Hollow vs. solid stem valves
#62
im late to the thread and what i would normally have said has already been posted, so all i am going to say is when you get into class racing and real competition, every gram absolutely matters, and valvetrains are complex beasts. the exception that i am aware of is pushrods. stiffness is king even at the expense of weight.
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Corona (09-30-2021)
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Corona (09-30-2021)
#64
Lance is on point with the:
👍 Cam core size and rocker ratio also a YB thread and conversation
#65
#66
Cam Core and Rocker ratio.... I think there's a thread with a similar question about weight of the valve train and each Head porter having a Baseline Weight for a Particular RPM° from Experience°. Nah, I don't think it was a thread I know it was now thinking about it...
G you like technical and I just try to keep it basic
😁
(Look above) as long as we get the Principal's correct 👍
https://www.yellowbullet.com/threads...-lift.2664069/
G you like technical and I just try to keep it basic
😁
(Look above) as long as we get the Principal's correct 👍
https://www.yellowbullet.com/threads...-lift.2664069/
#67
If I recall correctly, this control is why pro-stock engines run huge lift cam lobes and relatively low ratio rocker arms.
#68
larger cam lobe gives you more flexibility in lobe design, you can do inverse radius stuff and also run larger diameter lifters which are stronger/better.
i am not sure about the lower rocker ratio part. I know with higher ratios you can get more area under the curve.
Maybe lance means with equal area under the curve with a more aggressive lobe but less ratio its easier on parts?
i am not sure about the lower rocker ratio part. I know with higher ratios you can get more area under the curve.
Maybe lance means with equal area under the curve with a more aggressive lobe but less ratio its easier on parts?
#69
#70
I can only take an educated guess, probably 1.7:1, with about 1.125" valve lift. Since they implemented the rev-limiter the valve lift they run has actually gone up.
Remember that their camshaft tunnel diameter is 70mm. They can have a lot of lobe lift.
Remember that their camshaft tunnel diameter is 70mm. They can have a lot of lobe lift.
#72
With the Ls 55mm cam core
I was stuck on Ratio and lobe lift a wk or 2 ago for a future top end swap.
.430 lobe with a 1.8 ratio
or
.420 lobe with a 1.9 ratio
Using a .750 lifter wheel. The Rocker Ratio changes are Free.. but the Larger lobe is/was sounding better. Also the reason for the call for a part number about a wk or 2 ago...
I still don't know about the choice ..😂🤣 I laugh at myself a lot
I'm gonna find the time to ask a few people one day 😏
Hey Bipolar & ADD, who's laughing now 🤣
I was stuck on Ratio and lobe lift a wk or 2 ago for a future top end swap.
.430 lobe with a 1.8 ratio
or
.420 lobe with a 1.9 ratio
Using a .750 lifter wheel. The Rocker Ratio changes are Free.. but the Larger lobe is/was sounding better. Also the reason for the call for a part number about a wk or 2 ago...
I still don't know about the choice ..😂🤣 I laugh at myself a lot
I'm gonna find the time to ask a few people one day 😏
Hey Bipolar & ADD, who's laughing now 🤣
Last edited by Corona; 09-30-2021 at 05:16 PM.
#73
I was stuck on Ratio and lobe lift a wk or 2 ago for a future top end swap...
.430 lobe with a 1.8 ratio
or
.420 lobe with a 1.9 ratio
.750 lifter wheel
Rocker Ratio changes are Free.. but the Larger lobe is sounding better. Also the reason for the call for a part number about a wk or 2 ago...
.430 lobe with a 1.8 ratio
or
.420 lobe with a 1.9 ratio
.750 lifter wheel
Rocker Ratio changes are Free.. but the Larger lobe is sounding better. Also the reason for the call for a part number about a wk or 2 ago...
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Corona (09-30-2021)
#77
We still don't have anywhere near an answer to the question of when do you use hollow vs solid vs Ti, and spring choices etc.
I have beat the ever living **** out of a stock LS3 hollow stem intake valve engine for ~25k miles with 600 lift cams and comp dual springs on it to a 7400 rpm limiter many times.
I have also had a Manley solid stainless intake valve drop after 750 runs on an ls3 that used to turn 7500+ rpm every pass (that or the stock flycut cast piston failed and broke the intake valve when everything exploded...chicken or the egg).
You're building a new engine - New set of ls3 heads - stock ls3 hollow valves, solid stainless, hollow stainless, Ti? What springs? Why - budget, performance, risk vs investment etc?
As the teacher used to say - justify and explain your answers lol.
I have beat the ever living **** out of a stock LS3 hollow stem intake valve engine for ~25k miles with 600 lift cams and comp dual springs on it to a 7400 rpm limiter many times.
I have also had a Manley solid stainless intake valve drop after 750 runs on an ls3 that used to turn 7500+ rpm every pass (that or the stock flycut cast piston failed and broke the intake valve when everything exploded...chicken or the egg).
You're building a new engine - New set of ls3 heads - stock ls3 hollow valves, solid stainless, hollow stainless, Ti? What springs? Why - budget, performance, risk vs investment etc?
- Stock bottom end ls3 including stock lifters, stage 2 off the shelf cam. Will be run day in and out until something breaks, hopefully never does.
- Rowdy street car w/ forged 416 ls3 with short travel slow leakdown lifters, slaps harder than your mom last night stage 4 cam...will go on car show cruises, Mexico roll racing, and hits the track 10 times a year. Took the stock heads off for porting - still has the stock LS3 hollow valves. Do you change them?
