Cam and valvetrain longevity....??? low duration high lift...
11-28-2016, 02:46 PM
#1682
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Reversion totally my fault however. I told Bob I was going to run full dry riser exhaust. Build ended up running late into middle of season and I didn't want to wait another 3 weeks to have my EMI Thunder risers measured and modified to full dry extending through transom. I had the standard long bravo risers. I asked Bob if I could get away with the shorter risers and he said probably but to minimize idling below 1000 rpm so I did my best at that but still had a ton of no-wake zones to deal with. I don't blame him at all since I was the one who decided to cut that corner.
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11-28-2016, 08:27 PM
#1684
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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, 08:48 PM
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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.
The question is, at what point, are we getting far enough from the "normal" hydraulic roller profiles, where things may become an issue. I am no cam expert or grinder, but, I would think that, in order to get to higher lifts, the base circle gets reduced. When the base circle gets reduced, the lifter now hangs further down out of its bore. The side loads increase, as the angles get worse.
Up until recently, very few were running a std journal size, bbc camshaft with .400 lobe lift. And prob even fewer, doing it with a .700 wheel lifter. Now, for many years, it was done on SOLID ROLLER profiles. How many solid roller race lifters, used an encapsulated .700 wheel lifter? I have yet to see one.
If lifter wheel diameter, was a silly concept, and meaninless, why would so many guys today, getting more and more aggressive with camshaft designs, be moving to big diameter lifters, with .810 wheels, 55 mm cams, etc.
From what I saw on tims cam lobes, and a couple others, the indent marks, were on the opening side of the lobe. If it were a lack of valve spring psi, i would think we'd see issues on the flip side of the nose.
While it may not be the lifters fault, I am still waiting for a definitive answer from a pro cam grinder, on why so many of these cams, have the identical issue. Were they all not heat treated properly?
11-28-2016, 08:56 PM
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I hear ya, you know how easy I get lost in some of this, just sharing what I learn with talks with Randy, we talk like you and I do... trying to learn as much as I can ..
I know up until recently, crower, and isky, were using .750 wheel lifters. They recently switched to the johnsons.
The question is, at what point, are we getting far enough from the "normal" hydraulic roller profiles, where things may become an issue. I am no cam expert or grinder, but, I would think that, in order to get to higher lifts, the base circle gets reduced. When the base circle gets reduced, the lifter now hangs further down out of its bore. The side loads increase, as the angles get worse.
Up until recently, very few were running a std journal size, bbc camshaft with .400 lobe lift. And prob even fewer, doing it with a .700 wheel lifter. Now, for many years, it was done on SOLID ROLLER profiles. How many solid roller race lifters, used an encapsulated .700 wheel lifter? I have yet to see one.
If lifter wheel diameter, was a silly concept, and meaninless, why would so many guys today, getting more and more aggressive with camshaft designs, be moving to big diameter lifters, with .810 wheels, 55 mm cams, etc.
From what I saw on tims cam lobes, and a couple others, the indent marks, were on the opening side of the lobe. If it were a lack of valve spring psi, i would think we'd see issues on the flip side of the nose.
While it may not be the lifters fault, I am still waiting for a definitive answer from a pro cam grinder, on why so many of these cams, have the identical issue. Were they all not heat treated properly?
The question is, at what point, are we getting far enough from the "normal" hydraulic roller profiles, where things may become an issue. I am no cam expert or grinder, but, I would think that, in order to get to higher lifts, the base circle gets reduced. When the base circle gets reduced, the lifter now hangs further down out of its bore. The side loads increase, as the angles get worse.
Up until recently, very few were running a std journal size, bbc camshaft with .400 lobe lift. And prob even fewer, doing it with a .700 wheel lifter. Now, for many years, it was done on SOLID ROLLER profiles. How many solid roller race lifters, used an encapsulated .700 wheel lifter? I have yet to see one.
If lifter wheel diameter, was a silly concept, and meaninless, why would so many guys today, getting more and more aggressive with camshaft designs, be moving to big diameter lifters, with .810 wheels, 55 mm cams, etc.
From what I saw on tims cam lobes, and a couple others, the indent marks, were on the opening side of the lobe. If it were a lack of valve spring psi, i would think we'd see issues on the flip side of the nose.
While it may not be the lifters fault, I am still waiting for a definitive answer from a pro cam grinder, on why so many of these cams, have the identical issue. Were they all not heat treated properly?
11-28-2016, 09:03 PM
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Master Suffix Codes for Various Roller Lifter Wheel Diameters from comp's masters. They don't even list a .700 wheel as a suffix code
E – 0.812” (from 0.792” to 0.832”)
G – 0.850” (from 0.830” to 0.870”)
H – 0.950” (from 0.930” to 0.970”)
U – 2.000” (1.000” Radius Sliding Tappet)
No Suffix – Standard (from 0.750” to 0.790”)
From PRI
Big Rollers
Almost universally, the industry has responded to these challenges with bigger-diameter lifters, accommodating bigger-diameter rollers. “A normal solution with a roller lifter is to go bigger,” Bechtloff suggested. “Increasing the diameter of the body allows for a larger roller wheel, along with more needle bearings and perhaps an enlarged axle, in order to carry more load.”
