Reuse Head Bolts?

Discussion in 'Small Block Tech' started by MrSony, Aug 11, 2017.

  1. MrSony

    MrSony Well-Known Member

    Could I? The bolts look damn near new, no rust, no pitting, no gacked threads. It's not like I have to, I can rob the studs off of my other 350, just wondering. They aren't those TTY crap bolts are they?
     
  2. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Yes you can re-use the head bolts and no they are not torque to yield...
     
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  3. alec296

    alec296 i need another buick

    Get the correct tap and die. Clean threads in block and bolt threads.
     
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  4. 8ad-f85

    8ad-f85 Well-Known Member

    What class fit is the tap you are recommending?
    I would caution the OP to be very careful using just any tap, you do not want to cut new threads in the block.
    Probably better off to use an extra bolt with a couple vertical slots carved into it, such as from a cut off wheel, and run it in and out of each hole a few times with a reversable drill.
    The GM bolts should be 300m steel, and better than everything but ARP's
     
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  5. 300sbb_overkill

    300sbb_overkill Well-Known Member

    Yes, get a thread chaser tap to clean out threaded holes, don't just use a regular tap. You can get a full set of ARP thread chaser taps from Summit.

    Do NOT run a die on the bolts, clean the bolt threads with a wire wheel that is on a bench grinder. A die may cut into the rolled threads of the bolt making stress risers that can cause the threads to strip easier or the bolt to fail! If the threads are damaged enough that the only thing that will correct them is a die, then discard that bolt and get new ones.


    Derek
     
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  6. Stevem

    Stevem Well-Known Member

    In a pinch to clean out the block thread holes a use a bottom tap that I have very lightly polished back each cutting edge just enough to break the point and they work fine with no metal removal.
    GM head bolts are made from a good material and have the needed stretch section in there shank for proper Torque !
    If your not building a race motor and the bolt thread area have no rust pits I would clean and reuse them.
     
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  7. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    you can grab a bolt from the hardware store and cut two slits down the threads then use that to clean the block. I use a wire wheel to clean my bolts.
     
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  8. MrSony

    MrSony Well-Known Member

    All the bolts look new, didn't even look like they've ever had a wrench/socket on them. Threads are immaculate. It's really weird. It might just be because the only other engines I've messed with were chevys (water jackets) and my old "barn find" 350, because those bolts were rusted beyond repair. It's weird how clean these are. I can thread em in by hand.
     
  9. MrSony

    MrSony Well-Known Member

    Do you guys recommend some kind of lube for installation? ARP lube? Oil? Or dry, but clean the threads?
     
  10. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Use engine oil... Reading back through the posts i saw that 8ad had already mentioned cutting a slit in a spare bolt.

    Even if the bolts are clean its still good to ensure the blocks threads are clean so you know the bolts wont bind up.

    If the holes look clean just spray some WD-40 down the holes and run the bilts in and out a few times till they come out clean.
     
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  11. 300sbb_overkill

    300sbb_overkill Well-Known Member

    Yeah, if you're using factory head bolts then use a small amount of light machine oil or a very thin engine oil on the threads and on the bottom side of the head of the bolt.

    I believe the chassis manual recommends this as well IIRC, they didn't have ARP bolt lube back then(its been a while so I can't remember if they did or didn't?) and if you use that a different torque value would need to be engineered so the bolts don't over stretch. The ARP bolts aren't the same as the factory head bolts so you can't just torque to that value.(it would probably be close enough but I would probably lose sleep not knowing for sure)

    Don't use to much oil in the blind holes either or you could crack the block. Oil doesn't compress and if there is an excess of oil on the threads in a blind hole with no where for it to ooze out it can in some extreme cases cause the block to crack from the hydraulic pressure created from tightening the bolt down. Or the hydraulic pressure could cause a false reading on your torque wrench before the bolt is torqued down where it needs to be, so less is more here. Like a drop or 3 for the threads and a drop on the bottom of the head, just enough to make the surface look wet.


    Derek
     
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  12. MrSony

    MrSony Well-Known Member

    Will do.
     
  13. 8ad-f85

    8ad-f85 Well-Known Member

    Use whatever oil the manual suggests. Different weight will change torque readings or stretch.
     
  14. philbquick

    philbquick Founders Club Member

    If it's a non-turbo motor or a motor with under 13:1 compression I will re-use them.
     
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