Anyone seen these before on the Harmonic Balancer?

[Bossgold]

I went to pick up my engine today with good news after everything checked out. Was looking through the parts and ran across this Original felt gasket on the back of my 340 T/A Harmonic Balancer. Engine builder called it a diaper and said that these were Original to the small block 340 T/A's. He said the factory put these on in case of small oil leaks. It was on the back in the well area of the balancer and filled the area up. Never saw one of these and not sure what it is actually called.... any input or even if you know what these are would help...thanks

[1 Wild R/T]

Seen plenty, they come in the FelPro O/H gasket set I probably have a few down at my shop...

[Bossgold]

I was told they are to stop leaks from the crank seal...is that true

[1 Wild R/T]

Well not really stop but slow it down maybe...

[Chryco Psycho]

It might absorb some oil instead of dripping but not that much , I thought it was more of a dust ctacher in dirty environments

[Bossgold]

does anyone still use them?  Does it make more Original to put one on or no one cares?

[Chryco Psycho]

I never install them & I have never removed one on a teardown , I believe they were for industrial engines ,so I would leave it out