The following pictures show a 4.5" stroke 598ci BBF crank that originally had heavy metal installed----WRONG.
-The three pieces were installed intersecting each other to where there was NO STRENGTH of the crank metal between the pieces to hold the metal in place.
-And they were placed too close to the outer edge of the counterweight so that the only metal left to hold the two long pieces in place was the curls at either side.
-Then they found that they had too much weight so they drilled into one of the curls which seriouisly weakened that side curl.
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-This engine had been run for about 8 years but only a handful of runs each year so it had maybe 50 passes at the most down a 1/4 mile drag strip.
-The car owner ran the engine well less than 7000rpm---more like 6500 to 6600rpm.
-Then I got involved with him attempting to make the car faster----the engine started running higher rpm and these pieces of metal came loose at about 7100rpm
destroying one cylinder wall, two Oliver rods, two titanium valves and two JE pistons.
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-To save the crank I machined out the wounded area into a "T" slot----machined up a chuck of steel to hammer fit tightly into that "T".
-I installed 3 shorter pieces of heavy metal into the next counterweight----and then I made the "T" slot metal piece about .040" wider than the counterweight.
-There was plenty of room to have the bulge hanging out slightly and that little extra width made the balancing come out perfect without having to drill any holes.
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-The "T" slot chuck weighed right close to 453 grams which is 1 full pound.
-Had some knowledgable people calculate the weight at 8000rpm and that 1 pound piece becomes 18,000# at that speed and distance from the crank centerline.
-So I did some math and decided that the two ears that I made to fit in the slots of the "T" were good enough to contain that 18,000#.
-I also decide d that I didn't want to weld on the 4340 crank so I installed 3 high class bolts into and thru the metal chunk and threaded these bolts into the crank
as shown by the blue marker lines.
-I calculated that each of these bolts were capable of holding 8000# each so this assures me of more than double the retention I feel I needed.
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-The cost to repair this crank and to get it rebalanced was $750.
-The total bill to repair the engine was something over $5500.
 

Bill Jones' Photo Gallery Page 6

Repair Crankshaft After Heavy Metal Let Go