Valve train Puzzle

[ALZR1]

http://www.youtube.com/watch?v=bgQiABT05tM

here's the broken parts out of my enigne.


Al.

[XfireZ51]

So what gave way first? You should start a poll.
Chain
Valve locks
Cam bolt

[rkreigh]

very sorry to see the damage. these types of failures are rare

on the u tube video you suspect valve float

how high was the car revved???

can you describe what was happening when the failure occurred?

important thing now is to get the beast back on the road.

I just sold my stock takeout valves from the LPE LSV or I could help you out there.

may still have the lifters, but they are available.

doesn't look like the heads are hurt too bad, hows the short block?

[Dynomite]

http://www.youtube.com/watch?v=bgQiABT05tM

here's the broken parts out of my enigne.
Al.

Holy Crap....that is the worst I have ever seen !!!!!!!!!!!!!!!!!

What Happened????

[ALZR1]

[QUOTE=rkreigh;175082]very sorry to see the damage. these types of failures are rare

on the u tube video you suspect valve float

how high was the car revved???

can you describe what was happening when the failure occurred?

important thing now is to get the beast back on the road.

I just sold my stock takeout valves from the LPE LSV or I could help you out there.

may still have the lifters, but they are available.

doesn't look like the heads are hurt too bad, hows the short block?[/QUOT ]

The cylinder head and lifters I located already the rest of the Parts are coming from Pete.

as far as what happend to the motor that moment,I was in staging warming
up the tires motor reved up to 7500 RPM and one second later it grenaded.



Al.

[rkreigh]

7500 shouldn't be enough to float the valves

been there, done that, a whole bunch of times ;)

my bet is that a chain broke

sounds like you are in good hands and well on the way to getting it back together.

time for some MODS while it's apart if they haven't been done already

[WARP TEN]

http://www.youtube.com/watch?v=bgQiABT05tM

here's the broken parts out of my enigne. Al.

Hi Al--
It was great to see you Sunday but very sorry the engine gave up. Looks pretty bad in the video. Hope you can get it back together soon. Its a puzzle. Maybe valve float at that high (7500) rpm. Looks like something stoped the cams. Anyway, good luck on the rebuild!---Bob

[GOLDCYLON]

Im wondering if the Cam bolt sheared however the thinning lifter is also a concern. That happens over time not during a catastropic event.

Last time I saw a blow through on a cam cover it was a cam retention bolt failure.

[B17 Crew]

Sorry to see this happen your engine, hope you are up and running soon. When you flipped the cam cover over, it resembled damage that automotive author Hib Halverson had to his ’95 LT5. I recall seeing a photo of his cam cover with a hole very similar to your cam cover. His engine was running at high RPM as well. http://www.vetteweb.com/tech/vemp_0004_c4_zr1_upgrades/viewall.html

What kind of mileage do you have on your engine?

B17 Crew
:hello:

[LGAFF]

The line manager at Mercury told me many of the race engines they tested broke cam chains related to oil starvation on the lower half of the motor at high RPM. He said people always think the chains are the weak point but its the oiling system pushing all of the oil to the top end of the motor; sudden stoppage snaps the chains.

[scottfab]

The line manager at Mercury told me many of the race engines they tested broke cam chains related to oil starvation on the lower half of the motor at high RPM. He said people always think the chains are the weak point but its the oiling system pushing all of the oil to the top end of the motor; sudden stoppage snaps the chains.

Really sorry to see this happen. I see in the vid at 2:02 that the top chain guide in the valve cover is looking ok. Had you heard any piston slap before the event? Say at idle just after a cold start?
What oil were you using?
What mods were done to the engine if any?
This is not the worst I've see but as someone said. "it's rare".
We're ALL pulling for ya.
She's down but NOT out!

[XfireZ51]

I don't see how busted chains sheared 2 cam bolts. Agree w Bob, something stopped the cams. In any case, you'll have the car ready for the next 1/2 mile.
Maybe in October.

