VALVE SPRING QUESTION
Thread Starter
Burning Brakes
Joined: Nov 1999
Posts: 859
Likes: 17
From: Houston TX
VALVE SPRING QUESTION
I'm installing a Comp Cams 305 in my L98. :chevy
I am trying to decide which springs to use.
The guy from Comp Cams says that these springs will work:
CCA-983-KIT Oval Wire Springs = Single Spring No Damper / .836 I.D. / Seat Load 105@1.700 / Open Load 310@1.200 / Coil Bind 1.150 / Lbs.per.In. 410.
I can't find the max lift of these springs but the guy said they would work.
CraneCams sells these springs that they recommend for two cams I also looked at, one that had higher lift, and one that had lower. So I'm thinking that these would work as well.
CRN-99846-16 Single Valve Springs / .870 I.D. / Seat Load 115@1.750 / Open Load 350@1.175 / Coil Bind 1.100 / Lbs.per.In. 409
Also should I use Self Aligning rocker arms on here or not? Since the stock is self aligning should I stick with them? Will the Pro Magnum self aligning rocker arms fit under the stock 89 Corvette Center Bolt Valve covers?
I am trying to decide which springs to use.
The guy from Comp Cams says that these springs will work:
CCA-983-KIT Oval Wire Springs = Single Spring No Damper / .836 I.D. / Seat Load 105@1.700 / Open Load 310@1.200 / Coil Bind 1.150 / Lbs.per.In. 410.
I can't find the max lift of these springs but the guy said they would work.
CraneCams sells these springs that they recommend for two cams I also looked at, one that had higher lift, and one that had lower. So I'm thinking that these would work as well.
CRN-99846-16 Single Valve Springs / .870 I.D. / Seat Load 115@1.750 / Open Load 350@1.175 / Coil Bind 1.100 / Lbs.per.In. 409
Also should I use Self Aligning rocker arms on here or not? Since the stock is self aligning should I stick with them? Will the Pro Magnum self aligning rocker arms fit under the stock 89 Corvette Center Bolt Valve covers?
Drifting
Joined: Jul 2001
Posts: 1,418
Likes: 1
Re: VALVE SPRING QUESTION (White Lightning 89)
That cam calls for the 986 springs.The ovate spring they recommended is a single w/o a dampner.I would not use this spring!At 1.700 installed height it will bind at .550 lift.The 305 has .510 lift.It will over work the spring and 105 seat pressure is not enough in my opinion.Use the 986's.If you do not have guide plates use the guided rockers.They will work with a little clearancing of the valve covers.But really I think you should call Comp Cams and ask for Jay Adams ext 592.He is a TPI nut! We have put some really neat valve train-cam combos together in the past.Also if you have not already purchased the 305 he will be able to assist in a custom grind for your specific combo of parts.
Advanced
Joined: Jan 2000
Posts: 93
Likes: 0
From: Madera, CA
Re: VALVE SPRING QUESTION (White Lightning 89)
Always go with the cam grinders recommendation for the valve spring package. In this case, since both are available from Comp Cams, just call and ask them. Without the equipment and software to analyze the cam and match springs there isn't anyway for you to determine whether the cam would cause a different spring package to go into a harmonic surge. They have that information available to them.
The ovate spring was developed by LSM to reduce spring stress and increase the life of springs under racing conditions. I checked their website and they only have info on their Titanium Pro Stock springs, so they probably developed this one specifically for Comp Cams.
The ovate spring was developed by LSM to reduce spring stress and increase the life of springs under racing conditions. I checked their website and they only have info on their Titanium Pro Stock springs, so they probably developed this one specifically for Comp Cams.
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Re: VALVE SPRING QUESTION (White Lightning 89)
Your putting a 305H cam in an L98?
Ok, here's a few pointers. It needs dual springs. The springs they are recommending are not going to work for long and will float early.
This cam doesn't come on until 3500 RPM and pulls hard to 7000 RPM. You need springs that will not float. You need dual springs, which probably means you need the seats machined on the heads for bigger springs.
The real problem is your using this cam on an L98. The 305 is a BRACKET ONLY recommended cam...meaning it has low vacuum and extremely lumpy idle, so it kind of sucks for a L98 street engine cam.
Are you switching to a carb? If not, you will need a miniram. Even a superram probably will not give the intake that cam wants. The computer will have a hell of a time just keeping the engine running at low rpm's, so you will need to have a high idle, and high stall torque converter. A set of 4.11 gears would help too.
See, none of this sounds good for a L98 unless you bastardize the hell out of it.
This cam was even rough running in one of my 383's. I got better performance out of a milder roller cam with more lift ( and a lot better idle/mileage/driveability ).
Ok, here's a few pointers. It needs dual springs. The springs they are recommending are not going to work for long and will float early.
