ENGINE REBUILDERS PTY LTD
7 BARRETT STREET, FLEMINGTON VIC 3031,
TEL: (03) 9372 3111, FAX: (03) 9372 3122
ACN: 006 798 492 ABN: 74 006 798 492
www.engineaction.comTechnical Newsletter
FORD 5.4L V8 SOHC spark plug problem.
02/07/2009
PROBLEM:
The Ford 5.4 SOHC V8 has platinum spark plugs that are constructed from three main components: The ceramic inner body containing the electrode; the threaded hex drive outer body and a new form of earthing for the electrode. This earthing component is a stainless steel shield that bridges the inner electrode and fits over the ceramic inner for a total length of 30mm. This is much the same as a thimble. All three components are held together by a swaging crimp at the base of the outer threaded body.
We have been involved in assisting mechanics to remove this stainless steel shield from the cylinder head after a spark plug removal has left it behind.
CAUSE:
The swaged crimp can fail, causing the three main components to part company. This leaves a non-magnetic shield, 30mm long, stuck in the lower end of a deep spark plug hole. The last one had broken the ceramic at the crimp point and further complicated the removal as we now had two components to retrieve.
We suspect that a rattle gun has been used but no one would admit to this. The other probable factor was the wet brown muck that we found around the outer surface of the shield when we got it out. Can it be that ethanol fuel residue is acting as a binding agent that jams the shield into the lower part of the head.
CURE:
The broken ceramic end was removed using a spot of araldite on the end of the part it had snapped off from. (and using care not to glue both the shield and the ceramic together.)
After machining the outer body away from the stainless shield of a good spark plug, ($50.00 each), we then machined up a suitable small slide hammer made from some 8mm round sliver steel. The extraction end was machined and hand worked to fit down the inside of the shield and hook beneath the bridge at the sparking end. The shield was then extracted to everyone’s relief by the slide hammer method.
Sketch available on request.