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Spark plug female thread/bore at engine block - CLEANING
Sharing..........
Now that I know how thread chaser works, I DIY one myself.
M276 engine spark plug.
M12 x 1.25mm pitch is what you need. Minimum length 10cm of Allan bolt type, dont exceed 15cm.
Thread count minimum 25 or more.
White dot is where the thread starts, thus I dare not touch that area.
Opposite to white dot is the dirt collector channel.
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All job is finger powered only, no power tools allowed. Must feel the dirt resistance. In fact I do not use the rachet unless I am hitting "dirty" spot.
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Run the chaser 4 times, slowly collecting dirt.
I use BG cleaner chemical and wet the chaser male thread, otherwise the gunk will not come off easily.
1st chaser run
1st chaser run
2nd chaser run
2nd chaser run
Inspect female thread after each and every chaser run.
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Not bad the result...........
Other cylinders.
Before cleaning
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AFTER CLEANING
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Will continue...................
Last edited by S-Prihadi; Jul 10, 2025 at 04:04 AM.
Spark plug jammed up in the cylinder head bore is another worry if too much gunk.
Electrical grounding will also be better when the threads are clean, at cylinder head female bore and the male thread at the spark plug.
When both are clean, it is so easy to hand screw in till end stop, zero resistance.
There then 23Nm torqued.
The non threaded bore must also be clean, so no dirt can enter the spark plug bore and again better electrical grounding as the copper washer sits here and pass
current to the spark plug from the cylinder head ALU metal, which is the negative ground.
little tip is to magnetize the bolt and put grease in the groove to collect any junk cleaned off and try to keep out of cylinder.
go in a few turns and back out and clean and regrease as required.
But another way is old spark plug and cut groove in thread works great on small engine like yard equipment
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Thanks G
