broken spark plug, head damage?
Apr 20, 2009, 10:56 AM
#32
Slight chance you just have a low #2 compression and it just happens to be same cyl with a weak plug strap that broke off under mild detonation and was sent out across turbine and out tailpipe (or stuck in cat).
You could try this to help diagnose if compression testing does not convince you enough: Put some new copper plugs in, warm engine to about 150F, start in 2nd gear and go WOT from 3000 to redline then immediately stop and cut engine. Pull plugs right where you stopped and read. Cut off the metal from bottom of plug exposing all ceramic surfaces. You will see a ring that tells you temps in the area. Never did this myself though.
Colder plugs tranfer more heat allowing more protection from preignition. It will not stop detonation though
You could try this to help diagnose if compression testing does not convince you enough: Put some new copper plugs in, warm engine to about 150F, start in 2nd gear and go WOT from 3000 to redline then immediately stop and cut engine. Pull plugs right where you stopped and read. Cut off the metal from bottom of plug exposing all ceramic surfaces. You will see a ring that tells you temps in the area. Never did this myself though.
Colder plugs tranfer more heat allowing more protection from preignition. It will not stop detonation though
Apr 20, 2009, 11:25 AM
#33
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Slight chance you just have a low #2 compression and it just happens to be same cyl with a weak plug strap that broke off under mild detonation and was sent out across turbine and out tailpipe (or stuck in cat).
You could try this to help diagnose if compression testing does not convince you enough: Put some new copper plugs in, warm engine to about 150F, start in 2nd gear and go WOT from 3000 to redline then immediately stop and cut engine. Pull plugs right where you stopped and read. Cut off the metal from bottom of plug exposing all ceramic surfaces. You will see a ring that tells you temps in the area. Never did this myself though.
Colder plugs tranfer more heat allowing more protection from preignition. It will not stop detonation though
You could try this to help diagnose if compression testing does not convince you enough: Put some new copper plugs in, warm engine to about 150F, start in 2nd gear and go WOT from 3000 to redline then immediately stop and cut engine. Pull plugs right where you stopped and read. Cut off the metal from bottom of plug exposing all ceramic surfaces. You will see a ring that tells you temps in the area. Never did this myself though.
Colder plugs tranfer more heat allowing more protection from preignition. It will not stop detonation though
Apr 20, 2009, 12:08 PM
#34
That is the usual way of reading spark plugs.
It has been suggested that you do a leak down test to check your current motor condition. Either you have a present problem, or you don't. Other people responding have given you suggestions to find out if you are running lean in at least one cylinder, which caused your spark plug to burn off. You are free to take their advice, or ignore it. It may be that you just had a faulty plug. It may be a coincidence that that cylinder was lower in compression. You have to decide how much time and effort you want to invest to confirm your situation.
It has been suggested that you do a leak down test to check your current motor condition. Either you have a present problem, or you don't. Other people responding have given you suggestions to find out if you are running lean in at least one cylinder, which caused your spark plug to burn off. You are free to take their advice, or ignore it. It may be that you just had a faulty plug. It may be a coincidence that that cylinder was lower in compression. You have to decide how much time and effort you want to invest to confirm your situation.
Apr 20, 2009, 01:10 PM
#36
if the car is running fine, put in the new correct plugs and keep running it.
If you're truly ****, repeat the compression test. Do a leak down test if you want to confirm condition of the valves, etc. Take a look with a borescope if you want to see whether there was any damage from the loss of the single spark plug partial electrode. I'd not worry too much about it, unless you're having problems...
If you're truly ****, repeat the compression test. Do a leak down test if you want to confirm condition of the valves, etc. Take a look with a borescope if you want to see whether there was any damage from the loss of the single spark plug partial electrode. I'd not worry too much about it, unless you're having problems...
Apr 20, 2009, 02:24 PM
#37
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That is the usual way of reading spark plugs.
It has been suggested that you do a leak down test to check your current motor condition. Either you have a present problem, or you don't. Other people responding have given you suggestions to find out if you are running lean in at least one cylinder, which caused your spark plug to burn off. You are free to take their advice, or ignore it. It may be that you just had a faulty plug. It may be a coincidence that that cylinder was lower in compression. You have to decide how much time and effort you want to invest to confirm your situation.
It has been suggested that you do a leak down test to check your current motor condition. Either you have a present problem, or you don't. Other people responding have given you suggestions to find out if you are running lean in at least one cylinder, which caused your spark plug to burn off. You are free to take their advice, or ignore it. It may be that you just had a faulty plug. It may be a coincidence that that cylinder was lower in compression. You have to decide how much time and effort you want to invest to confirm your situation.
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