Summit 1104 VS Voodoo 60102
Race Director
Joined: May 2005
Posts: 10,674
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From: Millington Illinois
St. Jude Donor '08-'09
I am betting the 1.266 OD is designed to fit stock spring pockets but measure. I like the beehive springs, Better valvetrain stability at High RPM, less spring pressure required to maintain control of the valvetrain. Make more of a difference in high RPM applications. Downside is options on size and rate are limited, most require +.100 valves or retainers and they are over $300 with retainers and locks. For your application, If the recommemded spring fits the pockets and it is just a matter of removing a shim to to be able to use your existing pockets, retainers and locks and get the correct installed height I would lean toward that for $70.
Last edited by 63mako; Apr 23, 2012 at 07:19 PM.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Make sure you check the spring pocket. I bought a set of springs 1.47 one time for heads that were cut for 1.43. Only four hundreds different they would not go in the pocket.
I would think surely 1.266 would fit. But thats what i told myself on the bowtie chevy head its only 4 hundreds difference lol.
I would think surely 1.266 would fit. But thats what i told myself on the bowtie chevy head its only 4 hundreds difference lol.
Last edited by Little Mouse; Apr 24, 2012 at 12:47 AM.
Melting Slicks
Joined: May 2006
Posts: 2,590
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From: Nashville TN
St. Jude Donor '09
Heads are Brodix IKs and 64cc. I'm also using 1094 head gasket and estimate CR around 9:1. Currently using the springs that came with heads which I'm pretty sure they are the 1.250. Specs here
Thread Starter
Racer
Joined: Mar 2007
Posts: 377
Likes: 0
From: Holmen Wisconsin
Okay guys, here's what I got from Summit on my heads. They are cut for a 1.250" and a 1.550" spring. Current springs are 120 lbs seat pressure @ 1.700" installed height. 285 lbs @ 1.250" Max lift .520". I will call Lunati shortly...
Last edited by Camss57; Apr 25, 2012 at 03:37 PM.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
That 73943 lun. valve spring ment for your cam has a high 462 spring rate for a reason.
For $71.00 and the 1.266 would fit your current retainers, you now have the right springs for your cam choice.
Unless the summit supplied spring has a faily high rate i'm having some doubts on your tech advice.
Just because the summit spring has enough .520 lift thats not everything.
Last edited by Little Mouse; Apr 25, 2012 at 04:35 PM.
Thread Starter
Racer
Joined: Mar 2007
Posts: 377
Likes: 0
From: Holmen Wisconsin
How much is the spring rate on the springs summit supplied on the heads if you don't know find out ?.
That 73943 lun. valve spring ment for your cam has a high 462 spring rate for a reason.
For $71.00 and the 1.266 would fit your current retainers, you now have the right springs for your cam choice.
Unless the summit supplied spring has a faily high rate i'm having some doubts on your tech advice.
Just because the summit spring has enough .520 lift thats not everything.
That 73943 lun. valve spring ment for your cam has a high 462 spring rate for a reason.
For $71.00 and the 1.266 would fit your current retainers, you now have the right springs for your cam choice.
Unless the summit supplied spring has a faily high rate i'm having some doubts on your tech advice.
Just because the summit spring has enough .520 lift thats not everything.
How do I ensure I get the 1.75 install height? Do I just need to remove a .050 shim? Are the shims marked with how thick they are?
Le Mans Master
Joined: Apr 2006
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I was thinking if I had to go through the trouble of removing a shim from mine, why not put the correct springs? It's the same amount of labor. So all I need is the cam and lifter kit and just the springs for $71 (plus gaskets). I don't need the whole spring kit with retainers, I can just use my current ones correct?
How do I ensure I get the 1.75 install height? Do I just need to remove a .050 shim? Are the shims marked with how thick they are?
How do I ensure I get the 1.75 install height? Do I just need to remove a .050 shim? Are the shims marked with how thick they are?
I can't see a 1.266 spring needing a different retainer over the 1.250 spring.
If your going to make sure its right you have to measure all 16 of them.
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Thread Starter
Racer
Joined: Mar 2007
Posts: 377
Likes: 0
From: Holmen Wisconsin
"Having not read all the posts on here why were you needing to remove a shim from the way the heads came already set up ?"
I was going off of the below post by 63mako. I'm still learning here. I asked Lunati tech and they said the same thing about the shim to get to the 1.75 install height.
I was going off of the below post by 63mako. I'm still learning here. I asked Lunati tech and they said the same thing about the shim to get to the 1.75 install height.
