Recently replaced my c5 z06 stock valve springs. After they were replaced one started to make a noise so had mechanic check it out, one wasn’t torqued down properly no big deal I thought. So after fixing went for a drive nothing abusive and apparently broke the same valve that had been retorqued.So the question is could you break a spring from it not being tightened correctly.Spring broke with less than 30 miles on it didn’t damage the motor.Contacted PAC about broken valve spring they said send it in mailed in the broken valve spring and it was lost in the mail.So the big question it is do I replace all the valve springs over again or just replace the one that was broken with another PAC spring. The car has zero mods and 40,000 miles on it never raced tracked or abused

 

You know valve springs dont get torqued down right???

 

rocker arm was not torqued down enough

 

Stock rocker arm?

The rocker arm isn't tightened enough, it backs off, shouldn't affect the valve spring, UNLESS when "dancing around" the rocker crashes into the valve spring. Any indication of this, either on the rocker or the OD of the spring?

 

There was no indication on the rocker arm

 

Bad things can happen when a valve spring fails. Get the correct springs from another vendor.

 

Why PAC springs (I just installed PACs due to mods)? Which ones did you select? Car is completely stock? Your mechanic competent in the LS platform? To "break" a spring due to a loose rocker arm is a head scratcher.

 

And this adds positively to the discussion how?

 

Yea, i m lost on that one myself... then the spring gets " Lost in the mail".. hmm interesting

 

I put PAC 1218 springs in it was told that they were some of the best. Now I’m just gonna put factory GM springs back in it. I personally mailed the broken spring back to PAC myself through the US mail US mail lost it in Indianapolis. As far as my mechanics competency?? He had an LS turbo I figured he knew what he was doing.Biggest question to the forum is would you trust the other springs or would you go through the whole process again with different springs

 

i am not saying you don t know what you are doing, not at all.. PAC could say they never got tt to avoid looking after the problem, can t see that tho.
i just put pac 660 springs in my 02 Z, only because i think they are one of the best.
The vendor will not help you out with this ?
sorry to see this happening. good luck man.

 

I saw the dealer and it’s was like 7 bucks for the spring and those top retainers. Cheap easy fix. If you need the number I might have saved the package the spring came in.

 

It's an attempt to determine the competency/mechanical experience of the person doing the work. And along that line, it also helps determine if the installer knows the difference between the venerable SBC and the current LS series of engines. While I'm not positive, on a traditional SBC, it MIGHT be possible to tighten the rocker arm pivot bolt to where it puts the valve spring into a fully bound position, as the pushrod raises. Just making sure that isn't the case, here......

 

Running turbos on stock springs I wonder how long that last until the valve train was wrecked !
If your mechanical skills are even fair you could work on your own ls it’s all simple! We’re here to help you!

 

were the new springs heat cycled?

 

Louisvillec5, sorry to hear about your valve spring experience. I recently bought a 2002 Z06 (January of 2002 build date) and swapped out the valve springs and seals as preventative maintenance given the history of valve spring failures in late 2002 and early 2003 cars. To my knowledge, the GM valve springs that have since been used as replacements have been reliable.

I offer a few thoughts, below, based on my experience playing with cars and, most recently, with the new-to-me Corvette that I bought in December of 2019.

If you don't work on your car, being familiar with the scope of work should allow you to have informed conversations with your mechanic about the work to be done, better understanding what you will be charged for in terms of parts and labor, and better understanding any problems and needed fixes when things go wrong.

If you don't have a Corvette repair manual ...even if you do not do your own work, for starters you may want to get a copy of the Haynes Repair Manual "Chevrolet Corvette 1997 thru 2013 All models". It is about $24 at your local auto parts store and will pay for itself in no time.

Refer to Chapter 2, Part A, section 5 (removal and installation of rocker arms) and section 6 (replacing the valve springs, retainers and seals). Replacing the valve springs is pretty straight forward. For reinstalling the rocker arms, there is a specific sequence to torque the rocker arms that starts with the number one piston at top-dead-center and later requires the crankshaft to be rotated. Also, (not described in the manual) once the car is back together heat cycling the valves is recommended.

I just completed this work myself (admittedly not without excitement, which CF members and a fellow neighbor / retired GM mechanic graciously helped extricate me from trouble). The valve spring swap is kind of tough to screw up, but it is possible that things could go wrong particularly if the rocker arms are not torqued per the required sequence and crank rotation. [While I am no professional mechanic, I do agree with prior comments that a loose rocker arm is unlikely to break a valve spring...but unlikely things do happen.]

As for replacement valve springs, I'd recommend sticking with GM replacement parts if your engine is stock (even for the short run). I used GM Performance parts (valve springs, valve seals, valve cover gaskets, spark plug wires). Why? Because they are proven components (other than the 2002 - 2003 run of bad valve springs) that will avoid unwanted drama and trauma.

I sourced the parts for my valve spring swap from CULTRAG Performance. There are other vendors can set you up with the goodies that you need.

If you plan to mod the engine, you may want to complete any mods in stages where inter-related components are upgraded together (some examples: cams & valve train; CAI, intake manifold, headers, & cat-back; suspension, alignment settings, & tires). This approach will help you develop upgrades that work together, perform as intended, and avoid duplication of labor.

Hope you get back to enjoying you Corvette soon.

 

We are your repair manual lol !


I call bs on the above post! Only when your replacing crankshaft and timing Pistons, & camshafts-is when you ever need to worry about the engine being at TDC! I’ve have broke a valve spring! It requires replacing your valve cover gaskets as they most likely won’t form back in due to the constant heat expansion.It was a simple take off check the rocker arm and bearing as well as replacing the spring there’s a tool at Napa I paid 17.95! Replace 1 or replace them all up to you! I would just fix the 1 if it were me! grab your springs from a dealer is what I suggest unless you need a dual coil high performance if your turbo or s/c !

Ive also put new heads on the car without flipping my crank around for TDC. Why because even if you were replacing the valves when you torque down the rocker the spring will compress and extend the valve open thus leaving your firing /timing and all that other mumbo jumbo intact! It’s been done I’ve done it!
https://www.corvetteforum.com/forums...ange-help.html

 

Hence what he was trying to say is rather then replace 1 valve spring! That takes maybe a hour of your time and would cost you 35.00 you should prep for the modification world and run diamond forged pistons and forged billet rods. Billet crank! Hone & sleeve the bore! Beef up the heads valve train and cam and spend 10k on prevention lol to funny! Hey I mean if that’s the OP’s goal ! However it seems more they would like to fix the problem at hand. Right after I broke a spring that’s exactly were I went with it !

 

Op did you ever resolve the issue?