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Think I might be done for the season... [emoji35 ] AKA Spontaneous top-end re-rebuild

Thread: Think I might be done for the season... [emoji35 ] AKA Spontaneous top-end re-rebuild

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  1. 66Sprint's Avatar

    66Sprint said:
    Gotta be possible, .... They got in there to tap those holes.....






    15
    "I have a mind like a steel trap.....Old and rusty, of antiquated design, and hard to get stuff back out of...."
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  2. DieselKrampus's Avatar

    DieselKrampus said:
    Quote Originally Posted by 66Sprint View Post
    Gotta be possible, .... They got in there to tap those holes.....






    15
    That's what I was thinking. But it seems almost like they must've used a 90° drill head. Similar to what an air powered dental drill would look like. It's just so close to the lobes, that's the only way I could imagine it working.

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  3. DieselKrampus's Avatar

    DieselKrampus said:
    Quote Originally Posted by MarshallB View Post
    Perhaps a 6 or 12” drill bit extension with a bolt extractor bit might get you the clearance you need for the drill?
    I'm thinking maybe one of those flexible snake-like extensions for the Dremel might just work. Getting the bolt extractor in there might be more of a challenge. But, if need be, I could always cut the bolt extractor shorter with a cutoff wheel to get a little more clearance. Good ideas, for sure.

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  5. TOOLS1's Avatar

    TOOLS1 said:
    Quote Originally Posted by DieselKrampus View Post
    You didn't look at the pictures, did you?

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    Yes I did. I have done it on bolts that were deeper than that one.
    TOOLS
     
  6. DieselKrampus's Avatar

    DieselKrampus said:
    Quote Originally Posted by TOOLS1 View Post
    Yes I did. I have done it on bolts that were deeper than that one.
    TOOLS
    How did you manage to avoid welding the nut to the threaded portion of the hole, as well as the bolt shank? Seems to me like you would need some incredibly fine-gauge welding wire for it to be possible?

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    EDIT : I don't have enough experience with a TIG, nor a machine. And while I am quite confident in my abilities with a MIG, I'm not so sure I'd be able to pull that technique off on the first try. And this is definitely a one-shot type of situation. Last thing I want to do is ruin a perfectly usable cam by permanently welding a broken bolt into the hole.
    Last edited by DieselKrampus; 07-01-2019 at 09:04 PM.
     
  7. Boomer343's Avatar

    Boomer343 said:
    Take a bolt with the same thread and cut it off so that the head just clears the cam when it is threaded in. Take the bolt out and drill a hole in it, 1/8" should do it but go bigger if you can, then put the bolt back into the cam and fire up the mig. Gob a bead down the hole and onto the broken bolt. Give it a minute to cool then see if it backs out. I'd work from the backside. If your weld breaks then repeat.

    You should wrap the cam so no splatter gets onto a machined surface.
    Last edited by Boomer343; 07-01-2019 at 10:46 PM.
     
  8. MarshallB's Avatar

    MarshallB said:
    Quote Originally Posted by DieselKrampus View Post
    I'm thinking maybe one of those flexible snake-like extensions for the Dremel might just work. Getting the bolt extractor in there might be more of a challenge. But, if need be, I could always cut the bolt extractor shorter with a cutoff wheel to get a little more clearance. Good ideas, for sure.
    I was thinking of something like this in the extender, but finding one small enough for those bolts may be tricky: https://www.amazon.com/FasHuby-Damag...69-spons&psc=1

    It looks like you can get to both sides of the remnant? I'd be tempted to try gripping it from either end with a c-clamp/visegrips and some spare philips or torx bits to see if you could get enough friction to break it loose. Or if you can get a hole drilled through it, maybe a small self-tapping screw would give you a head with which to run it through. Just brainstorming here, hope it gives you some ideas
     
  9. drydreamer's Avatar

    drydreamer said:
    A "sweet spot" in these engine ( and similar ones ) sure aids assembly etc..

    A small gee clamp affair and some made "buttons" sounds like a good idea. Did the bolt have locktight applied?

    Just don't effectively "rivet" the remains in the bolt hole thread area.

    I would suggest unscrewing the remains out in the normal direction to avoid possible "burrs" etc..
    Last edited by drydreamer; 07-02-2019 at 03:39 AM.
     
  10. Yendor's Avatar

    Yendor said:
    They make extended lenght aircraft drills here is one source:
    This one is for a full set they are 12" in lenght and start at 1/16"

    https://www.garrettwade.com/long-air...%20Categorized

    This page has an individual 1/8th" drill for $7.09
    https://www.stewmac.com/Luthier_Tool...lthier%20Tools

    This last one is a page of indivudual M42 Cobalt Steel Drills in 12" lenghts

    I think this would solve your problem of getting in there and this is what they would have used to create the original holes.
    https://www.travers.com/cobalt-13517...elistname=SITE
    1970 CB 350 CAFE - Current Project on the bench,
    1972 CB 350 K4 Red - Now a Happy Rider ! !
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    1st Bike 1970 SL 350 (Brought home in Parts - Trailer/Trunk/Back Seat - I miss that bike),
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  11. DieselKrampus's Avatar

    DieselKrampus said:
    Cylinders and cylinder head freshly decked. New gaskets going in from the base gasket on up. Trying to continue making forward progress even as I try and figure out the camshaft situation. Will probably be taking a brief break from engine work over the 4th of July weekend to celebrate the holiday with friends and family. Will resume the project early next week.

    Interesting note: I had to egg-out the two holes in the headgasket where the dowel pins are, in order to make the new gasket sit flat on the cylinders. Installing the gasket right out of the package caused the center of the gasket to bow upwards, as if the outer two stud holes were not quite punched in exactly the correct location. After using a rat-tail file to carefully enlarge each hole inwards about 0.5-1.0mm, the gasket now sits perfectly flat and properly aligned on the top of the cylinders. Anyone else ever run into this issue?
    (Gasket came from the complete top end gasket kit which I got from 4into1.com)

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