When mine broke it was because a rod cut it in half. Of course, the rod wasnt connected to the piston anymore. Ive seen real high lift solid cams break when something went wrong up above in the valve train and the lobe couldnt push the lifter up, sometimes, pushrods that are too good are bad.

A common cause of cam breakage can be the harmonic balancer (dampner) itself.Either being "bad" or the wrong one for the application".

The 575SCI I mentioned that broke a cam had no broken valvesprings. Had no thrown rods.

Sure, it bent a bunch of valves and bent some pushrods.

But that's all.
This was in November.

odd

I have one in the garage I saved thats in 5 pieces.Started with valve,then piston,then rod,then piston pin sliced block,and upon disassembly a 5 piece camshaft.There was not a piece of piston more than 1" square.What a horrible noise that made.Its kinda cool how the piston gets sucked into the intake and redistributed into th other bores.

I have Crane solid rollers, cam broke at very rear, just before distributor gear. After talking to a couple builders, this is not new with Crane..Apparently this is the reduced cross sectional area that is where the gear is attached to the cam? Bottom line was that no damage other than cam! Oh baby, was I lucky!

I know this thread is getting old but if the next cam bearing behind the break was not installed with the oil hole lined up properly I'm thinking that journal might not have got oiled. May have led to it seizing and then causing the break.
Good luck. , Jerry.

Like Bob,
I broke a cam just in front of the distributor gear. It was a Crane hydraulic roller with the iron distributor gear, cam #168731 running in an HP500 motor. Only 60 hours on the cam and lifters. Everything else looked fine: the distributor gear, the oil pump, the cam bearings, etc... The motor was running at 2500 rpm at the time and simply shut off. Fortunately did no damage to anything else. Crane will warranty the cam since it is within one year of purchase, but what a pain in the rear. Makes me nervous about my other motor that has the same cam. With the cam in two pieces, you can see that the shaft is necked down at the point where the iron distributor gear is pressed on. Is this a bad design or what?

Yep, Sure Did. Broke a SBC Isky during break-in. no pun intended

Roby

add another crane cam to the list. 741 hydr. roller, broken at dist. gear after 65hours.......................................suck s, but still hoping for no other damage.....................

I heard of a 454 breaking a cam last week from my mechanic, secondary to hydrolock.

A quart of oil every 5 hours sounds a little high *to me*.
High oil temps wont kill your motor in the short trerm.
I ran a 377ci race motor for 3 seasons in my vette @7500 rpms, oil temps at 300*+ (water at 220*), but the mains finally let go durring a race at Laguna Seca, (still took 2nd place though).

Sorry to hear about your motor.