Rear main?

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73' mach 1

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Just when everything was awesome...

Well here we go again. I've posted in the past and found my oil pan was infact leaking from the rear bolts against the bell. Sealed that up the best I could and thought I had it. Decided to take a peak inside the bell with my cheap camera scope and found this..

Don't know how boned I am here but I can't see it leaking from the bearing so I guess it's the rear main. 

Crankcase still needs to be checked but unless I have the wrong spring PCV valve I can't see it as a problem. I have a breather on the otherside. 

If all is lost I'm just going to drive it until the clutch starts to slip...

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Don C

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You might try Lucas Engine Oil Stop Leak, that's the only one I would trust. Some of those stop leak products can damage seals by over-swelling them. So far the Lucas products I have used have been as advertised, but I haven't used the oil stop leak. 

 

73' mach 1

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You might try Lucas Engine Oil Stop Leak, that's the only one I would trust. Some of those stop leak products can damage seals by over-swelling them. So far the Lucas products I have used have been as advertised, but I haven't used the oil stop leak. 
As far as these things go how bad does it look? Is there anything better I could do for crankcase ventilation? Might not even be a problem to begin with. Guess there is really know way of telling how long my clutch has huh?

 

c9zx

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If it is an aftermarket crank, it likely has the flywheel bolt holes drilled through(not blind holes). You have to use thread sealer on the flywheel bolts or oil leaks around the threads. Chuck

 
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This would be a long shot but could be the reason. Boats that have two drive engines have one engine running one way and the other turns opposite to make the boat act right and go straight. When I was at the tech school a student built an engine for his car. Ground crank, new bearings, seals, pistons full rebuilt. It leaked oil. So the teacher had him tear down and put another rear seal in. Leaked just as bad. So they tore down again and the instructor noticed the hash marks on the seal surface were angled the wrong way. Was a crank for a boat motor that ran opposite direction. Had to find a normal car crank no leaks.

 

73' mach 1

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It's been a long 4.5 years putting this together. She did awesome on the dyno and runs awesome on the street. Think I'm just going to drive it until she gives me a reason not to. If she wants to mark her territory everywhere she goes...so be it.

 

mjlan

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how bad is it leaking?

 

Don C

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What kind of rear main seal was put in? If it is a 2-piece rubber/Viton/neoprene type seal were the locating pins for the rope style seals removed before the new seal was put in? Was a sealer used between the block and rear main cap?

 
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Galucha

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Man I've been there. Definitely want to be sure you removed the locating pin as Don mentioned. Not getting leaks with 2 piece seals is kind of a dark magic. You gotta pull every trick you can, and even then there's a chance it won't seal up - or just start leaking after 1,000 miles. Here's my list for doing them, and it usually works pretty consistently.

  • Spend the money and buy a good quality seal. i.e. Fel-Pro viton/silicone or Cometic
  • Its better to remove the crank when redoing a seal. There are tools out there (like a sneaky pete) that will let you do it without removing the crank, but you're increasing your chances of another leak
  • Offset the seal halves by about 3/8" from the block surface
  • Skim on a small amount of silicone on the seal ends where they butt against each other.
  • Use a small amount of silicone between the cap and block



If you can get your hands on some Motorcraft TA-31 gray silicone, go ahead and do that. Its the stuff they use at the Ford dealerships. You should just be able to go to their parts counter and ask for it. Works way way better than Permatex in my experience.

 

73' mach 1

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You might try Lucas Engine Oil Stop Leak, that's the only one I would trust. Some of those stop leak products can damage seals by over-swelling them. So far the Lucas products I have used have been as advertised, but I haven't used the oil stop leak. 
Unfortunately Don I don't have that information. My builder seems to have disappeared. Knowing that things would have to come apart after just going together isn't going to happen. This will have to get addressed the next time things come apart.

 
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