Spark Plugs, weird one at Advance

[old409]

I went to Advance to get some new spark plugs for my 1989, 2.9l and they gave me Autolite 765 plugs. I went to put them in and they didn't look right and they weren't right. The threaded portion was only about half as much thread as my old plugs (Champion RS14YC), came with the truck .

I thought they gave me the wrong plugs but 765 is the plug that comes up on their computer and also on several Autolite internet sites I checked out. While I was at Advance they showed me the Platinum plugs and they had the long thread section like my old plugs. I don't care for Platinum plugs so I have to go looking for plugs tomorrow. I want Autolite or Motorcraft regular plugs, not fancy plugs. Anybody know the correct Autolite plug for the 2.9l ? A stupid question for sure but after my trip to Advance I'm a little mixed up.

 

[Area 52]

765 is the correct Autolite plug.

 

[old409]

I don't see how the 765 Autolites could be threaded into the head far enough. They only have half the threaded portion that the old plugs had and also the Autolite Platinum plugs. Have you ever used the 765 plugs in your 2.9 ? Not trying to be argumentitive just seeking information.

I wonder if the 765 plugs I got were threaded wrong ?

 

[holyford86]

if you get a flashlight and look down into the plug hole you will see that the threaded portion of the plug is quite a bit deeper in the head than the tapered sealing surface, I wondered that myself, but I had the opposite discovery.

 

[RustedRanger]

They are fine. I was changing plugs at my uncle's shop one day and noticed the same thing. My uncle said that they did that to help keep the plug from siezing in the head.(threading half of it) We took micrometers and measured them and they are the same,just threaded differently.

 

[Area 52]

Have you ever used the 765 plugs in your 2.9 ? Not trying to be argumentitive just seeking information.

Have an older set of 765's in it now and a brand new set ready to be installed. Engine fires right up, idles fine, with MPG at 17.5 City/23.0 Hwy (4wd).

 

[old409]

You're right, the 765's went right in. Now All I have to do is find where my missing spark went. My TFI was bad and when I pulled #1 to get TDC I noticed my plug was shot, an over.080 gap. The rest were the same so I thought I'd change them while I was under the hood.

The TFI was bad acording to Auto Zone's test and my Ebay tester so I was hoping that would cure my truck. No such luck. Anyway, now when and if I ever get it running, I'll have new plugs.

Thanks for the info.