LeanPocket

iTrader: (6)

if so, what caused it to fail?

ls68firebird

That's a loaded question. By your question, i assume you had one spin. All of the variables need to be questioned not just a blanket blame on bolts. What brand of rods? Stock or aftermarket? What clearences on bearings during install? Was the torque on the bolt checked before removal? Were the bolts checked for abnormal stretch when removed? Were the rods resized ( if not supplied with the arp bolts ) after the install of the bolts? Which bolts- wavelock, traditional, etc.? What brand of bearings? Were the bearings correct for the chamfer on the crank? I have had a few rod bearings spin on traditional sbc's but i believe they were due to extremely high temps and detonation. The bolts did not fail, but caps were distorted. They weren't obvious to the eye but machine shop found it. These engines were in dirt circle track cars and running 7-8k rpm under full loads for some time. Then i have had engines with similiar builds melt to the ground ( dirt track drivers will never lift with only a few laps left ) and the bearings be o.k. Just seems too vague of a question without all the circumstances.

EDIT: and the most obvious question i overlooked. How was it running when it spun? Detonation? Lean? Was the crankcase oil diluted with fuel? Were the rods removed, retorqued and checked for size after brng failure? The list of questions goes on.

t_raven

iTrader: (12)

Bolt failure won't cause spun bearings. They either hold the cap to the rod or they break and don't. At that point the rod would probably find it's way out the side of the block. I mean assuming things stated above were right. If you installed them without having the rods resized, then that would cause a problem with the bearing. But if everything was set up right and the cap is still attached to the rod then the bolts are doing their job.

LeanPocket

iTrader: (6)

ok,

My best friend has a freshly built 383 stroker pushing over 500hp with ~1000 miles that spun a bearing; ill have to ask what rods/pistons/crank. I dont want to give out the name of the builder, but hes known to be a very good builder. The only thing I know for certain is the entire motor had a entire ARP make over. I diddnt build the motor so i cant confirm the procedure on how it was built. I can get a manifest or what was put on it and post it up.. if he lets me.

How was it running when it spun? It was in perfect running order prior to bearing being spun, and the car shut off while exiting an off ramp driving normal, turned the car back one and was knocking dirty. Pulled into a parking lot and shut her off.

LeanPocket

iTrader: (6)

oil was changed twice prior to spin aswell

mypoorLS1

iTrader: (4)

Bolts don't cause spun bearings.

ls68firebird

most spun bearings are a cause of detontation and or installer error. Other possibilities are poor tune, loss of oil pressure ( high rpm or high g turns without proper baffles or drainback), wrong width bearing on crank chamfer causing rubbing and heat ( when motor stalled, the hot bearing grabbled the crank, and when refired - it spun and knock,knock,knock) detonation actually can cause the sides of the bearing to "come in" and touch the crank causing it to wipe the oil off. If it wasn't knocking before it shut off and then knocked when refired, I would lean to why the bearing grabbed the crank. but that's just my two cents worth. I do not believe it was rod bolt related either.