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Discussion Starter · #1 · (Edited)
Ok guys, I searched before posting, found some things, but still came up short!! I am having issues with the rear main seal on my 521. I am running a 70' 460 block, Scatt crank, and all the goodies to go with it. I cannot get the rear main seal to NOT leak/pour oil out of it. It has to be the seal because the 2 oil galley plugs and the cam plug are sealed up tight with no signs of oil leaking. The block and rear cap have been checked by two different machine shops, the crank has been sent back to Scatt and checked out to be true and correct, no knurling/smooth. I am running a PCV system on the RH valve cover and an open breather on the LH valve cover so I should not be building any pressures. And yes, I am installing the seal correctly and dabbing a small amount of silicon where needed!! The oil pan is tightly sealed in the rear as well. Can you run a rope seal with the Scatt cranks??? I am totally out of things to try and looking for different opinions. If someone could shoot some my way, I would be very thankful and excited to try them!!
One thing I have to ask. I was asked what oil pressure I am running. I told that individual that it was around 65 to 70 running 3K RPM down the highway. He thought that I was running way to much pressure and that it was blowing passed the seal. I have to beg the differ, but thought that I would throw it out in the open!! Have a great evening and I hope to hear something back soon!! Thanks again!!

Waycooljr
 

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Call jegs , and order a one piece pan gasket, will stop your problem, it is made by milidon, works great for me, and is reusable.
 

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Discussion Starter · #3 ·
I got that gasket from Milodon, p/n;41005. You are correct in the sealing, that gasket is awesome! But that is not gonna be the fix here. Oil is still showing up somewhere!
 

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I had the same problem when I first put the 588 in my dragster this spring. Scat crank, A460 block. It was a steady drip after the engine got warmed up. The cure was a small bead of silicone in the groove in the cap where the seal sits.

I had always installed the seals dry before with just a dab of silicone on the seal ends and where the main cap meets the block. That wasn't good enough this time. The silicone in the groove sealed it up.
 

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Waycooljr

When you figure it out - please let me know because I have had my engine out 6 or 7 times, I have replaced the rear main seal 4 times. I tried the silcone in the groove and it didn't help/solve the problem. I even took it to a good machine shop and had them check everything and install the crank and it still leaks big time. I gave up and built a catch tray with an oil absorbent pad (automotive depends) so that it doesn't run on the ground.
 

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Discussion Starter · #6 ·
Well, I have always had excellent luck dabbing the seal in oil and rolling it in on the top half, careful not to peal any rubber off of the seal too. Small amt of silicon on seal ends and good to go. Like CSTMWGN, I too have had engine out 6 times, to my Dad's shop, 2 different machine shops, friends that build High performance engines/drag engines. No one can figure it out. I will try the silicon in the groove thing and see where that gets me. Might be tricky with the engine / crank still in the truck, but I'll get it done somehow. I can't keep yanking this engine out of my fully restored truck. New bolt heads are starting to show wear, and no matter how careful you are, the paint is showing signs of so many removals. This is definately not making me happy!!!
Thank-you all for your input. I am still open for options as I have no parts yet!!! I hate waiting for parts!!!! Thanks again!!
 

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Just to go out on a limb here, are you installing the seal offset a little?

My manual says to turn the seal so it sticks up about 3/8 - 1/2" on one side. This way the seal parting line does not line up with the cap parting line (if that made any sense!).

Good luck stopping the "undercoat while you drive system"! It sure can make a mess.

Bill
 

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Just to go out on a limb here, are you installing the seal offset a little?

My manual says to turn the seal so it sticks up about 3/8 - 1/2" on one side. This way the seal parting line does not line up with the cap parting line (if that made any sense!).

Good luck stopping the "undercoat while you drive system"! It sure can make a mess.

Bill
x2:D, aswell as rtv on back of seal like Dave said, very thin:D
 

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I had rear seal leaks too and I had been told the same thing about too much oil pressure, but when I took the bearing cap off I looked at the way it was machined I didn't think that could be the problem. On my engine there is a gap between the rear manin bearing and the seal. At the bottom of the bearing cap there is a long slot that lets oil drain back to the pan. Judging from the size of that slot I think it would take a LOT of oil coming out of the back side of the bearing to build any pressure at all to blow past the seal. Your bearing cap may be different than mine and I haven't been around this engine very long so I could be wrong (again!). But I am married so I am used to being wrong.
 

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Just to go out on a limb here, are you installing the seal offset a little?

