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#32688 - 12/13/06 03:13 PM new cheap magnum spring upgrade for moderate cams
patrick Offline
I Live Here

Registered: 01/20/03
Posts: 16102
Loc: Grand Haven, MI
hotroddave40 originally told us about the use of GM V-6 springs, which he said are a drop on, no machining required. I've been doing a little investigating. first of all, the specs I found on rockauto is this:

<a href="Sealed Power VS-1642 spring specs" target="_blank">http://info.rockauto.com/SealedPower/VS1642.html</a>

if you do the math, this yields a spring rate of 365 lb/in. backsolving for the free length yields a 1.898" free length based on these specs.

NapaOnline lists the free length as 1.94".

the Sealed Power VS1642 cross references to every GM 3100, pushrod 3400, and pushrod 3500 V-6 from 1993 to present. armed with this info, I went out and yanked a few (and the retainers) from a '94 grand am in a local junkyard. I have a friend where I used to work that runs the test lab there. he did some testing for me to verify the sealed power specs.

his findings on the sample I gave him:

Free Length: 1.875"
Travel before coil bind: .81"
Coil Bind Height: 1.065"

Spring Rate: 330lb/in

sounds like a definite possibility, the calculated spring rate was slightly higher than the comp 901's I have on my LA headed 360 now, the measured (12 year old spring) was slightly lower. but the measured used spring had a higher spring rate than all the comp cams beehives (pn 26995 looks to be essentially a "drop on" spring for a magnum head), albeit the GM spring is a little light on seat pressure, which could be adjusted with shims at the expense of lift capability. it would be interesting to get my hands on a MP R/T spring to do a comparison test, since MP give absolutely 0 specs on that

and now the the cheap part: the GM part numbers for these components are 10166343 for the valvesprings, and 10166344 for the retainers. if you go to the site www.gmpartsdirect.com and type those numbers in, you'll find the springs are $4.71 each, and the retainers are $1.52 each, compared to the manciniracing.com price for the MP .525" springs and retainers at $9.50 each fo the springs, and $8.95 each for the retainers.

so you can get brand new retainers and beehive springs for ~$125 to your door (gmpartsdirect estimates the shipping at ~$27!)

attached is the force curve from the instron he tested the springs on.


this weekend I will install a set on the magnum heads I have under the workbench and take pics for all to see. I'll also do my best to measure the current installed height of the stock springs vs. the installed height of these springs (using the 3100 retainers) in case of any changes there, so stay tuned.


Attachments
3134434-SPRINGRT.gif (336 downloads)

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#32689 - 12/13/06 04:34 PM Re: new cheap magnum spring upgrade for moderate cams [Re: patrick]
DARTSPORT340 Offline
super gas

Registered: 01/20/03
Posts: 1175
Loc: NC
BTT I want to see how this goes...
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#32690 - 12/13/06 07:05 PM Re: new cheap magnum spring upgrade for moderate cams [Re: patrick]
dmerc Offline
super stock

Registered: 12/17/04
Posts: 1061
Loc: New Mexico
Oh Man! This is great. I'm almost ready to redo a set of magnum heads for a 408 stroker motor and this info could not have come at a better time. Thanks for taking the time to share this
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#32691 - 12/13/06 08:04 PM Re: new cheap magnum spring upgrade for moderate cams [Re: dmerc]
gremlinsteve Offline
top fuel

Registered: 09/01/04
Posts: 1653
Loc: houston texas
have you given thought to a gm z06 spring?

steve
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#32692 - 12/13/06 08:12 PM Re: new cheap magnum spring upgrade for moderate cams [Re: gremlinsteve]
Magnum Offline
master

Registered: 01/24/03
Posts: 5275
Loc: Hamilton, Ontario Canada
Good work Patrick
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#32693 - 12/14/06 07:14 AM Re: new cheap magnum spring upgrade for moderate cams [Re: gremlinsteve]
patrick Offline
I Live Here

Registered: 01/20/03
Posts: 16102
Loc: Grand Haven, MI
Quote:

have you given thought to a gm z06 spring?

steve




yup, in fact the 3100 retainer is the same as an LS1/LS6 retainer, they offer a little more seat pressure, and up to .6" lift capability....but, the LS1/6 springs are 1.8" IH, and a smaller lower ID, so some machining will be required on the head to fit them. the V-6 springs should be a drop on, no machining required for those on a budget and can't/don't want to afford $100-$150 in machining, and have moderate lift cams (in the ~.5" and under lift range)...LS6 springs are 315lb/in w/105lb seat pressure installed at 1.8".
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#32694 - 12/14/06 10:16 AM Re: new cheap magnum spring upgrade for moderate cams [Re: patrick]
Anonymous
Unregistered


Thanks Patrick!
Good job, I was waiting for this info for a while. I'll tune in to see how the installation worked.

