Valvespring experts?
12-07-2001, 03:13 AM
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Valvespring experts? So, with my current cam (which I suspect is bad) I get valvefloat above 6500rpms. Its been like this for ages. Its happened both with the comp 941 springs, and the 1.43" comp 987 springs which I currently have. I'll be changing the cam to a fresh one to see if its the issue (this cam has always been noisier than my other 2 aftermarket cams), but it brings up an interesting topic.
If you have valvefloat, what do you need to change in your springs? More closed pressure? More open pressure? Does closed or open pressure kill lifters faster, or are they both equally important in killing lifters?
I've done a bit of looking and I know people have run all of the following springs on their car. What would *you* choose if you were having valvefloat issues at high rpms?
I provided the pressure with the valve closed and the install height is given. I also provided the pressure at peak lift (which for this example is .560 since its a common number).
Comp 918 (small diameter spring)
130@1.800 installed height
305@ 0.560" lift
rate 313lbs/in
Comp 941 (small diameter spring)
135@1.750 installed height
385@ 0.560 lift
rate 447lbs/in
Comp Dual 978
146@1.800
372@ 0.560 lift
rate 403lbs/in
Comp Dual 987 <- what I currently have
138@1.750
330@ 0.560 lift
rate 304lbs/in
Crane 893's
165@1.750
393@ 0.560" lift
rate 408 lbs/in
KMotion K800's
176@1.800" <img src="images/icons/shocked.gif" border="0"> Seen this kill a stock ls1 lifter
412@0.560" lift
rate 421 lbs/in
Input on this?
[ December 07, 2001: Message edited by: jmX ]</p>
If you have valvefloat, what do you need to change in your springs? More closed pressure? More open pressure? Does closed or open pressure kill lifters faster, or are they both equally important in killing lifters?
I've done a bit of looking and I know people have run all of the following springs on their car. What would *you* choose if you were having valvefloat issues at high rpms?
I provided the pressure with the valve closed and the install height is given. I also provided the pressure at peak lift (which for this example is .560 since its a common number).
Comp 918 (small diameter spring)
130@1.800 installed height
305@ 0.560" lift
rate 313lbs/in
Comp 941 (small diameter spring)
135@1.750 installed height
385@ 0.560 lift
rate 447lbs/in
Comp Dual 978
146@1.800
372@ 0.560 lift
rate 403lbs/in
Comp Dual 987 <- what I currently have
138@1.750
330@ 0.560 lift
rate 304lbs/in
Crane 893's
165@1.750
393@ 0.560" lift
rate 408 lbs/in
KMotion K800's
176@1.800" <img src="images/icons/shocked.gif" border="0"> Seen this kill a stock ls1 lifter
412@0.560" lift
rate 421 lbs/in
Input on this?
[ December 07, 2001: Message edited by: jmX ]</p>
12-07-2001, 04:15 AM
#2
Re: Valvespring experts? stiffer seat/open pressures both will damage lifters overtime.
my honest opinion is change cam grinds.. unless you just want to keep being frusterated <img src="images/icons/smile.gif" border="0">
my honest opinion is change cam grinds.. unless you just want to keep being frusterated <img src="images/icons/smile.gif" border="0">
12-07-2001, 01:09 PM
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Re: Valvespring experts? JMX,
It sounds like your car has some very aggressive ramps to float the valves at 6,500 with your HD dual spring setup. I personnaly am not a big fan of high open pressure dual valve spring setups or mega acceralation ramps. The way I would set up an LS1 with an aggressive lobe profile would be to use Comp 918 springs with the lightweight Comp lifters and the ARE rev kit. Lighter valves and retainers would also help.
When you get into float, you either need to reduce valvetrain weight, or add open spring pressure, or use a cam with less aggressive lobes or a combination of all three.
Personally I'd rather add the spring pressure at the lifter (which is the heaviest valvetrain component) with a rev kit than to add it at the valve with dual springs. The rev kit puts the extra pressure on the lifter body and not the lifter plunger so you won't collaspe lifters. It also keeps the extra pressure and stress off the pushrods and rocker arms to keep them from failing.
