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98 C3500 6.5 turbo service truck
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Discussion Starter · #1 ·
Awhile ago I posted about "a horrible clanking noise", I found out what happened and today I just got the truck running again. 1 new piston and a pair of valves (plus all the gaskets and such to get there and back). Anyway something got into cylinder #2 and chewed up and cracked the piston, and bent both valves. This engine had less than 3K on a long block. But being as just over a year the warranty was expired. Besides the "Premium rebuild" was just BS, and I would not want any more dealings with them. So what could the object have been? The remnants I found in the turbo (exhaust side), with no visible damage to the turbo. The pieces are metallic, attract to a magnet and have rounded edges. I am sure that if it was a nut or bolt it would not have been so crumbled. If it were a hard brittle piece it would not have the rounded edges. In my mind that leaves a cast piece? I saw nothing missing from the cast head, and between the head and turbo is only aluminum, Since the compressor vanes on the turbo have no marks on them I'm sure it came post turbo. But what, and how? If it was a fastener or tool, I could see that in my assembly and install I had somehow dropped it in unnoticed in the intake plenum. I am certain though it is not a fastener or tool. Any ideas?
 

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Could be what's left of a valve guide...:confused:
 

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98 C3500 6.5 turbo service truck
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12 Posts
Discussion Starter · #3 ·
Maybe If whoever rebuilt the head was sloppy enough to have some piece from some other head get lodged in the intake. Makes the best sense so far. Maybe they tumble the heads in bulk?
 

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92 cheverolet Scottsdale 6.5 turbo diesel
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Too long a bolt in too short a hole cracking the casting ! Common in Fords not so much in chevys..
 
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1995 Chevrolet Silverado Z71 6.5 TD
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Could be what's left of a valve guide...:confused:
I thought valve guides are made of brass or bi-metal to be softer than the valve itself.
 

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98 C3500 6.5 turbo service truck
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Discussion Starter · #7 ·
I looked online and saw guides are often sintered metal. That would explain the crumbled pieces. But even mostly the same for a piece off a cast head. Since mine had no chunk missing off it I still suspect it came from the rebuilder. The one I paid way too much for. Thinking "you get what you pay for". This time that was not the case.
 

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1995 Chevrolet Silverado Z71 6.5 TD
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435 Posts
I looked online and saw guides are often sintered metal. That would explain the crumbled pieces. But even mostly the same for a piece off a cast head. Since mine had no chunk missing off it I still suspect it came from the rebuilder. The one I paid way too much for. Thinking "you get what you pay for". This time that was not the case.
I stand corrected. ;)
Sintered or powdered metal (P/M) valve guides are typically made from low alloy steel grades containing mainly iron-copper-carbon and exhibit ferritic/pearlitic microstructures. Compositions containing higher carbon levels ( ie more than 1.6%) exhibit carbides and free graphite. Copper levels may vary from 2 to 12%.
 
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