Engine questions 500
#21
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#22
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Joined: Apr 2006
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From: Toledo Oh
You guys are just running the wrong stuff. Im running a special set of matched unbreakium rockers using a proprietary unobtainium alloy for the roller bearings. I have a friend who was a rocket scientist for Nasa and he hooked me up.
#23
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Joined: Oct 2007
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From: yorkville,il
yea that new alloy pro comp uses is the BOMB,lol.
#25
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From: Gull Lake
#26
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Seriously though, thanks for the help on this one.
#27
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Joined: Jul 2004
Posts: 11,332
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From: chicago
I don't think the "cycle life" thing is that cut and dry. Theres guys out there running crane gold rocker arms in boat engines that have been thru quite a few hours. I changed mine out in 2010, and they were stamped from 1985. They had lots of time on them. out of 32 Rocker arms, 1 had a cracked Trunnion. What gave up, wasnt the aluminum body, but it was the steel part of the rocker arm!
Mercury used those crane gold aluminum rockers on everything from the old 370hp 454's, to 420's, HP500s, 500EFI's, 600sc's, 800sc's, 575sci's, 525efis, 525sc's, and so on. Granted those were not extreme engines, and none of them were running big spring pressures or extreme cylinder pressures.
I'd be willing to bet, take that rocker arm that goes 700 hours on a 420hp merc, and stick it on a blown engine making 2hp per ci, lots of spring pressure, and the exhaust rocker has to open the valve against extreme cyl pressure, and its not going to go nearly 700 hours. Throw in a jerky cam, and it might go 50 hours before eating chit.
Mercury used those crane gold aluminum rockers on everything from the old 370hp 454's, to 420's, HP500s, 500EFI's, 600sc's, 800sc's, 575sci's, 525efis, 525sc's, and so on. Granted those were not extreme engines, and none of them were running big spring pressures or extreme cylinder pressures.
I'd be willing to bet, take that rocker arm that goes 700 hours on a 420hp merc, and stick it on a blown engine making 2hp per ci, lots of spring pressure, and the exhaust rocker has to open the valve against extreme cyl pressure, and its not going to go nearly 700 hours. Throw in a jerky cam, and it might go 50 hours before eating chit.
#29
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Joined: Jan 2006
Posts: 3,599
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From: taxachusetts
on my friends 1075s in a big OL,were just a little past that on hours.so far,185hrsish and we plan on another 75 this summer.I check them and the lash every 25.lash hasn't moved all that much.




