for the extra detail. Hopefully this will be a rear seal for life.

Just to clarify,.010 proud on each half so .020 crush total.

Previous post reads poorly. It was a question. To clarify,am I shooting for .020 total crush (.010 on each haif)? Thanks.

the tree man wrote:Previous post reads poorly. It was a question. To clarify,am I shooting for .020 total crush (.010 on each haif)? Thanks.

That is what I personally try to obtain ... then offset the seal on installation a bit with one side being 1/4" proud so, the split does not line-up directly with the Block/Main Cap split.

Checked my new Fel-Pro 2948 Viton seal. Yikes,.090 out of both block and cap,.180 total! Looks like I found my issue.

Chasing my tail now. Trimmed the new seal accordingly and installed it. Felt confident on the repair and "almost" passed on verifying the fix. Should know better. I overfilled the engine and tilted it backward to swamp the rear seal. Left it overnight and dang if it didn't still leak,about 70% less but still slobbering plenty. Pulled it all apart again and trashed my new pan gasket in the process. Lower half of the seal was tight and dry when I removed it from the cap but I could see oil was still weeping past the upper half in the block and drooling down the outside of the cap. I can just see past the crank half way in the machined groove for the seal up in the block there is what appears to be a series of very slight stutter/chatter marks running laterally across the surface where the seal seats. Not sure if that's caused by the metal ring on the over crushed seal working to find room or if the block was machined like that in '72. Slathered some Ultra Black in there and reinstalled the works. I'll refill the engine tomorrow and see what happens. This kind of garbage depresses me.

Goop fixed it. Hopefully for a long time.