Header

OK so I’ve had this cam sitting around collecting dust for 6+ months so it’s about time put it in the Z06 just need some valve springs. Cam specs are 23x/25x .660"/.660". So far springs I'm considering are:

1. Cam Vendor’s Springs .675" max lift (no specs available for open/closed seat pressure), $365 + shipping.

2. Patriot Gold Extreme .660" max lift (Spring Pressure Closed: 155 lbs. @ 1.800" Spring Pressure Open: 410 lbs. @ 1.140"), $275 + shipping.

3. PRC EHT .675" max lift (Spring Pressure Closed: 161 lbs. @ 1.800" Spring Pressure Open: 472 lbs. @ 1.150"), $350 shipped.

I'm leaning towards the PRC's, but looking for some opinions. The Cam vendor won't give me any info on their spring other than "That's what we recommend & nobody else's will last as long as ours". Another local C6Z owner had some issues with the springs that Cam vendor used on his car (broken inner springs & torn up valve seals after 4K miles). Vendor claims they've since changed spring manufactures, but won't give me any specific info so I'm hesitant. Patriots have been the spring of choice for the majority of my local LSx crowd & they are cheaper, but I'm a little concerned about running at the high end of what they say max lift is (.660 lift cam vs .660 max lift spec). Also Patriot seat pressures are just a little lower than the PRC's. Opinions?

Also curious about reusing the stock LS7 3/8” pushrods w/the cam listed above. Cam vendor claims stock pushrods are all they use on all their customer cars. Mine have about 20K miles on them. Thanks.

Randy@RaginRacin

Since this is our Punisher Cam I will hapily chime in and let you know that we have been recommending installing the Manley Nextek 700 Spings with this camshaft.
170@1.810
446@1.110
Coil Bind 1.050

You will need to shim them accordingly.

We also addressed the seal issue(Not a broken Spring) in another thread here a few months ago. I'll be happy to explain it to you if you would like to give me a call.

We will normally reuse stock LS7 pushrods with stock heads and then make a change when we mill the heads.

Thanks.

Shawn

KLLRVET

Are the nexTek springs what I got with my cam?

tjwong

Just my guess but I would bet they are supplied by an offshore manufacturer more than likely Brazilian. I can't imagine why a vendor won't divulge information especially specs such as installed height, spring pressures, coil bind demensions and other data. LG may not tell you their cam specs but they surely will divulge spring specs.

My personal choices would be Ferrea endurance springs, Comps new 26926 springs or their 921 springs depending on cam specs, Nextek Manley springs or the Pac dual springs.

dfinke23

Header

Shawn, thanks for the reply. I wasn't trying to name you guys out, I even edited my post about an hour after initial posting to generalize the duration #'s (guess in retrospect I should have just posted lift & left duration specs out all together). Also you are correct on the failure I mentioned it was just valve seals, no problems with broken inner springs. Sorry I had confused it in my mind with another inner spring failure from an LS1 Fbody I was helping a buddy with recently.

Even though I own a Z06 I try not to spend my $$$ blindly. I attempt to thoroughly research every purchase weather it’s $50 or $5,000. After purchasing the cam new in the box from another forum member back in early April (a few weeks prior to the damaged seal incident previously mentioned) I called you to inquire on spring pricing. During that call when I inquired about the manufacturer of the springs you said they were custom built for Ragin & that you didn’t recommend any other springs. At the time if you had said we sell & recommend Manley Nextek springs I would have felt more comfortable.

Anyway the intent of this post was not to dig on Ragin Racin, rather get some real world feedback on the PRC EHT & Patriot Springs. Both have great reputations in the LSx world, but the subset of people running .660”+ lift on a primarily daily street driven application is fairly small outside the C6Z crowd. Thanks for the info on the Manley springs, that’s helpful (I’ll PM you for pricing). If you care to chime in from a technical perspective on why either of other springs I mentioned won’t work with the lift and/or lobe profile of the Punisher that would be great. Thanks!

HNK

When i asked, i wasnt told

HNK

you used a .675 with my package, so which brand was it?

Randy@RaginRacin

675 springs are proprietary. Here are the specs for them.
171lbs@1.810
485lbs@1.150
Coil Bind - 1.050

From a cost perspective these are excellent springs with excellent wear characteristices.

The Manley goes through more treatment processes making it a better choice. It also has a larger inner diameter keeping it safely away from the seals, which "MANY" popular springs have a problem with.

We refuse to use the Patriot springs, as they are cheap and will fatigue faster than anything. They will not work well with our cams and we don't suggest them on anything with more than 600 lift. My consensus is that they are good for old LS1 grinds.

Randy@RaginRacin

Tom,

We are happy to divulge information when asked. Sometime the right qustions aren't asked and so it doesn't get answered completely. Maybe my fault and I didn't catch the question correctly. In any case we will supply the information.

Shawn

HNK

Right you are about the patriot junk. Two failures without any support from them. Can you pm me the price?

thesubfloor

I wouldn't recommend the PRC EHTs as they were fine for a while in my engine but have been breaking pretty frequently lately. I just installed a set of PAC 1521's last night so I'm hoping they'll be a little more resilient.

Header

What lift cam & how many miles? Whats breaking inner or outer spring?

thesubfloor

Carlos (myhardtop) asked me to not divulge the cam specs on the forum but I was assured by Richard at West Coast Cylinder Heads (who initially recommended and sold me the springs) that there shouldn't have been any issues running them with my setup.

Not really sure of the mileage since I only drive the car to the track when I race it, but I had the motor rebuilt last November and didn't have any problems until April when my ET slowed down by over a 1/2 second one night. After checking everything but the valvetrain, I finally pulled the valve covers off and found that 2 different springs had broken. Thinking that I had possibly just gotten a bad batch I installed a replacement set only to have another two break a few weeks later. I tried installing a third set but they keep breaking which is why I finally decided to try the PAC’s.

