Inner valve springs AFU...
Thread Starter
Teching In
Joined: Jan 2012
Posts: 18
Likes: 0
Inner valve springs AFU... so, i just got home from deployment last week and the wife has been driving my car for the past 6 months. the first thing i notice is my clutch is barely alive. i think the only reason you can still drive it is i have a centerforce df and the weights are keeping it alive, (barely)...
next, there is much more valvetrain noise than i remember so i pulled the valve covers off and found that 13 of my inner valve springs grenaded!!! i have quite the project ahead to make sure everything is ok.
question is why though? when i installed everything i made sure i checked installed height and was assured by a respected pp dealer that everything was compatible. i am going to list all parts in my valvetrain and hope that someone smarter than me has an idea.
Cam: 227/234 .616/.614 115 lsa
ls7 lifters
7.425" hardened pushrods
stock rockers
26926 dual springs (only inner springs AFU)
if it was just one spring that broke i wouldnt think too much, but 13!!!??? i thought i had a relatively mild setup, and im trying really hard not to be mad at the wife! lol.
thanks in advance for any ideas guys
next, there is much more valvetrain noise than i remember so i pulled the valve covers off and found that 13 of my inner valve springs grenaded!!! i have quite the project ahead to make sure everything is ok.
question is why though? when i installed everything i made sure i checked installed height and was assured by a respected pp dealer that everything was compatible. i am going to list all parts in my valvetrain and hope that someone smarter than me has an idea.
Cam: 227/234 .616/.614 115 lsa
ls7 lifters
7.425" hardened pushrods
stock rockers
26926 dual springs (only inner springs AFU)
if it was just one spring that broke i wouldnt think too much, but 13!!!??? i thought i had a relatively mild setup, and im trying really hard not to be mad at the wife! lol.
thanks in advance for any ideas guys
Thread Starter
Teching In
Joined: Jan 2012
Posts: 18
Likes: 0
that wouldnt have caused the inner springs to break though would it? im trying to find my invoice now to make sure they are the 926's, but im replacing the springs now anyways so that will solve that issue.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Getting a bunch of springs in one set that are bad and having them grenade is not very likely. Certainly possible, stranger things have happened. But I wouldn't bet my engine on it.
The most common cause of valve spring breakage is binding. The spring coils actually contact each other. Two solid objects trying to occupy the same space at the same time is a bad thing.
When you installed the springs, did you use a micrometer to measure the installed height? Yours should be no less than 1.776" (good year, that).
Did you buy new spring retainers specifically made for those springs?
It's not your wife's fault, don't be mad at her about the valve springs. It's the fault of whoever built the engine. Besides, it's just a car. If it breaks, fix it. That's what we car guys do.
BTW, welcome home.
The most common cause of valve spring breakage is binding. The spring coils actually contact each other. Two solid objects trying to occupy the same space at the same time is a bad thing.
When you installed the springs, did you use a micrometer to measure the installed height? Yours should be no less than 1.776" (good year, that).
Did you buy new spring retainers specifically made for those springs?
It's not your wife's fault, don't be mad at her about the valve springs. It's the fault of whoever built the engine. Besides, it's just a car. If it breaks, fix it. That's what we car guys do.
BTW, welcome home.
You need to check the remaining 3 and look for evidence of wear marks, as this would tell you whether or not the coils were binding.
You say the clutch is shot as well, its entirely possible that its been mechanically over-revved unbeknownst to you. I'd be curious to know what the pistons look like.
You say the clutch is shot as well, its entirely possible that its been mechanically over-revved unbeknownst to you. I'd be curious to know what the pistons look like.
"and was assured by a respected pp dealer that everything was compatible. " So much for that theory.
Sounds like you didn't you check for correct p rod length. Y/n??
A couple clues:
1. The clutch is shot. Too many hi rpm shifts?
2. Missed some of them, and put the rpms to the moon. [Thus the inners are broken.]
Would be interesting to see what the tops of the pistons look like.
*** uming the springs are in @1.776, [like Bob said], and your cam is @ .614, that's a tite line of .060 clear...A couple missed shifts, and ????
Wifey didn't loan your car to her 16yo cousin, did she??
Sounds like you didn't you check for correct p rod length. Y/n??
