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#7905 - 02/15/14 01:35 AM Valve spring pressure question
kc8oye Offline
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Registered: 01/27/11
Posts: 1433
Loc: Grand Blanc, MI
Is it better to go high, or go low if I can't find the exact valve spring I need???

The springs I'm using now, are rated 240 lbs open @ .450 lift..

the cam I have calls for 273-297 open pressure. at .465 lift

I've never been aware of any issues with these springs.. at least not up to my rev limiter at 6000

but i want to swap to 1.6:1 rockers for a total lift of .490
that would set my open pressure @ 254.. still rather low..

the other spring that I could use... goes to the high side a little bit..

it would 316 lbs @ .490 lift...
_________________________
13.970 @ 98.37mph that NOS bottle in my closet says I see 12's this summer.

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#7906 - 02/15/14 02:57 AM Re: Valve spring pressure question [Re: kc8oye]
Sam/bones Offline
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Registered: 02/05/11
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I do hedge to the lighter side with a flat tappet cam
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#7908 - 02/15/14 07:50 AM Re: Valve spring pressure question [Re: kc8oye]
kc8oye Offline
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Registered: 01/27/11
Posts: 1433
Loc: Grand Blanc, MI
kinda what I was thinking sam.. especially w/o the ZDDP in the oil now days..
_________________________
13.970 @ 98.37mph that NOS bottle in my closet says I see 12's this summer.

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#7909 - 02/15/14 08:09 AM Re: Valve spring pressure question [Re: kc8oye]
kc8oye Offline
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Registered: 01/27/11
Posts: 1433
Loc: Grand Blanc, MI
I think my head is going to explode.. Summit Racing gives me one set of specs in an email from their tech dept.. but then recommends a set of springs with a different set of specs.. and funny enough.. i was able to find springs with the same specs they recommend.. AND they will work with the .490 lift I want to run.

this is what they e-mailed me:
Quote:
Here are the recommend specs.

Installed Height (in): 1.700 in.
Seat Pressure at Installed Height (lbs): 104-116 lbs.
Open Height (in): 1.210 in.
Open Pressure (lbs): 273-297 lbs.


these are the specs of the springs Summit reccomends I use
Quote:
Installed Height (in):1.750 in.
Seat Pressure at Installed Height (lbs):125 lbs.
Open Height (in):1.200 in.
Open Pressure (lbs):325 lbs.


and these are the springs I will problaby use..
Quote:



Hi-Tech, LT-1/Z-28 Chev SB 1.250" Diameter Valve Springs
LT-1/Z-28
Style: Single w/Damp.
O.D.: 1.250
I.D.: .870
Seat Press.: 120 @ 1.700
Open Press.: 300 @ 1.250
Coil Bind: 1.160
Max Lift: .510
_________________________
13.970 @ 98.37mph that NOS bottle in my closet says I see 12's this summer.

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#7911 - 02/15/14 04:15 PM Re: Valve spring pressure question [Re: kc8oye]
Sam/bones Offline
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Registered: 02/05/11
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your problem is that you are talking to summit, there are not the manufacturer, and you are talking to numbnuts that don't know there ass from a hole in the ground
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#7913 - 02/15/14 09:23 PM Re: Valve spring pressure question [Re: kc8oye]
Greg Offline

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SBC Mouse V8
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Registered: 02/01/11
Posts: 1911
Loc: Middle East
lolup


Yep, Ran into that during my 496 Build.


You wouldn't believe the confusion caused by GM when they re-used the "LS6" designation from the early 70's

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#7914 - 02/16/14 08:23 PM Re: Valve spring pressure question [Re: Sam/bones]
kc8oye Offline
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SBC Mouse V8
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Registered: 01/27/11
Posts: 1433
Loc: Grand Blanc, MI
Originally Posted By: Sam/bones
your problem is that you are talking to summit, there are not the manufacturer, and you are talking to numbnuts that don't know there ass from a hole in the ground


yeah... the first time I asked for the spring pressure requirements of the cam. .they sent me an email that said "use these springs" not exactly the answer I wanted..

still the guys over at Competition Products were helpful smile

I suspect this cam was made by Elgin as they make a cam with the _EXACT_ same specs. i've noticed tho.. summit changed their listed specs by a few thou.. probably trying to hide that fact.. smile
_________________________
13.970 @ 98.37mph that NOS bottle in my closet says I see 12's this summer.

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