What’s been happening is that the outer spring has been breaking and I won’t even notice there’s a problem unless I’m at WOT.

Header

Shawn so any of these springs will need to be shimmed 0.160" to make up for the difference in installed height (1.800" for LS1 vs 1.960" for LS7) correct?

1.8t

I have heard great things about these springs.

Randy@RaginRacin

The LS7 do not install that high. It usually takes .03-.06 of Shim. We usually shim to around .060-.070 from coil bind as recommended by Manley.

Jason 98 TA

First of all, let’s discuss the .675” spring. We endurance tested the springs for 20,000,000 cycles at 0.650” net lift. Considering that the valve train runs at half crankshaft speed, that is 40,000,000 engine revolutions and that is over 15000 miles (at an average engine speed of 3000RPM). Additionally, the calculated life of the spring before losing significant load is 1.84E+12 (1,840,000,000,000 cycles of the valve train) and that is way out there in miles. In addition to all of this, we have placed these springs in some radical engines that are being driven very aggressively; and to date, we have had no issues. The most likely cause of a break in these applications is a fatigue break that can be caused by several factors in the entire “valve train” and its drive mechanism. One of these factors is “valve lofting” and the destructive energy and forces accompanying it.

With all of the information above, we are confident that there is no “drop-in” size, dual-spring that can provide the RPM capability combined with the lift capability of the .675” PRC spring.

That being said, the realities are that any good cam lobe designer can design a lobe(s) that will break any spring made! Also, the wrong combination of parts operated at the “correct engine RPM” can induce “valve lofting” and other damaging forces, vibrations and impacts.

The physical characteristics of the lobe, lifter (weight, preload, and bleed rate); pushrod (length, configuration, and wall thickness), rocker arm (ratio, rigidity, mounting method), all affect the life of the valve spring in many different ways. These are so complex that the only way to assure that a spring will live on a given combination is to test a set-up on a Spintron. Unfortunately, most engine builders don’t have the time, money or a Spintron on which to test the various combinations they sell. That’s what separates Texas Speed components from most other LS companies in the industry.

Anyone who has done a significant amount of valve train testing on a Spintron will tell you that “valve lofting” is the number one cause of valve train (and primarily valve spring) failures. NASCAR teams at Talladega and Daytona have successfully used “controlled lofting” in a very narrow engine RPM range; but that is a very unique situation and lofting must be avoided if a valve train is to live.

The primary causes of lofting are 1) inadequate pushrod stiffness for the spring rate and acceleration rate of the cam lobe; 2) poor camshaft lobe design (inadequate “smoothing” algorithm in the lobe design program); 3) poor camshaft lobe finishing; 4) excessive rocker ratio for the lobe design; 5) inadequate rocker “stiffness.”

A couple of the things we like to do if at all possible to solve potential problems are

1. Use 5/16x3/8” “double-taper” pushrods
2. Use cam lobes that are proven to have provided good “valve train life” in the past. Keep in mind that the more “aggressive” a cam lobe design becomes, the greater the inertia forces increase and that leads to “lofting,” especially at higher speeds.



A couple of “set-up” suggestions will also help:
1. The preload of all hydraulic roller lifters should be somewhere between 0.060” minimum and) and 0.120.” I personally prefer a preload of 0.080.” I have done hundreds of Spintron/dynamometer tests evaluating lifter preload and its effects on valve train stability and power output. The deeper preload keeps the power curve from “dropping off a cliff” once you pass the peak power point. This really helps stabilize the valve train and reduces the tendency for lofting just past the power peak. I cannot tell you why it happens; I just know that it always works. Shallow preloads, 0.008” to 0.040” cause the power to drop off quickly and substantially. They also tend to induce lofting more quickly. This is especially true with preloads under 0.015” because the aluminum block/engine assembly expands at least 0.015” when the engine temperature stabilizes and that eliminates any preload and introduces a hammering shock to the pushrod as the “lash” is being taken up by the cam lobe.
2. Use the thin viscosity oils for high engine speed operation. They allow the lifter to “bleed down” quicker at times when the pushrod is flexing and a “pumping” action is occurring in the lifter reservoir. Thin viscosity oils have tremendous “film-strength,” and film strength is what protects the lobe.

Finally, I want to state that to get the RPM capability of the .675” PRC spring, the spring material is more highly stressed (Extra High Tensile Chrome Silicon wire) than the PRC .650” spring. The more highly the material is stressed, the less forgiving it is to a “system that is out of control.” Unfortunately, you cannot get one characteristic without compromising somewhere else. Extra High Tensile material works great as long as the system is not experiencing external forces that are adding to the stress in the system!

If anyone has any good testing data such as Spintron data with any of these setups you guys are running please let me know. It does no good for someone to say this spring sucks because a certain application had a problem. This is exactly the reason we test all our components & spend so much time on R&D. Just because someone sells a combo doesn’t make it a good setup or a well designed combo.

Jason 98 TA

Hey Ragin Guys,

Matt had said your using a old Crane lobe at .670" lift, can you shoot me over the specs so we can research a little bit?

I happen to know someone that worked in Crane Valvetrain that will help us wit this one.

The guy that worked at Crane said the only .670 lobe lift stuff they had was a bbc lobe not a LS lobe. He said:

If somenone used an "old lobe" from a BBC or similar application and tried to have an LS cam made with it; the lobe would need to be redesigned to compensate for the larger basecircle of the LS. If that redesign wasn't done precisely, troubles could occur

10SECNZ

You were given the wrong info. Crane was making our cams before they went under. They are .661 lift or a 367 lobe and not from a bbc design. Designed for a lsx. Will be glad to discuss. Give me a call if you would like more info.