donk316

LA1 V6 valve spring:
Free length- 48.5mm (1.89")
Installed load (valve closed)- 320 N @ 43.2mm (75 lb @1.701")
Compressed load (valve open)- 1036 N @ 32mm (230 lb @ 1.26")
app. # of coilis- 6.55
camshaft lobe lift (intake & exhaust)- 6.9263mm (0.2727")

LS1 V8 valve spring:
Free length- 52.9mm (2.08")
Installed load (valve closed)- 340 N @ 45.75mm (76 lb @ 1.8")
compressed load (valve open)- 980 N @ 33.55mm (220 lb @ 1.32")
camshaft load lift- 7.04mm (.277") intake, 7.13mm (.281") exhaust

So you can see the LS1 springs will produce loads similar to the LA1 springs at our compressed height, but at our installed height they will produce significantly more pressure, which will help close the valve and keep the lifter on the cam at high rpm.

Also of note, the LS1 valve stems are 8mm same as ours, but LS1 valve seals won't fit the LA1. That's right, our valve guides are thicker. Go figure.

You need the LS1 valve springs and seats (a copper shim that goes between the spring and the head), and valve seals from the older 3.1L "T" V6

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The GM 3.4L valve spring (PN:12363215) is far better than the LS1 spring and they are under $10 ea Canadian!

105lbs seat pressure @ installed height of 1.70"
296Lbs open pressure @ 1.20"

The GM HD valve springs (PN:330585) cost $11 ea. CA, and are good to .560" lift and have

140 lbs seat pressure @ 1.75"!!

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3.4 as in the camaro 3.4L RWD block, or the 3.4 dohc block? I haven't heard about 3.4L springs with that kind of seat pressure before

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It is for the 3.4L OHV engine, Camaro's etc. The information is from the GM Performance Cataloge, and the part #'s are real. I phoned a Chevy dealer and asked about them.
Also, those springs must be used with the P/N:12363216 retainer. They are a 4140 heat treated steel retainer, and measure 1.203" in dia.
Also, the 3.4L OHV springs are good for .500" lift

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The GM 3.4L valve spring (PN:12363215) is far better than the LS1 spring and they are under $10 ea Canadian"

is there such a need for that much more seat pressure on the valve springs then from the ls1 springs?? and whats the free length? sounds like a nice find though

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The HD springs require machining of the head. They're 1.379" in diameter. On the other hand the regular RWD 3.4 springs are the correct diameter. I have to agree with Tree, what would anyone need a seat pressure like that for? It's not like the bottom end would take those kinds of RPMs.

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true that the bottom end would not... but.. they are cheaper then the ls1 springs are they not? if we can use those...... what else must be changed?

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According to GM, you just need the P/N:12363216 retainers with the 3.4L springs. Also, they are recomended by GM for the GM Performance Cam (also the crane H-260-2 cam) The rods are rated for 7000 rpm, but the crank can take much more than that. I know of people who have exceeded it

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ive been using the LS1 springs for 3 years now with no issues of valve float and any problems with in suficcient spring pressure.

they have a large Advantage over the GMPP springs:

they are a beehive "conical" spring. hence at the top of the spring they get smaller in diameter, which = lighter and less valvetrain mass.. they still get the job done and do it with out being a bulky spring. they are actually cheaper than the GMPP spring. with the conical spring you get a smoother and better spring rate without the extra weight, they also keep the spring from needing the secondary spring like the GMPP one does due to the varried diameter.

the GMPP spring SAYS to use the GM retainer blah blah blah.. DONT ORDER THEM your wasting your money. the Springs and retainers are designed for IRON heads which use a 11/32 diameter valve. NOT a 8mm valve. Yes for a 2.8L or 3.1L or 3.4L IRON headed engine you need those retainers but for an alum head you dont.

the retainers WONT work nor the locks for the GMPP spring with the smaller 8mm alum head valves. With the the GMPP springs you need to use the stock GM 3.1L retainers and locks.

this is the other advantage of the LS1 spring, the retainers are also smaller and lighter compared to the stock 3.1L and the GMPP spring retainers.

i have pics of how the GMPP retainers for the 3.4L spring dont work if you want to see it.

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sorry to keep picking away at this guys

but the GMPP#12363216 springs are what other people have used before with the stock retainers (and shims???) i'm assuming with no problems...

however colin you've said that the ls1 springs are cheaper and less bulky/lighter then the 3.4L OHV springs (gmpp ones that you refer to) which are both more effective then the lt1 springs

all in all.. the LS1 springs using stock retainers and shims are what i should be using?

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you need these parts for the LS1 springs to work at all.

LS1:

12 springs
12 retainers
24 valve locks (keys)
12 spring seats (shims)
and a set of 3.1L "T" valve seals (3100/3400 valve seals dont fit under the LS1 springs)

however you CAN use 3X00:

Retainers and Locks with the LS1 springs.

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For those interested in part numbers....

i have heaps of part numbers for **** in my tool box here at work i just never post them, but since i just ordered another set of LS1 parts for a guy's set of heads im doing up and i have the sheet in front of me i might as well post them.

LS1 Spring p/n 12553696
LS1 Retainer p/n 10166344
LS1 Lock/key p/n 10166345
LS1 spring seat p/n 12565118

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Phew! cut and paste finger hurts now.....stolen fair and square from some Cavalier forum. I know some guys here are running ls1 springs but it will be good for the "search" function.

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Calgary - August 1, 2004 Fiero Fiesta

*ALL THROTTLE AND NO BOTTLE*