Ideas on wtf went wrong here?

05sonic4.6

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im looking for ideas at what may have caused a few of my exhaust valve to just decide to bend, this is basically a brand new engine I put together and the machine shop rebuilt the heads and install the new springs for me. There is zero ptv contact, thank the car gods, timing is spot on, rockers and lash adjusters are in perfect shape so wtf could have caused his to happen? im thinking the machine shop messed something up when they rebuilt the heads but I want input before I start yelling at people.

In the pic the rocker is still on the lash adjuster it's just the stem is literally bent over to left and this pic wasn't even the worst example, on the other head the valve stem was bent completely in front of the rocker and the rocker was punching down on the retainer. Any input would help thanks.
 

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05sonic4.6

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How bent the valve stem is, still sitting in the head as it was when I pulled the valve cover. Looking for possible reason as to how it could happen without ptv contact, timing being off or defective rocker and lash adjuster.
 

05sonic4.6

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Yes I was thinking guides as well, just wanted to hear more of the same opinion before I start raising hell, in case there is something I'm not thinking of.
 

Badd GT

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hard to imagine a machinist not catching that, the valve seat would have to be ground crooked as shit to make the valve seal.
 

RED09GT

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Can you remove the follower-and the valvespring? Right now it just looks like the follower isn't sitting in the right spot. Can't see or diagnose anything with those parts still in place.
 

eighty6gt

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How do you know there was no piston to valve contact?

Did the engine ever run?
 

05sonic4.6

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Yes ran it for about 20 miles if that, then started having backfire through the intake. One rocker came completely out from under the cam, luckily it found a spot to sit were it didn't hit anything.

That and thr heads are off now. No ptv contact visible.
 

slackinoff

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Yes ran it for about 20 miles if that, then started having backfire through the intake. One rocker came completely out from under the cam, luckily it found a spot to sit were it didn't hit anything.

That and thr heads are off now. No ptv contact visible.

Sorry to see this. But hey, count your blessings....that could have been so much worse had it dropped a seat or the valve, or the follower (with a "Slingblade billybob" accent -Some call it a rocker, I call it a follower..... mmmhmmm) getting into something.

I am super interested into what could have caused this....right now we are entertaining the idea that the guide was put in soooo bad, the then valve job was wako off? Do I have the theory correct?
 
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RocketcarX

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The rocker popping out prolly bent the valve. Where you found if and where is went are likely two different things.
PTV issues bend the valve inside the chamber, not in the cam valley.
 

05sonic4.6

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Sorry to see this. But hey, count your blessings....that could have been so much worse had it dropped a seat or the valve, or the follower (with a "Slingblade billybob" accent -Some call it a rocker, I call it a follower..... mmmhmmm) getting into something.

I am super interested into what could have caused this....right now we are entertaining the idea that the guide was put in soooo bad, the then valve job was wako off? Do I have the theory correct?

Yeah I was so relived to see that my pistons were not hit at all, I was thinking the worst when I first pulled the valve covers off and saw how messed up everything is.

But yes I believe your theory is on the right track at least. It's strange as well that from what from I can tell it's only the exhaust valves that are bent, I think 4 or 5 of them I can't remember I have to look again ha. The part of it that really gets my blood boiling is I told the machine shop right off the bat I didn't want the heads rebuild I just wanted the shaved flat and the new springs put in and the guy pulled them completely apart anyway and told me they needed a rebuild when I know they didn't.

The rocker popping out prolly bent the valve. Where you found if and where is went are likely two different things.
PTV issues bend the valve inside the chamber, not in the cam valley.

Rockers/followers don't just pop out of place without some underlying issue though, the valves geometry has to be completely out of wack. From what I could see the follower hadn't come in contact with anything else and was sitting just bellow the valve tucked in between the valve spring and the cover.
 

WJBertrand

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I wonder if the lash adjusters were primed? If they were dry, they might have let the followers move out of position due to too much clearance.
 

05sonic4.6

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i wonder if the lash adjusters were primed? If they were dry, they might have let the followers move out of position due to too much clearance

I spun the motor for a good 20 seconds without the plugs in before starting it.

how high did you spin the engine before all the backfire started occurring ?

It was Maybe 4K. never went higher than that when I drove it.
 

thump_rrr

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I spun the motor for a good 20 seconds without the plugs in before starting it.



It was Maybe 4K. never went higher than that when I drove it.
But did you prime the lifters before they were installed and did you pressurize the oiling system prior to turning the motor over, even by hand?
 

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