Cam and valvetrain longevity....??? low duration high lift...
11-28-2016, 09:05 PM
#1692
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I just don't buy into that concept, that running a fully encapsulated lifter is stronger, and more gooder, than a forked style lifter. The biggest baddest, highest revving, all out KILL engines, are running fork style lifters.
11-28-2016, 09:09 PM
#1693
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the bigger body for sure makes sense because theres more meat there, Randy explained it to me before but I would have to search messages, was a long time ago.. I think it's more in comparison with hydraulic have the ability to loft, and both being small wheel over larger body lifters. said the wheel diameter change over body strength, the bod was more important for durability over wheel size, I just know what I am told or read, he's the engineer not me lol
11-28-2016, 09:26 PM
#1694
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I do know Crower, Isky and Teague all use the .700 wheel Hydraulic Johnson, Teague using them in applications up to 1300 HP, the way it was explained to me the pressure angle going from .700 to .750 is minimal and it was better to have durability of the full body lifter over fork body...
I think many factors come to play, my buddy that owned 41 Apache The Chief, had 3 Bob cams look like mine, with Morels... that was 5 years ago.... so maybe its case by case and cam spec situation.
I think many factors come to play, my buddy that owned 41 Apache The Chief, had 3 Bob cams look like mine, with Morels... that was 5 years ago.... so maybe its case by case and cam spec situation.
11-28-2016, 09:40 PM
#1696
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If youre spreading forks, on a lifter thats body made from forged alloy steel bar stock, on a hydraulic roller 6,000rpm engine, you have some severe setup issues.
So what was the smoking gun , as to why the cams looked like they did? And whats going to make sure it doesnt happen again?
So what was the smoking gun , as to why the cams looked like they did? And whats going to make sure it doesnt happen again?
11-28-2016, 10:15 PM
#1698
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If youre spreading forks, on a lifter thats body made from forged alloy steel bar stock, on a hydraulic roller 6,000rpm engine, you have some severe setup issues.
So what was the smoking gun , as to why the cams looked like they did? And whats going to make sure it doesnt happen again?
So what was the smoking gun , as to why the cams looked like they did? And whats going to make sure it doesnt happen again?
11-28-2016, 10:36 PM
#1700
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Randy,
There is often an element of mechanical noise associate with the (Morel 4603, Crane) lifters that is inherent to the design of the lifter that lends itself to overall performance capability. Unfortunately, there is also an element of mechanical noise in lesser brands and cheap offshore knockoffs due to the lack of holding tighter tolerances. Most OEM replacement type hydraulic roller lifters have a cast body and .700” diameter wheel. These are not suited to even moderate performance applications in the marine environment. It is best to select a lifter with an 8620 body and .750” wheel to maximize durability. These are the lifters we will address.
For initial startup we suggest ¾ to a tick past full turn, although there are numerous opinions on that dimension. Do not be concerned as the plunger travel is ~ .142” and a full turn on a 7/16-20 stud is .050”, on a 1.7 rocker ratio that results in a .079” plunger drop. The Morels are individually pressure checked prior to release, in certain cases aeration in the checking fluid causing intermittent ticking on initial run in, which is usually mitigated in less than an hour. I have seen cases where as little as 1/8 turn has been the differentiation in a significant reduction of mechanical noise.
Other factors to consider;
• Run adequate spring force. Controlling the mass of a BBC valve train requires a window of spring rate dependent upon RPM. A quality hydraulic roller lifter will accommodate 200 # seat and 500 # open. Too little spring force is often the most damaging element in marine valvetrain.
• Lifter to bore clearance is critical! This is the most under validated spec in the entire engine. The vast majority of “stuck lifter” failures is resultant of too tight lifter to bore clearance, not component failure. Too loose comes with its own set of problems.
• Oil viscosity factors heavily into tight tolerance hydraulic roller lifters.
I would request a build sheet as a matter of course on these engines.
Bob
There is often an element of mechanical noise associate with the (Morel 4603, Crane) lifters that is inherent to the design of the lifter that lends itself to overall performance capability. Unfortunately, there is also an element of mechanical noise in lesser brands and cheap offshore knockoffs due to the lack of holding tighter tolerances. Most OEM replacement type hydraulic roller lifters have a cast body and .700” diameter wheel. These are not suited to even moderate performance applications in the marine environment. It is best to select a lifter with an 8620 body and .750” wheel to maximize durability. These are the lifters we will address.
For initial startup we suggest ¾ to a tick past full turn, although there are numerous opinions on that dimension. Do not be concerned as the plunger travel is ~ .142” and a full turn on a 7/16-20 stud is .050”, on a 1.7 rocker ratio that results in a .079” plunger drop. The Morels are individually pressure checked prior to release, in certain cases aeration in the checking fluid causing intermittent ticking on initial run in, which is usually mitigated in less than an hour. I have seen cases where as little as 1/8 turn has been the differentiation in a significant reduction of mechanical noise.
Other factors to consider;
• Run adequate spring force. Controlling the mass of a BBC valve train requires a window of spring rate dependent upon RPM. A quality hydraulic roller lifter will accommodate 200 # seat and 500 # open. Too little spring force is often the most damaging element in marine valvetrain.
• Lifter to bore clearance is critical! This is the most under validated spec in the entire engine. The vast majority of “stuck lifter” failures is resultant of too tight lifter to bore clearance, not component failure. Too loose comes with its own set of problems.
• Oil viscosity factors heavily into tight tolerance hydraulic roller lifters.
I would request a build sheet as a matter of course on these engines.
Bob