What cam are you currently running?
[ December 07, 2001: Message edited by: 2quick4u ]</p>
It sounds like your car has some very aggressive ramps to float the valves at 6,500 with your HD dual spring setup. I personnaly am not a big fan of high open pressure dual valve spring setups or mega acceralation ramps. The way I would set up an LS1 with an aggressive lobe profile would be to use Comp 918 springs with the lightweight Comp lifters and the ARE rev kit. Lighter valves and retainers would also help.
When you get into float, you either need to reduce valvetrain weight, or add open spring pressure, or use a cam with less aggressive lobes or a combination of all three.
Personally I'd rather add the spring pressure at the lifter (which is the heaviest valvetrain component) with a rev kit than to add it at the valve with dual springs. The rev kit puts the extra pressure on the lifter body and not the lifter plunger so you won't collaspe lifters. It also keeps the extra pressure and stress off the pushrods and rocker arms to keep them from failing.
What cam are you currently running?
[ December 07, 2001: Message edited by: 2quick4u ]</p>
12-07-2001, 01:16 PM
#4
Re: Valvespring experts? Well....
What I understand is that both *can* flatten the lifter. For each lifter, there is a theoretical max on both #s that can be withstood over time. Also, the 1.7 ratio is important. If there is a 150 lb seat closed seat pressure, the lifter will feel 1.7*150 or 255 lbs of pressure when opening the valve and, if it has a max open pressure at .560 lift of say 380 lbs, thats 1.7*380 = 646 lbs..
Lets look at what the valvespring does over the course of one rotation of the cam lobe. First the lobe pushes up on the lifter and the pushrod. The rocker amplifies the motion by 1.7 X's using leverage, and then pushes on the momentum of the valve plus the resistance of the spring. This is at the beginning of the springs motion, so the spring starts by providing closed seat pressure and then building linearly (or close to it) until it reaches the the end of the opening ramp. Then the opening motion of the valve starts to slow so that it can turn around and close. The momentum of the opening valve actually works against the spring and the curve of the top of the valve. The valve wants to keep opening (an object in motion wants to stay in motion). The spring holds the valve to the rocker and the rocker to the pushrod and the pushrod to the lifter and the lifter to the cam as the lobe of the cam starts to try and turn the valve around, past its peak lift, and start to close it. If the spring is not strong enough, it cant hold these together and the valve(and the rest of the valvetrain) do a sort of ski jump off of the lobe of the cam. This is called valve float. Because of where in the cycle it occurs, it is mostly related to the spring pressure with the valve open at its peak lift, rather than the closed seat pressure. The closed seat pressure only needs to be enough to control the valve as it closes again and hold it against the cam. At higher RPMs, a weak closed seat pressure can cause valve bounce, where resonances caught in the valvetrain escape at the closing of the valve adn cause the valve to bounce off of the seat as its closed.
What you can do then is derive from this a curve of pressure applied to the rocker tip by the combination of the valve and the spring. It looks alot *like* the curve of the cam lift on paper, but it includes the pressure of the spring, linearly connected to lift and *also* the momentum of the valve.
A hydraulic lifter works with two important concepts. The first is that the average pressure over time exerted by oil through an orifice into the lifter and onto the plunger (the little piston in the lifter that the pushrod rests on) is MORE than the average pressure caused by the pushrod pressing down on the plunger. If it is LESS, the pushrod will deflate. The second way a lifter works is to have valving in it such that sudden force on the plunger cannot push out much oil (a small orifice). Some lifters have fancy valving that allows oil to go into to lifter faster than it can come out.
So that brings us back to our question: Given either the stock lifters or the CompR lifters, what combination of big heavy intake valves, rocker ratio,and spring pressure curves will flatten a lifter whe the oil is at its least viscous (hot, synthetic, clean, etc)
I can tell you that 1.8 rockers, 2.08 valves, and K-Motion K-800s are too much for any oil viscosity. I flattened my STOCK lifters.
it *seems* that 1.7 rockers, 2.08 valves, and Crane 99893 springs do not flatten the COMP R lifters and on the other side, are strong enough to hold onto a Hammer cam lobe at 6700 rpm.
