I got the Z28 springs in the mail. The spring will fit over the guide but not the damper. Every time I turn around its more money. Well I'm tired of dropping cash into this conversion to vortecs. Can part or all of the damper be removed? Now before everyone says "don't remove the damper", can anyone tell me exactly what will happen if I do? I know it is to suppress harmonics but if the RPM's stay below 5500, is it as much of a concern. The new ovate spring that is out on the market doesn't use a damper. The original vortec spring doesn't use a damper. Is the damper installed merely to cover the manufacturers behind by being conservative because they don't know what application the springs are going to be used for. I'm a numbers guy and I like to know the risks and probabilities when making a decision. I know the benefits. I know the risk and downside of a broken valve spring. What i don't know are the probability of failure in this application (454/480 lift cam on vortecs that have been modified to handle the lift and 5500 rpm max). I have seen on other sites where guys are running springs without dampers. Can anyone help me out?


Clyde

Clyde,
The spring is designed to work with the damper. If you saw what a valve spring was doing at even 4000 rpm's in slow motion, you would not even think of modifying it. At 4000 rpm's the valve opens 33 times each second :eek: Dont let anyone try and tell you there are no harmonics at low rpm's. You want to build a performance engine ... do it right. Pull the heads and have them properly machined to work with the springs.
Just my opinion,

A cheaper route would be to sell the Z28 springs and order a set of GM LT4 springs.

They're good to .525 lift and best of all, the will sit right in the Vortecs with ANY machining in the pockets or on the towers. At least mine did on 906 castings.

The LT4 spring is a single spring w/o a damper.

Dwayne

Don't forget you need new retainers for the LT4 springs too.

Later
Steve

Isn't the LT4 spring a larger outside diameter? Will it fit in the stock pocket?

Where did you get the Z28 springs from?

We put a set of Comp Cams springs on ours (.480 lift), and they fit without modifications.

I got them from Competition products. They are listed as Z28/LT1 springs.

Clyde

my lt4 springs fit and worked perfectly too

I'm looking at my old copy of Competition Products cat., (page 20), and right under the Z- Springs are the LT-1/ZZ3/350HO springs that are rated at 444 psi vs 400 psi if you calculate the rates.

And they are listed as 1.273" OD vs 1.250" dia. so is there a problem with them fitting in the Vortec spring pockets at the outer edges???

AND I will say that the prices listed for both spring sets seem like "great" deals if your lift is OK!!!

pdq67

I feel like an ass. For some inexplicable reason I thought Z-28 and LT4 springs were the same thing. I was WRONG!

My springs are the LT4 springs, not Z28 springs. I did not know that Z-28 springs used dampers.

I will not say "My bad" and expect all to be well. I know it isn't. It was my mistake and I hope not too many people suffered from my mistake.

Clyde, you will have mail soon.

I have LT4 valve springs in my vortecs (they measure 1.33" I believe) they definately wouldnt fit in my 062's without enlarging the spring pockets.

How do the LT4 springs compare to actual "Z28" springs?

I did use the LT4 retainers also. And Yes the LT4 springs sat right down in the spring pockets w/o needing any machining. I have heard some guys say they had to open up the spring pockets a bit but mine did not. I think they are listed as 1.32 OD

Dwayne

Originally posted by New68SS:
A cheaper route would be to sell the Z28 springs and order a set of GM LT4 springs.
They're good to .525 lift and best of all, the will sit right in the Vortecs with ANY machining in the pockets or on the towers. At least mine did on 906 castings.I agree! graemlins/thumbsup.gif
I used the complete GM Hot Cam kit which included the LT4 spring setup on my Vortecs.
A simple installation and required NO machining of spring pockets. Worked very well with the .525 lift of that hyd. roller cam.

Guys,
Vortec heads are not all machined the same.
No casting number is immune to the spring problem.
On some the Z28 will drop right down on the seat. Some need the lower part of the guide machined.
The LT4's will drop in on some & on some the pocket isn't large enough.
Most need the top of the guide cut down for anything over .450-.460 lift.
Don't care if they are 906 or 062 you need to check the heads you have.
I have a brand new set sitting in the shop that will take neither spring without machining but would have gone to about .490 lift on the valve I checked :confused:
Go figure :(

Mine speced out to have like .550" of retainer-to-valve seal clearance (give or take a few) with aftermarket umbrella style seals. When I bought the LT4 springs I tried putting them in and they'd seat directly on top of the groove around the spring pocket. Which goes to show all vortecs are not created equal, I guess.

I've been running these LT4 springs with a fairly large cam and they kinda scare me. They dont float or anything but I still don't quite trust them - Next time the heads are off I'm going to get some 1.44" dual springs.

Thanks for all the help. I decided to cut the guides down and I ordered the cutter and arbor from Comp Cams. Cost was about $65 with shipping.

Hopefully this is it. If i spend any more money on this conversion, I'm going to have to start sleeping in the Chevelle. I've got about $700in the complete package including new heads, intake, gaskets, valve covers, springs and tools.

Clyde

The vortec heads definately seem to have some spring clearance issues. The 1st set I used about 5 years ago I dropped a set of comp cams 981-16's right in. The next set I had machined for a set of 1.44" dual springs...no problem there either. 3rd set...both had exactly the same casting numbers but definately was not the same heads. 1 was "hencho en mexico" :eek: and a slightly rougher casting than the american version, but the ports and chambers was measured out identical. The spring seats for both heads was VERY different...1 would take the 1.44" spring no problem, but no way on american one :confused: 4th set, I dropped in a set of edelbrock performer rpm/torquer springs, only maching was cutting the guides for retainer to guide clearance. So it seems to be luck of the draw on these heads.