Hang Time 27

Thanks again. I did not have a chance to tear into it before leaving home - broke at 12:30am at night in the middle of the Cheasapeake Bay, I was lucky to get a tow. I'll yank it the day after I get home, the 24th, and update this thread on which color it is.............

HARDCORE A/O

It's just a thought, but have you checked the rear cam bearing(s) to see that it's in straight, has the right clearance etc. Seems to me it's definitely something wrong with the engine since the rebuild and if the bearing is cocked even slightly it might cause the cam to wobble and twist just enough that after a fairly short period the cam would break at that point which must be the weakest part of the cam.

formula31

I was thinking something like that too, Ive seen #5 bearing pocket out of line. Worth looking at anyway.

Hang Time 27

Sure, I've heard plenty of recomendations for checking specs etc., but how about an instance of another manufacturers cam breaking at that same point??

Hang Time 27

Cam that broke was black. I dug up my crane solid lifter cam that I took out last sept(broke a lifter and wiped lobe after alcohol induced over), and it seems to have the copper color. It had over 100hours on it. Gonna call Summit...........................

Hang Time 27

Crane has updated the ever popular "741" cam - different ramp design and different part number - it is now a "021" . All specs on the cam card are still the same, while the "description" now includes the "Marine performance application with dry aftermarket pipes".

They have resolved thier copper/black cam issues - they are all copper now - dropped the other hardening process. They are re-imbursing me for the purchase price upon reciept of the broken cam. They also have a new spring out for this cam in marine applications, but they will not be out to suppliers until end of August..........

35/25

Hang Time,

I guess I am glad to hear that your broken cam ended up being one of the black ones. Did you actually talk with the Crane guys to confirm what I was telling you, that they were having this mysterious failure problem with the black roller cams? Gee, I guess it's just tough luck for us who had to go through their R&D process. Like I said before, Crane warranties the cam ($350 or so) but YOU have to pull the motor, take it apart, re-assemble and re-install in the boat. If you are handy, it's only your time and a few hundred bucks for gaskets, etc. If you are like most boat owners, you have to bring the boat in to a shop and pay thousands to have that job done.
Anyway, I hope I was some help to you in solving your problem.

Hang Time 27

New "741" cam came in from Crane, new part # "021", part of thier "Z" series cams, but was still black in color!!!! Crane admitted to problem last year, and said cams would all be copper now.....But it wasn't!! Trying to decide if I should give them one more chance and have summit search for a copper one ...........

Found a few signs of water in exhaust port, pulled heads and found a small crack in one of my merlin 310cc heads above exhaust valve - just seeping, not near valve seat, not enouph to make a mess of anything else thank god. So now I'm trying to decide where to go with that....Don't know if they make that head anymore, and would still have to smooth chambers and gasket match intakes on new one to match other head....
So much for the simple "cam swap and splash it"......

35/25

I think you know what my suggestion is on that cam you received. Crane may have started making the new 021 grind when they still used both heat treating methods and therefore both types (black and copper) are still on the store shelves. Unless you specify to Summitt that you need a copper one, they will just grab any cam from their inventory and send it out. It seems that 60 to 70 hours of run time is the threshold on those black cams. If you put that new black 021 in, and in 60 hours it breaks again (with absolutely no warning) you will be kicking yourself bigtime.

excursion

Just pulled my motor apart tonight after loosing it on Sunday.
This cam was put in over the winter rebuild and have about 45 hours on them and the gear end was cut off so clean.
Will be in contact with Crane in the morning. I will have a pic in the a.m.