Doesnt appear the rest of the engine could (thats another subject, TBD :-/ )
I need to find out from Nick what 2.08" intake valves he used and how much they weigh. Heavier valves need more spring pressure, YET can also contribute more to flattening lifters with their momentum.
More data-points?
thanks,
Chris
[ December 07, 2001: Message edited by: Visceral ]</p>
What I understand is that both *can* flatten the lifter. For each lifter, there is a theoretical max on both #s that can be withstood over time. Also, the 1.7 ratio is important. If there is a 150 lb seat closed seat pressure, the lifter will feel 1.7*150 or 255 lbs of pressure when opening the valve and, if it has a max open pressure at .560 lift of say 380 lbs, thats 1.7*380 = 646 lbs..
Lets look at what the valvespring does over the course of one rotation of the cam lobe. First the lobe pushes up on the lifter and the pushrod. The rocker amplifies the motion by 1.7 X's using leverage, and then pushes on the momentum of the valve plus the resistance of the spring. This is at the beginning of the springs motion, so the spring starts by providing closed seat pressure and then building linearly (or close to it) until it reaches the the end of the opening ramp. Then the opening motion of the valve starts to slow so that it can turn around and close. The momentum of the opening valve actually works against the spring and the curve of the top of the valve. The valve wants to keep opening (an object in motion wants to stay in motion). The spring holds the valve to the rocker and the rocker to the pushrod and the pushrod to the lifter and the lifter to the cam as the lobe of the cam starts to try and turn the valve around, past its peak lift, and start to close it. If the spring is not strong enough, it cant hold these together and the valve(and the rest of the valvetrain) do a sort of ski jump off of the lobe of the cam. This is called valve float. Because of where in the cycle it occurs, it is mostly related to the spring pressure with the valve open at its peak lift, rather than the closed seat pressure. The closed seat pressure only needs to be enough to control the valve as it closes again and hold it against the cam. At higher RPMs, a weak closed seat pressure can cause valve bounce, where resonances caught in the valvetrain escape at the closing of the valve adn cause the valve to bounce off of the seat as its closed.
What you can do then is derive from this a curve of pressure applied to the rocker tip by the combination of the valve and the spring. It looks alot *like* the curve of the cam lift on paper, but it includes the pressure of the spring, linearly connected to lift and *also* the momentum of the valve.
A hydraulic lifter works with two important concepts. The first is that the average pressure over time exerted by oil through an orifice into the lifter and onto the plunger (the little piston in the lifter that the pushrod rests on) is MORE than the average pressure caused by the pushrod pressing down on the plunger. If it is LESS, the pushrod will deflate. The second way a lifter works is to have valving in it such that sudden force on the plunger cannot push out much oil (a small orifice). Some lifters have fancy valving that allows oil to go into to lifter faster than it can come out.
So that brings us back to our question: Given either the stock lifters or the CompR lifters, what combination of big heavy intake valves, rocker ratio,and spring pressure curves will flatten a lifter whe the oil is at its least viscous (hot, synthetic, clean, etc)
I can tell you that 1.8 rockers, 2.08 valves, and K-Motion K-800s are too much for any oil viscosity. I flattened my STOCK lifters.
it *seems* that 1.7 rockers, 2.08 valves, and Crane 99893 springs do not flatten the COMP R lifters and on the other side, are strong enough to hold onto a Hammer cam lobe at 6700 rpm.
Doesnt appear the rest of the engine could (thats another subject, TBD :-/ )
I need to find out from Nick what 2.08" intake valves he used and how much they weigh. Heavier valves need more spring pressure, YET can also contribute more to flattening lifters with their momentum.
More data-points?
thanks,
Chris
[ December 07, 2001: Message edited by: Visceral ]</p>
12-07-2001, 02:20 PM
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Re: Valvespring experts? [quote]Originally posted by 2quick4u:
<strong>JMX,
It sounds like your car has some very aggressive ramps to float the valves at 6,500 with your HD dual spring setup. I personnaly am not a big fan of high open pressure dual valve spring setups or mega acceralation ramps. The way I would set up an LS1 with an aggressive lobe profile would be to use Comp 918 springs with the lightweight Comp lifters and the ARE rev kit. Lighter valves and retainers would also help.
