Ka24de detonation marks on pistons - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

240trooper · 08-01-2015, 02:38 PM

Anyone have this problem?

dbeiler · 08-01-2015, 03:53 PM

Appears to be preignition damage. Were you running the correct heat range spark plugs? Using the correct size headgasket? (0.20 over) The slightest little piece of metal jutting out into the combustion chamber can get hot enough to cause preignition. Was the gasket leaking any coolant? Were the pistons or valves carboned up?

Whenever valve work is being done on an installed head, the cylinder being worked on ABSOLUTELY, POSITIVELY MUST have the piston at TDC on compression stroke. It's impossible to drop a valve if the piston is up and nearly touching it. Your idiot friend obviously has no education on engine work. Don't ever let idiots touch your car again.

08-01-2015, 02:38 PM	#1
240trooper Zilvia Addict Join Date: Sep 2003 Location: Torrance, California Posts: 791 Trader Rating: (10) Feedback Score: 10 reviews	Anyone have this problem? __________________ 2.7L

08-01-2015, 03:53 PM	#2
dbeiler Zilvia Junkie Join Date: Jun 2012 Location: Lancaster county, PA Age: 34 Posts: 465 Trader Rating: (4) Feedback Score: 4 reviews	Appears to be preignition damage. Were you running the correct heat range spark plugs? Using the correct size headgasket? (0.20 over) The slightest little piece of metal jutting out into the combustion chamber can get hot enough to cause preignition. Was the gasket leaking any coolant? Were the pistons or valves carboned up? Whenever valve work is being done on an installed head, the cylinder being worked on ABSOLUTELY, POSITIVELY MUST have the piston at TDC on compression stroke. It's impossible to drop a valve if the piston is up and nearly touching it. Your idiot friend obviously has no education on engine work. Don't ever let idiots touch your car again.