stock lifter limitations
Thread Starter
TECH Apprentice
Joined: Nov 2001
Posts: 339
Likes: 0
From: Indianapolis, IN
stock lifter limitations at what point are the stock lifters the limitation in the valve train?
is it related to ramp? or lift? or just plain @.050" duration
what is the best remedy for this if you are pushing the limits? that ARE Rev Kit or a better roller lifter with appropriate pushrods?
thanks
Matt
is it related to ramp? or lift? or just plain @.050" duration
what is the best remedy for this if you are pushing the limits? that ARE Rev Kit or a better roller lifter with appropriate pushrods?
thanks
Matt
TECH Senior Member
Joined: Nov 2001
Posts: 10,341
Likes: 1
Re: stock lifter limitations That is a good question and I am wondering that myself.
The cam I am going with is
228/228 112LSA .588 lift!!
Not sure what the best choice for lifter would be?
I am going to shift at 6600rpm and probably make peak power around 6400-6500 on the dyno.
Cheers,
Chris
The cam I am going with is
228/228 112LSA .588 lift!!
Not sure what the best choice for lifter would be?
I am going to shift at 6600rpm and probably make peak power around 6400-6500 on the dyno.
Cheers,
Chris
Re: stock lifter limitations I had been told by one place that alot of the folks using stock lifters don't see all of the advertised lift because the stock lifter bleed down.
I am running Comp R lifter and I have yet to prove they were worth the money. <img src="gr_stretch.gif" border="0">
I am running Comp R lifter and I have yet to prove they were worth the money. <img src="gr_stretch.gif" border="0">
TECH Resident
Joined: Nov 2001
Posts: 768
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From: houston
Re: stock lifter limitations yea but you start getting some loft ground in the cam and really spin that motor jihn and you will see they are worth it.
the stock lifter does bleed down too.
steve frank
the stock lifter does bleed down too.
steve frank
Re: stock lifter limitations Matter of fact I had heard of some cams having big lift but the theory behind it was that some of those .570-.590 cams weren't gonna see all that lift from bleeddown.
I'm actually a support of the Comp R lifters, I would not spin a hydraulic motor north of 7000 w/o aftermarket lifters...
John
I'm actually a support of the Comp R lifters, I would not spin a hydraulic motor north of 7000 w/o aftermarket lifters...
John
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Re: stock lifter limitations no... the ramp of the cam and the spring pressure are what beat on lifters, IMHO. I recently had alot of problems with stock lifters. 1.8 ratio rockers and K-motion K-800s flattened the lifters, and power bailed out around 6100 rpm.
I replaced the rockers with stock, and put in Crane springs that werent nearly as hard as the K800s. Still hard, but not that hard.
By this point I had destroyed a lifter. I replaced the whole set with Comp R. I dont see that much of a difference between the stock and Comp R lifters. They were a replacement for me for a broken/abused stock set.
jmX has a few problems with the Comp R lifters not staying up when you want to pull the cam out. He solved that problem with 16 telescoping magnets, but it is still worth mentioning. Others implied that their CompRs had stayed up just fine.
The only other performace factor that is different appears to be the fact that the stock lifters have about .150-.180 bleed down plunger room. The CompRs, while I have not seen them in a vice, sound like they only have approx .080. Just an FYI for cars that dont have adjustable rockers, cam base circle changes, and people dont always use the right length pushrods or measure preload.
\chris
I replaced the rockers with stock, and put in Crane springs that werent nearly as hard as the K800s. Still hard, but not that hard.
By this point I had destroyed a lifter. I replaced the whole set with Comp R. I dont see that much of a difference between the stock and Comp R lifters. They were a replacement for me for a broken/abused stock set.
jmX has a few problems with the Comp R lifters not staying up when you want to pull the cam out. He solved that problem with 16 telescoping magnets, but it is still worth mentioning. Others implied that their CompRs had stayed up just fine.
The only other performace factor that is different appears to be the fact that the stock lifters have about .150-.180 bleed down plunger room. The CompRs, while I have not seen them in a vice, sound like they only have approx .080. Just an FYI for cars that dont have adjustable rockers, cam base circle changes, and people dont always use the right length pushrods or measure preload.
\chris
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Verdad Gallardo Re: stock lifter limitations But they might overcompensate for bleeddown by running a ton of lift and/or maybe running a lot of oil pressure to pump the lifters more solid?
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: stock lifter limitations Keep in mind lifter collapse is result of spring pressure not hi lift. You need the right amount of spring pressure, but not too much. Now what is keeping people from adjusting hydraulic factory lifters with say only .010" before plunger is bottomed? I have done this with Gen. 1 small blocks, and that .010" is just enough to allow for heat expansion/contraction of engine components. This way lifter acts like a solid and cant collapse more than .010". As long as this adjustment doesnt block oil flow to pushrod this should work. What do you guys think?
Re: stock lifter limitations Visceral, incorrect valvetrain geometry and too much spring pressure can cause lifters to collapse as well. Many folks do not ever measure their lifter preload.
Re: stock lifter limitations Some of you guys have the lifter preload backwards. Hydraulic lifters bleed down at low rpm, but not high rpm. At high rpm, the lifter will want to pump up and go solid. If you have the pushrod at the bottom of the lifter and the lifter pumps up at high rpm, your valves will never close all the way and you will lose mucho horsepower.
Ideally, you want to have the hydraulic lifter preload as small as possible...meaning the plunger depth should be around .010" (in a perfect world). This way, when the lifter goes solid (at high rpm), you will not be hanging the valve open. Shallow plunger depth...good. Deep plunger depth...bad.
Ideally, you want to have the hydraulic lifter preload as small as possible...meaning the plunger depth should be around .010" (in a perfect world). This way, when the lifter goes solid (at high rpm), you will not be hanging the valve open. Shallow plunger depth...good. Deep plunger depth...bad.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: stock lifter limitations PatrickG, you are right but your explanation is accurate if loss of valve control at high rpm happens, thats why lifter pumps up because it sees slack from pushrod rocker and valve not staying on cam.The idea i have listed on this page above, would eliminate all rpm, bleed down please reread it and comment on this.
Re: stock lifter limitations In a perfect world (where the hydraulic lifter always has constant pressure from the pushrod even at very high rpm), your theory would work...however, with the typical variety of performance valve springs used on LS1s, I don't think it's possible. Once you exceed 6500 rpms, there is a very natural tendancy for a hydraulic lifter to pump up...mainly because the pressure on the lifter does not remain constant. I'm afraid for your theory to work in practice, you would have to run at least 160 lb spring pressure at the seat and over 400 lbs open to achieve this.
Sounds like we're trying to accomplish the same thing from different methods. My way would rely on the hydraulic lifter going solid from not running enough spring pressure, and yours would be making the lifter go solid by collapsing (in a way) the lifter to make it go solid by running too much spring pressure. Both methods could work...I've just found my way is a very popular way to get increased rpms without resorting to higher spring pressure.
Sounds like we're trying to accomplish the same thing from different methods. My way would rely on the hydraulic lifter going solid from not running enough spring pressure, and yours would be making the lifter go solid by collapsing (in a way) the lifter to make it go solid by running too much spring pressure. Both methods could work...I've just found my way is a very popular way to get increased rpms without resorting to higher spring pressure.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