- LY6 junkyard motor (iron 6.0 w/ L92 heads), hydraulic roller with a sloppy stage 2 cam and an ebay turbo making 1000 hp turning 6500 rpm or less - Gas pedal has two positions, 0 and 30psi, but is just a daily driver.
- Super clean ls3 grand sport corvette with 10k miles - medium sized LLSR will turn up to 7500, likely won't drive past 7000 much, and probably will just show off the dyno sheet and drive 100 miles a year. Just bought M311 heads and needs to pick valves. Has all other premium bolt-ons like carbon clutch, fast intake, 2" headers etc etc.
- 14:1 compression drag engine and street race machine SBE ls7, LLSR cam but not too crazy - endurance type lobes for good stability and life, 7500+ rpm expected with a single plane, runs mid 8's in a fox body, but the motor only cost $10k to piece together - Might do race week, probably just a race car. The heads are off for porting - do you leave the stock Ti valves? Install Solid, hollow stainless, or expensive aftermarket Ti? Which springs?
As the teacher used to say - justify and explain your answers lol.
#78
We still don't have anywhere near an answer to the question of when do you use hollow vs solid vs Ti, and spring choices etc.
I have beat the ever living **** out of a stock LS3 hollow stem intake valve engine for ~25k miles with 600 lift cams and comp dual springs on it to a 7400 rpm limiter many times.
I have also had a Manley solid stainless intake valve drop after 750 runs on an ls3 that used to turn 7500+ rpm every pass (that or the stock flycut cast piston failed and broke the intake valve when everything exploded...chicken or the egg).
You're building a new engine - New set of ls3 heads - stock ls3 hollow valves, solid stainless, hollow stainless, Ti? What springs? Why - budget, performance, risk vs investment etc?
As the teacher used to say - justify and explain your answers lol.
I have beat the ever living **** out of a stock LS3 hollow stem intake valve engine for ~25k miles with 600 lift cams and comp dual springs on it to a 7400 rpm limiter many times.
I have also had a Manley solid stainless intake valve drop after 750 runs on an ls3 that used to turn 7500+ rpm every pass (that or the stock flycut cast piston failed and broke the intake valve when everything exploded...chicken or the egg).
You're building a new engine - New set of ls3 heads - stock ls3 hollow valves, solid stainless, hollow stainless, Ti? What springs? Why - budget, performance, risk vs investment etc?
- Stock bottom end ls3 including stock lifters, stage 2 off the shelf cam. Will be run day in and out until something breaks, hopefully never does.
- Rowdy street car w/ forged 416 ls3 with short travel slow leakdown lifters, slaps harder than your mom last night stage 4 cam...will go on car show cruises, Mexico roll racing, and hits the track 10 times a year. Took the stock heads off for porting - still has the stock LS3 hollow valves. Do you change them?
- LY6 junkyard motor (iron 6.0 w/ L92 heads), hydraulic roller with a sloppy stage 2 cam and an ebay turbo making 1000 hp turning 6500 rpm or less - Gas pedal has two positions, 0 and 30psi, but is just a daily driver.
- Super clean ls3 grand sport corvette with 10k miles - medium sized LLSR will turn up to 7500, likely won't drive past 7000 much, and probably will just show off the dyno sheet and drive 100 miles a year. Just bought M311 heads and needs to pick valves. Has all other premium bolt-ons like carbon clutch, fast intake, 2" headers etc etc.
- 14:1 compression drag engine and street race machine SBE ls7, LLSR cam but not too crazy - endurance type lobes for good stability and life, 7500+ rpm expected with a single plane, runs mid 8's in a fox body, but the motor only cost $10k to piece together - Might do race week, probably just a race car. The heads are off for porting - do you leave the stock Ti valves? Install Solid, hollow stainless, or expensive aftermarket Ti? Which springs?
As the teacher used to say - justify and explain your answers lol.
#79
Spanks you as well as others who've done other higher rpm builds or type of engines, Know this:
If it's set up correctly not Dependant on valve material used it will hold up.. being lighter just allows more rpm & less maintenance , which is HP without the extra weight which hinders Rpm. At which Rpm point does a Valve switch needed to be considered?
Budget decides that. As you listed a Hollow stem which Weighs more than a Titanium valve and a Solid valve Weights more than Either...
Springs Control all listed @ any giving Rpm. Losing weight is only a benefit to the point of a person's budget. 👍 If we've got great springs would it not be possible to get 9000 rpm with a Solid stem valve using a Shaft mounted system with a larger type push rod?
Budget and or rules. + A seen valve out of Control from testing.
If it's set up correctly not Dependant on valve material used it will hold up.. being lighter just allows more rpm & less maintenance , which is HP without the extra weight which hinders Rpm. At which Rpm point does a Valve switch needed to be considered?
Budget decides that. As you listed a Hollow stem which Weighs more than a Titanium valve and a Solid valve Weights more than Either...
Springs Control all listed @ any giving Rpm. Losing weight is only a benefit to the point of a person's budget. 👍 If we've got great springs would it not be possible to get 9000 rpm with a Solid stem valve using a Shaft mounted system with a larger type push rod?
Budget and or rules. + A seen valve out of Control from testing.
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G Atsma (09-30-2021)
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Corona (09-30-2021)