Millenium Z06

This is my thought too, a single valve failure due to a mechanical over rev is not the norm and only one valve guide broke and was pushed back out of the head? IDK, seems strange to me.

stefuel

What bothers me is of all the dropped valve LS7 head pictures, I don't remember one where the guide wasn't still in the head. In the original short video here showing the side to side movement of the valve with the spring still installed, what happened to the rest of the guide above the head casting? Did that break off and stay up with the spring???
If someone who had never replaced a guide installed it...ya perhaps there wasn't a tight enough fit. But for someone like AHP who has installed perhaps thousands of guides to let one slip by that was falling out loose doesn't cut it with me.

What scares me now is, if it's the builders fault and there is not enough clearance between the pistons and valves AND they just installed new parts without correcting the problem, it will happen again.

Dirty Howie

I don't think I have missed one thread over all the years and also don't remember seeing a guide drop out of a head ......


DH

whitec5sc

tw78911sc

was the car dyno tuned? motor could have been zinged on a pull

427V8BB

MTPZ06

And I still think its highly possible someone missed a gear under load, valve kissed a piston bent stem and damaged guide. We don't know that there isn't more bent valves, etc., were not there to see or inspect anything further, we don't know who did the new engine assembly, we don't know who did the head swap. Too many unknowns to determine what truly happened...

racebum

i'm still waiting for the day any vendor says "sorry about that, our mistake. here let us fix that for you"

past 10 years i have seen that....mmm zero times

too obsessed with profits i guess

then again i've never really understood the love of money

~STOLEN~

this is weird on both sides
ive read every post and everyone brings up good points. I feel if he missed a gear and over revved the motor, MORE than one vale would be affected.
If timing was off, car wouldnt have ran more than 10 seconds, thats if it even started. Every valve would have made contact.

HOWEVER, whatever was in there was in there for a while, and bounced around a lot, then i think eventually partially went out the exhaust.

i would imagine that combustion changer is that bad from oil being in there due to there being NO guide at the end of failure.

BUT, like another said, ive never seen a dripped GUIDE scenario in the 4 years ive been following.

IM on the fence, but i do feel like there is more to the story on BOTH sides, and AHP claims the "too busy to keep up" with the thread on the forum, but they will chime in EVERY time someone mentions, got my AHP heads today LOL

ibtl haha

grcor

If this is over rev damage, who could have done it? It has been mentioned that it could have been done on the dyno or the owner could have done it. I will add one more to the list that no one has mentioned. What if someone at the shop took the car out after it was ready for the owner to pickup and drove it like they stole it? Like we never heard that one happen before, even at new car dealerships it happens.

sccaGT1racer

To all the people who think the valve guide should have went out the exhaust. Ive pulled pieces of piston out of intake manifolds on engine failures that the valves were still intact.

racebum

i seriously hate this about the aftermarket car world. not even singling out one company. a LOT of them do this. people are basically wallets with legs

atomic 505hp

Like I said this is frustrating, but if this happen at AHP the customer would have been taken care of 110% and they might of not even said anything and just fixed it and no one would have know. Just wanted to tell my story. I dont have any reason to make it up. Just telling how it went down. New motor breaking it in, no over rev. or missed gear. I dont think someone took it for a joy ride, employees have faster cars then me. Plus they have cameras.
I have talk to some head company's on how valves are pressed in and there might have been a fracture in manufacturing the valve or when it got pressed in had a fracture then came apart when it got hot. The valve disintegrated under load. Engine's have exploited and still have valve guides in place.
So far 100 miles and changing oil. Keeping fingers, toes and butt hairs crossed. Time heals all wounds, hopefully it will heal my wallet too.

American Heritage

We fully stood behind our product and sent the customer a replacement head and fully inspected the other head even know our failure analysis eventually lead us to the conclusion that the failure was caused by someone other than us (the failure was caused by driver/tuner/installer).


Our goal is to help the corvette/LS community and to have happy/fully satisfied customers. We do this by providing excellent products backed up by excellent customer service.

It is sad to hear what happened to the OP but the main issue/ignition point here is that the customer/OP wanted us to pay for damage to parts that we never sold him, touched or ever had anything to do with...

We send out 200+ sets of LS7 heads a year all over the world and never have a problem with any of them. We take great time and effort to make sure our product is right before it ever leaves our facility.


In no way are we avoiding this thread or any discussion but we are point blank extremely busy. There are only so many hours in the day and when you sell as many heads and long blocks as we do in combination with a booming install and dyno tuning side my days get very long. Anyone that knows me (or get my 2am emails) knows I put in 16 hour plus days and am one of the most dedicated individuals to my craft that you will find. Even my GM (general manager) puts in 12 hour plus days at our facility.


As stated in our first post if anyone has any questions regarding this feel free to email me/us. We are in no way avoiding any discussion about this or anything else as we have nothing to hide or to avoid. This failure was not caused by a failure on our part but instead on the installation end which was provided by another facility.

We are an open book that is here to help the corvette community. We have been saying this for 5+ years which is evident by our years of 5 star feedback. We are here to help.

Turbokraft

^^^^Your company can't control all the variables, I understand. That you have not ignored the subject and have responded professionally speaks volumes about your company and product support. I feel the pain and frustration of the owner as well, a lot of money was spent to repair the car. Not practical for everyone I but I bet there are zero failures that were installed and tuned at your facility. For the record I have stock heads(very nervous) .

tommyc6z06

Michael_D

Valve guide inserts are pressed into the guide bore from the top. It is an interference fit, and each alloy will have specific fitment recommendations in different heads (mostly due to coefficients of thermal expansion). A considerable amount of force is required to drive them out. Sometimes you can use a pneumatic hammer and knock them out, or use a press, or bore them out, thread them and pull them out..... Point being - they don't just "drop". Something has to drive them out. In this case, it appears that PTVC occurred, and the bent valve managed to either drive or pull the insert.

What did the pushrods on this cylinder look like? Were they bent?

njk4o5

wait your not supposed to shift from 4th to 2nd at WOT?

Dale1990

Not if you're spinning more than about 3800 RPM in 4th.

MTPZ06