[CAPRIRACER468]

hey racers i got my motor apart(bbf). it was a stock stroke with eagle I-BEAM rods. i was running 9.08 in the 1/4 on the bottle 225 shot.everything had been working great till we put the 275 shot on it. 2 passes one was a 5.76 in the 1/8 and the other a 5.80 then boom. damage as followed. cyl 1 rod sheard off beat the block up un cyls 1 and 5. punched a whole in the block by #1 cyl. cam took a hit broke 2 lifters, broke the oil pump off,bent 4 push rods, 4 valves, 2 pistons,2rods. i can also tell the mains have been walking. i should have went with a better rod. good parts, heads, crank,6pistons,6 rods, send cam out.

[EagleAutosports]

What causes main cap walk is harmonics. With a serious engine, even 4 bolt splayed caps won't save you. What fasteners were you using? The harmonics overwhelmed them and the caps walk side to side, eventually breaking the fastener or cracking the block, which leads to a loss in oil pressure and causing the wrist pin to shear off and at speed, image that rod banging around in there. I would think that cap walk was going on for a little while before the rod let go.

[CAPRIRACER468]

you could be right it had the stock bolts and caps. i never got a chance to up date the bolts to arp studs.

[blueracecar]

wow thats alot of spray on stock stuff,you were lucky it held together that long

[CAPRIRACER468]

yep! i now it was pretty fun to. i was told that good block would take about 800hp and a nodular crank would take 850hp, eagle I-beam rods about 650 or so hp.i now by the numbers we were make a hole lot more than that. looking at 600 cub inch motor rite now. so it will be back!