Crank shaft galling

Discussion in 'PSI Superchargers Tech Questions' started by Andy C, Dec 27, 2015.

  1. Andy C

    Andy C Member

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    BBC with RCD hub 2 keys, bryant crank.
    I had the crank all galled up this season... had to cut the hub in half to remove... this season was the worst

    What is good to use during assembly to stop/limit galling.
     
    #1
    Andy C, Dec 27, 2015
  2. Bob69

    Bob69 Member

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    Firstly make sure your snout and hub are clean and not galled up already.
    Are you using a 3/4 snout bolt or smaller. 3/4 is best use a RCD bolt or ARP similar quality.
    Solvent clean snout and hub and thread of fastener.
    Use Loctite super stud holder.
    Install hub using a stud to pull on, do not hammer on.
    clean out thread inside snout. Use Loctite on thread of fastener. Tighten up really "f eee nn" tight.
    Even with a screw blower running 125 over it don't come loose.
    You don't need luck just patience.
    Bob
     
    #2
    Bob69, Dec 27, 2015
  3. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    First question is are you using a steel or Ti hub?

    Second question is what are you using for a bolt/washer? Torque on Crank bolt?

    Third question - are you using any kind of pulley support?
     
    #3
    Will Hanna, Dec 27, 2015
  4. tad1011

    tad1011 Member

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    We put never- sieze on crank, red Loctite on bolt and torque to 300 ft. pounds. Screw blown deal @ 128 over. Never any guiling issues.
     
    #4
    tad1011, Dec 27, 2015
    TADHemiracer likes this.
  5. TADHemiracer

    TADHemiracer Member

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    First off, you may need to send the crank off the have the snout re-machined to it's original OD. Secondly, you may need a new crank hub. Thirdly, after getting good parts back, I would use motor oil on the snout to hub install, use a stud to pull it on with. In my case, I fabricated a torque arm that mounts to the crank hub and is long enough to land on the chassis tube so I could put a 24" breakover bar on the crank bolt and stand my 200 pound self on it to torque the crank bolt to 400#. You can not torque the crank bolt on the engine stand very well. Just torque it after the motor is in the chassis. Good part tolerances and proper torque is necessary. You are not going to break the 3/4" grade eight bolt at 400# torque. As Will mentioned above, use a proper thick spacer washer to provide sufficient support outwardly to the crank hub.
    Not rocket science, just tried and true experiences. Just saying.
     
    #5
    TADHemiracer, Dec 27, 2015
  6. Andy C

    Andy C Member

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    RCD BBC crank support, long hub made from steal... 3/4 bolt... all RCD parts... screw 120over, spinning 9600 rpm. RCD key material, (the key is fine)

    so, what you are saying, I need to pull on... what lube should i use???

    the crank is being fixed...
     
    #6
    Andy C, Dec 27, 2015
  7. TOL

    TOL Active Member

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    Rear flange crank pulley or mid flange crank pulley? What are you torqueing the bolt to? Seems kind of an odd occurrence if you have a crank support in place. Are you having detonation issues with your tuneup? Do you leave on a 2-step?
     
    #7
    TOL, Dec 28, 2015
  8. sunday driver

    sunday driver driver

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    Best stuff we found to stop the transfer of the metal to the hub, it is black glue, you put it on the frost plug on a regular engine.
     
    #8
    sunday driver, Dec 28, 2015
  9. secondwindracing

    secondwindracing top alcohol

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    use a cat 9 bolt..Dave
     
    #9
    secondwindracing, Dec 28, 2015
  10. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    Well I think the first thing you need to get is a Titanium hub. This will help with the galling issue.

    It is important that you get a minimum grade 8 bolt if not a grade 9 bolt if you are going to go above 250 lbs of torque. Some of the RCD bolts are not designed for this type of torque and will either be too close to yield to provide proper clamping or break. Automan makes a grade 9 washer to help absorb this type of torque without galling on the bolt head.

    PSI made a conical pulley support that helps spread the load out. Wizards sells a similar version now.

    I have heard everything from red loctite to other exotic pre lubes on the crank. With a ti hub and a good crank bolt at 300+, I have had no problems with a good anti-seize. I recommend the Bostick Nickel anti-seize.
     
    #10
    Will Hanna, Dec 29, 2015

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