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FE Power Forums => FE Technical Forum => Topic started by: dj work on August 21, 2023, 07:34:11 PM

Title: Rough 1 piece rear main seal ?
Post by: dj work on August 21, 2023, 07:34:11 PM
I'm gonna pull my 482 out of my 66 Fairlane this winter to fix a few oil leaks. It was built back around 2005.It has a scat stroker crank and I have always had a rear main seal leak. I understand that these early cranks didn't come with the oil grooves cut in at the rear of the crank. I read about these 1 piece rear main seals. Has anyone here tried them? I'd like to hear any info about these seals. Also what is a good oil pan gasket for my canton t-shaped oil pan? Thanks
Title: Re: Rough 1 piece rear main seal ?
Post by: jmlay on August 21, 2023, 08:52:10 PM
https://fepower.net/simplemachinesforum/index.php?topic=11542.msg127324#msg127324
Title: Re: Rough 1 piece rear main seal ?
Post by: fekbmax on August 21, 2023, 09:27:50 PM
Milodon #40450 oil pan gasket. A little pricey but hard to beat. 
Title: Re: Rough 1 piece rear main seal ?
Post by: blykins on August 22, 2023, 05:52:30 AM
I'm gonna pull my 482 out of my 66 Fairlane this winter to fix a few oil leaks. It was built back around 2005.It has a scat stroker crank and I have always had a rear main seal leak. I understand that these early cranks didn't come with the oil grooves cut in at the rear of the crank. I read about these 1 piece rear main seals. Has anyone here tried them? I'd like to hear any info about these seals. Also what is a good oil pan gasket for my canton t-shaped oil pan? Thanks

I use plain old Felpro cork gaskets.  They seal very well, will hold up to 15 inches of vacuum with a dry sump pump. 

I'd also skip the 1-piece rear main seal.  You have to cut them and walk them around the crankshaft.  By the time you do all of that, you're not really gaining any usefulness.
Title: Re: Rough 1 piece rear main seal ?
Post by: Rory428 on August 22, 2023, 11:28:20 AM
I have never used a 1 piece FE rear main seal, but to me, the thought of getting a 1 piece seal, having to cut it through on 1 spot, then bend and twist it around to get past the flywheel flange, and then try to straighten it out again, and hope it doesn`t leak where it was cut, seems like more of a risk than I am wiling to gamble on. And to me, it seems that the rear cap side seals, and between the cap and the block, are more of an issue to seal up, than the 2 piece rubber crank seals anyhow.
Title: Re: Rough 1 piece rear main seal ?
Post by: My427stang on August 22, 2023, 06:56:18 PM
I like Mahle/Clevite rear mains. JV707P

I don't think I like a cut 1 piece, not because I ever used one, but I am not sure how you would get the proper crush to seal where you cut. I suppose if they have a strong core and you could cut carefully they would work

Also agree with Brent on cork pan gaskets, anytime I try a fancy one, all it did was cost more money.  Cork is easy-breezy and cheap
Title: Re: Rough 1 piece rear main seal ?
Post by: Tunnelwedge on August 23, 2023, 04:33:14 AM
The Canton pan may have a tray/screen with it so you need two gaskets.
Remember to change the oil pump pick up gasket well you are in there.
It's the glue that seals it. I like Permatex Ultra Black, but really any colour will work.
 
Title: Re: Rough 1 piece rear main seal ?
Post by: dj work on August 23, 2023, 11:16:59 PM
I want to thank you all for your replies. There's lots of info here like always. Thanks
Title: Re: Rough 1 piece rear main seal ?
Post by: Cyclone03 on August 27, 2023, 09:17:21 AM
Sorry off topic but maybe relevant.
This summer I assembled a 351c using the complete FelPro set. The rear main seal protruded 1/4” above the block surface ,one side flush even with the crank in place.
I thought that excessive so I trimmed one end of each half to a more normal .050” each half with the crank in place.
Leaked pre oiling on engine stand.
I got another new FelPro seal,same dimension but installed as is,leak again while pre oiling!
Spent $30 on a Cometic ,about .050” protrusion, no leaks.

Discussing this with an engine builder friend his thought was trimming the seal caused a leak due to poor crush,then the untrimmed leaked because it held the cap from mating with the block. The condition of the mangled parting line of the seal showed that could be a problem.

So we now can add gaskets and seals to things we have to check prior to install.
Title: Re: Rough 1 piece rear main seal ?
Post by: blykins on August 28, 2023, 04:45:48 AM
Sorry off topic but maybe relevant.
This summer I assembled a 351c using the complete FelPro set. The rear main seal protruded 1/4” above the block surface ,one side flush even with the crank in place.
I thought that excessive so I trimmed one end of each half to a more normal .050” each half with the crank in place.
Leaked pre oiling on engine stand.
I got another new FelPro seal,same dimension but installed as is,leak again while pre oiling!
Spent $30 on a Cometic ,about .050” protrusion, no leaks.

Discussing this with an engine builder friend his thought was trimming the seal caused a leak due to poor crush,then the untrimmed leaked because it held the cap from mating with the block. The condition of the mangled parting line of the seal showed that could be a problem.

So we now can add gaskets and seals to things we have to check prior to install.

I check the rear seal bore with the crankshaft out of the block.  I also stagger the seals and clock them.  Putting them in without the crank and torquing the cap down will let you get a good bird's eye view of how everything looks:  if the cap sits down flush, if the seal surface is nice and round, etc.  There's a fine line on if it will survive if the seal end protrudes a little bit.  You need a little crush, but not too much.