When you get into float, you either need to reduce valvetrain weight, or add open spring pressure, or use a cam with less aggressive lobes or a combination of all three.
Personally I'd rather add the spring pressure at the lifter (which is the heaviest valvetrain component) with a rev kit than to add it at the valve with dual springs. The rev kit puts the extra pressure on the lifter body and not the lifter plunger so you won't collaspe lifters. It also keeps the extra pressure and stress off the pushrods and rocker arms to keep them from failing.
What cam are you currently running?
[ December 07, 2001: Message edited by: 2quick4u ]</strong><hr></blockquote>
To be honest, I think the ramps are screwed....This was supposedly one of the very first Comp Xtreme lobed cams produced...at least thats the story I got as I waited 2-3 months to get the cam while comp supposedly tried to get the lobe right. The specs are 224/230 .538/.538 with a 114LSA. Dont have the full card in front of me unfortunatly.
I have manly valves and titanium retainers, but the intake valve is 2.08 so it may be heavier than most peoples.
What are these lightweight lifters you speak of? I have the "comp R" or promagnum lifters already...they didnt feel like they weighed any less than the stock ones.
Reguardless, I'm not going crazy with my cam specs so I think its more of an issue with my cam right now than with my valvetrain. I'll be ordering a cam in the next few days.
<strong>JMX,
It sounds like your car has some very aggressive ramps to float the valves at 6,500 with your HD dual spring setup. I personnaly am not a big fan of high open pressure dual valve spring setups or mega acceralation ramps. The way I would set up an LS1 with an aggressive lobe profile would be to use Comp 918 springs with the lightweight Comp lifters and the ARE rev kit. Lighter valves and retainers would also help.
When you get into float, you either need to reduce valvetrain weight, or add open spring pressure, or use a cam with less aggressive lobes or a combination of all three.
Personally I'd rather add the spring pressure at the lifter (which is the heaviest valvetrain component) with a rev kit than to add it at the valve with dual springs. The rev kit puts the extra pressure on the lifter body and not the lifter plunger so you won't collaspe lifters. It also keeps the extra pressure and stress off the pushrods and rocker arms to keep them from failing.
What cam are you currently running?
[ December 07, 2001: Message edited by: 2quick4u ]</strong><hr></blockquote>
To be honest, I think the ramps are screwed....This was supposedly one of the very first Comp Xtreme lobed cams produced...at least thats the story I got as I waited 2-3 months to get the cam while comp supposedly tried to get the lobe right. The specs are 224/230 .538/.538 with a 114LSA. Dont have the full card in front of me unfortunatly.
I have manly valves and titanium retainers, but the intake valve is 2.08 so it may be heavier than most peoples.
What are these lightweight lifters you speak of? I have the "comp R" or promagnum lifters already...they didnt feel like they weighed any less than the stock ones.
Reguardless, I'm not going crazy with my cam specs so I think its more of an issue with my cam right now than with my valvetrain. I'll be ordering a cam in the next few days.
12-07-2001, 02:23 PM
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Re: Valvespring experts? Those extreme cam lobes NEVER work well above 6500rpm, its always been the case. Just swap cams, nothing you can do will make them work at that RPM. Maybe you should go the other way and try a 212/218 comp cam, you'll still make 400rw, and have a smoother setup. <img src="images/icons/wink.gif" border="0">
12-07-2001, 02:23 PM
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Re: Valvespring experts? Visc, good amount of explanation there. Thanks.
That C1 cam probably has less agressive lobes than mine right now....but its just a guess.
That C1 cam probably has less agressive lobes than mine right now....but its just a guess.
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12-07-2001, 02:49 PM
#8
Re: Valvespring experts? C1 is going to be more aggressive. More lift for the same duration at .050". (.566" lift for 224 @ .050 and just 275 degrees total duration at .006, that's pretty fast)
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12-07-2001, 03:01 PM
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Re: Valvespring experts? I'm running a Lunati 242/242/114 with 987's and my car doesn't float valves when it's been take up to 7000 rpms.