Ran

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#32695 - 12/21/06 11:12 AM Re: new cheap magnum spring upgrade for moderate cams
patrick Offline
I Live Here

Registered: 01/20/03
Posts: 16102
Loc: Grand Haven, MI
Update:

well, I finally made it out to the garage to do some measuring, etc. and take some pics. pics will get up here in the next few days.

the GM springs do fit as a drop on. on my particular set of heads, they are quite snug around the "pilot" area. that's the good news.

here's the (arguably) not so good news. the closest I could measure my installed height on my stock, looks to be original valve job heads, was 1.625" (1 5/8"). the 3.1L retainers actually reduced installed height by around 1/32" (to ~1.593" IH) using the mag keepers. using the 3.1L keepers, it increased IH to about 1.65", BUT, the tip of the valve was below the retainer, and the rockers hit the retainer first. if you've got a cam that's ~.45" lift or less with 1.5's, you should be ok with these springs as is.


for my project, using these springs, since I have a .462/.470 cam (will be .493/.501 with the mag rockers) I want to see my installed height to be at least 1.63", since these springs coil bind at about 1.065". that means

1) either the spring pad would need to be machined down ~1/32-1/16" to get adequate installed height, or
2) the valve will need to be sunk in about that amount with the valve job.

a bit of a bummer, but since the heads need a valve job anyway, it shouldn't be any added expense to sink the valves in 1/16", not like machining the spring pockets, which would be an additional operation, and an additional charge.

I wonder what effect sinking the valve into the head has for flow...


again, YMMV, et al.
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#32696 - 12/21/06 11:23 AM Re: new cheap magnum spring upgrade for moderate cams [Re: patrick]
HemiRick Offline
master

Registered: 03/07/03
Posts: 4302
Loc: Memphis
Sinking the valves almost always has a bad effect on flow.
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#32697 - 12/21/06 11:50 AM Re: new cheap magnum spring upgrade for moderate cams [Re: HemiRick]
ZIPPY Offline
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Registered: 01/20/03
Posts: 14466
Loc: S.E. Michigan
If I was building one (which I might, sometime in '07), I would probably just use the MP .600 lift springs which Mancini shows at 7.99, right between the cost of the two listed.

Not sure why a drop in spring would be advertised for .600 lift, when retainer to guide interferance will come into play well before that. I guess that is a roundabout way of saying the guides will have to be cut down which is no biggie.

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#32698 - 12/21/06 12:31 PM Re: new cheap magnum spring upgrade for moderate cams [Re: ZIPPY]
Gas_Bandit Offline
master

Registered: 01/19/03
Posts: 4820
Loc: near Alexandria, VA
Sounds like way too much effort to only be able to use a cam not worth using with the better magnum heads anyway.
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#32699 - 12/21/06 12:40 PM Re: new cheap magnum spring upgrade for moderate cams [Re: Gas_Bandit]
BBR Offline
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Registered: 01/19/03
Posts: 7054
Loc: Texas
Patrick, will a lash cap fit with the GM keepers and Mag retainer?

If I were doing a set of mag heads that probably could stand to have a new VJ, I'd go with the more readily available 11/32 valves. There's a billion different valve lengths/springs/locks/retainers to choose from if you do that.

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#32700 - 12/21/06 02:56 PM Re: new cheap magnum spring upgrade for moderate cams [Re: ZIPPY]
patrick Offline
I Live Here

Registered: 01/20/03
Posts: 16102
Loc: Grand Haven, MI
Quote:

If I was building one (which I might, sometime in '07), I would probably just use the MP .600 lift springs which Mancini shows at 7.99, right between the cost of the two listed.