My manual says to turn the seal so it sticks up about 3/8 - 1/2" on one side. This way the seal parting line does not line up with the cap parting line (if that made any sense!).

Good luck stopping the "undercoat while you drive system"! It sure can make a mess.

Bill
Bill, you beat me too it. I always offset the seal and have never ever had even a drip. Still dab a little silicone around the corners. Permatex makes a product that we use at work on industrial pumps thats called GASKET ELiMINATOR.I use it in place of 3rd member gaskets and it works great.It stays plyable. I would smear a bit of it on the seal when you install it.
Another thing,are you sure it's coming from around the crank? Make sure you put some sealer around the top left bellhousing bolt when you put it in through the china wall, they will sometimes leak around the threads.
 

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Bill, you beat me too it. I always offset the seal and have never ever had even a drip. Still dab a little silicone around the corners. Permatex makes a product that we use at work on industrial pumps thats called GASKET ELiMINATOR.I use it in place of 3rd member gaskets and it works great.It stays plyable. I would smear a bit of it on the seal when you install it.
Another thing,are you sure it's coming from around the crank? Make sure you put some sealer around the top left bellhousing bolt when you put it in through the china wall, they will sometimes leak around the threads.
I'm going to have to look for that Permatex stuff, sounds pretty good. Thanks for the lead!!

Bill
 

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Discussion Starter · #12 ·
Ya, I have been offsetting the seal about a half an inch or so with the silicon. I don't have sealer on the LH upper trans bolt, but have teflon taped it. I will try sealer there too. Does it hurt to offset the seal with the two halfs on the top and bottom of the crank, then slide the main cap over them both? That way your split ends would be totally covered by the block and cap! Thanks all for the great ideas!! I overnighted stuff from Summit so hopefully I can get the truck up and running for the community parade on the 4th!!!!
 

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Ya, I have been offsetting the seal about a half an inch or so with the silicon. I don't have sealer on the LH upper trans bolt, but have teflon taped it. I will try sealer there too. Does it hurt to offset the seal with the two halfs on the top and bottom of the crank, then slide the main cap over them both? That way your split ends would be totally covered by the block and cap! Thanks all for the great ideas!! I overnighted stuff from Summit so hopefully I can get the truck up and running for the community parade on the 4th!!!!
Thats what I have always done:)
 

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Discussion Starter · #15 ·
Also take a look at the knurling on the crank sealing surface. They have been known to be done in the wrong direction and will force oil past the seal.
Doug, I have heard something about that. Turned out, if I remember correctly, that was the marine cranks that had the knurling the opposite direction to feed the seal oil, instead of take excess oil away? On this crank, the seal area looks exactly like the bearing surface, very smooth.
 

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I was wrong on the maker of Gasket Eliminator. It's made by LOCTITE.
Sorry bout that:)
 

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Discussion Starter · #17 ·
I was wrong on the maker of Gasket Eliminator. It's made by LOCTITE.
Sorry bout that:)
I may have some of this stuff hangin around somewhere!!!!! I may give that a try!
 

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Are you POSITIVE its the rear main seal giving you hell? I ask this because of 2 different oil drip issues I have fought. SBC wouldn't do it in the garage no matter how I revved it. Took the car around the block and stood on it, pulled into the garage... cup of oil on the cement. Looked like rear main- turned out to be a loose oil restrictor in the rear of the block by the cam plug.

My current 545BBF had a drip that would gravitate to the rear seal area before it would fall on the garage floor. Ended up being the rubber gromets for the crank case evac breathers seeping. It would trickle down the valve cover almost invisible, then the rear side of the block and follow it inwards to the rear.

FWIW, just might want to try other culprits.
 

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Discussion Starter · #19 ·
Well, I know for a fact the it is not the rear cam plug or the oil port plugs in the rear of the block. They are installed with sealer, then sealed around them. Plus, if this amount of oil was leaking from that area, the flexplate would be wet, which it isn't. I have a 2" body lift so I can see the rear of the engine: valve covers, intake, etc. and everything is dry from up there. I have used enough silicon on the oil pan that I could be a rich man if I owned stock in it!!!! I am going to install a Fel-Pro viton seal #2948 in it this time. They claim the viton seal is a bit more for the sever duty race engines I guess? I am gonna try it though and seal the whole dang thing in there!! If that doesn't work, I guess it will have to come completely out for the 6th time since restoration is complete. YUCK!!!
 

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The only thing that viton seal will do is remove $30 from your wallet - been there done that (TWICE). The FRPP HiPo seal is the same deal as the FelPro but cheaper.
 
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