This cam doesn't come on until 3500 RPM and pulls hard to 7000 RPM. You need springs that will not float. You need dual springs, which probably means you need the seats machined on the heads for bigger springs.
The real problem is your using this cam on an L98. The 305 is a BRACKET ONLY recommended cam...meaning it has low vacuum and extremely lumpy idle, so it kind of sucks for a L98 street engine cam.
Are you switching to a carb? If not, you will need a miniram. Even a superram probably will not give the intake that cam wants. The computer will have a hell of a time just keeping the engine running at low rpm's, so you will need to have a high idle, and high stall torque converter. A set of 4.11 gears would help too.
See, none of this sounds good for a L98 unless you bastardize the hell out of it.
This cam was even rough running in one of my 383's. I got better performance out of a milder roller cam with more lift ( and a lot better idle/mileage/driveability ).
Drifting
Joined: Jul 2000
Posts: 1,861
Likes: 1
From: Bremerton WA
St. Jude Donor '09
Re: VALVE SPRING QUESTION (BBA)
I ran the CC-305 in my Super Ram 383. It idled fine (about 800-850 rpm)and had enough vacuum for brakes to work fine so there isn't much of an issue there. I don't contest that the SR may not be the best intake for the cam. I didn't get a chance to run it with a MR. I didn't have any trouble making it idle fine and it had good street manners. It's all in the tuning (I program and burn my own chips). Hell, I even still got about 28 mpg highway and about 13-16 mpg around town after the 305 upgrade. So what if the LPE 219/219 got 30 mpg highway and 14-18 around town... small sacrifice.
Springs- The cam does work well with K-Motion K-800 springs. You can find them in the Summit catalog for about $90. All the specs are there in the catalog as well. I ran them with the CC-305 and 1.6 roller rockers with no problem. They are a double coil spring and can take a lot of lift. You should look into these. They have really good spring pressures as well.
Cory
Springs- The cam does work well with K-Motion K-800 springs. You can find them in the Summit catalog for about $90. All the specs are there in the catalog as well. I ran them with the CC-305 and 1.6 roller rockers with no problem. They are a double coil spring and can take a lot of lift. You should look into these. They have really good spring pressures as well.
Cory
Thread Starter
Burning Brakes
Joined: Nov 1999
Posts: 859
Likes: 17
From: Houston TX
Re: VALVE SPRING QUESTION (mountainmotor)
Yes, its that grind for the Roller block.
It doesn't seem like that aggressive of a cam to me. I only went with it because anything bigger would be too much duration for the T.P.I. This one is probably too much as it is. Drivability doesn't mean much to me. I'd drive a pro-stock around if I could fill it up at the gas station (or afford it). I can make do.
Also planned mods in the future warrant this to be an excellent cam for me as well.
I wanted single springs because as soon as I have the resources, these heads will go in the attic, and aftermarket will go on. I wanted them to stay stock.
It doesn't seem like that aggressive of a cam to me. I only went with it because anything bigger would be too much duration for the T.P.I. This one is probably too much as it is. Drivability doesn't mean much to me. I'd drive a pro-stock around if I could fill it up at the gas station (or afford it). I can make do.
Also planned mods in the future warrant this to be an excellent cam for me as well.
I wanted single springs because as soon as I have the resources, these heads will go in the attic, and aftermarket will go on. I wanted them to stay stock.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Drifting
Joined: Dec 1999
Posts: 1,462
Likes: 1
From: Reno nevada
Re: VALVE SPRING QUESTION (White Lightning 89)
It's a simple math. cam lobe lift X rocker ratio Example .340 X 1.5 = .510
Or the reverse if you know lift with a 1.5 rocker .510/1.5 = .340
.340X1.6=.544
Or the reverse if you know lift with a 1.5 rocker .510/1.5 = .340
.340X1.6=.544
Thread Starter
Burning Brakes
Joined: Nov 1999
Posts: 859
Likes: 17
From: Houston TX
Re: VALVE SPRING QUESTION (Lt1er)
Cool... :cool:
I'l have to store that formula in my calculator with all the other formulas that I should know but don't... :crazy:
U must bezza Colledge Congratuate. :D
:seeya
I'l have to store that formula in my calculator with all the other formulas that I should know but don't... :crazy:
U must bezza Colledge Congratuate. :D
:seeya
Drifting
Joined: Jul 2001
Posts: 1,418
Likes: 1
Re: VALVE SPRING QUESTION (White Lightning 89)
I see where you are headed now.That ovate spring is pretty expensive and I think Comp recommended where you would not have to machine the head for the other spring.Since you are not going to run it long Scoggin-Dickey uses a Crane bulk spring for there Hot Cam kits.I would call and ask for Brian and see what a set of them would cost.Good luck and I think that is a nice cam for now and the future.
