Alum head leakage
Seasoned HDF Member
Joined: Nov 2006
Posts: 12,878
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From: la la land jerzey
8 times is a light amount over the years
we shoot the bace even on real heads when we do an over haul as the number of plug changes causes a wallow out of the base
many times the scores are deeper on one side
we shoot the bace even on real heads when we do an over haul as the number of plug changes causes a wallow out of the base
many times the scores are deeper on one side
Last edited by johnjzjz; Dec 16, 2022 at 02:55 PM.
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Joined: Jun 2022
Posts: 58
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From: Sebastopol
Well after taking my heads to a good machine shop it’s wasn’t the threads it was the decking for the plug seating .
since plug don’t seal at the threads like pipe threads the landing for the plug needs to be tire,
these aftermarket were not.
since plug don’t seal at the threads like pipe threads the landing for the plug needs to be tire,
these aftermarket were not.
Tourer
Joined: May 2011
Posts: 469
Likes: 158
From: Alberta
Glad you got it fixed.
You don't want to use any kind of sealant on the threads of the spark plug. For them to function as designed, they need to have metal to metal contact with the heads for proper heat transfer. Anything on the threads can inhibit the heat transfer. All new spark plugs have something on the threads to prevent them from seizing in the heads, so you don't have to put anything on the threads. About 15 ft lbs torque is pretty normal for new spark plugs.
You don't want to use any kind of sealant on the threads of the spark plug. For them to function as designed, they need to have metal to metal contact with the heads for proper heat transfer. Anything on the threads can inhibit the heat transfer. All new spark plugs have something on the threads to prevent them from seizing in the heads, so you don't have to put anything on the threads. About 15 ft lbs torque is pretty normal for new spark plugs.
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From: Sebastopol
All good advice. Everything I’ve ever known about plugs really didn’t make me think it was the threading, even being after market heads. The landing surface was my last guess.
If your ever in Petaluma ca. and looking for a great motorcycle machine shop that does empty your pocket, look up Engine Dynamics great people.
If your ever in Petaluma ca. and looking for a great motorcycle machine shop that does empty your pocket, look up Engine Dynamics great people.
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