Any damage to stock valvetrain
Yeah I haven't been around, I know.
I moved and everything else going on. I've been back on for a couple days and doing some reading.
When I worked for Saturn it was a big issue if someone used to heavy of an oil or anytime you removed the cams the lifters would pump up and the valves hang open. The same lifters are used elsewhere on GM cars too.
I am trying to get back to my car now and plan on ordering cams. I am thinking about being the one to try 272 IN 280 EX. Hmm...
I moved and everything else going on. I've been back on for a couple days and doing some reading.
When I worked for Saturn it was a big issue if someone used to heavy of an oil or anytime you removed the cams the lifters would pump up and the valves hang open. The same lifters are used elsewhere on GM cars too.
I am trying to get back to my car now and plan on ordering cams. I am thinking about being the one to try 272 IN 280 EX. Hmm...
Last edited by timzcat; Feb 22, 2005 at 10:29 AM.
Originally Posted by EM@WORKS
So this is our abbreviated findings. We installed a "test" valve spring next to a stock valve spring at the same cylinder and found that the hydraulic lifter height increased with the lower rate spring (see pics below) while on the base circle and on the cam lobe.
(This was a complete running motor that was just opened up at the valve cover for testing with oil etc.)
At the test spring where the lifter was considerably higher, there was absolute contact with the retainer and stem seal. However we have never seen lifters protrude this high in a 4G63 when opening up a recently running engine. This leads us to believe that a clearance test while using a "test" spring is invalid.
When using other brand springs including the WORKS ones and visually checking clearance with what looks like a normal lifter height, there is no doubt that the clearence is very close if any.
In conclusion, we could not determine stock retainer to stem seal interference with "high" lift cams because we do not know the actual hydraulic lifter height during engine operation which would affect the rocker arm height at the valve.
The unanimous vote here at WORKS is that we will put our springs and Ti retainers in every EVO we own when changing to a higher lift cam. Cheap insurance and peace of mind is priceless.
(This was a complete running motor that was just opened up at the valve cover for testing with oil etc.)
At the test spring where the lifter was considerably higher, there was absolute contact with the retainer and stem seal. However we have never seen lifters protrude this high in a 4G63 when opening up a recently running engine. This leads us to believe that a clearance test while using a "test" spring is invalid.
When using other brand springs including the WORKS ones and visually checking clearance with what looks like a normal lifter height, there is no doubt that the clearence is very close if any.
In conclusion, we could not determine stock retainer to stem seal interference with "high" lift cams because we do not know the actual hydraulic lifter height during engine operation which would affect the rocker arm height at the valve.
The unanimous vote here at WORKS is that we will put our springs and Ti retainers in every EVO we own when changing to a higher lift cam. Cheap insurance and peace of mind is priceless.
First of all I think this will go down as one of the most "on topic" and informative threads on EVOM ever. I appreciate everyones input and think it is great that 3 different unaffiliated vendors can have a discussion without any slander 
. I have to admit that I have learned a thing or two from this thread myself.
At any rate, while the lifter info is very interesting (thanks timzcat) it doesnt relate to the contact. Here is why:
If you take the lifter, and spring out of the equation you are left with the only items in question (valve, retainer, stem seal).
I will repost our original findings, all measurements taken at the valve which is how HKS posts the lift measurements for their cams.
First we measure the length of exposed valvestem from the valveseal to the tip with valve in closed position (as shown below) 24.42mm
then we subtract the length from tip to the bottom of the retainer 14.27mm
what we are left with is 10.15mm of useable valve travel before the retainer will contact the seal.
for reference........ HKS cams have 10.8/10.2 mm of lift at static (non running) when the car is at 7000rpm you get a dynamic "surge" of the valvetrain exagerating the condition.
Jason
. I have to admit that I have learned a thing or two from this thread myself.At any rate, while the lifter info is very interesting (thanks timzcat) it doesnt relate to the contact. Here is why:
If you take the lifter, and spring out of the equation you are left with the only items in question (valve, retainer, stem seal).
I will repost our original findings, all measurements taken at the valve which is how HKS posts the lift measurements for their cams.
