SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: renegade on July 18, 2009, 04:27:06 PM
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Have you guys ever heard of brakeing a cam shaft in half? the cam was a ISKY roller brand its a freind of mines boat. its only 2 years old this cam. when it happend he was idileing not running it hard. just wondering if you guys ever heard of this? factory defect W.T.F.
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I would send it back to Isky and have them check the material. I've seen a few cams break and most of the times it was just a bad batch of metal that was overlooked.
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I had it happen with a crower cam about 10 years ago. Mine broke into "3" pieces. I've never seen it before or since. The bearings were all fine, the other pieces came right out.
It did look like a metal issue, like it was hanging together by a small area for a good while then broke apart. That cam was about 3 years old.
I was just starting up on plane and the 3 inch section got caught between a rod and the side of the block on the way down through the engine. When I looked under the cover and saw a push rod sticking out the hole in the oil pan we got out the oars.
End of story...
Gotta make a correction here... that was a CRANE cam I had that broke. The crower was in the 440 and never broke. Sorry about that!
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I had it happen a couple times years ago in cars. 1 was Crower, the other a Crane. both broke at speed during a 1/4 mile pass, though. Just because it failed at idle doesn't mean the damage wasn't done at speed. (Still sounds like a bad piece to me).
Both cases the cam was sent back and free replacements were sent. In the case of the Crane, it was a small block chebbie and they replaced the damaged block as well! (This was back in the early 80's).
Hopefully no more damage was done to the engine, but I'd be ripping the whole thing down anyway to be sure.
Ray
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Have you guys ever heard of breaking a cam shaft in half? the cam was a ISKY roller brand its a freind of mines boat. its only 2 years old this cam. when it happend he was idileing not running it hard. just wondering if you guys ever heard of this? factory defect W.T.F.
Stranger things have happened in high performance engines. As far as tracing back what might have actually been the cuprit of the failure: was it actually the cam or was the cam really the victim of a different engine parts failure? Two years of time on a roller cam, billet steel or not, isn't anybody's "fault"...most certainly not Isky's. Not saying that billet steel roller cam cores won't last longer in most cases, I am simply saying that engine parts fail from time-to-time. If Isky cares to see the cam core for their own educational purposes (such as Carillo does with their scattered connecting rods), then by all means send it to them. But in the meanwhile just start putting a new engine together and certainly don't think this is their fault.
LO
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Well come to find out that a big piece of silacon got stuck in the oil pump pick up screen. at idle for 25 mins under the london bridge caused one of the cam bearings to lock up. thats what happens when you use silacon instead of a gasket on the intake manifold!!