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Wierd spark plug device...

Wierd spark plug device...

CDT540

Jeeper
Posts
84
Thanks
6
Location
Austin TX
Vehicle(s)
1983 CJ7
258, 5 spd
I was pulling the plugs out an '83 CJ7 (AMC 258 i6 / 4.2l -4 spd) and the plugs in the back two cylinders had the device in the picture attached to them. I googled them and they were listed as either adapters for using plugs that would not have otherwise fit the thread pattern or "anti-foulers". You can't see from the pics but the firing end is sealed up with just a small holed drilled in it. I guess the idea is that it keeps excess oil off the plug tip. Anyone ever seen these used before?

Chris
Austin TX
'83 CJ7 AMC 258 i6 / 4.2l -4 spd

Spark Plug1.webp

Spark Plug2.webp
 
Yes they are to keep your plugs from fouling out. Looks like its time for a rebuild. Those two plugs must be getting a lot of oil on them is why they used them.
 
Yes they are to keep your plugs from fouling out. Looks like its time for a rebuild. Those two plugs must be getting a lot of oil on them is why they used them.

That's what I thought also. It does like to puff blue smoke. Looks like this going to be longer term project than I expected.
 
The easist way I think is to just buy a longblock then all you need to do is change all the outer stuff over to the new engine and install and give them your old one as a core and it will come with a warranty.
 
Yeah I agree with the longblock approach. This significantly changes the cost and scope of the project so now I am reassessing the "to do" list to determine where to apply Limited funds first. The CJ has 168,000 miles so I knew a rebuild was in its future but I had hoped not to have to do it right out of the gate.
 
I would run it without them and see what happens. Was it running poorly or were you just checking things out?

If you wanted to do some other stuff first I wouldn't scramble to rebuild the engine. Make sure you aren't running 5w-30 or some real thin oil too.
 
I would run it without them and see what happens. Was it running poorly or were you just checking things out?

If you wanted to do some other stuff first I wouldn't scramble to rebuild the engine. Make sure you aren't running 5w-30 or some real thin oil too.

The Jeep had been sitting for three years when I bought it. It does not run great but I kinda expected a few cob webs. I really have not driven it much, maybe 5 or 10 miles total. I really wanted to go thru everything first before I put to many miles on it.
 
Way back in the day, I had those on my worn out AMC 304 . If I'm not mistaken, it was recommended to me NOT to have those on more than 3 or 4 cylinders. I believe I had those on 6 cylinders when it was time to call it quits on that engine.

I bet you start fouling plugs like crazy when you take them off.
 
Now hold on.

Let's look at this in a logical manner.

Compression test? This will really tell the story.

Hows the oil look?

New plugs and see how they look? How does it run?

Might be just valve guide seals.

That device looks like a real "100 miles per gallon" widget. :D
 
Damn 73CJ you have the best picture up there.

Been stuck in the desert southwest for 9 yrs and the thing I miss most is cruising around in the snow. Deep or shallow.

I've seen those installed before and in my experience they are there when you have stem seal leaks. Problem has to be pretty bad to warrant those things though. If it were mine, Id remove them and check the plugs every couple hundred miles to gauge how bad the problem is.

Def. wouldn't worry about it though.
 
I was burning oil like mad when I got my CJ up and running in 2009. About a quart every AMC 150 -200 miles and fouled plugs every time. It had last run in 1981 and only had 39K miles. Compression was good, so I replaced the valve seals for about $6 and it solved that problem.
 
Yup, most common issue after a rig sits for a long time. They just dry up.
 
I used them for an O2 sensor mount. I cut off the cup and welded the threaded side into the exhaust pipe near the manifold. An O2 sensor threads right in and I can monitor my fuel/air ratio. Neat Trick.
 

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