[LGAFF]

Was there any damage to the cam bearing surface or cam lobes?

[ALZR1]

I don't see how busted chains sheared 2 cam bolts. Agree w Bob, something stopped the cams. In any case, you'll have the car ready for the next 1/2 mile.
Maybe in October.


the chain broke because of the lifter breaking and getting in the way of the cam turning,some of the lifter parts were stuck in the head.
the last oil used was AMSOIL 10/40 HIGH ZINC CONTENT,but I don't think
it was the oil that caused the failure.


AL.

[ALZR1]

Was there any damage to the cam bearing surface or cam lobes?


not at all.

[rhipsher]

Is this the LPE stroker Al?

[XfireZ51]

Is this the LPE stroker Al?

It's an FBI stroker

[LGAFF]

jeal lifters:)

[Blue Flame Restorations]

Sorry about your loss, Al....

I bet you'll get it running better than ever=D>

[ALZR1]

Sorry about your loss, Al....

I bet you'll get it running better than ever=D>

you got that right Bret.
it's and FBI stroker,but the problem is not with the bottom half.



AL.

[LGAFF]

So do you think its just a quality control issue with the lifters? There are several articles on-line stating its a crap shoot when you buy them due to the # of suppliers

[Blue Flame Restorations]

Lots of the lifters are made in China these days. I can't get US made solid lifters for a 235 six cylinder motor any longer. And yes, they do break.

[ALZR1]

So do you think its just a quality control issue with the lifters? There are several articles on-line stating its a crap shoot when you buy them due to the # of suppliers

Mine are Melling lifters and made by Eaton.

AL.

[Dynomite]

Mine are Melling lifters and made by Eaton.

AL.

Were they Mellings JB 2236?
How long had they been installed?
Is there anything that might have contributed to lifter failure other than poor quality lifter?

If so...what does Pete have to say about Mellings JB 2236 as they are as identical to stock lifters as you can get?
Lifters (http://forums.corvetteforum.com/c4-zr-1-discussion/2942622-tech-info-lt5-new-rebuild-zero-compression.html#post1579115169)

[ALZR1]

Were they Mellings JB 2236?
How long had they been installed?
Is there anything that might have contributed to lifter failure other than poor quality lifter?

If so...what does Pete have to say about Mellings JB 2236 as they are as identical to stock lifters as you can get?
Lifters (http://forums.corvetteforum.com/c4-zr-1-discussion/2942622-tech-info-lt5-new-rebuild-zero-compression.html#post1579115169)

we use the same lifters,Bob and Pete think that the cams moved,and that started the train wreck.

AL.

[Dynomite]

we use the same lifters,Bob and Pete think that the cams moved,and that started the train wreck.

AL.

Cams moved? You mean timing changed?
Such that you had valve contact with pistons?
I know it is close depending on head work, valve work, timing and Cams.....I had light (but you could see) eyebrows on all pistons on a set of heads not too long ago.

[ALZR1]

Cams moved? You mean timing changed?
Such that you had valve contact with pistons?
I know it is close depending on head work, valve work, timing and Cams.....I had light (but you could see) eyebrows on all pistons on a set of heads not too long ago.

Yes that's what I mean (changed valve timing).

AL.

[GOLDCYLON]

I don't see how busted chains sheared 2 cam bolts. Agree w Bob, something stopped the cams. In any case, you'll have the car ready for the next 1/2 mile.
Maybe in October.

I think the cams started to walk to due to the shearing the rest is a train wreck of catastrophic events. Chain broke after all the bits and pieces ground the cams to a halt. Lifters shattered as they got in the way. Valves bent as all the pieces started to share the same space.

Very ugly Even when I lost my secondaries system the very small pieces bent 2valves.

[ZR1-AL]

http://www.youtube.com/watch?v=bgQiABT05tM

here's the broken parts out of my enigne.


Al.


I hate to see broken LT5's :saluting:

Al, I was trying to connect with you since I'm local but your inbox is full. Can you email me at newnode@mac.com