2009 Yukon 2500 LY6 Dropped Valve seat

[Shackman7878]

2009 Yukon XL 2500 186k miles Ex fire chief command vehicle

Was getting a Misfire code cylinder 8, and rich code bank 2. Put a new Spark plug and Ac Delco Injector Cylinder 8 and swapped the Lead and coil to different cylinders cleared the codes and drove it 50 miles then the code came back but what I thought was a Lifter tick (Not DOD). After taking the Valve covers off and running the truck and listening with a stethoscope noticed the rocker on cylinder 8 intake side was crunchy sounding. So I made the choice to pull the Heads and glad I did. Checked the piston did not go very deep and did not bend the connecting rod when I ran the piston all the way up. Last 2 photos are from the machine shop and the guy did an amazing Job. Will post more photos Later in the week due to the snow storm coming my way.

 

[Shackman7878]

Added more photos.

 

[Tonyrodz]

Super lucky. Mine dropped a valve too--not so lucky.

 

[Geotrash]

Super lucky. Mine dropped a valve too--not so lucky.

Were you running dual valve springs when it broke, Tony?

 

[Geotrash]

2009 Yukon XL 2500 186k miles Ex fire chief command vehicle

Was getting a Misfire code cylinder 8, and rich code bank 2. Put a new Spark plug and Ac Delco Injector Cylinder 8 and swapped the Lead and coil to different cylinders cleared the codes and drove it 50 miles then the code came back but what I thought was a Lifter tick (Not DOD). After taking the Valve covers off and running the truck and listening with a stethoscope noticed the rocker on cylinder 8 intake side was crunchy sounding. So I made the choice to pull the Heads and glad I did. Checked the piston did not go very deep and did not bend the connecting rod when I ran the piston all the way up. Last 2 photos are from the machine shop and the guy did an amazing Job. Will post more photos Later in the week due to the snow storm coming my way.

Fantastic that it didn't do more damage! Those clean cylinder heads sure are pretty.

 

[Tonyrodz]

Were you running dual valve springs when it broke, Tony?

Running Beehive springs from Brian Tooley.

 

[mikeyss]

2009 Yukon XL 2500 186k miles Ex fire chief command vehicle

Was getting a Misfire code cylinder 8, and rich code bank 2. Put a new Spark plug and Ac Delco Injector Cylinder 8 and swapped the Lead and coil to different cylinders cleared the codes and drove it 50 miles then the code came back but what I thought was a Lifter tick (Not DOD). After taking the Valve covers off and running the truck and listening with a stethoscope noticed the rocker on cylinder 8 intake side was crunchy sounding. So I made the choice to pull the Heads and glad I did. Checked the piston did not go very deep and did not bend the connecting rod when I ran the piston all the way up. Last 2 photos are from the machine shop and the guy did an amazing Job. Will post more photos Later in the week due to the snow storm coming my way.

The same thing happened to me about 2 years ago, except the seat broke in half and landed on the piston and shattered it. What head casting you have?

 

[Shackman7878]

The same thing happened to me about 2 years ago, except the seat broke in half and landed on the piston and shattered it. What head casting you have?

Casting was 823

 

[mikeyss]

Casting was 823

Mine was too, I ended up buying TSP performance heads to eliminate any other failures.

 

[Shackman7878]

Mine was too, I ended up buying TSP performance heads to eliminate any other failures.

Right now After this project I would break even If I sell the yukon now. Maybe a option for the tahoe but would love to drop a L94 in it.

 

[Shackman7878]

Installed the lifters and guides, head gaskets and heads bolts are snugged down for now. Weather allows will do the cylinder head torque sequence tomorrow.

 

[Shackman7878]

Truck is up and running.

 

[Shackman7878]

Also did the trunnion upgrade kit, One had square and powder bearings, and 2 fell out with little to no pressure. Used my 1950 Arbor press.

 

[Shackman7878]

Lightning never strikes the same place twice..... my friends 2014 Caprice 6.0 L77, What we though was a Bad DOD lifter turned into a nightmare this engine was rebuild under Warranty at a Chevy dealership 5 years ago. The head bolts you can take off with one hand and a breaker bar. So the Yukon was cylinder #8 Caprice was #7