I ran 941's with my old P2 clone cam 221/224/113 and it was fine up to 7000 but it didn't make any real power up there.
If your cam is bad it will be worn and I bet your lifters will be tired...
If you are running stock lifters your preload should be no more than .050 right?
I run the Comp R's and they are probably at like .020 preload, getting them down to .010 is too damn time consuming and Comp said it was no big deal anyway they have tested them up to .050 and there was not a huge difference in that vs zero lash.
I ran 941's with my old P2 clone cam 221/224/113 and it was fine up to 7000 but it didn't make any real power up there.
If your cam is bad it will be worn and I bet your lifters will be tired...
If you are running stock lifters your preload should be no more than .050 right?
I run the Comp R's and they are probably at like .020 preload, getting them down to .010 is too damn time consuming and Comp said it was no big deal anyway they have tested them up to .050 and there was not a huge difference in that vs zero lash.
12-07-2001, 03:21 PM
#10
Re: Valvespring experts? [quote]Originally posted by Pro Stock John:
<strong>
If you are running stock lifters your preload should be no more than .050 right?
I run the Comp R's and they are probably at like .020 preload, getting them down to .010 is too damn time consuming and Comp said it was no big deal anyway they have tested them up to .050 and there was not a huge difference in that vs zero lash.</strong><hr></blockquote>
I saw the stock lifters take .150 once. (back to me smooshing lifters) I know that Geoff at Thunder once measured some pretty huge potential on stock lifters once too. Now, I cant say that operating at up to .100 or more preload wasnt what caused my lifter to eventually fail, but it OVERextended and crushed the retaining wire.
On the other hand, I believe Comp when they say that .050 is all the preload they can deal with.
One of the tricks with the LS1 "bolt down to 18-22 lbt ft and go" preload is that there needs to be some pretty large room for error. I used to flinch everytime someone mentioned using stock pushrod lengths (or not even thinking about it) with milled heads, but after seeing what the stock lifters will do, I have no doubt its within their safe grasp. I am NOT sure its within the CompR's abilities to handle that kind of slop (>.050 preload). Remember: The lifter preload will change everytime you change the cam, since the cam Base Circle is reduced on higher lift cams...
Note... if the valve tip is staying in the same place, for every 1 unit you tighten down the rocker stud, (1+1.7)/1.7 = 1.59 units of preload is added. I dont know what the thread pitch is for m8 thread though. But if I were assembling a new configuration of valvetrain peices-parts (tm), I'd be measuring preload and determining the right length of pushrod. (jmX and I did this with a effective, cheap pushrod length checker from either Summit or Jegs. If it was from Jegs, it probably cam with a cool yellow bumper sticker too.)
I (for once ;-) ) agree with Terry here though.
I dont do extreme energy lobes. Too much for anything over 6000 rpm IMHO if its 220 or larger.
chris
valvetrain expert wannabe
[ December 07, 2001: Message edited by: Visceral ]</p>
<strong>
If you are running stock lifters your preload should be no more than .050 right?
I run the Comp R's and they are probably at like .020 preload, getting them down to .010 is too damn time consuming and Comp said it was no big deal anyway they have tested them up to .050 and there was not a huge difference in that vs zero lash.</strong><hr></blockquote>
I saw the stock lifters take .150 once. (back to me smooshing lifters) I know that Geoff at Thunder once measured some pretty huge potential on stock lifters once too. Now, I cant say that operating at up to .100 or more preload wasnt what caused my lifter to eventually fail, but it OVERextended and crushed the retaining wire.
On the other hand, I believe Comp when they say that .050 is all the preload they can deal with.
One of the tricks with the LS1 "bolt down to 18-22 lbt ft and go" preload is that there needs to be some pretty large room for error. I used to flinch everytime someone mentioned using stock pushrod lengths (or not even thinking about it) with milled heads, but after seeing what the stock lifters will do, I have no doubt its within their safe grasp. I am NOT sure its within the CompR's abilities to handle that kind of slop (>.050 preload). Remember: The lifter preload will change everytime you change the cam, since the cam Base Circle is reduced on higher lift cams...
