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new cheap magnum spring upgrade for moderate cams

Posted By: patrick

new cheap magnum spring upgrade for moderate cams - 12/13/06 10:13 PM

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.

Attached picture 3134434-SPRINGRT.gif
Posted By: DARTSPORT340

Re: new cheap magnum spring upgrade for moderate cams - 12/13/06 11:34 PM

BTT I want to see how this goes...
Posted By: dmerc

Re: new cheap magnum spring upgrade for moderate cams - 12/14/06 02:05 AM

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
Posted By: gremlinsteve

Re: new cheap magnum spring upgrade for moderate cams - 12/14/06 03:04 AM

have you given thought to a gm z06 spring?

steve
Posted By: Magnum

Re: new cheap magnum spring upgrade for moderate cams - 12/14/06 03:12 AM

Good work Patrick
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/14/06 02:14 PM

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".
Posted By: Anonymous

Re: new cheap magnum spring upgrade for moderate cams - 12/14/06 05:16 PM

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

Ran
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/21/06 06:12 PM

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.
Posted By: HemiRick

Re: new cheap magnum spring upgrade for moderate cams - 12/21/06 06:23 PM

Sinking the valves almost always has a bad effect on flow.
Posted By: ZIPPY

Re: new cheap magnum spring upgrade for moderate cams - 12/21/06 06:50 PM

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.
Posted By: Gas_Bandit

Re: new cheap magnum spring upgrade for moderate cams - 12/21/06 07:31 PM

Sounds like way too much effort to only be able to use a cam not worth using with the better magnum heads anyway.
Posted By: BBR

Re: new cheap magnum spring upgrade for moderate cams - 12/21/06 07:40 PM

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.

Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/21/06 09:56 PM

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?
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/21/06 09:57 PM

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.
Posted By: GO_Fish

Re: new cheap magnum spring upgrade for moderate cams - 12/22/06 02:54 AM

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.
Posted By: HotRodDave

Re: new cheap magnum spring upgrade for moderate cams - 12/22/06 11:39 PM

Could you give us a side by side comparison with the stock mag info?
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/23/06 12:55 PM

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?

Attached picture 3157038-P1010079.JPG
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/23/06 12:57 PM

another one, side by side. you can see how much more of a beehive the GM spring is--the retainer is much smaller.

Attached picture 3157044-P1010080.JPG
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/23/06 01:06 PM

side by side assembled on the head

Attached picture 3157057-P1010081.JPG
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/23/06 01:08 PM

side shot, showing stock rocker on the GM sprung valve. bolt is simulating the pushrod

Attached picture 3157061-P1010085.JPG
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/23/06 01:10 PM

close up of GM springs on the head

Attached picture 3157063-P1010086.JPG
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/23/06 01:13 PM

close up of mag spring and GM spring on the head

Attached picture 3157069-P1010087.JPG
Posted By: VITC_GTX

Re: new cheap magnum spring upgrade for moderate cams - 12/23/06 05:51 PM

Patrick-

Scott Brown sent me the MP high-lift springs (P4876062) for my Magnum heads to work with his cam (.520 lift). I was looking to get the retainers (P4452032) for them, but like you said they are like $9 each. Can I get an OEM set off of a 2.2 or 2.5 from a jy that will work instead?
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/25/06 06:08 PM

they should (2.2L/2.5L retainers). I'd love to see some spring rate and coil bind height info on those MP springs...
Posted By: HotRodDave

Re: new cheap magnum spring upgrade for moderate cams - 12/25/06 08:37 PM

Took my computer like an hour to down load them but looks like what I been doing. Glad to here I wasn't off my rocker about this. 2 motors and soon a third running around here set up like this.
Posted By: GO_Fish

Re: new cheap magnum spring upgrade for moderate cams - 12/26/06 02:02 AM

Quote:

they should (2.2L/2.5L retainers). I'd love to see some spring rate and coil bind height info on those MP springs...



Yeah, its kind of odd that they don't publish any of the specs on their Mag springs... you have to dig even to find the installed height. Don't know what they are thinking, but I don't like it.
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 12/30/06 02:04 PM

Quote:

Took my computer like an hour to down load them but looks like what I been doing. Glad to here I wasn't off my rocker about this. 2 motors and soon a third running around here set up like this.




what cams are you running with these springs, out of curiousity. I'm planning on swapping the mag heads on my XE262 shortblock, which will yield like .493/.501 lift, which from my measurements, look marginal, unless I sink the valves about .030 or so.....

for someone currently running a .440-.450 lift cam (which turn into a .470-.480 lift cam) these would be the cat's meow...
Posted By: dgc333

Re: new cheap magnum spring upgrade for moderate cams - 12/30/06 02:17 PM

Quote:

Patrick-
Can I get an OEM set off of a 2.2 or 2.5 from a jy that will work instead?




I am using 2.2/2.5 retainers with the MP springs and they work out just fine. You do need to use the locks from the magnum retainers though. The 2.2/2.5 uses a multi-groove lock where the magnum is a single groove.
Posted By: HotRodDave

Re: new cheap magnum spring upgrade for moderate cams - 01/24/07 01:35 AM

Patrick did you find out any more, like preasure on the seat and mabey .500 lift?
Posted By: patrick

Re: new cheap magnum spring upgrade for moderate cams - 01/24/07 09:34 PM

should be able to calculate that out by looking at the free length and spring rate.

"blueprint" specs were free length of 1.94", and spring rate of 365lb/in, so with the 1.6" IH I measured with the 3100 retainers, that would yield a seat pressure of 124lb, and a .5" lift pressure of 306lb.

the springs I had tested were 1.875" free length, 330lb/in, and the installed height (on my heads) will be ~1.6". so seat pressure should be .275*330, or 91 lbs, and .5" lift will be .775*330, or 256lb.

remember, coil bind was measured at .81" lift on those springs, (1.065") so .5" lift with my measured IH would only leave you .035" before coil bind. I think I'll probably use these springs, but I'll see about sinking the valves .030" or so (to gain IH), which will leave me ~.060 before coil bind with my cam. This seems like the most cost effective way, since I plan on getting a VJ done on them anyway, and I'll probably get a 5 angle 75/60/45/30/15 so sinking them shouldn't hurt flow as much with the 15 degree cut...I'd wager it'll add a CC or two to my combustion chamber, though.
Posted By: HotRodDave

Re: new cheap magnum spring upgrade for moderate cams - 02/08/07 05:01 AM

Could this go to the archives for future referance? Lots of goo info here, Thanks Patrick!!
Posted By: ZIPPY

Re: new cheap magnum spring upgrade for moderate cams - 09/18/07 05:44 PM

Quote:


Yeah, its kind of odd that they don't publish any of the specs on their Mag springs... you have to dig even to find the installed height.




P5249464 116lbs @ 1.625, 251lbs @ 1.125

P4876062 131 @ 1.625, 305 @ 1.125

Rec'd installed height of 1.64 for both, can't find coil bind height for either one.
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