440 valve failure

[lewtot184]

Over revved one time to many.

 

[Roman1970RR]

If it were me, I’d try to replace just that valve/piston (& check the rod). You can pull 1 head and get at what you need without even pulling the engine

Yeah pulling one head and reassessing it. I need to make sure there isn’t any chunks of steel in the engine though which is concerning

 

[RemCharger]

Here’s an example of keepers that had the tangs sheered off…….
There no indications of any problems on the other 15 valves/retainers/keepers.
The valve spring on the position that failed was down 30-40lbs from how it was installed.
The other 15 were still fine.

Before these keepers finally let go, they had moved up the stem to the top of valve, and there are witness marks on the top of them from contact with the rocker arm roller wheel.

So, the failure is a result of lack of control of the valve…….. because the spring lost a bunch of pressure, and that hammering finally won the battle over the tangs of the keepers.
The unanswered question remained……. Why did that one spring give up?

View attachment 1662856

View attachment 1662857

Would that be more common with an extreme energy type cam?
Asking because I have some heads that look bad , came off a 6500rpm 383 w/ 284xe
I haven't pulled the springs yet

 

[Geoff 2]

Correct me I am wrong, but.......the original Chrys keepers that had the 2-3 round ribs. Didn't the keepers butt together in the retainer, leaving the valve 'loose' on the keepers?

 

[lewtot184]

Correct me I am wrong, but.......the original Chrys keepers that had the 2-3 round ribs. Didn't the keepers butt together in the retainer, leaving the valve 'loose' on the keepers?

haven't used those locks in years but pretty sure the exhaust locks let the valve rotate but intake locks didn't.

 

[PRHeads]

Would that be more common with an extreme energy type cam?
Asking because I have some heads that look bad , came off a 6500rpm 383 w/ 284xe
I haven't pulled the springs yet

I would def expect there to be plenty of signs of valvetrain unhappiness from running an XE284 regularly to 6500rpm in a BBM(unless solid lifters were being used).

 

[PRHeads]

I wouldn’t mind a good look at the topside of that retainer……..

 

[PurpleBeeper]

Yeah pulling one head and reassessing it. I need to make sure there isn’t any chunks of steel in the engine though which is concerning

Agreed. It all depends on how quick you shut it off. I’ve done this myself successfully

 

[1 Wild R/T]

Agreed. It all depends on how quick you shut it off. I’ve done this myself successfully

It depends purely on luck.... If you think your quick enough to shut down an engine before damage occurs consider this... At 3000 RPM the piston will travel up and down it's bore 50 times per second... Pure luck... Period...

 

[RemCharger]

Thanks , well sort of, it has the comp pro magnums set at .004 hot PL. Never had a noise, idled , ran great. But it did have the struggle past 5 grand and then would smarten up to 65. I think you've mentioned that with these cams.

I would def expect there to be plenty of signs of valvetrain unhappiness from running an XE284 regularly to 6500rpm in a BBM(unless solid lifters were being used).

 

[Roman1970RR]

Righto guys I think I want to look at a crate motor as I’m struggling to find good engine builder here I want to get back on the road and rebuild this motor over time. Anybody know the best and most reliable crate motor supplier? Needs to ship to Australia!

 

[Roman1970RR]

Well there it is.

 

[dvw]

Well that answers that question.
Doug

 

[PRHeads]

That’s ugly!!

 

[ckessel]

Time for a re-do.

 

[hofferwood]

OUCH!!

 

[RemCharger]

Cheap stealth valves

 

[WileERobby]

Sorry to say I'm not surprised.

It depends purely on luck.... If you think your quick enough to shut down an engine before damage occurs consider this... At 3000 RPM the piston will travel up and down it's bore 50 times per second... Pure luck... Period...

Agreed... I've never in 50+ years seen anyone that lucky.

 

[PRHeads]

I’d be pretty surprised if the root cause of the failure was that the valve just broke, “for no reason”.

I believe with disassembly and careful examination of the valves/springs/locks from the valves that didn’t break, some light would be shed on the actual cause of the broken valves.
But…….maybe not.

 

[lewtot184]

Wrong parts, poor assembly, excess abuse sets up some crazy harmonics in the valve train. I doubt anything would tolerate that for any length of time.