First we measure the length of exposed valvestem from the valveseal to the tip with valve in closed position (as shown below) 24.42mm
then we subtract the length from tip to the bottom of the retainer 14.27mm
what we are left with is 10.15mm of useable valve travel before the retainer will contact the seal.
for reference........ HKS cams have 10.8/10.2 mm of lift at static (non running) when the car is at 7000rpm you get a dynamic "surge" of the valvetrain exagerating the condition.
Jason
I am not arguing the measurement you got, but I don't understand why Buschur comes up with something different. 
I guess part of my point was there is some loss at the lifter from the spring pressure vs. oil pressure. I don't know that I would out and out say that just because HKS states that the lift is 10.2 mm that the actual or net lift is 10.2 mm.
I think the gross lift is probably 10.2 and that doesn't take into account for lifter height or any of the other variables. Are you saying that HKS specifically states that their lift number is the amount the valve travels? I ask because it is odd for a manufacturer to state numbers in this manner because the cannot control all the variables like rocker ratios, etc. The can only control the actual lift at the cam.
We all know hydralic lifters are not the most efficient method but solid is just too noisey and needs adjustment so for production car purposes no manufacturer is going to touch them.
I guess part of my point was there is some loss at the lifter from the spring pressure vs. oil pressure. I don't know that I would out and out say that just because HKS states that the lift is 10.2 mm that the actual or net lift is 10.2 mm.
I think the gross lift is probably 10.2 and that doesn't take into account for lifter height or any of the other variables. Are you saying that HKS specifically states that their lift number is the amount the valve travels? I ask because it is odd for a manufacturer to state numbers in this manner because the cannot control all the variables like rocker ratios, etc. The can only control the actual lift at the cam.
We all know hydralic lifters are not the most efficient method but solid is just too noisey and needs adjustment so for production car purposes no manufacturer is going to touch them.
HKS, Crower, Jun, and us all quote lift numbers at the valve. It is really a simple equation because all the lifter does is take up lash at the rocker/cam interface. If the lifter is changing valve lift then there is an internal problem with the motor. The lifter oil galley is regulated to approximately 30 psi. The rocker ratio (1.7 to 1) and cam profile remain constant.
We are talking with David Buschur about the interference and he is very helpful, I think we can all benefit from this.
We are talking with David Buschur about the interference and he is very helpful, I think we can all benefit from this.
So Revolver said they are comparing notes with Buschur on this issue but no one has come back to give an answer in which they agree or still do not agree.
It'd be nice if we could get an answer. Not that I don't trust Revolver but they obviously have a vested interest in them hitting. I want to get in on the group buy if I need springs, but honestly I'd rather not do them if I don't have to.
It'd be nice if we could get an answer. Not that I don't trust Revolver but they obviously have a vested interest in them hitting. I want to get in on the group buy if I need springs, but honestly I'd rather not do them if I don't have to.
At this point, I believe they have agreed to disagree about clearance... and somewhere between then and now, David said that if their product was better than the one he was using, he would switch. Revolver responded with "a set is in the mail". David probably just got them in the last day or two.
Regardless of contact or not, I'd made up my mind that I wanted more "rev"... my dyno graph shows my northward march of hp was halted not by power falling off, but lack of "headroom" in the rev range (HKS 272's and some "massaging" from yours truly). Ever since David said that the OE Evo springs are weaker than OE DSM springs, I've always had the thought of getting rid of them in the back of my mind. Revolver just stepped in and made an offer I couldn't refuse.
Specs for the Revolver set here: https://www.evolutionm.net/forums/sh...99#post1698499
Regardless of contact or not, I'd made up my mind that I wanted more "rev"... my dyno graph shows my northward march of hp was halted not by power falling off, but lack of "headroom" in the rev range (HKS 272's and some "massaging" from yours truly). Ever since David said that the OE Evo springs are weaker than OE DSM springs, I've always had the thought of getting rid of them in the back of my mind. Revolver just stepped in and made an offer I couldn't refuse.
