Big Block Valve Spring Help Please
#2196077
11/14/16 10:11 AM
11/14/16 10:11 AM
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Bunk
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I need solid recommendations for new valve springs. I have a 440 with a MP Purpleshaft .484 lift cam but I am about to install 1.6 roller rockers. These new 1.6 rockers will put the lift to .516. Based on what I've learned so far I should limit seat pressure to about 120 lbs and open pressure to 300 lbs. I currently have MP 933 springs with a max lift suggesting of .510. I'm sure a spring suitable will be single but with a damper. Suggestions with real world experience needed please. Thanks! Greg
The beginning of knowledge is the fear of GOD.
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Re: Big Block Valve Spring Help Please
[Re: Bunk]
#2196080
11/14/16 10:30 AM
11/14/16 10:30 AM
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YO7_A66
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Do you know what the current cam spring pressure ratings are for the 484 cam? Going from 1.5 to 1.6 rockers may require a little more spring pressure, so having the original spring pressure specs would help. Do you know what the current installed heights are? This would also help to find a spring rated at your same IH. The WOT rpm would help too. Once you can get this info, the engine guru's will be able to estimate the spring pressures for you.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Big Block Valve Spring Help Please
[Re: Bunk]
#2196168
11/14/16 01:59 PM
11/14/16 01:59 PM
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Thanks! The Mopar Performance 933's have an installed height of 1.83/1.86. Spring pressures are 310 lbs open and 115 lbs closed. The spring diameter is 1.532 OD and wire diameter is .224. I'm shifting at 6000 rpm's.
The beginning of knowledge is the fear of GOD.
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Re: Big Block Valve Spring Help Please
[Re: Bunk]
#2196245
11/14/16 04:06 PM
11/14/16 04:06 PM
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Cab_Burge
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Two things on valve springs and installed height, never assume that the specs. are correct Do you have the tools needed to verify the installed height and the installed pressures and coil bind height? If not either buy a height mike or inside calipers and a decent spring pressure gauge or take the heads to a good machine shop that can set them up properly for you I can't believe that any Mopar after market valve spring set for a BB won't work up to .550 lift with at least .080 clearances from coil bind and have more than 360 lbs. open another thing to check is the accuracy of the rocker arm ratio, get a light weight checking spring and make a old hydraulic lifter into a solid so it won't loose lift and see how much lift you have at the retainers(both intake and exhaust) with zero lash and do the math on the true rocker arm ratio I've seen a bunch of ductile iron rocker arms of all brands have a lot less ratio than advertised Good luck on your project, there are a lots of ways to make more power
Last edited by Cab_Burge; 11/14/16 04:07 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Big Block Valve Spring Help Please
[Re: Bunk]
#2196255
11/14/16 04:13 PM
11/14/16 04:13 PM
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I don't have these tools and I just need a solid recommendation for a set of valve springs that my machinist can work with. Any recommendations? Thanks!
Last edited by Bunk; 11/14/16 04:14 PM.
The beginning of knowledge is the fear of GOD.
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Re: Big Block Valve Spring Help Please
[Re: Cab_Burge]
#2196325
11/14/16 06:21 PM
11/14/16 06:21 PM
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YO7_A66
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This is the Comp #911 single/damper (OD=1.524") spring chart. Once you know your recommended seat pressure, then reference the installed heights to see if this spring will work or not. This spring is real close to your existing OD of 1.532".
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Big Block Valve Spring Help Please
[Re: Bunk]
#2196370
11/14/16 07:39 PM
11/14/16 07:39 PM
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Thanks Y07! That one is much closer to my budget and it has been confirmed by a tech at Comp Cams to be the one for the job.
The beginning of knowledge is the fear of GOD.
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Re: Big Block Valve Spring Help Please
[Re: Bunk]
#2196458
11/14/16 10:12 PM
11/14/16 10:12 PM
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Bunk
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Thats a great suggestion but I've been running these 933's for almost 20 years and I'm thinking fresh springs for peace of mind if nothing else.
The beginning of knowledge is the fear of GOD.
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Re: Big Block Valve Spring Help Please
[Re: BSB67]
#2196516
11/14/16 11:50 PM
11/14/16 11:50 PM
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Bunk, What installed height did Comp tell you to use for the 911's?
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Big Block Valve Spring Help Please
[Re: YO7_A66]
#2196648
11/15/16 09:39 AM
11/15/16 09:39 AM
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Bunk, What installed height did Comp tell you to use for the 911's? Comp 911 16 spring installation height is 1.90 but I have found a new set of Edelbrock RPM springs with retainers and locks that I'm going to use. I will get my machinist to set them up properly for me. Thanks again for you help Y07!
Last edited by Bunk; 11/15/16 09:42 AM.
The beginning of knowledge is the fear of GOD.
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Re: Big Block Valve Spring Help Please
[Re: DrCharles]
#2196650
11/15/16 09:41 AM
11/15/16 09:41 AM
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I don't know what pistons you are running, but it's probably worth checking piston-to-valve clearances Wiseco Pro Tru's with 6 cc valve reliefs and they sit in the hole .034.
The beginning of knowledge is the fear of GOD.
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Re: Big Block Valve Spring Help Please
[Re: Bunk]
#2196659
11/15/16 10:42 AM
11/15/16 10:42 AM
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YO7_A66
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Bunk, Your welcome! But please keep in mind that you may need to raise the seat/open pressures of what ever spring you end up using to keep up with the new 1.6 rocker arms and 6000rpms. Did you receive an answer to how much spring pressure to use with the 1.6 rocker arm swap? If not, here are a few contacts that you can use to confirm that you are using enough spring pressure for your new 1.6/6000rpm swap. Just get them the details of what you are doing and ask for their spring pressure recommendations. sales@manleyperformance.com gwarner@cranecams.com techsupport@lunatipower.com thomas.Fleegle@pspring.com (PAC)
Last edited by YO7_A66; 11/15/16 11:12 AM.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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