These guys are steering you right. Burn a call to Lunati Tech support. Tell them the installed height of your springs, spring pocket size and that you want the Voodoo 60102 and you want their beehive springs and required hardware to fit your heads and valve length that will work with their 60102 cam. That way you get what works with no issues. The spring you referenced have an installed height of 1.750. If the beehives are out of your price range they have a -.050 retainer that will work with those springs and your current setup if you have a 1.700 installed height now. You might have a .050 shim under the existing springs you could remove and everything you have might work with just a spring change. Would have to see what you have to determine what to do. You have to get this right for the cam to live.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
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"Having not read all the posts on here why were you needing to remove a shim from the way the heads came already set up ?"
I was going off of the below post by 63mako. I'm still learning here. I asked Lunati tech and they said the same thing about the shim to get to the 1.75 install height.
I was going off of the below post by 63mako. I'm still learning here. I asked Lunati tech and they said the same thing about the shim to get to the 1.75 install height.
Thread Starter
Racer
Joined: Mar 2007
Posts: 377
Likes: 0
From: Holmen Wisconsin
Heres what you know. The springs that come on your heads can handle .520 lift thats plenty for the cam your going to use. What if they have a very good spring rate ?. You need to find out more about the springs you have how they compare on rate before you consider them unusable.
They said they would work fine with the 60102.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
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If you look at a comp extreme fast rate cam same lift slightly higher duration. They recomend there 981 spring with 370 spring rate. 1.70 install height 1.254 dia. 1.150 to coil bind. At 1.250 it has 273 lbs pressure, 105lbs at 1.70 install height.
Last edited by Little Mouse; Apr 25, 2012 at 08:03 PM.
Thread Starter
Racer
Joined: Mar 2007
Posts: 377
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From: Holmen Wisconsin
I will try Summit again during the day to see if they can contact the company that makes the heads for them to see what the spring rate is. They called them today for me to get me the spring pocket size. Summit wouldn't tell me who makes the heads for them.
Race Director
Joined: May 2005
Posts: 10,674
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From: Millington Illinois
St. Jude Donor '08-'09
To figure spring rate on the above spring take 285 (open)- 120(seat) =165 (rate @ .45 lift). 165 divided by .45 = 367 inch/Lbs rate. Same formula works with the Comp spring posted or the correct lunati spring.
Comp tech told this guy his springs would be fine. See what happened. You don't know who your talking to on the tech line. Might be some High school kid with a part time job.
http://forums.corvetteforum.com/c3-t...like-cr_p.html
http://forums.corvetteforum.com/c3-g...ieve-this.html
Thread Starter
Racer
Joined: Mar 2007
Posts: 377
Likes: 0
From: Holmen Wisconsin
Spring rate on your heads is 367. Recommended Lunati spring rate is 462. I would change them. The springs you have will work. For how long is the question. To many flat tappet cam failures out there to take the chance for $70 and a little extra work.
To figure spring rate on the above spring take 285 (open)- 120(seat) =165 (rate @ .45 lift). 165 divided by .45 = 367 inch/Lbs rate. Same formula works with the Comp spring posted or the correct lunati spring.
Comp tech told this guy his springs would be fine. See what happened. You don't know who your talking to on the tech line. Might be some High school kid with a part time job.
http://forums.corvetteforum.com/c3-t...like-cr_p.html
http://forums.corvetteforum.com/c3-g...ieve-this.html
To figure spring rate on the above spring take 285 (open)- 120(seat) =165 (rate @ .45 lift). 165 divided by .45 = 367 inch/Lbs rate. Same formula works with the Comp spring posted or the correct lunati spring.
Comp tech told this guy his springs would be fine. See what happened. You don't know who your talking to on the tech line. Might be some High school kid with a part time job.
http://forums.corvetteforum.com/c3-t...like-cr_p.html
http://forums.corvetteforum.com/c3-g...ieve-this.html
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
http://www.lunatipower.com/Tech/Valv...pringTech.aspx
Last edited by 63mako; Apr 25, 2012 at 10:22 PM.
Thread Starter
Racer
Joined: Mar 2007
Posts: 377
Likes: 0
From: Holmen Wisconsin
well you can believe both lunati and summit or just install the lunati spring.
If you look at a comp extreme fast rate cam same lift slightly higher duration. They recomend there 981 spring with 370 spring rate. 1.70 install height 1.254 dia. 1.150 to coil bind. At 1.250 it has 273 lbs pressure, 105lbs at 1.70 install height.
If you look at a comp extreme fast rate cam same lift slightly higher duration. They recomend there 981 spring with 370 spring rate. 1.70 install height 1.254 dia. 1.150 to coil bind. At 1.250 it has 273 lbs pressure, 105lbs at 1.70 install height.
http://www.compperformancegroupstore...ory_Code=HFTXE
Is this the Comp cam you are referring to?
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Behive springs and retainers are going to be at least $200.00 so you may as well figure on the lunati springs at $70.00.
If your heads are 67 chamber 170 runner they were made by world products. There called the SR torquer by world products.
Last edited by Little Mouse; Apr 26, 2012 at 04:05 PM.