94 5.0 Spark Plug Gap - Ford Truck Enthusiasts Forums

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94 5.0 Spark Plug Gap

 
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Old 01-16-2019, 12:08 AM
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94 5.0 Spark Plug Gap

I really feel foolish for not being able to remember and having to ask. What is the correct spark plug gap for SP450 / ASF42C on a 1994 302? The vehicle sticker says 0.052-0.056 but the Haynes says 0.044. I am almost certain that the repair manual is incorrect and that it is 0.054. Am I right to assume this? I've had these trucks for years and just can't remember having an issue with this. Maybe that is because I always just went by the sticker and never looked it up in the Haynes book.



 
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Old 01-16-2019, 12:30 AM
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I'd use official Ford specs over something out of a third party generic publication.
 
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Old 01-16-2019, 01:18 AM
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Originally Posted by Tedster9 View Post
I'd use official Ford specs over something out of a third party generic publication.
That is my thoughts. However my new Motorcraft SP450A / ASF42CA replacement plugs came pre-gapped at 0.044.
 
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Old 01-16-2019, 02:24 AM
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Anywhere between .44 and .46 is acceptable.
 
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Old 01-16-2019, 07:03 AM
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Interesting. That manual then goes on to say to use the information on the sticker. Maybe they changed the spec at some point with a TSB or whatever?
 
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Old 01-16-2019, 09:25 AM
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.044 - .046 is the correct spec AFAIK.
 
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Old 01-16-2019, 01:27 PM
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This is really strange that I don't remember having an issue like this and have had 4 of these era trucks. It seems parts stores and other online vehicle look up sources think that it is 0.054. I'm wondering if the closer gap is carbed setups and the wider gap is EFI setups.
 
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Old 01-16-2019, 01:37 PM
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My '94 Ford factory manual states the correct gap for a 302 is .052-.056. Spark plug gap for a 351 is .042-.046.

I THINK pre roller 302's the recommended gap was .042-.046



Sorry for the crappy pic.
 
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Old 01-16-2019, 01:57 PM
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.054 is the correct gap for a Triton V8.
 
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Old 01-16-2019, 02:22 PM
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Originally Posted by EllieMae94 View Post
My '94 Ford factory manual states the correct gap for a 302 is .052-.056. Spark plug gap for a 351 is .042-.046.

I THINK pre roller 302's the recommended gap was .042-.046



Sorry for the crappy pic.
Since it is on the hood decal and in the actual shop manual, it must be the correct spec. Wonder why it differs from the rest, maybe it was the introduction of the roller cam.
 
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Old 01-16-2019, 03:08 PM
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That's right, the earlier 302's the gap was .042-.046. Around 1994 they widened it to .052-.056. Prior to my 351w swap, I ran my 302 around .055 and it ran like a top.
 
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Old 01-16-2019, 04:12 PM
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Originally Posted by EllieMae94 View Post
That's right, the earlier 302's the gap was .042-.046. Around 1994 they widened it to .052-.056. Prior to my 351w swap, I ran my 302 around .055 and it ran like a top.
I'm almost positive that I always set them at this as well, just don't remember ever seeing conflicting information on it.

 
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Old 01-17-2019, 02:23 AM
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I would do whatever the hood decal says, assuming it's the original hood and original engine.

​​​​​​My 1995 specs .052"-.056" and I run them at .054".the Autolite 25 plugs come pregapped to around that spec.
 
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Old 01-18-2019, 02:36 PM
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Well I know one thing for sure. A gap of 0.070 - 0.075 is not the correct gap. These have been in the truck for 35k miles or so and are 4-5 years old. No wonder the truck wasn't running its best and was pinging under load for the last month or two. The new plugs are gapped at 0.054 and running smooth now.


 
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Old 01-18-2019, 04:36 PM
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Originally Posted by TexasGuy001 View Post
Well I know one thing for sure. A gap of 0.070 - 0.075 is not the correct gap. These have been in the truck for 35k miles or so and are 4-5 years old. No wonder the truck wasn't running its best and was pinging under load for the last month or two. The new plugs are gapped at 0.054 and running smooth now.
Yeah I would say .070" is a little out of spec lol. I don't run copper plugs for any more than 20k miles, they just don't last as long as the iridium or platinum plugs.
 

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