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Secondary tensioner bolt broke?

Discussion in 'SVT Shelby GT500' started by cheetohead04, Jul 20, 2019.

  1. cheetohead04

    cheetohead04 Member Established Member

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    noticed a slight tap when I started my car up. The secondary timing chain tensioner broke on the drivers side. Didn’t hurt the motor luckily. Has anyone had this happen? It was an arp bolt and a billet tensioner from mmr.
     
  2. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    I've seen one posted here before which had to do with a broken bolt, but was the passenger side. Did the bolts break or did the tensioner break?
     
  3. cheetohead04

    cheetohead04 Member Established Member

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    The actual bolt broke clean off. Heads were done by a pretty reputable shop. Was using a mmr tensioner and arp bolts.
     
  4. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    Where did it break? Did both bolts break? Did you torque the bolt with an in/lb wrench? ARP fasteners are much stronger than the stock bolts, but breaking one would tend to make me think it was torqued past its limits. I'm guessing you didn't have a catastrophic failure. Nothing wrong with that outcome.
     
  5. lexustech48

    lexustech48 RIP FoMoCo 1903-2014 Premium Member Established Member

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    Going with different brand tensioners, but I bought "ARP" bolts from MMR. It's a little unnerving to hear of them breaking.

    @cheetohead04 are you running aggressive cams? Heavy duty secondary chains? Launching off a 2 step?
     
  6. cheetohead04

    cheetohead04 Member Established Member

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    It looks like both bolts broke off flush with the threads in the head. I didn’t install them. Another shop did
     
  7. cheetohead04

    cheetohead04 Member Established Member

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  8. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    Are there enough threads left to grab onto to remove the ends of the bolts or will you have to drill them out and use an easy out? If the broke flush at the surface of the bolt hole, I'd suspect they were overtightened. Since all the tensioners do is exert pressure on the secondary chain, unless something else failed and grabbed it, I can't see it would be subject to forces high enough to break the bolts. The stock bolts are much lower grade. Good luck. I hope you can get the bolts out easily.
     
  9. fullboogie

    fullboogie Well-Known Member Established Member

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    If broken off enough that you can't grab it with anything, use a dremel with a cutoff wheel to slot the end. Turn it out with a screwdriver. It's worked for me in other circumstances.
     

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