Managed to destroy a dual valve spring

[AdamK47]

Car started running like crap shortly before arriving home last night. Thought it might have been a bad spark plug or wire. Never saw a CEL, so I then thought it might have been something mechanical like a broken valve spring. Popped the valve cover today to confirm and sure enough...

 

[lavaheadache]

looks like a easy fix, no?

 

[phucheneh]

Quality metallurgy right there.

Or just terrible spring design. Is it just me or are all the coils touching? That's a stock camshaft/rockers?

edit: wait...I thought the valve was just open...no, the one beside it is. What's going on there? Bent valve?

 

[jaha2000]

Most times broken springs come with bent valves....

 

[KentState]

This is the same replacement engine from the last failure?

 

[AdamK47]

I'm taking the head off after work today to see if there is any damage to the valve or piston. I could just replace the spring and do a compression test. I'd still be worried even if the compression test passes.

 

[AdamK47]

This is the same replacement engine from the last failure?

The short-block was replaced. Heads remained the same.

 

[Jimzz]

Who made those springs?


But some early Z06 Corvettes had problems with broken valve springs and most did not bend the valve and that was with a single beehive spring.
I'd just replace the spring myself and test.

 

[skyking]

I would not. TDC the piston, remove keeper and broken spring. Rotate valve to check for bend. Reinstall new stuff and compression check. I seriously doubt any damage that would not include a bent stem.

 

[AdamK47]

Did a lot of wrenching after work today.

Love taps.

Valve doesn't completely close.

 

[boomerang]

What do you think was the cause?

 

[bruceb]

So it looks like a slightly bent valve and minor damage to the piston. You will need to decarbon the piston top and see just how bad the actual material is hurt. Worst case, new piston. Best case, clean it up and see what happens after.

 

[skyking]

bummer. You going to yank the piston too?

 

[Gillbot]

Ahh the downfall of fun......

 

[AdamK47]

Ahh the downfall of fun......

No more of this

Oh well, I had planned on getting a boosted AES built 390 LQ9 and a G-Force 9" IRS with a mini-tub anyway.

 

[Gillbot]

Sounds like money. I was always too cheap for that noise.

 

[phucheneh]

I think his piston is fine. Looks like it just scraped the carbon off the valve relief. Tiny bit of emory cloth or something to knock down any sharp spots and it should be good to go.

Piston vs valve results in piston victory every time.

I'd try and be as close to 100% sure of what happened as you can, though. Work out the order of things and know why they happened...valve probably bent because it hit the piston. Valve probably hit the piston because the spring broke...why'd the spring break? Rockers and pushrods okay? Valve guide and seat okay?

Are broken valve springs something that is known to happen on those engines?

 

[AdamK47]

The valve springs I purchased are PRC dual .675". From what I gather is that they had a bad batch of them last year and I happen to have them.

It's uncommon for dual valve springs to break like this on NA LSx engines.

The piston is OK. I can grind down the pushed up bits of metal from the valve taps.

 

[Gillbot]

I think his piston is fine. Looks like it just scraped the carbon off the valve relief. Tiny bit of emory cloth or something to knock down any sharp spots and it should be good to go.

Piston vs valve results in piston victory every time.

I'd try and be as close to 100% sure of what happened as you can, though. Work out the order of things and know why they happened...valve probably bent because it hit the piston. Valve probably hit the piston because the spring broke...why'd the spring break? Rockers and pushrods okay? Valve guide and seat okay?

Are broken valve springs something that is known to happen on those engines?

If he has stock pistons, there are no valve reliefs........

 

[jagec]

If he has stock pistons, there are no valve reliefs........

There are now.

One of them, at least.

 

[Gillbot]

He may as well fly-cut the rest now and go bigger valves, more cubes, ported everything, forged, boosted and ... what else can he "repair" while he's in there......

 

[phucheneh]

LOL. I totally thought that was a stock relief. I could sweat I saw one on the piston next to it in that black mass.

That's a fairly impressive dent, then.

 

[CPricecrispi]

Amazed it didn't go through the piston, so it's a bad case scenario but not the worst one.

I've would've been a dumbass and given it one rev to 4500 RPMs and shot the valve into the oil pickup.

 

[olds]

He may as well fly-cut the rest now and go bigger valves, more cubes, ported everything, forged, boosted and ... what else can he "repair" while he's in there......

Sounds like me. Blew an intake manifold gasket on my 455.
Had the intake off and ended up pulling heads, going to a bigger cam, new springs, roller tip rockers...
It never ends.

 

[SparkyJJO]

Sounds like me. Blew an intake manifold gasket on my 455.
Had the intake off and ended up pulling heads, going to a bigger cam, new springs, roller tip rockers...
It never ends.

Having to fix something is always a good excuse to upgrade while you're at it

Downside is the bank account can get a little empty :hmm: