Spark Plug Gasket Question
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
Spark Plug Gasket Question
I purchased a set of AC Delco 41-629 plugs and they came with metal gaskets. My question is does the flat side or the rounded side of the gasket goes up against the cylinder head hole?
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
Spark Plug Gasket Question
I purchased a set of AC Delco 41-629 plugs and they came with metal gaskets. My question is does the flat side or the rounded side of the gasket faces toward the electrode?
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
The round side is the one I always put agains the head so it'll crush. right, wrong, indifferent, I don't know, but that's how I've always done it and never had any problem.
Your heads are designed for gasketed plugs? My aluminum heads are for gaskets, but there are lots of heads, both aftermarket and factory that use tapered seat plugs.
Your heads are designed for gasketed plugs? My aluminum heads are for gaskets, but there are lots of heads, both aftermarket and factory that use tapered seat plugs.
Last edited by TimAT; Jul 23, 2009 at 07:24 PM.
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
The round side is the one I always put agains the head so it'll crush. right, wrong, indifferent, I don't know, but that's how I've always done it and never had any problem.
Your heads are designed for gasketed plugs? My aluminum heads are for gaskets, but there are lots of heads, both aftermarket and factory that use tapered seat plugs.
Your heads are designed for gasketed plugs? My aluminum heads are for gaskets, but there are lots of heads, both aftermarket and factory that use tapered seat plugs.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
I believe the tabs that 'screw' onto the spark plug threads are on the flat side...so that would mean that the round side should be what mates with the seat on the head. That also makes logical sense, as the rounded surface would seal better against the chamfered surface on the head.
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