Not sure why a drop in spring would be advertised for .600 lift, when retainer to guide interferance will come into play well before that. I guess that is a roundabout way of saying the guides will have to be cut down which is no biggie.




yeah, and frankly there isn't enough install height IMHO to get .6" lift without getting into spring breakage problems....biggest kicker with the MP springs are if all the 2.2's have been crushed out of yards around you. the retainers are like $9 ea (vs. $1.50 ea for the GM/LS1) for the MP number....

I wonder how much you can machine out of the spring pocket to get more IH?
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#32701 - 12/21/06 02:57 PM Re: new cheap magnum spring upgrade for moderate cams [Re: BBR]
patrick Offline
I Live Here

Registered: 01/20/03
Posts: 16102
Loc: Grand Haven, MI
Quote:

Patrick, will a lash cap fit with the GM keepers and Mag retainer?

If I were doing a set of mag heads that probably could stand to have a new VJ, I'd go with the more readily available 11/32 valves. There's a billion different valve lengths/springs/locks/retainers to choose from if you do that.






don't know. probably not. the keepers are flush with the top of the valve.

yeah, that's what I'm thinking--if you're doing a serious mag head, long chevy 1.94 valves are probably the way to go.
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#32702 - 12/21/06 07:54 PM Re: new cheap magnum spring upgrade for moderate cams [Re: patrick]
GO_Fish Offline
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Registered: 07/18/03
Posts: 6161
Loc: Maryland
Quote:


I wonder how much you can machine out of the spring pocket to get more IH?



I think the Magnum head porting directions say not to remove ANY metal from the roof of the ports (beneath the spring seat) because there is not much metal there. So the opposite is probably true also when machining from the top.
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#32703 - 12/22/06 04:39 PM Re: new cheap magnum spring upgrade for moderate cams [Re: patrick]
HotRodDave Offline
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Registered: 01/29/05
Posts: 7959
Loc: Kalispell Mt.
Could you give us a side by side comparison with the stock mag info?
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#32704 - 12/23/06 05:55 AM Re: new cheap magnum spring upgrade for moderate cams [Re: HotRodDave]
patrick Offline
I Live Here

Registered: 01/20/03
Posts: 16102
Loc: Grand Haven, MI
I'll try get one of the stock mag springs tested for spring rate and coil bind height. according to the info sheet for them sealed power replacements, the OEM mags calculate out a spring rate of ~240lb/in. It probably won't happen before new years, though.

anyhoo, here are some pictures. **WARNING, THEY'RE BIG** and darn, they show off every detail of how dirty these heads are from being yanked of a motor and sitting under a bench for a year....

The GM springs/retainers and the springs retainers on my mags (I'm assuming they're stock) are shown side by side. Magnum on the left, GM V-6 on the right for all pics.

hotroddave- do these pics parallel what you saw with these springs?


Attachments
3157038-P1010079.JPG (515 downloads)



Edited by patrick (12/23/06 06:25 AM)
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#32705 - 12/23/06 05:57 AM Re: new cheap magnum spring upgrade for moderate cams [Re: patrick]
patrick Offline
I Live Here

Registered: 01/20/03
Posts: 16102
Loc: Grand Haven, MI
another one, side by side. you can see how much more of a beehive the GM spring is--the retainer is much smaller.


Attachments
3157044-P1010080.JPG (454 downloads)

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1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2006 Inferno Red Dodge Caravan SXT 2011 Toxic Orange Dodge Charger R/T

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#32706 - 12/23/06 06:06 AM Re: new cheap magnum spring upgrade for moderate cams [Re: patrick]
patrick Offline
I Live Here

Registered: 01/20/03
Posts: 16102
Loc: Grand Haven, MI
side by side assembled on the head


Attachments
3157057-P1010081.JPG (484 downloads)

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1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2006 Inferno Red Dodge Caravan SXT 2011 Toxic Orange Dodge Charger R/T

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#32707 - 12/23/06 06:08 AM Re: new cheap magnum spring upgrade for moderate cams [Re: patrick]
patrick Offline
I Live Here

Registered: 01/20/03
Posts: 16102
Loc: Grand Haven, MI
side shot, showing stock rocker on the GM sprung valve. bolt is simulating the pushrod


Attachments
3157061-P1010085.JPG (413 downloads)

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