Dropped valve migrating?

Ever been on a snipe hunt?

This story sounds like an urban legend. If you really destroyed a valve, I guess it is possible that a few bits of it (like sawdust) could blow back and end up in strange places but this sounds like a lot of Texas stories that start with the line "Now, this aint no shit..."

A race car driver told me (that his mechanic had told him) that a valve had dropped in a too-lean engine, and on engine teardown the valve (or maybe just the head, I think) was found in a different cylinder from where it started. How is it possible for a valve to migrate like that? ______________________________________________________________

You need to be more specific. Was it the valve or the head that was moving from cylinder-to-cylinder? Each type of movement has a different diagnosis. Did the moving valve/head go to an adjacent cylinder or skip a cylinder (or jump to the opposite bank)?

If you can talk to the mechanic who made the original story, maybe there would be more information.

Good luck,

Rodan.

"Rodan" wrote in news:VXwel.1592$Aw2.1056 @nwrddc02.gnilink.net:

No I didn't. You have severely edited my original comments without any indication to readers that you have done so.

You have paraphrased me, at best.

Severe editing by "Rodan" distorts my original post. Please read original post.

Wish I could, believe me. I have told all I know.

Don't know.

Don't know, sorry.

Frankly impossible at this point.

I was kinda hoping somebody might have some idea of how a valve(head) might make its way out of its native cylinder, run up and down whatever manifold runners, and travel to whatever other cylinder, regardless of the details.

From the ones i have seen, when one valve head breaks off it often breaks all the others off too. Its possible a valve fragment got blown up into the intake and then sucked into another cylinder.

Paul wrote in news:WFAel.15018$ snipped-for-privacy@nlpi065.nbdc.sbc.com:

This may have happened, but my guy didn't know much beyond what he told me.

That's sort of what I figured. I thought it had to be a piece instead of the whole valve head.

I was at a motorcycle show once many years ago. One booth was run by a particular racing team, which had a small "house of horrors" exhibit displaying catastrophic mechanical failures suffered during competition. One of the exhibits was an engine in which a valve head had broken off in one cylinder. The valve head did not migrate, but did hammer the absolute piss out of the cylinder it was in, including bending/breaking the other valves. Never having seen anything like that before, I was taken aback by the amount of damage that can occur from such a failure. That's what made me ask about the migration in the Sprint car engine.

A lot of circle track guys rely on this as a crutch... I raced for a long time and when I had money I ran the engine right on the lean edge... when I was broke, I richened it up from 63 main jets to 68's.

I have seen this numerous times.. it isnt all that uncommon for chunks to migrate. HTH, Ben

Its just not possible for a WHOLE valve (or even an intact valve head) to do that. Think about it- a valve head is by definition bigger around than the seat/port opening. Now a large chunk...*maybe*.

ben91932 wrote in news: snipped-for-privacy@z6g2000pre.googlegroups.com:

Thanks. I didn't know all that, which is why I asked.

Sure it is. My old Pontiac had 2.11" Intake Valves and 1.66" exhaust valves. If an exhaust valve head broke off it might fit through the intake opening.

That said, I don't see it happening. I can see chunks floating around, but the odds of an actual valve breaking off and making into another cylinder... not likely. But, hey, I've fished pushrods out of the oilpan after grenading an engine, so anything's possible.

Ray