Question About Solid Roller Valve Springs
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Question About Solid Roller Valve Springs I just saw that Comps catalog lists its '977' spring, a 155@1.85", 419@1.25", 442#/in rate spring for its street solid roller cams. Came across this because a head being investigated for another application came with a 953 which is 162@1.9, 484@1.25 and a 496#/in rate.
Those are similar (actually softer at the seat, stiffer over the nose) than the flat tappet late model racing springs. I thought roller springs for something other than dedicated drag racing, even street roller springs, where closer to 220-250@2.000 or 1.900 and 550-600 over the nose with a rate depending on lift.
Obviously, I must be mistaken. What is the practice in springs for solid roller cams?
Thanks,
David
Those are similar (actually softer at the seat, stiffer over the nose) than the flat tappet late model racing springs. I thought roller springs for something other than dedicated drag racing, even street roller springs, where closer to 220-250@2.000 or 1.900 and 550-600 over the nose with a rate depending on lift.
Obviously, I must be mistaken. What is the practice in springs for solid roller cams?
Thanks,
David
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From Crane Cams:
Applications are generally used for serious street/strip use and full competition. Most are not used in "daily-drivers" where day-to-day reliability is stressed. Instead, most of these cams are intended for "winning performance." These cams are designed with "very aggressive" opening and closing rates. High seat pressures are necessary to keep the valves from bouncing when they come back to the seat. In all cases, the valve action and spring pressures required mandate the use of high-strength, one-piece valves.
a. Seat Pressures are determined by valve/retainer weight, engine RPM and life expectancy of components
before replacement is required.Milder roller cams require 165# on the seat as an absolute
minimum. 180-200# is common for most modest performance applications. 220-250# is common for
most serious sport categories and some circle track professional categories. Pro-Stock and Blown
Alcohol/Fuel drag applications use as much as 340-400# on the seat. (The racers sometimes change
springs as often as every 1/4 mile run!)
b. Open Pressures need to be high enough to control the valvetrain as the lifter goes over the nose of
the cam. Ideally, the minimum amount of open pressure to eliminate or minimize valvetrain separation
is desired. Any excess open pressure only contributes to pushrod flex, which can aggravate valvetrain
separation. For serious racing applications this can be determined only by experimentation and track
testing. For general guidelines we offer the following
i. Street/Strip performance with long cam/lifter life desirable, 350-450# open.
ii. Circle track and moderate bracket racing 450-600@ open.
iii. Serious drag racing and limited distance circle track racing 600# and more.
a. Seat Pressures are determined by valve/retainer weight, engine RPM and life expectancy of components
before replacement is required.Milder roller cams require 165# on the seat as an absolute
minimum. 180-200# is common for most modest performance applications. 220-250# is common for
most serious sport categories and some circle track professional categories. Pro-Stock and Blown
Alcohol/Fuel drag applications use as much as 340-400# on the seat. (The racers sometimes change
springs as often as every 1/4 mile run!)
b. Open Pressures need to be high enough to control the valvetrain as the lifter goes over the nose of
the cam. Ideally, the minimum amount of open pressure to eliminate or minimize valvetrain separation
is desired. Any excess open pressure only contributes to pushrod flex, which can aggravate valvetrain
separation. For serious racing applications this can be determined only by experimentation and track
testing. For general guidelines we offer the following
i. Street/Strip performance with long cam/lifter life desirable, 350-450# open.
ii. Circle track and moderate bracket racing 450-600@ open.
iii. Serious drag racing and limited distance circle track racing 600# and more.
Originally Posted by DavidNJ
I just saw that Comps catalog lists its '977' spring, a 155@1.85", 419@1.25", 442#/in rate spring for its street solid roller cams. Came across this because a head being investigated for another application came with a 953 which is 162@1.9, 484@1.25 and a 496#/in rate.
Those are similar (actually softer at the seat, stiffer over the nose) than the flat tappet late model racing springs. I thought roller springs for something other than dedicated drag racing, even street roller springs, where closer to 220-250@2.000 or 1.900 and 550-600 over the nose with a rate depending on lift.
Obviously, I must be mistaken. What is the practice in springs for solid roller cams?
Thanks,
David
Those are similar (actually softer at the seat, stiffer over the nose) than the flat tappet late model racing springs. I thought roller springs for something other than dedicated drag racing, even street roller springs, where closer to 220-250@2.000 or 1.900 and 550-600 over the nose with a rate depending on lift.
Obviously, I must be mistaken. What is the practice in springs for solid roller cams?
Thanks,
David
Good luck, Ed
Got a little bit of a silly situation going on for my setup. I'm in the process of deciding to run the cam I have currently or offload it and run something with less lift. This car will be a street strip deal with 7/16 pushrods. The cam I have now has .754/.760 lift with titanium valves and 300/700+ closed/open pressure springs and the valve covers have valve spring oilers in them. Am I an idiot to consider running this kind of gross lift on the street (.015ish lash and figure around .020 deflection or less for a net lift of around .720ish)??? Should I offload this thing and look at something with .680ish gross and down? Any suggestions are appreciated and good thread!!!
Any valve springs out there you'd recommend for some decent life out of a setup like this? Also, what interval would you recommend spring pressure be checked in a setup like this? Thanks a bunch!
Any valve springs out there you'd recommend for some decent life out of a setup like this? Also, what interval would you recommend spring pressure be checked in a setup like this? Thanks a bunch!
