The same engine team that did the FE/FT 332/352/361/390/406/410/427/428 engine design did the 144-170 engines. But they left a lot out in the 18 month crash development of the 1960 XK Falcon engine.
Most of the great advances of that legandary Big Block FE engine never filtered down to the smallFords. On the big ones, the rocker ratios in those were 1.73 and 1.76, but in the small six, the same parts yield 1.65 and 1.62 or so, but instead we have downgraded stock ratios of just 1.5:1 and the occasional Thomas 1.6;1 that you find on the internets ebay. Its taken years for the Falcon/ Mustang six to get the same support, and its still limited to, at most, 1.65:1 rocker ratios, no where near the 1.73:1 the X-flow, or 1.8 and 1.9 of the OHC's. And no where near the solid cammed 352's 1.76:1 that saw the light of day in late 1959.
There are many FE parts around which are better alternatives to the ones we have, but beggars cannot be choosers in this case.
Yep, in fact, the info I have is the same, that on there own, roller tips themselves are almost entirely useless.
Why do later Gen 3 and 4 GM small block LSx's use non roller tip rockers with full roller fulcrums in its engines?
Because roller tips cannot mechanically reduce friction very much, they are in signicant compared to the wrenching and heat from the rocker shaft. All roller tips slide and the contact area is always rubbed as a rise over run.
The only reason for using them, is a gain in rocker ratio from a nominal 1.5 to 1.6;1. That is 6.7% in lift, and whatever that is as a duration at 50 thou lift, probably 2 degrees. That's worth 15 cfm at peak lift, but less on the bulk flow on the up and down cycle. On a constrained stock, at birth 256 degree duration at lash cam with insufficient 50 thou duration, its worth some extra torque and power, maybee 2% if your lucky.
A better cam with stock new rockers at 1.5:1 will see a lot more, but its all a matter of only spending what you can afford.
Most of the great advances of that legandary Big Block FE engine never filtered down to the smallFords. On the big ones, the rocker ratios in those were 1.73 and 1.76, but in the small six, the same parts yield 1.65 and 1.62 or so, but instead we have downgraded stock ratios of just 1.5:1 and the occasional Thomas 1.6;1 that you find on the internets ebay. Its taken years for the Falcon/ Mustang six to get the same support, and its still limited to, at most, 1.65:1 rocker ratios, no where near the 1.73:1 the X-flow, or 1.8 and 1.9 of the OHC's. And no where near the solid cammed 352's 1.76:1 that saw the light of day in late 1959.
There are many FE parts around which are better alternatives to the ones we have, but beggars cannot be choosers in this case.
Yep, in fact, the info I have is the same, that on there own, roller tips themselves are almost entirely useless.
Why do later Gen 3 and 4 GM small block LSx's use non roller tip rockers with full roller fulcrums in its engines?
Because roller tips cannot mechanically reduce friction very much, they are in signicant compared to the wrenching and heat from the rocker shaft. All roller tips slide and the contact area is always rubbed as a rise over run.
The only reason for using them, is a gain in rocker ratio from a nominal 1.5 to 1.6;1. That is 6.7% in lift, and whatever that is as a duration at 50 thou lift, probably 2 degrees. That's worth 15 cfm at peak lift, but less on the bulk flow on the up and down cycle. On a constrained stock, at birth 256 degree duration at lash cam with insufficient 50 thou duration, its worth some extra torque and power, maybee 2% if your lucky.
A better cam with stock new rockers at 1.5:1 will see a lot more, but its all a matter of only spending what you can afford.