Note... if the valve tip is staying in the same place, for every 1 unit you tighten down the rocker stud, (1+1.7)/1.7 = 1.59 units of preload is added. I dont know what the thread pitch is for m8 thread though. But if I were assembling a new configuration of valvetrain peices-parts (tm), I'd be measuring preload and determining the right length of pushrod. (jmX and I did this with a effective, cheap pushrod length checker from either Summit or Jegs. If it was from Jegs, it probably cam with a cool yellow bumper sticker too.)
I (for once ;-) ) agree with Terry here though.
I dont do extreme energy lobes. Too much for anything over 6000 rpm IMHO if its 220 or larger.
chris
valvetrain expert wannabe
[ December 07, 2001: Message edited by: Visceral ]</p>
12-07-2001, 03:40 PM
#11
Re: Valvespring experts? BTW, directed at NOONE in particular
Im gonna immortalize:
***Chris's Cam suggestions***
You want- Smoother idle, probably pass emmisions with a raised idle (900), m6, within 5hp of top hydraulic cams
You get- MTI B1
You want- Fun, "suggestive" idle, no concern for emmisions, m6, great HP
You get- MTI C1 (hammer cam) or ThunderRacing 224/224 on a 112
You want- Fun, "suggestive" idle, no concern for emmisions, m6, 2-3 hp less than best, but quiet valvetrain
You get- MTI T1
You want- Automatic tranny
You get- Someone else to recommend a cam
Now: NOTE NOTE NOTE
I have had awesome experiences with the knowledge and experience with cams from Geoff at ThunderRacing and Jeff at MTI. You will not go wrong. BUT, there are other very knowledgable people around (MMS, HoS, ChrisB for example). Buy a cam from someone you trust completely. They should ask you a *alot* of questions before they recommend a cam.
Buy a cam from someone who took part in designing the lobe, and can tell you duration at .200 lift
like I said, I just wanted to put this down on ..er... screen, since everytime someone asks a "what cam should I get" question, I think the answer is probably pretty simple given all the right info.
chris
Im gonna immortalize:
***Chris's Cam suggestions***
You want- Smoother idle, probably pass emmisions with a raised idle (900), m6, within 5hp of top hydraulic cams
You get- MTI B1
You want- Fun, "suggestive" idle, no concern for emmisions, m6, great HP
You get- MTI C1 (hammer cam) or ThunderRacing 224/224 on a 112
You want- Fun, "suggestive" idle, no concern for emmisions, m6, 2-3 hp less than best, but quiet valvetrain
You get- MTI T1
You want- Automatic tranny
You get- Someone else to recommend a cam
Now: NOTE NOTE NOTE
I have had awesome experiences with the knowledge and experience with cams from Geoff at ThunderRacing and Jeff at MTI. You will not go wrong. BUT, there are other very knowledgable people around (MMS, HoS, ChrisB for example). Buy a cam from someone you trust completely. They should ask you a *alot* of questions before they recommend a cam.
Buy a cam from someone who took part in designing the lobe, and can tell you duration at .200 lift
like I said, I just wanted to put this down on ..er... screen, since everytime someone asks a "what cam should I get" question, I think the answer is probably pretty simple given all the right info.
chris
12-07-2001, 03:49 PM
#12
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Re: Valvespring experts? If you had .150 lifter preload I am surprised the car even ran. You'd hardly have any compression from the valved hanging open.
JMX if you have 224/230/112 I would not shift that higher than maybe 6500 at the track no?
JMX if you have 224/230/112 I would not shift that higher than maybe 6500 at the track no?
12-07-2001, 04:00 PM
#13
Re: Valvespring experts? [quote]Originally posted by Pro Stock John:
<strong>If you had .150 lifter preload I am surprised the car even ran. You'd hardly have any compression from the valved hanging open.