A couple clues:
1. The clutch is shot. Too many hi rpm shifts?
2. Missed some of them, and put the rpms to the moon. [Thus the inners are broken.]
Would be interesting to see what the tops of the pistons look like.
*** uming the springs are in @1.776, [like Bob said], and your cam is @ .614, that's a tite line of .060 clear...A couple missed shifts, and ????
Wifey didn't loan your car to her 16yo cousin, did she??
Last edited by Old Geezer; Mar 28, 2014 at 07:57 AM.
Thread Starter
Teching In
Joined: Jan 2012
Posts: 18
Likes: 0
yeah, i used the retainers for the 925's. cant remember exact measurement for installed height, will measure again once i get ahold of a micrometer.
the reason i put the 7.425" pushrods in was bc i had been told by multiple people that it would help with valvetrain noise. when we measured it was slightly over 7.4, and that the extra .020 to .025 would act like a slight preload on the lifters.
the wife assures me that she was the only one driving the car and that she doesnt remember over revving the engine. she did admit to racing a 5th gen on the highway but said once she got a car length on him she let off. so who knows... im trying to find a borescope to check out the pistons. i would rather not tear the heads off again, but ill post pics if i find anything.
as long as everything checks out, i have my eye on a a set of lunati golds that should work well. im thinking i will go with 7.400" pushrods even if its a little noisy.
im sticking with the centerforce df, it always held really well and felt very good.
lastly, what calculators do you guys use for valvetrain geometry?
the reason i put the 7.425" pushrods in was bc i had been told by multiple people that it would help with valvetrain noise. when we measured it was slightly over 7.4, and that the extra .020 to .025 would act like a slight preload on the lifters.
the wife assures me that she was the only one driving the car and that she doesnt remember over revving the engine. she did admit to racing a 5th gen on the highway but said once she got a car length on him she let off. so who knows... im trying to find a borescope to check out the pistons. i would rather not tear the heads off again, but ill post pics if i find anything.
as long as everything checks out, i have my eye on a a set of lunati golds that should work well. im thinking i will go with 7.400" pushrods even if its a little noisy.
im sticking with the centerforce df, it always held really well and felt very good.
lastly, what calculators do you guys use for valvetrain geometry?
With stiffer and harder valve spring they tend to be more brittle when cold, so you always want to let the engine warm up some before doing any driving. If you just start it up and take off with a cold engine like with stock springs, then your nice aftermarket valve springs will have a much shorter life.
Hmm where is your rpm rev limiter at? I run patriot duals and had a lil larger cam with ls7 lifters and 7.4 pushrods. Ran that setup for almost 2 yrs pretty hard! Still using same springs with larger cam today. I would get new springs and 7.4s.
The locators that Comp uses are .520" ID which allows the inner springs to contact the seals. There have been cases where the inner springs pulled the seals off the guides so that might be part of the issue.
Also when I checked those retainers on bone stock heads they checked at 1.820", the springs don't coil bind until 1.000"
I would not run dual gold springs, they don't tend to last.
Our kits uses .505" ID, install around 1.780" and coil bind around 1.050" so there's less chance of spring surge.
Also when I checked those retainers on bone stock heads they checked at 1.820", the springs don't coil bind until 1.000"
I would not run dual gold springs, they don't tend to last.
Our kits uses .505" ID, install around 1.780" and coil bind around 1.050" so there's less chance of spring surge.
Thread Starter
Teching In
Joined: Jan 2012
Posts: 18
Likes: 0
The locators that Comp uses are .520" ID which allows the inner springs to contact the seals. There have been cases where the inner springs pulled the seals off the guides so that might be part of the issue.
Also when I checked those retainers on bone stock heads they checked at 1.820", the springs don't coil bind until 1.000"
I would not run dual gold springs, they don't tend to last.
Our kits uses .505" ID, install around 1.780" and coil bind around 1.050" so there's less chance of spring surge.
Also when I checked those retainers on bone stock heads they checked at 1.820", the springs don't coil bind until 1.000"
I would not run dual gold springs, they don't tend to last.
Our kits uses .505" ID, install around 1.780" and coil bind around 1.050" so there's less chance of spring surge.
would you recommend staying with my 7.425 pr or going with 7.400?