cracked ignition chambers
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Posting Guru
Joined: Jul 2006
Posts: 1,148
Likes: 13
From: Cleburne
cracked ignition chambers
I just finishe pulling my heads, and found the ignition chambers are cracked all the way to the head gasket. It looks like something that can be replaced, is this true. What causes this? I also have a cracked piston crown, could this be caused by turbo pressure. I have a 89 f250 non turbo, with banks sidewinder. Or is it normal wear. preshate it
Post Fiend
Joined: Nov 2004
Posts: 5,638
Likes: 1
From: Manitoba
Ignition chambers as you call them are called Precups.... If the crack ventures into the head gasked fire ring surface and beyond you will loose compression..... so any close ones should be replaced...... you can knock them out from behind via either injector or GP hole with a punch. There is a max/min depth below head and above head surface for the replacement PC to be dealt with..... A gentle dressing to an important minimum thickness of the head may be required.
Contact an AERA affiliated shop they have all the special info you need...
Contact an AERA affiliated shop they have all the special info you need...
Last edited by PLC7.3; Feb 18, 2007 at 12:34 PM.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
As PLC said the precups are replaceable, the 7.3 style has an 88 embossed on it.
As for the cracked piston, my first thoughts would be excess heat, passing a glow plug tip, valve contact or cranking the engine with a hydrolocked piston.
Check the valves in that cylinder to make sure they are not bent.
Turbo boost would blow the head gasket before it cracked the piston without some other influence.
As for the cracked piston, my first thoughts would be excess heat, passing a glow plug tip, valve contact or cranking the engine with a hydrolocked piston.
Check the valves in that cylinder to make sure they are not bent.
Turbo boost would blow the head gasket before it cracked the piston without some other influence.
