moderate Z28

I got a set of used LT4 valve springs and the kit came with shims.
My ? is are you supposed to use these shims or am I okay without them? I have already installed 4 valve springs without them. I wasnt sure if I needed them. Did everyone else with a hotcam install the shims? Thanks.

halucinator

iTrader: (3)

The shims are required to install the springs to the correct height and pressure. If not you might not have enough spring pressure to close the valves quick enough, especially in the higher rpm range.

moderate Z28

My Dad told me to leave them off. He said they could cause spring failure and his response was " why do they want you to put shims on it? Why didnt they just make the spring a little bigger/longer?" This makes sense. Anyone else have an opinion on wether I need them? Did these shims originally come with the LT4 Hotcam kit?

Badazz 97 TA

iTrader: (18)

do you have a picture? im pretty sure i used them with my hck. its been a while since i installed it, my memory is going blank right now


heres what came with mine. everything pictured WAS used during the swap. no leftover parts. anything look familiar????

BALLSS

"shims" are spacers in various thickness used underneath the spring to raise it to correct "installed" height. You need a tool to measure correct height. You may/may not need shims, just have to measure each valve as you go along the spring install.

Good time to replace valve stem seals if swaping springs.

96lt1m6

iTrader: (31)

is it a shim or just the anti galling seat that is placed under the springs to avoid damaging(galling)the aluminum seat.

shbox

You always want to use shims, if they are needed to correct the installed height, but don't confuse them with the locators used on aluminum heads that go under each valve spring.
Generally speaking, LT4 springs were designed not to need shims, but every head is not the same, so measuring for correct installed height and the use of shims is a normal thing to do.

leadfoot4

iTrader: (1)

That's what I thought!!

leadfoot4

iTrader: (1)

Why would you want to use "used" valve springs?? I put a set of the LT-4s in my car about 5 years ago, and paid around $75 for the whole deal (springs, retainers, shims) brand new, from Scoggin Dickey.

moderate Z28

http://store.summitracing.com/largei...12480002_w.jpg
Looks like the kit didnt come with shims. I will get a pic in a little while. I am replacing the valve seals and these springs are used but only have a few miles on them. This car will only get 1,000 miles on it in a year if its lucky. Its my Wifes weekend car, shes easy on it, and Im outta money.

ss.slp.ls1

iTrader: (36)

I don't know how to say this any other way...but I would never ask your Dad for any car fixing/modding advice ever again.

moderate Z28

Heres a pic. It says This side up V.S.I. 203 So its a shim right? Do I need it?

GIZMO

iTrader: (8)

Use the factory spring seats. Anything that is running the LT4 valve spring does not need to shim the springs for correct valve spring installed height. As stated above, the only correct way to shim springs is to use a installed height measuring tool. Never run used valve springs. They are way too important to performance to take the risk.

ss.slp.ls1

iTrader: (36)

You are supposed to put the shims under the factory spring seats (locators).

But I agree to use a spring height measuring tool to verify the installed height, but I think the shim is needed to get the correct measurement.

GIZMO

iTrader: (8)

Sorry, I meant the factory spring shims (part number 10212809). Not the pictured shim. As stated above, if you install the spring in direct contact with the head you will eat up the casting.

moderate Z28

Im confused now. This is what I did. I installed the LT4 valve spring with new valve seals on all the same hardware that was already on it. The same keepers and retainers (pieces that fit into top and bottom of the spring) that were on the old springs. No shims anywhere. The spring is not directly on the head because it sits in the retainer just like the old springs. Am I good to go?

GIZMO

iTrader: (8)

You should be fine. The piece that goes on the bottom of the spring is what we were talking about. No need to add additional shims.

ss.slp.ls1

iTrader: (36)

Well as far as I know, you are supposed to be installing the shims under the factory spring seats.

I have the Crane 10308 dual spring kit, it also comes with shims and utilizes the stock seats. I installed them w/ the shims.

ss.slp.ls1

iTrader: (36)

Wait, does the LT4 spring kit even come with shims new? From searching it seams that it doesn't. So then I guess you are installing them correctly.

Buy your Dad's comment on never needing shims under a spring does not go for every spring. Many times you do need one or more shim, depending on the springs used, installed height, and spring pressures required.

moderate Z28

Thanks everyone. Sorry for all the ?'s. Its my first time with valve springs but my Dad has done them alot (on older cars). He didnt like them because he said he has never had to use shims before. What exactly are those pices called that fit into the top and bottom of the spring? Seems like they are called many different things. Is there any kind of tool I can run down and buy to measure installed height? I have a few tool stores nearby.