Notices

"Burnt" spark plugs

Thread Tools
 
Old 12-22-2010 | 05:07 PM
  #1  
Thread Starter
Registered
 
Joined: Apr 2010
Posts: 166
Likes: 1
From: Panama city, Panama
Default "Burnt" spark plugs

Went out for a small run yesterday and once i got back i noticed that 2 plugs were burnt. pics below of one burnt and one not burnt. Also, one of the cylinders has no compression now. I think im taking the head of that side to check if the valves are closing correctly.

Any suggestions as to what may have caused this?
Attached Thumbnails "Burnt" spark plugs-img00449-20101222-1321.jpg  
CafeRacerPTY is offline  
Reply
Old 12-22-2010 | 07:14 PM
  #2  
Registered
 
Joined: Mar 2010
Posts: 62
Likes: 0
From: Salisbury, NC
Default

The porcelain has a green tint. Green=lean. Tuliped an exhuast valve or a lifted ring land is my guess. Now, why did it go lean in that hole????
JeremyAnderson is offline  
Reply
Old 12-23-2010 | 07:25 AM
  #3  
Registered
 
Joined: Nov 2005
Posts: 4,554
Likes: 3
From: Fredericksburg, Va
Default

it's not good....what is the engine setup ??
ezstriper is offline  
Reply
Old 12-23-2010 | 07:45 AM
  #4  
Ted G's Avatar
Charter Member
20 Year Member
Charter Member
 
Joined: Jan 2001
Posts: 7,663
Likes: 2
From: Edgerock Baby!!
Default

Looks like detonation damage, if you really have 0 compression you likely holed a piston.
__________________
Chesapeake Bay Powerboat Association
www.cbpba.com
Ted G is offline  
Reply
Old 12-23-2010 | 09:15 AM
  #5  
Throttle Fever's Avatar
VIP Member
15 Year Member
VIP Member
 
Joined: Nov 2008
Posts: 503
Likes: 0
From: Bend Oregon
Default

Originally Posted by Ted G
Looks like detonation damage, if you really have 0 compression you likely holed a piston.
I am with Ted, Lets hope we are wrong.
Throttle Fever is offline  
Reply
Old 12-23-2010 | 10:36 AM
  #6  
Registered
 
Joined: Aug 2005
Posts: 6,306
Likes: 1
From: Between A Womans Leggs in IL
Default Fixx

All the above! or blown head gasket between cylinders,if so hopefully it didn't hurt the deck of the block..502???
FIXX is offline  
Reply
Old 12-23-2010 | 12:02 PM
  #7  
Registered
20 Year Member
 
Joined: Jun 2004
Posts: 1,949
Likes: 37
From: Omaha, Nebraska. Boat on the Mighty Mo! Longest river in the USA!
Default

What cylinders? What year?

Whey you burn a hole in piston you will see metal all over the plug and the plug will look worse than that.
I would also go with blown head gasket.

I had a problem last year with zero compression in one cylinder, it was an exhaust seat. Valve was not closing all the way.
1BIGJIM is offline  
Reply
Old 12-23-2010 | 12:24 PM
  #8  
Registered
15 Year Member
 
Joined: Sep 2006
Posts: 1,167
Likes: 60
From: toledo ohio
Default

my guess is a head gasket,was there any water in the hole?
lightning jet is offline  
Reply
Old 12-23-2010 | 04:15 PM
  #9  
Registered
 
Joined: Nov 2005
Posts: 4,554
Likes: 3
From: Fredericksburg, Va
Default

don't think a head gasket would burn the end of a plug off like that...
ezstriper is offline  
Reply
Old 12-23-2010 | 05:55 PM
  #10  
Thread Starter
Registered
 
Joined: Apr 2010
Posts: 166
Likes: 1
From: Panama city, Panama
Default

no water in the hole. the pistons are new 4.530, block is a 502 bored to .06

i think that i have a combination of problems, thin head gasket (.03) hot spark plugs and low octane gas.

the oil was clean as well
CafeRacerPTY is offline  
Reply


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.