Myself and others have had issues with Marine Kinetics custom cams. Boat is headed to Alaska in the spring, I want off the shelf cams, and lighter springs

Also, it would be very interesting to know what cam the newer 520 is using. Relatively short risers on a manifold from the factory. You can be sure that reversion isn't an issue with that cam.

Good info here:
mercury 540 565 camshaft specs

Be careful with "lighter springs' on anything that has any kind of lobe much past .300 /.520 lift unless you ABSOLUTELY never turn it at wot. I just freshened 2 540s for Cass from Va that had beehive valve springs and real mild lobe crane cams and there was definately signs of lofting /losing wheel contact on back side of cam lobes and that had less then 150 hours on it and very little wot time.
Aside from the Morel lifter failure , what other issues did you have with your MK cams? If I remember correctly, I used a identical cam or real close for a customer with similar requirements (extended idling. fishing, etc) and I remember Bob telling me a guy out on west coast was running the grind he was recommending on a twin engine fishing boat. I thought at 225/230 @.050 and .570 lift it was quite mild, the engine would idle at 600 easily and last I heard from that customer he had 500/600 hours on it, also has Johnson lifters in it because the pattern of Morell lifter failures had already came to light when I built this one. Good luck ,on your new builds and keep us posted on what cams you get and the results you see.
How many total hours did you get from your old cams before they failed or whatever happened or was it just the one lifter failure, Im always curious . I also had one engine that was the last engine I used Morel lifters in back around 2014 or so had a lifter failure around 2019/2020. I had encouraged my customer to have me remove them and switch to Johnsons but he felt since they were working hed roll the dice. That whole Morel sending lifter body's to Mexico for production or speeding up machining, whatever it was, took them from one of the best Hydraulic rollers to being a pariah in the marine industry, Smitty

Hello everyone!

I’m finally have most of the parts I need to start final assembly of new engines except valve springs.

Engines typically turn 3400 to 3600 at cruise power. Then idle for extended periods. I do open it up occasionally. Rev limiters are set at 5250. ZZ502 lifters.

This boat is used offshore, dependability is at top of the list!

“BBC Gen VI Billet Camshaft - 500efi” SKU: API 169621-TCM

Cam purchased from Teague. See attached cam card.



Any suggestions for springs would be appreciated!!



Thanks



Steve

Since you purchased cam from Teague, why not ask him instead of reinventing the wheel on here. Bob has been doing this along time, problem can rattle off part numbers off the top of his head.

Marine Kinetics, forgot the ol boys name, that’s his MO. Lobes too aggressive. Never tested anything. He got ran off a long time ago.

If you'd like a ballpark idea of what the spring requirements are, use the calculator halfway down this page:

Valvetrain Engineering Services - Allmond Marine

Boat is back in the water and running great. Time to change out break in oil to Mobile One. I used Mobile One 10/40 last time around. I'm leaning towards 10/30 this time because I'm running
new GM shortblocks (ZZ502), and most likely have tighter clearances. Oil temp at the pan will hover around 220+ at fast cruise, pressure is 40 psi at hot idle, and around 75 psi underway.

For break in I used Lucas 30wt, which seemed fine. Oil temp and pressure was normal on both engines.

Would the 10/30 oil be best, or stick with the 10/40?

I appreciate all of you!

Steve

I find this chart to be particularly helpful:

https://drivenracingoil.com/c-138953...viscosity.html