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Well, the issue, probably the only issue is the springs. With your setup you already have copper seats, bronze guides, beaded locks, and caps. However, the spring is doing a lot of work.
Question 1: Are your heads appropriate for the lift? If the answer is yes, then it is a spring question. If the answer is no, then you can work on getting rid of the lift right away.
Question 2: What are the rest of your cam specs. I would like to run a Hooter's Cup cam on the street. They have modest lift--.655. However, they are very, very aggresive. 28deg or less major intensity. Maybe 80 deg or less between .050 and .200. Comp says they eat springs.
Question 3: How much are you willing to spend for springs? Isky has springs at $230, $430, and $530 all with the same specs. (say 9345, 9945, and 9945RAD). Are you willing to spend $1000+/year on springs?
Net...there is no performance reason, other than head flow dynamics and spring life, not to run a real cam. However, those are real limitations. If you plan on 20k miles a year on the street, you probably what something milder. If you plan on 1k miles/year on the street...go for it!!! It sounds like you already have over $4k in your valvetrain, so I would say go for it!
Note: The cost of the cam is actually small compared to the cost of the springs. If your have the time and the energy to change them, you can give different grinds a whirl. Comp and others are always coming out with new grinds for competitive racing series.
Question 1: Are your heads appropriate for the lift? If the answer is yes, then it is a spring question. If the answer is no, then you can work on getting rid of the lift right away.
Question 2: What are the rest of your cam specs. I would like to run a Hooter's Cup cam on the street. They have modest lift--.655. However, they are very, very aggresive. 28deg or less major intensity. Maybe 80 deg or less between .050 and .200. Comp says they eat springs.
Question 3: How much are you willing to spend for springs? Isky has springs at $230, $430, and $530 all with the same specs. (say 9345, 9945, and 9945RAD). Are you willing to spend $1000+/year on springs?
Net...there is no performance reason, other than head flow dynamics and spring life, not to run a real cam. However, those are real limitations. If you plan on 20k miles a year on the street, you probably what something milder. If you plan on 1k miles/year on the street...go for it!!! It sounds like you already have over $4k in your valvetrain, so I would say go for it!
Note: The cost of the cam is actually small compared to the cost of the springs. If your have the time and the energy to change them, you can give different grinds a whirl. Comp and others are always coming out with new grinds for competitive racing series.
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Thanks man! This cam is the comp extreme street lobes on both sides which are 38 degrees from advertised to .050 (slow) and only 78 degrees from .050 to .200 (fast). Erik from HPE spoke with Gordon at Comp and he said i'd be ok with this setup with my 1.95 rockers, titanium valves, street driving, and the big springs (300ish/700ish) I have now with a max rpm of 7500. After the replies i've gotten from other threads i'm going to go through with this and see how it does. The heads have 2.18 valve and flow pretty well up high, although they do drop 1 cfm from .600 to .700 so they, and the sb2 intake with 1550 cfm throttle body should "use" the extra lift I think.
Ha ha, don't expect 20,000 miles a year out of these valve train parts, that's for sure. It seems as I can atleast expect thousands from them though. This car will be a street strip type deal anyway and i'll be checking the valve train regularily, especially when I first implement this combination.
Ha ha, don't expect 20,000 miles a year out of these valve train parts, that's for sure. It seems as I can atleast expect thousands from them though. This car will be a street strip type deal anyway and i'll be checking the valve train regularily, especially when I first implement this combination.
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1.95 rockers??? That is way, way serious. Comp recommended that with the street rollers??? Comp has several grinds designed for high ratio rockers.
A cam is $400-500, the cost of a set of springs. Have or have your engine builder review the different lobes for your application and get a recommendation.
300# is a lot of seat pressure for an endurance application. Isky had their new SuperRAD PSI wound springs. The 1695, $630 a set I believe, is 250# at 2.050 and 280# at 2.000. Spec'd at 735# at 1.25, which is in your lift range.
P.S.
I was looking at the milder 1685, 250# at 2" and 500#/in rate, vs the 1695's 605#/in rate.
A cam is $400-500, the cost of a set of springs. Have or have your engine builder review the different lobes for your application and get a recommendation.
300# is a lot of seat pressure for an endurance application. Isky had their new SuperRAD PSI wound springs. The 1695, $630 a set I believe, is 250# at 2.050 and 280# at 2.000. Spec'd at 735# at 1.25, which is in your lift range.
P.S.
I was looking at the milder 1685, 250# at 2" and 500#/in rate, vs the 1695's 605#/in rate.
My engine builder is the one i've been discussing all this with and he's spoken with Gordon, a comp tech who actually knows what's going on (there are only a few in my opinion), and he said it would be just fine! I've looked at some lobes which say they are designed for this size rocker but they are all way fast from advertised to .050, faster then what i've got now which I don't like cause if the lifter is actually following the lobe this is where parts get beat up (advertised to .050 I mean). They are a little fast from .050 to .200 which was my concern but like I said, Gordon said it would work according to Erik Koenig, my engine builder. I've talked to a few comp guys myself and they said it would work also. I'm going to try it out and keep a very close eye on things and see what happens. Thanks!
Also, I will certainly look into some spring alternatives if these Kam Motion deals don't work out. Thanks!
Also, I will certainly look into some spring alternatives if these Kam Motion deals don't work out. Thanks!
