Re[2]: Landry's Timing...

[jmbrodsky@domain.elided]

     John L,
     
        The cam gear (the big one) has half of the teeth on its 
     circumference shaved off smooth.  No root, nothing.  The entire ring 
     of teeth is gone for about 200deg of rotation.  I'm hypothesizing that 
     the teeth began to fail, one at a time (the two backfires) and each 
     time a tooth broke clear away, the timing slipped one tooth.  The gear 
     has the entire tooth structure removed to a point somewhat below the 
     outer hardening.  Really, no joke.  I was kind of shooting in the dark 
     with Tark's problem.  Just that very rarely do engine problems 
     suddenly manifest themselves without warning, short of catastrophic 
     failure as mine did, and as Tark is realting.  You can see the teeth 
     have a circumferencial crack that is about 1/32" below the root depth 
     of the teeth.  Like the gear was 'peeling' itself away from the ring.  
     I don't know.  I pulled about 4 teaspoons of pieces out of the pan, 
     and one hunk of gear ring and sector, and the crank gear is fully 
     intact except for the hammered gear tooth tips.  Your guess is as good 
     as mine.
     
        I'll show it to you and you can guess too.  So far, every engine 
     race builder guru around here has no clue.  None of them has EVER seen 
     a gear fail, let alone like this.  Whole teeth gone.  They fit pretty 
     tight too, it's not like there was a shock load.  Anyway, it runs fine 
     now, and so should everyone elses.  Are you going to replace yours in 
     the 392?  Look at the old ones VERY carefully and see if there is 
     maybe just maybe a circumferencial crack beneath the teeth.
     
        I callzem like I seezem.
     

     -Joel Brodsky
        www.physics.arizona.edu/~jbrodsky

         '76 IHC Scout II Spirit 345/tf727 RE8000, Cibie40s, custom 
                rear tire rack, 6 different color body panels.
                Not much sport, all utility.
         '75 IHC Travelall 150 4wd 392/tf727 Hummer brush guard, 
                3/4T rear springs, Hella Rallye 2000s, Con-Ferr 5x7,
                Class IV hitches front and rear, 3" Exhaust.
                1st Place, Rocky Mountain IH Rendezvous,
                3rd Place, Tulare IH Western Regionals.
         '74 IHC Travelall 150? 2wd 392/tf727 "The 'new' one"
                Factory AM/FM, Cruise, Tilt, AC, Captains Chairs,
                Rblt: Alt, carb, fuel pump, ps pump, water pump, dash,
                seats, rear door, starter, master cyl, what could be left?