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Old 04-15-2002, 01:41 AM   #1
O'l Buck
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Post Yuck, broken rings, burnt pistons

my $20 327 is now down to bare block. I found out for sure where all the oil was going now. The moron that put the thing together forgot to stagger the ring gaps, and it has 2 pistons with burnt tops, broken and burnt ring lands, broken and missing pieces rings. Thank got it didn't hurt the cylinder walls. It's already .060 over and I'm not real crazy about boring it any more. It's been a long time since I've seen pistons in this bad of shape. Can anyone tell me what caused the burnt pistons and broken lands??? I forget what all will do this. The engine is only supposed to have less than 500 miles on the overhaul and I'd believe it. The bearings still look new and so do the pistons that arent destroyed.

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Ol' Buck: '72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84
ralleys and 31/10.5s

Angel girl: 67 Cutlass convertible
330, 3spd stick

Greener: 90 GMC Jimmy
350/auto
Chad Stephens
Orleans,NE

no name yet: 72 442 under serious construction
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67 K-20 350, SM465, Eaton rear, 4.56 no spin option
00 Dodge 2500 4x4, 24V cummins, 5 speed

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Old 04-15-2002, 11:49 AM   #2
Woody
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Running an engine very lean on fuel will burn the piston tops. Other than that I don't know.....

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Old 04-15-2002, 12:20 PM   #3
O'l Buck
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these things look like someone attacked them with a torch and a hammer. Just down 1 side of each piston. I've seen diesel truck engines do this with bad injectors, but never pulled a gas piston that looked like this, I was wondering if maybe it was a fault in the pistons, since it's only 2 of them and the others are perfect.

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Ol' Buck: '72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84
ralleys and 31/10.5s

Angel girl: 67 Cutlass convertible
330, 3spd stick

Greener: 90 GMC Jimmy
350/auto
Chad Stephens
Orleans,NE

no name yet: 72 442 under serious construction
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67 K-20 350, SM465, Eaton rear, 4.56 no spin option
00 Dodge 2500 4x4, 24V cummins, 5 speed

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South Central Nebraska
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Old 04-15-2002, 12:24 PM   #4
69 longhorn
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Are they # 3&5,or # 4&6 ?
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Old 04-15-2002, 01:41 PM   #5
O'l Buck
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69 Longhorn, they are #3 and #5

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Ol' Buck: '72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84
ralleys and 31/10.5s

Angel girl: 67 Cutlass convertible
330, 3spd stick

Greener: 90 GMC Jimmy
350/auto
Chad Stephens
Orleans,NE

no name yet: 72 442 under serious construction
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67 K-20 350, SM465, Eaton rear, 4.56 no spin option
00 Dodge 2500 4x4, 24V cummins, 5 speed

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South Central Nebraska
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Old 04-15-2002, 01:55 PM   #6
69 longhorn
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Thats a hot spot,when they overheat(2 ex ports close together). Is there evidence of a blown head gasket?
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Old 04-15-2002, 02:00 PM   #7
O'l Buck
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no, but the head gaskets were gone when I bought the engine, it was an auction deal and the guy had taken the heads off to investigate the oil burning problem. He said it only had less than 500 mi on the overhaul and figured the guy he had put it together broke an oil ring or something. It's bored .060, do you think maybe there is a problem with cylinder walls being too thin??

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Ol' Buck: '72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84
ralleys and 31/10.5s

Angel girl: 67 Cutlass convertible
330, 3spd stick

Greener: 90 GMC Jimmy
350/auto
Chad Stephens
Orleans,NE

no name yet: 72 442 under serious construction
__________________
67 K-20 350, SM465, Eaton rear, 4.56 no spin option
00 Dodge 2500 4x4, 24V cummins, 5 speed

Chad
South Central Nebraska
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Old 04-15-2002, 02:05 PM   #8
69 longhorn
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I would sure have it checked for cracks/warpage in the deck area,but It sounds like it blew a head gasket to me. I havent run any +060 blocks,but from what i understand,it shouldnt be a problem.Good luck....69 longhorn.
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Old 04-15-2002, 02:09 PM   #9
O'l Buck
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I think I'll run it up to the machine shop. I hate to spend the money to put it together and have the same problem again. I wonder if it happend because the ring gaps were aligned, not staggered. 4 of the pistons had the rings aligned. Pretty sloppy overhaul if you ask me. Is it possible for the fire to flow down through the ring gaps and cut the pistons when they are not staggered??

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Ol' Buck: '72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84
ralleys and 31/10.5s

Angel girl: 67 Cutlass convertible
330, 3spd stick

Greener: 90 GMC Jimmy
350/auto
Chad Stephens
Orleans,NE

no name yet: 72 442 under serious construction
__________________
67 K-20 350, SM465, Eaton rear, 4.56 no spin option
00 Dodge 2500 4x4, 24V cummins, 5 speed

Chad
South Central Nebraska
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Old 04-15-2002, 02:14 PM   #10
tom hand
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I had a 60 over 350 that started burning oil on one cylinder for no reason. When a motor burns oil on just a couple of cylinders it will detonate just on those cylinders but it is much harder to hear. My 60 over 350 melted the head off valve which finished off the head, piston and block. I sure a lot of people will tell about their 60 over blocks that they had no problem with,but I think once you get to 60 over it's kinda like forrest's box of chocolate.

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72 GMC Sierra SWB almost finished---- 84 Softail
Olive Branch MS

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Old 04-15-2002, 02:18 PM   #11
O'l Buck
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it could very well be detonation, the guy used the motor in a 70 c-30 dually to haul tractors and farm equipment around delivering and picking them up from his shop. He said it ran great and pulled good, but it burned a Qt of oil every 50 miles from the day it left the shop. He said he only ran it a couple weeks like that and then pulled it out. I wish he hadn't waited so long.

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Ol' Buck: '72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84
ralleys and 31/10.5s

Angel girl: 67 Cutlass convertible
330, 3spd stick

Greener: 90 GMC Jimmy
350/auto
Chad Stephens
Orleans,NE

no name yet: 72 442 under serious construction
__________________
67 K-20 350, SM465, Eaton rear, 4.56 no spin option
00 Dodge 2500 4x4, 24V cummins, 5 speed

Chad
South Central Nebraska
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Old 04-15-2002, 04:34 PM   #12
Longhorn Man
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I think tom hand is right
Quote:
it's kinda like forrest's box of chocolate
I have seen an 80 over 350 on the street as a daily driver.
Guy had bigger balls than I do, that's for d@mn sure.

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'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite.
If you need a pic posted, E-mail me at longhornmail@yahoo.com
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