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RX11:
I stand corrected on the production Gen2 springs. However, excessive spring pressure has a very small HP cost. Opening a valve against a heavy spring does require more power, however closing a valve against a heavy spring gives virtually all of it back. There are greater frictional losses to be sure with a heavier spring, but if you are rollerizing the tappets and the axle and tips of the rockers friction and the resulting heat are minimized.
Thanks for the clarification on the reason for conicals on the LS motors, I was using a fuzzy recollection from a foggy memory.
Not sure what you mean by obscene, but more pressure keeps you out of more problems. I suppose we'll have to agree to disagree on this point.
It boils down to this: with more RPM you need more pressure, with more aggressive lift, you need more pressure. What's too much? It's actually hard to say. How safe is too safe? Are you willing to accept some increased wear and a slight HP hit for peace of mind? What's too little? when valves start kissing pistons and the motor goes flat just as you reach maximum RPM. Call me a scaredy cat, but I'd like engine maintenance to be more predictable and on my schedule. I've replaced a couple full sets of bent valves (on V8s) and it was costly and wasteful. I'll take some extra pressure, please.
My comments in the last post were mostly addressed to the fellow with the crate motor. LS springs in that motor are doable, but there are more options for the iron motor that he might benefit by exploring.
ikessky:
Nope the mods ain't done yet. I sent the test heads off and then put a hold on things when another part of the project took a different direction. The fellow I sent them to thought the 1.800" valves would be no problem to do, and they may be worthwhile. Anyway they are on hold.
The 1.460" springs are a viable alternative. They come in "obscene" versions as well as "R-rated" versions. Sorry, no "G-rated" versions. Moderate pressure, high pressure whatever you want.
There is one thing you would have to get over if you use 1.460" springs. When the valves of the adjacent I/E pair are on their seats, their retainers are .030" apart. Intuitively one might say, "Yipes!, run away!" But that .030" is as close as they are ever going to get. It looks freaky, but it's fine.
sg99
I stand corrected on the production Gen2 springs. However, excessive spring pressure has a very small HP cost. Opening a valve against a heavy spring does require more power, however closing a valve against a heavy spring gives virtually all of it back. There are greater frictional losses to be sure with a heavier spring, but if you are rollerizing the tappets and the axle and tips of the rockers friction and the resulting heat are minimized.
Thanks for the clarification on the reason for conicals on the LS motors, I was using a fuzzy recollection from a foggy memory.
Not sure what you mean by obscene, but more pressure keeps you out of more problems. I suppose we'll have to agree to disagree on this point.
It boils down to this: with more RPM you need more pressure, with more aggressive lift, you need more pressure. What's too much? It's actually hard to say. How safe is too safe? Are you willing to accept some increased wear and a slight HP hit for peace of mind? What's too little? when valves start kissing pistons and the motor goes flat just as you reach maximum RPM. Call me a scaredy cat, but I'd like engine maintenance to be more predictable and on my schedule. I've replaced a couple full sets of bent valves (on V8s) and it was costly and wasteful. I'll take some extra pressure, please.
My comments in the last post were mostly addressed to the fellow with the crate motor. LS springs in that motor are doable, but there are more options for the iron motor that he might benefit by exploring.
ikessky:
Nope the mods ain't done yet. I sent the test heads off and then put a hold on things when another part of the project took a different direction. The fellow I sent them to thought the 1.800" valves would be no problem to do, and they may be worthwhile. Anyway they are on hold.
The 1.460" springs are a viable alternative. They come in "obscene" versions as well as "R-rated" versions. Sorry, no "G-rated" versions. Moderate pressure, high pressure whatever you want.
There is one thing you would have to get over if you use 1.460" springs. When the valves of the adjacent I/E pair are on their seats, their retainers are .030" apart. Intuitively one might say, "Yipes!, run away!" But that .030" is as close as they are ever going to get. It looks freaky, but it's fine.
sg99
cause i had to spend money ...
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