Was replacing my 25-30k mi 918's with Lunati springs I got from LE.

When I got to cyl 5 I pulled both springs and the intake one was broken. Retainer held it together until I pulled retainer off and had a two piece spring.

Don't know how long it was broken and fortunately I did not have any carnage. Like many I bought them about 8+ years ago.

PICS:
Lunati sprink kit
Lunati Spring (double)
LUNATI springs installed at 1.780
Pic of broken 918
Batch # of 918 springs

 

I'm gonna say we should assume there were no errors in the setup. right?
Care to say how they were run? Installed height versus Comp's specs, open height versus coil bind height, etc.? what cam? what kinda life did they lead - rev to? how often?

 

This wasn't a 918 failure, this was YOUR FAILURE.

Yet again you prove your raging ignorance.

You ran a part FAR TOO LONG and are blaming the part.

They should have been changed much sooner, inspected for pressure at say 10-15k and changed at 20k maybe less given the fact it took 8 years to put those miles on.

 

I think its time for you to just shut the **** up. You are not helping anyone with your ignorant posts. I can't beleive the mods have let this go on so long.

 

Springs were installed at 1.800" as per spec. Cam is Comp 466 (218/224, .570 int/.565 exh lift) and 918 spring is spec for that cam. I shift at 6400 RPM max. Motor has seen about 40 1/4 mi passes

Dwayne. If it makes you feel better spewing insults while hiding behind a keyboard...sad. You treat your family and co-workers with the same self righteous ego crap? Fing sad punk, grow up.

 

One of the mods PMs me to ask me to add intelligent information to threads. He has specifically asked me not to call anyone stupid is doing so though.

30K miles on springs that endup breaking with an aftermarket cam is operator error PERIOD.

The insults are because he is blaming decent parts for his failure and his LONG history of ignorance.

We all screwup not all of us are smart enough to learn from it.

If a coworker or family member does something stupid I have no problem saying that long as they are smart enough to learn from the situation. If not I wont bother. On these forums though YOU may not be smart enough to learn from your mistakes but hopefully I can help others who read this.

 

Well Dwayne you come into yet another thread and spew your verbal abuse.

So you are not calling me stupid as the moderator has told you not to but you say I have a "long history of ignorance". Pretty much the same name calling as stupid.

Dwayne, maybe in the "world according to Dwayne" I and everyone else is. Fortunately for the rest of us we don't live in the world as you perceive it.

You are called out frequently for posting abusive name calling posts without adding any useful information to the thread. You came on this one and spewed the same crap. You can leave now, we all hear you..

The 918 spring failed, period. It was installed correctly with a fairly mild cam. Since you claim I am ignorant and ran them to long...let me elaborate for "you" since it apparently matters. I did remove springs on cyl # 1 at 12k mi when I did a re-lash to inspect them and pressure test them years ago. The spring that failed was on cyl 5. They two springs I checked by pressure test were fine. Did it at a machine/head shop when I was having some parts balanced. I did not remove the rest of the springs but did "visually" look at each one, even while motor was running with valve covers off. If you note where the spring broke it was the part that wraps around the retainer. It may have been broken at 12k mi, heck after 10 miles, I don't know as I did not notice it. On removal I still did not notice until I pulled the retainers off the springs to keep as spare parts. I was going to throw the springs away since they were getting tired.

Even with reasonable efforts to monitor the springs I had one fail. You seem to think that 25-30k miles on springs is to long. Maybe in the way you use your Caprice it is. Yes I have a aftermarket cam and yes I did check them previously and yes I checked them again at the current mileage and now found one broken. I would not categorize that as being "ignorant" but apparently you do.

Was I lucky there was no damage as a result, yes. So my diligence in swapping springs did pay off. The spring may not have been broken but just cracked and when removing retainer it broke. All the retainers were "snug" on the springs. The spring was not deformed in any way when I removed it. Now with retainer off and the spring in two pieces it will not "stay" together as it did when I removed it so it possibly was at the point of cracked but not broken all the way through until I removed the retainer

My point of posting was to show "my" 918 failure as there have been several reports of them breaking over the years. FAR more than any other spring commonly used on the LT1's. You have posted several times that springs are a wear item, and they are, which is why I monitored them at 12k mi and now at 25-30k mi. Yet you call me ignorant for not finding it earlier...

You have learned a great deal on these forums over the years, built a quick car. Terrific. It isn't what I would build nor is what I did what you would. That is a difference you can't seem to understand. People chose builds suited to their preferences/needs. Sometimes they are not for max performance as to get that some other priorities of the end result can not be met (smog, drivability, etc).

You have valid experience and knowledge to contribute to threads. Yet you chose to belittle and name call people. Not a mature character trait but one you have had for years on this and other forums.

 

918's have had problems for along time tho. Mine lasted me less then 5k miles before one of them snapped in half. at a 2k rpm cruise down the highway. Installed to height and installed properly. **** just happens.

 

No amount of your arguing changes the fact 30K miles on springs with an aftermarket cam is operator error. We all know there was a bad batch when Comp went offshore for the supplier.
That isn't what happened here.
They were run far too long that is the complete story.

