Is this an overcrushed rear seal?
+3
norm
gt350hr
the tree man
7 posters
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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.
the tree man- Posts : 124
Join date : 2019-10-07
Age : 64
Location : Winnipeg,Canada
the tree man- Posts : 124
Join date : 2019-10-07
Age : 64
Location : Winnipeg,Canada
Re: Is this an overcrushed rear seal?
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.
the tree man- Posts : 124
Join date : 2019-10-07
Age : 64
Location : Winnipeg,Canada
Re: Is this an overcrushed rear seal?
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.
gt350hr- Posts : 662
Join date : 2014-08-20
Location : Anaheim , CA
Re: Is this an overcrushed rear seal?
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.
the tree man- Posts : 124
Join date : 2019-10-07
Age : 64
Location : Winnipeg,Canada
Re: Is this an overcrushed rear seal?
Is that a "high performance" fel-pro?
norm- Posts : 261
Join date : 2009-08-06
Location : michigan
Re: Is this an overcrushed rear seal?
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.
the tree man- Posts : 124
Join date : 2019-10-07
Age : 64
Location : Winnipeg,Canada
Re: Is this an overcrushed rear seal?
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.
stanger68- Posts : 502
Join date : 2015-12-05
Location : Birmingham, Al
Yes, over crushed
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.
FDB- Posts : 9
Join date : 2011-07-05
Gregaust likes this post
Re: Is this an overcrushed rear seal?
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
Not knocking your suggestion at all but any info is good .
The one piece seals from Kaase would be interesting to try
Gregaust- Posts : 626
Join date : 2009-08-09
Keep square
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- Posts : 9
Join date : 2011-07-05
Gregaust likes this post
Re: Is this an overcrushed rear seal?
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.
Gregaust and FDB like this post
Re: Is this an overcrushed rear seal?
Thanks for the extra detail. Hopefully this will be a rear seal for life.
the tree man- Posts : 124
Join date : 2019-10-07
Age : 64
Location : Winnipeg,Canada
Re: Is this an overcrushed rear seal?
Just to clarify,.010 proud on each half so .020 crush total.
the tree man- Posts : 124
Join date : 2019-10-07
Age : 64
Location : Winnipeg,Canada
Re: Is this an overcrushed rear seal?
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- Posts : 124
Join date : 2019-10-07
Age : 64
Location : Winnipeg,Canada
Re: Is this an overcrushed rear seal?
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.
Mike R likes this post
Re: Is this an overcrushed rear seal?
Checked my new Fel-Pro 2948 Viton seal. Yikes,.090 out of both block and cap,.180 total! Looks like I found my issue.
the tree man- Posts : 124
Join date : 2019-10-07
Age : 64
Location : Winnipeg,Canada
Gregaust likes this post
Re: Is this an overcrushed rear seal?
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.
the tree man- Posts : 124
Join date : 2019-10-07
Age : 64
Location : Winnipeg,Canada
Re: Is this an overcrushed rear seal?
Goop fixed it. Hopefully for a long time.
the tree man- Posts : 124
Join date : 2019-10-07
Age : 64
Location : Winnipeg,Canada
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