JMX if you have 224/230/112 I would not shift that higher than maybe 6500 at the track no?</strong><hr></blockquote>
Valve wasnt hanging open... the plunger was that far down in the lifter. Not a good situation, but interesting nonetheless. With the crane 1.8s, the preload was adjustable, and I was trying to quiet down a particular rocker/pr/lifter. Interestingly, with the reloacted coilpacks, I was able to adjust the rockers for preload while the car was running, in an effort to use the least preload to get the valvetrain quiet. (not something I would suggest, just interesting)
chris
<strong>If you had .150 lifter preload I am surprised the car even ran. You'd hardly have any compression from the valved hanging open.
JMX if you have 224/230/112 I would not shift that higher than maybe 6500 at the track no?</strong><hr></blockquote>
Valve wasnt hanging open... the plunger was that far down in the lifter. Not a good situation, but interesting nonetheless. With the crane 1.8s, the preload was adjustable, and I was trying to quiet down a particular rocker/pr/lifter. Interestingly, with the reloacted coilpacks, I was able to adjust the rockers for preload while the car was running, in an effort to use the least preload to get the valvetrain quiet. (not something I would suggest, just interesting)
chris
12-07-2001, 04:31 PM
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Re: Valvespring experts? [quote]Originally posted by Pro Stock John:
[QB]I'm running a Lunati 242/242/114 with 987's and my car doesn't float valves when it's been take up to 7000 rpms.
If your cam is bad it will be worn and I bet your lifters will be tired...
If you are running stock lifters your preload should be no more than .050 right?
I run the Comp R's and they are probably at like .020 preload[QB]<hr></blockquote>
My cam was bad the moment I put it in....its had this issue since day 1. Its most definitly not worn.
I have CompR lifters at 20 thousanths preload...have had them for quite some time. It didnt matter what preload I ran in reguards to my high rpm issue. Both 7.350" and 7.400" pushrods gave me the same amount of excessive valvetrain noise, and both floated the valves at the same point in the power band. Car ran the same both ways.
I think the cam is just bad. Maybe it doesnt match the cam card, maybe it does, but its gonna get swapped out.
My 230/230 .566/.566 112 cam had NONE of these issues and I lost no power between 6200 and 6800 rpms...just flat smooth power. Thats all I want now.
[QB]I'm running a Lunati 242/242/114 with 987's and my car doesn't float valves when it's been take up to 7000 rpms.
If your cam is bad it will be worn and I bet your lifters will be tired...
If you are running stock lifters your preload should be no more than .050 right?
I run the Comp R's and they are probably at like .020 preload[QB]<hr></blockquote>
My cam was bad the moment I put it in....its had this issue since day 1. Its most definitly not worn.
I have CompR lifters at 20 thousanths preload...have had them for quite some time. It didnt matter what preload I ran in reguards to my high rpm issue. Both 7.350" and 7.400" pushrods gave me the same amount of excessive valvetrain noise, and both floated the valves at the same point in the power band. Car ran the same both ways.
I think the cam is just bad. Maybe it doesnt match the cam card, maybe it does, but its gonna get swapped out.
My 230/230 .566/.566 112 cam had NONE of these issues and I lost no power between 6200 and 6800 rpms...just flat smooth power. Thats all I want now.
12-07-2001, 04:32 PM
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Re: Valvespring experts? [quote]Originally posted by Pro Stock John:
<strong>
JMX if you have 224/230/112 I would not shift that higher than maybe 6500 at the track no?</strong><hr></blockquote>
Its on a 114. My 230/230 112 liked to be shifted at 6750rpms though.
<strong>
JMX if you have 224/230/112 I would not shift that higher than maybe 6500 at the track no?</strong><hr></blockquote>
Its on a 114. My 230/230 112 liked to be shifted at 6750rpms though.
12-07-2001, 04:35 PM
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Re: Valvespring experts? [quote]Originally posted by Terry Burger:
<strong>Those extreme cam lobes NEVER work well above 6500rpm, its always been the case. Just swap cams, nothing you can do will make them work at that RPM. Maybe you should go the other way and try a 212/218 comp cam, you'll still make 400rw, and have a smoother setup. <img src="images/icons/wink.gif" border="0"> </strong><hr></blockquote>
I've made 400rwhp plenty of times, with a 218/224, a 230/230, and this 224/230....the only reason I'm trying all this stuff is so I can find out what works and what doesnt....I'd be 100% happy with my current cam and I'm done experimenting for hte most part EXCEPT that this cam is fuxored. Now I'm having to do an unplanned 4th cam swap...bleh. Either way, this 224/230 drives just fine...I'll be going with a C1 or a thunder 224 cam. Not quite sure yet. Whatever it is will be on a 114 lsa.
