Curing?? a rear main leak in a 215

Discussion in 'Small Block Tech' started by jon-p, Jan 15, 2018.

  1. jon-p

    jon-p Little olds

    Twice I installed the 2-piece seals that are sold by aluminum V8 gurus. After about 10 minutes of run time they started dripping oil. Then I installed the Fel Pro version of the rope seal and it immediately dripped oil but not as bad as the rubber seals. So after a year and 3 engine pulls, I thought that the only solution was to machine the rear of the block for a Rover 1-piece seal, but failing to find a machinist with experience to do this, I latched on to an old solution to the problem. MG V8 owners claim that the new rope seals just don't work as well as the original asbestos ropes, and engine builders claim that the new modern non-asbestos ropes "burn". Yep, when I removed the Fel Pro rope seal, the journal was brown just as if it had burned.
    Possibly the answer was found in the back of an old auto parts store in a small town in South Carolina. There a friend found several very old rope seals from the past. He tested these seals with a torch and they smoked but did not catch fire. We assume that they are asbestos.
    I installed a likely looking pair and guess what. After 2 hours of running. not one drop of oil. Every time I run the motor, I peek beneath the car fearing the dreaded oil drops. So far, so good.
     
    Dadrider likes this.
  2. 8ad-f85

    8ad-f85 Well-Known Member

    It's a fairly common problem with rope seal engines.
    I'm sorry that nobody alerted you to the issue before you went through so much.
    Glad to see it running again.
     
  3. philbquick

    philbquick Founders Club Member

    Glad you finally have resolution to that problem. question: When you installed the 2 piece seals did you tilt it slightly? Put the upper seal in and push it around so it sticks out about 3/8" and put the other side in the cap complementary to the upper. I did this in my GN and it hasn't leaked a drop in 12 years.
     
  4. 8ad-f85

    8ad-f85 Well-Known Member

    OP should link from his other post(s) on this, there were many of the questions people are going to ask already answered.
    The problem was more suggestive of a non concentric seal groove requiring corrective machining, although not proven yet.
     
  5. Jim Blackwood

    Jim Blackwood Well-Known Member

    Interestingly enough, with a rope seal it wouldn't matter if the seal groove was cut off center. The crank journal runs true and the rope will fill the gap.

    Finding the old asbestos rope seals is going to be a pretty good trick though.

    Jim
     
  6. 8ad-f85

    8ad-f85 Well-Known Member

    That's the reason many OEM blocks don't hold any tolerance on that feature or have a call out on the print.
     

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