Causes Of/How To Prevent Crank Hub Microwelding?

Discussion in 'InsideTopAlcohol.com Tech Questions' started by BEDNAR1320, Jan 26, 2019.

  1. BEDNAR1320

    BEDNAR1320 Member

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    Now that I got my stuck crank hub off I found that it Microwelded itself to the crank snout.

    That raises the question of how to prevent it from happening again. Last time I took it off it was fine. Switched to a Bryant crank from a forged and added a crank support. After that it was Microwelded. No other changes to the engine. Is this common with billet cranks? Could the crank support have something to do with it?

    Thoughts?
     
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  2. BEDNAR1320

    BEDNAR1320 Member

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    It pressed on tightly and I used never sieze when I installed it.
     
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  3. TOL

    TOL Active Member

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    Bearing support in front of, or behind, crank pulley?.....
     
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  4. BEDNAR1320

    BEDNAR1320 Member

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    In front
     
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  5. rb0804

    rb0804 Active Member

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    Never seize and get you a good crank bolt. Torque to 300 ft. Lbs. not 275, 325, etc....300. This came from an old top fuel guy I hang with. When we started torquing them is when we stopped having issues. You can also go with dissimilar metals, enter the titanium hub.

    Is your tuneup different than before the crank support? Bigger blower, different fuel system etc.? I’ve also found if you keep it off the limiter or away from detonation it seems to make the disassembly process a good bit easier. One of the worse ones I’ve had stuck had an outboard support on it, but that was before I was torquing. I wonder if the outboard support makes the micro welding worse? Ever notice how much that degree ring wonders around?
     
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  6. BEDNAR1320

    BEDNAR1320 Member

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    Same tune up, blower, etc. The only time it hits the limiter is for less than a second before launch, same as before I had this issue. No detonation, bearings look fine.

    The only differences are the billet crank and crank support.
     
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  7. BEDNAR1320

    BEDNAR1320 Member

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    In case you missed it on the other thread I started, I had to cut a slot and split the hub to get it off.
     
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  8. Mike Canter

    Mike Canter Top Dragster
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    To micro weld means there is movement in the hub. I would get a new RCD crank bolt and put the 280 to 300 ft lbs of torque on it. In the future you should switch to a splined crank and hub.
     
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    lucky devil likes this.
  9. tc1216

    tc1216 Member

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    Switched from std. anti-seize, to a nickel based anti- seize, never had a hub seize ever again.
     
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  10. drew556

    drew556 Member

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    Have to be careful of what anti seize you use and torque the bolt as mike and others said had a titanium hub and didn’t tourqe the bolt and it welded to crank and red makes a bad ass puller that picks up all 6 bolts that helps a lot when they are stuck we made our own 6 bolt puller works good but splined is the way to go
     
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  11. drew556

    drew556 Member

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    Rcd not red makes the puller got to love auto correct
     
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  12. BEDNAR1320

    BEDNAR1320 Member

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    I saw that puller rcd makes looks like a pretty nice piece
     
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  13. REEHL EQUIPMENT

    REEHL EQUIPMENT Authorized Merchant

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    Make sure you are using heat treated keystock, not soft stuff.
     
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  14. drew556

    drew556 Member

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    Yep we learned that the hard way to cost us a first round win at the elite 50k race went on two step let go of the button and sheared the keys car dies and all we could do is watch Keith Haneys tail lights drive away
     
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  15. BEDNAR1320

    BEDNAR1320 Member

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    All good info here guys, thanks!

    My crank will need the snout repaired, lots of micro welding. Going to call Shaftech today, anyone have other suggestions? The closer to Florida the better...…..
     
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  16. drew556

    drew556 Member

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    We have one at mile high crankshafts gettin snout fixed right now not really close to Florida but they do go work
     
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  17. jay70cuda

    jay70cuda Active Member

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    Shaft tech is amazing. They’ve done amazing work for me over the last 10 years. And it’s hard to beat the pricing for making a crank right again.
     
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  18. REEHL EQUIPMENT

    REEHL EQUIPMENT Authorized Merchant

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    Is anyone making splined BBC stuff yet?
     
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  19. REEHL EQUIPMENT

    REEHL EQUIPMENT Authorized Merchant

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    Johnny West makes a puller that uses the Pro Jack pump, if you have Pro Jacks. Works GREAT!
     
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  20. BEDNAR1320

    BEDNAR1320 Member

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    In case anyone is interested, you can get grade 9 bolts from Specialty Fasteners. They torque to 400#.....
     
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