<strong>Those extreme cam lobes NEVER work well above 6500rpm, its always been the case. Just swap cams, nothing you can do will make them work at that RPM. Maybe you should go the other way and try a 212/218 comp cam, you'll still make 400rw, and have a smoother setup. <img src="images/icons/wink.gif" border="0"> </strong><hr></blockquote>
I've made 400rwhp plenty of times, with a 218/224, a 230/230, and this 224/230....the only reason I'm trying all this stuff is so I can find out what works and what doesnt....I'd be 100% happy with my current cam and I'm done experimenting for hte most part EXCEPT that this cam is fuxored. Now I'm having to do an unplanned 4th cam swap...bleh. Either way, this 224/230 drives just fine...I'll be going with a C1 or a thunder 224 cam. Not quite sure yet. Whatever it is will be on a 114 lsa.
12-07-2001, 04:59 PM
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Re: Valvespring experts? I'm just joking with you because no matter what you do, you still wind up at 400rwhp. Might as well put an LS6 cam in there and be done with it. <img src="images/icons/wink.gif" border="0">
12-07-2001, 05:20 PM
#18
Re: Valvespring experts? [quote]Originally posted by jmX:
<strong>
I'll be going with a C1 or a thunder 224 cam. Not quite sure yet. Whatever it is will be on a 114 lsa.</strong><hr></blockquote>
Something tells me that noone would be able to tell the slightest bit of difference between those two cams. Which is cheaper? Available sooner?
chris
<strong>
I'll be going with a C1 or a thunder 224 cam. Not quite sure yet. Whatever it is will be on a 114 lsa.</strong><hr></blockquote>
Something tells me that noone would be able to tell the slightest bit of difference between those two cams. Which is cheaper? Available sooner?
chris
12-07-2001, 05:24 PM
#19
Re: Valvespring experts? [quote]Originally posted by jmX:
<strong>
Now I'm having to do an unplanned 4th cam swap...bleh.</strong><hr></blockquote>
Hey! Thats better than an unplanned **5th** head r&r ;-)
chris
Who has to put in head studs because the head bolt threads in the block are getting tired
<strong>
Now I'm having to do an unplanned 4th cam swap...bleh.</strong><hr></blockquote>
Hey! Thats better than an unplanned **5th** head r&r ;-)
chris
Who has to put in head studs because the head bolt threads in the block are getting tired
12-07-2001, 05:29 PM
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Re: Valvespring experts? [quote]Originally posted by Visceral:
<strong>
Something tells me that noone would be able to tell the slightest bit of difference between those two cams. Which is cheaper? Available sooner?
chris</strong><hr></blockquote>
Obviously the non-MTI one will be cheaper, just like everything else <img src="images/icons/wink.gif" border="0">
I'm the last one that needs lecturing on if I'll be able to tell the difference between cams. <img src="images/icons/grin.gif" border="0"> Its valve clearance that is the concern...few extra degrees here or there might be the difference between a piston with a little valve mark in it or not.
Terry, I bet an ls6 cam would put down 405rwhp, just like all the rest, but in my car only. <img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" />
<strong>
Something tells me that noone would be able to tell the slightest bit of difference between those two cams. Which is cheaper? Available sooner?
chris</strong><hr></blockquote>
Obviously the non-MTI one will be cheaper, just like everything else <img src="images/icons/wink.gif" border="0">
I'm the last one that needs lecturing on if I'll be able to tell the difference between cams. <img src="images/icons/grin.gif" border="0"> Its valve clearance that is the concern...few extra degrees here or there might be the difference between a piston with a little valve mark in it or not.
Terry, I bet an ls6 cam would put down 405rwhp, just like all the rest, but in my car only. <img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" />