Roger I can't wrap my head around how you have a new motor need rebuilding within what the first year and you blindly defend the vendor, but then at 30K miles you break a valvespring and you blame the manufacturer. That is not logical or reasonable.

Years ago on my first heads/cam setup I wore out a set of 918s don't remember exact details but something like a year and 10K miles and the car lost a couple tenths, fresh springs this time nitrided 918s solved the problem.

 

30 k is a lot of miles for a moderate sized cam to not be checking the pressure. Usually at the end of every season I run a checker on my mild hydraulic cam and check cylinder pressure as well.

Not pointing fingers but I think it would be a really good idea for you to get a spring tester and check them every 7 to 10k.

 

I had a 918 fail way back about 7 or 8 years ago. Called Comp and they wanted to know the box number that had the batch number, etc, etc. The springs had maybe 500 miles on them and were setup properly. They sent replacements free of charge. You might want to give them a call. I'm pretty sure they weeded the bad ones out years ago.

 

It's humorous to think you can inspect a spring at a certain mileage interval, call it good, and run it for that interval again. Valvesprings don't give warning signs like that. They go from looking perfect to breaking in a few thousand engine revolutions. You need to understand up front how long they're good for, and throw them away when they reach that point.
If you had been running a mild cam, I wouldn't fault you for expecting 30k miles from them. But XFI lobes revving to 6400.....no way.

 

I had 3 or 4 break on me. And they didn't have 1k miles on them.
Shimmed perfectly- lower .525 range lift - it was a few years ago.... 2012 or so.
Comp 918's were garbage ten years ago and they still can't be trusted.....
I purchased some PAC 1518's - haven't had any issues....
I ordered a cam from Advanced induction( different application) and he recommended the 'pac's ......
My point is 'don't buy the comp 918's'!!!!

 

So, open height was 1.230.
What is coil bind height on those springs?
Just wondering if they were surging unnecessarily because of too MUCH clearance.
Not defending the springs or you, just wondering if they were helped or hindered by that.

 

What 96 and others are trying to say is basically, stock last a long time but when you start modifying certain parts longevity suffer, there is a fine line between a race and street car and as said those XFI lobes are hard on a valve train, some people install parts that say Race Only and then wonder why they break with everyday street use.

 

Those 918s look a lot different than the ones I just installed so they must have changed something over the years. Even the coil bind is different.

 

To those still bashing 918s the fact they didn't break sooner is proof he got them from a good batch.
Now the car with likely pickup some performance with fresh springs, they are shot before they break.

Far as low mileage breakage last spring a friend put in fresh Manley Nextexs one broke at 35 miles a second at 135miles while pulling into a parking lot took out the whole motor. Springs have a certain amount of "infant mortality" as I have heard bowtienut call it.

 

Let me start by saying I'm ignorant! (I just want to beat everyone else...)

I must have got a miracle batch. I have ran mine for ~9-10 years with no issues. I have a tendency to run the car hard (6700RPM's) and have probably ~75,000 miles on those springs. Am I saying everyone should run em' till they break?? By no means!!

 

Comments regarding how long a 918 will last and when they should be inspected/ pressure checked are duly noted, especially with aftermarket cams with more aggressive lobes than others.

I looked through purchase records and mileage. These 918 springs had just over 24k mi on them. 42 1/4 mi passes over the 8 years.

Bow Tie makes the point on if the springs checked out OK at 12k mi than they should be checked at 18k or sooner, not 24k. Noted.

Even though the springs checked out with no pressure loss at 12k (btw 38 of my 42 1/4 mi passes had been done by 12k mi) I knew and was prepared to swap them at about 25k mi.

Opinions of swapping them sooner are noted and in hindsight that would appear to be what was needed assuming the cause of the break was fatigue not a manufacturing error. The reality is I don't know when the spring broke and if it was "infant mortality" and broke soon after initial install. Fortunately the spring did not come apart and cause any damage

Again when I pulled the spring it was still "together" but actually two pieces once I removed the retainer. Given the movement of springs in a running motor, especially spinning high RPM, I am lucky it did not come apart whenever it was it did break

The Lunati spring Lloyd puts in his stage 2 heads is a nice polished quality spring. While it to is a wear item Lloyd advises with "my" XFI lobes (218/224 cam) I check them at 40k mi. if they measure 135 on the seat (20 lbs less than new) he says replace. The Lunati is a double spring so if one breaks there is a better chance of not dropping a valve but certainly no guarantee. It will take me 10 years to put 40 k mi on the car, likely longer.

For 30696....at 70k mi on any spring let alone running a cam...I would say you got your $ worth so might want to swap them while they are still in one piece

 

No, you missed the point I was trying to make. Forget about checking them. Based upon the assumed quality of the spring and the cam one is running, decide up front what the life is, and throw them away when you get there. No checking. An impending fatigue failure won't necessarily show up as reduced pressure; only if it's already on the verge of failing.
I've never had a set of 918's in my hand so can't say for sure, but I'd assume they're nowhere as fatigue resistant as you described the polished Lunati springs.