BBC Crank Support Issue

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by BEDNAR1320, Dec 19, 2017.

  1. BEDNAR1320

    BEDNAR1320 Member

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    I run an RCD crank support and the problem I'm having is with the sealed bearing. After only a few passes the seals come out of the bearing and it slings grease everywhere. I've tried two different bearings and they both did the same thing. It's not out of alignment with the crank and the snout that goes into the bearing runs true.
    Anyone else have this issue?
     
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  2. Comax Racing

    Comax Racing Member

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    Have you tried a zz bearing with the metal seals. They are alot tighter then the plastic seals.

    Corey
     
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  3. BEDNAR1320

    BEDNAR1320 Member

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    No I haven't, got a part number?
     
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  4. td3829mk

    td3829mk Member

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    Brian, I'm sure it doesn't help when your crank is bouncing all over the place....sorry I had to. Lol.

    Mike
     
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  5. BEDNAR1320

    BEDNAR1320 Member

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    LOL!
     
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  6. Comax Racing

    Comax Racing Member

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    Part number is easy. Just add "zz" suffix to what ever your bearing number is and that will denote the metal seals. They are made for high heat applications and the seals are crimped in. Hope they will stay put for you.

    Corey
     
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  7. BEDNAR1320

    BEDNAR1320 Member

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    Thanks, Corey!
     
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  8. MaineAlkyFan

    MaineAlkyFan Active Member

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    The ZZ bearings are not 'sealed' but shielded. The metal shields are crimped to the outer race and have a small air gap around the inner race. They do not have a rubber contact web seal like the R suffix bearings. The ZZ seals will definitely stay in, but they might still sling grease out of the air gap.

    I don't know the bearing size, but if it is available in an agricultural bearing, it will have both the crimped metal seal and the web contact rubber seal.

    Chris Saulnier - Team Tigges
    Mechanic Falls, Maine
     
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  9. BEDNAR1320

    BEDNAR1320 Member

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    Thanks for the info guys. The bearing number is 6210.
    According to Mc Master Carr, the precision, hi speed sealed bearing is rated for 4800rpm, the sheilded bearing is rated for 8000rpm. The sealed bearing is what I have been using, the sheilded bearing has the metal "seals", but like Chris has mentioned, they are not completely sealed.

    Guess I'll try one and see what happens.
     
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  10. BEDNAR1320

    BEDNAR1320 Member

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    After more online research I have found an SKF bearing PN 6210ZZC3 that is rated for 10,000rpm.
     
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  11. Comax Racing

    Comax Racing Member

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    I have used these on various pieces of industrial equipment and I ave never seen a metal shielded bearing sling grease. At worst they drip a bit when they are hot. Imho they will be ok.

    Corey
     
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  12. BEDNAR1320

    BEDNAR1320 Member

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    #12
    Last edited: Dec 20, 2017
  13. MaineAlkyFan

    MaineAlkyFan Active Member

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    As far as the bearing itself (balls & races) are concerned they will both support the 8000rpm rating. The lower rating for the sealed version is to protect seal integrity. They are also speed rated relative to load over time, so there is quite a bit of safety factor seeing that in this application the constant run time is so short. If you want to get all teched out about it there is a bunch (way too much... LOL) of info in the SKF design guide.

    SKF Rolling Bearing Design Guide

    Chris Saulnier - Team Tigges
    Mechanic Falls, Maine
     
    #13

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