Duramax Diesels Forum Truck of the Week
  #1  
Old 08-19-2018, 03:10 PM
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Yngdmax92 Yngdmax92 is offline
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Default Worn valve bridges??????

Working on a 2008 lmm, it came to me either the head already pulled and the main problem was the 3 cylinder dropped a valve and needed a piston replacement. Pulled the trans and front diff, dropped pans and slid the rod and piston out and installed a new rod and piston. Through a new std rod bearing in it, new rod bolts etc. Went to put the valve train together after I got one new valve bridge because the one was damaged from the dropped valve..... I started seeing what happened. And I for the life of me can't figure out why. E er valve bridge on this engine is worth. So bad they the stems are just about to pop through the bridge and eventually drop another valve down the road, so I got 16 new valve bridges but I still don't understand what would be the cause of this.

Engine is said to have good oil pressure, said to have the oil changed regularly and I can't see any signs of anything relating to oil starvation. Rocker assemy has been disassembled to check for any discoloration, rod bearing looked like normal wear. What else can I look for to pin point why this happened, I do not want the truck to leave my shop without me knowing I fixed the problem.

Truck is a plow truck, had proper lash setting from what I could tell, has moonshine tune and stock trans, nothing crazy. Any opinions???
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2003 2500 hd cc/sb (leftovers) MPS 63.5 ihi, built trans, airdog 150, 30 overs..... Sold


New and improved! 2007 classis lbz LS ec/sb

Egr delete, pcv re-route, PIPED, airdog 4g 165,

Danville performance tunes.

Last edited by Yngdmax92; 08-20-2018 at 05:44 AM.
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  #2  
Old 08-20-2018, 11:46 AM
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Yngdmax92 Yngdmax92 is offline
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Bump
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2003 2500 hd cc/sb (leftovers) MPS 63.5 ihi, built trans, airdog 150, 30 overs..... Sold


New and improved! 2007 classis lbz LS ec/sb

Egr delete, pcv re-route, PIPED, airdog 4g 165,

Danville performance tunes.
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  #3  
Old 08-20-2018, 12:17 PM
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PureHybrid PureHybrid is offline
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Default

Never encountered this, even on high mile engines. I'd say junk material.

Possible one spring or guide is tight, causing the bridge to rock back and forth excessively. Are the valve stems rounded on top?
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Old 08-20-2018, 12:43 PM
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head gaskets upside down? iirc it blocks an oil passage up there but the rocker rails and so on should be trash
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Old 08-21-2018, 03:53 AM
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Found the problem and jumped to conclusion, I called my good friend I met on here name Trevor.

He hasn't seen anything like this either, so since it only dropped the valve on the passenger side, I pulled apart the other side to see if I could possibly see what the issue is and I found it. The valve lash was probably set to around 1/4"..... I could almost remove the bridge with out loosening the rocker assembly

This truck has 256k miles on it and it appears like someone has been in this engine before. Wether they adjusted the lash or not, o have no clue but if they did they were doing it wrong. This engine must of sounded terrible!

Going to replace the one bent push rod, all the bridges and complete overhead adjustment. Should be good to go.

Thanks for the help fellas
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2003 2500 hd cc/sb (leftovers) MPS 63.5 ihi, built trans, airdog 150, 30 overs..... Sold


New and improved! 2007 classis lbz LS ec/sb

Egr delete, pcv re-route, PIPED, airdog 4g 165,

Danville performance tunes.
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