: Spark Plug Gap

01-10-06, 10:57 AM
Can someone please confirm the proper gap for me?

My 1997 printed service manual states .060". The old plugs (149,000 miles old) that came out were missing the platinum pads, but were still .060" at the maximum...some weren't even that...so I suspect the gap at the factory was less than .060".

I have seen some references to .050" as the proper gap (meaning the service manual is incorrect). There are numerous errors for sure in the service manual...just trying to find out if this is another one of them.

Thanks in advance.

01-10-06, 11:28 AM
'99 FSM calls for A/C Delco 41-950's with a .050 gap

01-10-06, 12:52 PM
I just checked and my underhood sticker indicates a gap of .060". I wonder what the difference is between the different years...or if even my UNDERHOOD STICKER can be misprinted. It's odd -- it's obvious that my original plugs weren't originally gapped at .060" -- because they're STILL not that wide open. But that's what the decal says...

Can anyone else with a 1997 model anything (Seville, Eldorado, DeVille) verify what their underhood decal says? Many thanks.

01-10-06, 01:22 PM
.060 on my underhood sticker.

01-14-06, 09:55 PM
To follow up, it seems that every year in the 93-99 range BUT 1997 calls for .050". The 1997 calls for .060". I came upon a piece of information that went something like this... The supplier and spec for the Northstar spark plug changed frequently over the years, and the gaps were adjusted accordingly. .060" is the "better" gap as it allows for a slightly larger/stronger spark, but either gap works just fine with a plug of this design. The ignition system is designed to handle plugs gapped at least .070", so the slightly larger gap on the '97 models will not threaten the coils/wires.

01-16-06, 09:48 AM
96-99 .045"

01-16-06, 10:16 AM
hogstamogsta, where does that information come from? My '97 says .060", most others say .050", but I've never seen .045" yet. Is that just what you run yours at, or did you find a reference somewhere to that gap?