MILD THUNDER

iTrader: (3)

You can make a rocker arm out of super duper nasa specd space age steel, but theres still bearings in them, and most rocker failures ive seen, have been from a failed bearing or trunnion . Rarely do the bodies snap, unless of course your binding springs, or some other valvetrain follies

MILD THUNDER

iTrader: (3)

Now start talking 800 plus pounds of open pressures , higher ratio rockers,big rpm and thats another story. A mild marine hydraulic roller, 1.7 rocker, ehh.

I think we often overlook whats worked for many decades , and fix problems that dont really exist. If reliabilty is a concern, much of that is in the cam design, springs, lifters, etc. Stick an aggressive high jerk lobe in your engine, and its gonna beat chit up irregardless.

Bawana

No matter whatever material they are made of. The complete valve train has to be set up properly. I can't count the times I have seen on high end and stock motors where the valve train needed more then just a little attention. Wrong push rod lengths, roller tip hanging half off the valve stem, incorrect rocker stud, springs not setup right etc............. Then a rocker breaks, and there it is blame the sob rocker.

Bawana

Well Mild, I don't foresee ever ever ever building a marine motor for myself with that kind of open pressure...LOL I personally like Hydraulic roller cams in my own motors.

MILD THUNDER

iTrader: (3)

Aside from the rocker issues on the 525efi engines, which may have been a bad batch of bearing cages, or , the lack of spring pressure on the 525s, i dont know of many rocker failures on merc racing engines.

The 400hp, 420hp, 440hp, 450hp, 460hp, 465hp, HP500, 500efi, 575, 600sc, 800sc, all used a crane alum rocker.

Not suggesting its the best, but, its what i use, and will continue to use. Only problem is they are running low on stock on them everywhere currently !

BUP

iTrader: (9)

I see you have been reading up MT ^^^^

maybe inside joke OEM manual ???

cmattj

Your spot on. Our automotive BBC 12 deg Cylinder heads wound up side loading during the opening process on the same cyl (wiping out even on a shaft rocker trunion) .. Thanks to my engine guy we started using offset .001+ or - on the push rod tip end to solve the issue. Who would have thunk that eh? Im liking the stock marine set ups that are forgiving .

14 apache

iTrader: (1)

Don't forget the 370hp

mike tkach

iTrader: (3)

i just want to say don,t be afraid of the scorpian endurance arms and all they make is made in the usa with american materials.i will spend a few xtra bucks to buy american made parts.

GPM

Just curious, can anyone actually answer the posters question,