Novak said, “Bigger diameters, bigger wheels, bigger axles, bigger everything. People are building engines with more than one-inch lift on the camshaft, which is quite large. And then the spring pressures are through the roof”—with 1450 pounds open no longer unusual. “So we’ve been making .937 lifter bodies for a while, and now we’re up to 1.000 inch—and they are just getting bigger. We have turbocharged racers who seem to be trying to destroy everything—and we keep improving our components, to stay one step ahead of them. In blown and turbocharged applications, you have to have very good material, because you’re forcing the valve open against exhaust pressure.”
Partridge agreed that, in any application, “the largest lifter wheel diameter and the stiffest pushrod we can use work the best. There are lifter diameters available now for every conceivable use that were not available until the last few years.” These include .903- and .907-inch diameter drop-in lifters with .850 wheels, for small and big block Fords and Chevrolets. “Chrysler applications are available in .903 diameter with a .815 wheel; and 1.00 and 1. 062 diameters with a wheel size of.920.”
CV Products now offers keyed .937 and .904 OD lifters through its Xceldyne brand. “The keyway is integrated into the body for less distortion and improved alignment between the keyway and the roller-wheel-to- cam-lobe interface,” said Loden, who also pointed to such sophisticated features as “priority oiling, and the proprietary material used for superior strength of the body.” Additionally, the pushrod cup is machined integrally with the body, “allowing for excellent stiffness and mass reduction, along with excellent surface finishing and OD tolerances.”
“Typically,” advised Jack McInnis of Erson Cams, Louisville, Kentucky, “an increase of five mm in the diameter of the cam core should be accompanied by an increase of about .020 inch in the diameter of the lifter wheel, to keep the wheel’s speed down to a level where it can survive.” Erson now offers one-inch keyed lifters with .910-inch wheels, and .904 lifters with .810 wheels. “If an engine is fitted with a new, larger-diameter and more aggressive camshaft, resulting in higher rpm operation, but the lifters, pushrods and valve springs are not upgraded to suit, valve float becomes a factor and will take a toll on all those components.”
Higher stresses have required tighter quality control as well. “We’ve been using newer, strong materials with enhanced heat-treating,” said Bechtloff. “Surface finishes and coatings are also used to extend the longevity of the parts. All Crane roller lifter bodies are made from heat-treated 8620 alloy steel. Many of the newer camshaft designs are made from tool steel and are through-hardened. These changes are all predicated on the fact that the racer is using higher valve spring tensions and increased rpm.”
E – 0.812” (from 0.792” to 0.832”)
G – 0.850” (from 0.830” to 0.870”)
H – 0.950” (from 0.930” to 0.970”)
U – 2.000” (1.000” Radius Sliding Tappet)
No Suffix – Standard (from 0.750” to 0.790”)
From PRI
Big Rollers
Almost universally, the industry has responded to these challenges with bigger-diameter lifters, accommodating bigger-diameter rollers. “A normal solution with a roller lifter is to go bigger,” Bechtloff suggested. “Increasing the diameter of the body allows for a larger roller wheel, along with more needle bearings and perhaps an enlarged axle, in order to carry more load.”
Novak said, “Bigger diameters, bigger wheels, bigger axles, bigger everything. People are building engines with more than one-inch lift on the camshaft, which is quite large. And then the spring pressures are through the roof”—with 1450 pounds open no longer unusual. “So we’ve been making .937 lifter bodies for a while, and now we’re up to 1.000 inch—and they are just getting bigger. We have turbocharged racers who seem to be trying to destroy everything—and we keep improving our components, to stay one step ahead of them. In blown and turbocharged applications, you have to have very good material, because you’re forcing the valve open against exhaust pressure.”
Partridge agreed that, in any application, “the largest lifter wheel diameter and the stiffest pushrod we can use work the best. There are lifter diameters available now for every conceivable use that were not available until the last few years.” These include .903- and .907-inch diameter drop-in lifters with .850 wheels, for small and big block Fords and Chevrolets. “Chrysler applications are available in .903 diameter with a .815 wheel; and 1.00 and 1. 062 diameters with a wheel size of.920.”
CV Products now offers keyed .937 and .904 OD lifters through its Xceldyne brand. “The keyway is integrated into the body for less distortion and improved alignment between the keyway and the roller-wheel-to- cam-lobe interface,” said Loden, who also pointed to such sophisticated features as “priority oiling, and the proprietary material used for superior strength of the body.” Additionally, the pushrod cup is machined integrally with the body, “allowing for excellent stiffness and mass reduction, along with excellent surface finishing and OD tolerances.”
“Typically,” advised Jack McInnis of Erson Cams, Louisville, Kentucky, “an increase of five mm in the diameter of the cam core should be accompanied by an increase of about .020 inch in the diameter of the lifter wheel, to keep the wheel’s speed down to a level where it can survive.” Erson now offers one-inch keyed lifters with .910-inch wheels, and .904 lifters with .810 wheels. “If an engine is fitted with a new, larger-diameter and more aggressive camshaft, resulting in higher rpm operation, but the lifters, pushrods and valve springs are not upgraded to suit, valve float becomes a factor and will take a toll on all those components.”
Higher stresses have required tighter quality control as well. “We’ve been using newer, strong materials with enhanced heat-treating,” said Bechtloff. “Surface finishes and coatings are also used to extend the longevity of the parts. All Crane roller lifter bodies are made from heat-treated 8620 alloy steel. Many of the newer camshaft designs are made from tool steel and are through-hardened. These changes are all predicated on the fact that the racer is using higher valve spring tensions and increased rpm.”