Specs for the Revolver set here: https://www.evolutionm.net/forums/sh...99#post1698499
Last edited by Zeus; Feb 26, 2005 at 12:24 AM.
i just learnd so much about cams and valve stuff. thanks to y'all can anyone tell us what s ur experience with revolver cams and valvetrain? it is really cool to see such an high lift # on revolver cams than hks.
i wonder how much whp can it make ?
i wonder how much whp can it make ?
Maybe I missed something but has anyone asked HKS for their opinion in this matter? I looked at their web site and while they suggest springs I couldn't find anything that addresses this potential problem.
Revolver ValveSpring specs for those that are interested:
Originally Posted by mttam510
Lo (free length) : 47.74mm / 1.879"
L1 (installed length): 38.1mm
F1 (installed load): 75 lb/in
L2 (working/valve-open length): 27.3mm (HKS) 26.6mm (Revolver
F2 (working/valve-open load): 163 lb/in @10.8mm (HKS) 172 lb/in @11.5mm(Revolver)
Sc: (spring rate): 214.6 lb/in
Lc: (block/closed/coil-bound length): 23.5mm
Fc: (block/closed load): 206.8 lb/in
The modulus of elasticity in tension, also known as Young's modulus E, is the ratio of stress to strain on the loading plane along the loading direction. This is a very important number when it comes to spring design. The Modulus for the wire that we call out for this design = 206844 N/mm2. No need to worry, we use a high TENSILE CrSi (chrome-silicon) wire, heat treat and shot peened properly as well.
L1 (installed length): 38.1mm
F1 (installed load): 75 lb/in
L2 (working/valve-open length): 27.3mm (HKS) 26.6mm (Revolver
F2 (working/valve-open load): 163 lb/in @10.8mm (HKS) 172 lb/in @11.5mm(Revolver)
Sc: (spring rate): 214.6 lb/in
Lc: (block/closed/coil-bound length): 23.5mm
Fc: (block/closed load): 206.8 lb/in
The modulus of elasticity in tension, also known as Young's modulus E, is the ratio of stress to strain on the loading plane along the loading direction. This is a very important number when it comes to spring design. The Modulus for the wire that we call out for this design = 206844 N/mm2. No need to worry, we use a high TENSILE CrSi (chrome-silicon) wire, heat treat and shot peened properly as well.
I talked with the guys at Revolver, as they called me. I thought they were sending a set of springs but that was about 2 weeks ago and I don't have a set yet. I guess it won't matter as they have openly posted their results above.
To be honest I am confused with some of the wording in your desciption above.
Seat pressure is 75 pounds?
Open pressure at 10.8 mm (.424) valve lift is 163?
Coil bind happens at .923? That one can't be right, is it?
Thanks,
David Buschur
www.buschurracing.com
To be honest I am confused with some of the wording in your desciption above.
Seat pressure is 75 pounds?
Open pressure at 10.8 mm (.424) valve lift is 163?
Coil bind happens at .923? That one can't be right, is it?
Thanks,
David Buschur
www.buschurracing.com
Originally Posted by davidbuschur
I talked with the guys at Revolver, as they called me. I thought they were sending a set of springs but that was about 2 weeks ago and I don't have a set yet. I guess it won't matter as they have openly posted their results above.
Originally Posted by davidbuschur
Seat pressure is 75 pounds?
Originally Posted by davidbuschur
Open pressure at 10.8 mm (.424) valve lift is 163?
Originally Posted by davidbuschur
Coil bind happens at .923? That one can't be right, is it?
Thanks for sending them out. I will call you guys when I get them. So the Lc#, that is coil bind on the spring then? If so that is unreal as I have never seen a spring for a 4g63 go past .620 before it was bound. 2.35mm=.923. How is that possible, the wire would have to be very thin in the spring to even get close.
Stock EVO springs bind at .490. Seat pressure is 62 pounds and open is 140 pounds. For you guys reading all this.
David Buschur
www.buschurracing.com
Stock EVO springs bind at .490. Seat pressure is 62 pounds and open is 140 pounds. For you guys reading all this.
David Buschur
www.buschurracing.com