Cracked cylinder

9 LIVES

9 LIVES

Demolition Expert
Joined
Oct 29, 2006
Messages
4,051
What usually causes something like this? Two cracks on #4 cylinder wall. You can catch your fingernail on them. The go from top to bottom...

I've got a new motor since this photo was taken. :doh:
 

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Hydro-locking from too much fuel or a leaking head gasket? Excessive sustained boost pressure over 120psi? I'm just guessing here.
 
That just looks like scoring to me, cracks usually don't go in perfectly straight lines, ring ends or small piece of something scoring.
 
When I found it I had a blown headgasket after a 100PSI run.
 
Something I noticed that might be linked was after the truck would sit for lets say overnight. If you pulled off the radiator cap it would spew out coolant as if the radiator was pressurized still.
 
Joesixpack said:
That just looks like scoring to me, cracks usually don't go in perfectly straight lines, ring ends or small piece of something scoring.
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You're probably right- I didn't see they were prefectly straight. Those look like ring gashes rather than a cracked wall.
 
Yeah a broke ring will make that, pieces of steel from who know's what, the cylinders are pretty soft stuff. Sure wish our little motor's had induction hardend liners.

Your photo suggests you have a broken top ring, by were the marks terminate. It was at least the top ring doing it anyways.
 
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