Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!

Blown head gasket, only to find pistons upside-down...

Thread Tools
 
Search this Thread
 
Old 07-14-2011, 08:15 PM
  #1  
Member

Thread Starter
iTrader: (3)
 
kerplunk318's Avatar
 
Join Date: Jun 2007
Location: Virginia
Posts: 291
Likes: 0
Received 0 Likes on 0 Posts
Blown head gasket, only to find pistons upside-down...

The picture says it all... Where do I go from here? The valves don't look bent but should I pressure test them? I have to pull the motor and swap the pistons around; will I have to re-hang the rods so they can all go back into the same bores?
Old 07-15-2011, 12:24 AM
  #2  
Moderator

 
Apeiron's Avatar
 
Join Date: Jan 2000
Location: Mercedes Norte, Heredia, Costa Rica
Posts: 20,981
Likes: 0
Received 9 Likes on 8 Posts
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Re: Blown head gasket, only to find pistons upside-down...

Getting the heads checked would be a good idea. Honing and re-ringing should be enough to swap the pistons from side to side.
Old 07-15-2011, 12:12 PM
  #3  
Guest
Guest
 
Posts: n/a
Re: Blown head gasket, only to find pistons upside-down...

What about the rod offset?
Old 07-15-2011, 12:32 PM
  #4  
Moderator

 
Apeiron's Avatar
 
Join Date: Jan 2000
Location: Mercedes Norte, Heredia, Costa Rica
Posts: 20,981
Likes: 0
Received 9 Likes on 8 Posts
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Re: Blown head gasket, only to find pistons upside-down...

They're aftermarket pistons, I doubt they have a rod offset.
Old 07-15-2011, 12:36 PM
  #5  
Member

Thread Starter
iTrader: (3)
 
kerplunk318's Avatar
 
Join Date: Jun 2007
Location: Virginia
Posts: 291
Likes: 0
Received 0 Likes on 0 Posts
Re: Blown head gasket, only to find pistons upside-down...

Is a re-ring imperative? The motor has less than 4k miles on it.
Old 07-15-2011, 12:38 PM
  #6  
Moderator

 
Apeiron's Avatar
 
Join Date: Jan 2000
Location: Mercedes Norte, Heredia, Costa Rica
Posts: 20,981
Likes: 0
Received 9 Likes on 8 Posts
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Re: Blown head gasket, only to find pistons upside-down...

The rings are broken-in to the cylinders they're in now. They won't seal in different ones.
Old 07-15-2011, 12:41 PM
  #7  
Moderator

 
Apeiron's Avatar
 
Join Date: Jan 2000
Location: Mercedes Norte, Heredia, Costa Rica
Posts: 20,981
Likes: 0
Received 9 Likes on 8 Posts
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Re: Blown head gasket, only to find pistons upside-down...

Originally Posted by ronnjonn
What about the rod offset?
Ahhh ok, I see what you mean... yeah, they'll probably have to be rehung.
Old 07-15-2011, 12:53 PM
  #8  
Member

Thread Starter
iTrader: (3)
 
kerplunk318's Avatar
 
Join Date: Jun 2007
Location: Virginia
Posts: 291
Likes: 0
Received 0 Likes on 0 Posts
Re: Blown head gasket, only to find pistons upside-down...

Originally Posted by Apeiron
Ahhh ok, I see what you mean... yeah, they'll probably have to be rehung.
I'm willing to bet the guy who put the motor together put half the pistons in wrong... won't know 'til I pull it.

http://www.jepistons.com/TechCorner/Pin-Offset.aspx

The pistons did seem really loud when cold.
Old 07-15-2011, 01:01 PM
  #9  
Moderator

 
Apeiron's Avatar
 
Join Date: Jan 2000
Location: Mercedes Norte, Heredia, Costa Rica
Posts: 20,981
Likes: 0
Received 9 Likes on 8 Posts
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Re: Blown head gasket, only to find pistons upside-down...

Those pistons probably don't even have pin offset. The problem is the connecting rods. They have a side that has to face the other rod on the pin, and a side that faces the crank throw. Essentially you need to turn the piston 180 degrees without turning the rod, which can't be done without taking the rods off.
Old 07-15-2011, 04:22 PM
  #10  
Junior Member
iTrader: (1)
 
DarthBubba's Avatar
 
Join Date: Jun 2011
Location: Austin, TX
Posts: 24
Likes: 0
Received 0 Likes on 0 Posts
Car: N/A
Re: Blown head gasket, only to find pistons upside-down...

Originally Posted by kerplunk318
I'm willing to bet the guy who put the motor together put half the pistons in wrong... won't know 'til I pull it.
I'd be having a little chat with that guy.
Old 07-15-2011, 06:14 PM
  #11  
Supreme Member

iTrader: (1)
 
travis401's Avatar
 
Join Date: Mar 2007
Location: Arlington, Tx
Posts: 3,525
Likes: 0
Received 6 Likes on 5 Posts
Car: 91 Camaro RS
Engine: empty bay (for now)
Transmission: Built T-56
Axle/Gears: 3.42 stock posi disc
Re: Blown head gasket, only to find pistons upside-down...

Thats just bad workmanship. you can clearly see were the valve was contacting the piston, so they are most likely damamged in one way or another. Best thing to do would be to pull each rod/piston assembly at a time, pull the piston off the rod, and rotate it 180 degrees. then reinstall with new spirolocks on the pins. and i would most def have the heads checked out for bent/damaged valves.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
NinjaNife
Tech / General Engine
27
08-23-2015 11:49 AM
lakeffect2
Cooling
11
08-23-2015 08:44 AM
NWAsonoma
TBI
4
08-18-2015 05:45 PM



Quick Reply: Blown head gasket, only to find pistons upside-down...



All times are GMT -5. The time now is 05:30 PM.