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wrong size spark plug?

xcm

xcm

NAXJA Forum User
Location
Southern Oregon
SO, while working on a friends newer xj (its a renix, newer to US).... we discovered that the spark plugs he has installed seem to be waay too large.... theres no way to get a socket in there... the sides of the head are in the way....
if i had to guess, id say less then 1/8th on each side... definately wont be getting a socket in there...

is it possible the PO put in the wrong plugs? it allmost seems impossible, as he would have to hand thread them in the final few turns...

all the 4.0s ive worked on have a 5/8ths spark plug... these LOOK like 19mm, but obviousy i cant get one on it to check

whats the deal? remove the head, and replace the head? i cant think of any other way...
 
Failing that, you could also try getting a rubber strap and a metal or plastic "loop" buckle and grabbing the porcelain part. You can also try pliers, but that would be a 'weapon of last resort' - and you'll want some sort of soft covering so you don't scratch the glaze (and compromise the strength of the porcelain.)

But yes, all the listings I've seen for 4.0L plugs have been for the 5/8" "peanut" plugs, so they're probably wrong. I didn't think they made 13/16" hex plugs with the 14m/m thread tho - they're usually 18m/m.
 
ok, so im gonna buy a couple sockets, and modify them, im thinking kinda slot them longitudinally, similarly to a o2 socket... but on 2 sides... theres more room on the top and bottoms of the hex part of the plug... that or thin wall it.

ill start with an 18mm and a 13/16th.... its -+1 from 19, im confident...
thanks for your help oem tech
 
Just a thought- could the head have been stripped out and then crudely repaired with some type of heli-coils and oversized plugs?- I saw this once on a honda- some special socket with two external tabs gripped the coil instead of the plug and removed it and the plug together.

can you post pictures of your freak-jeep?- close up of one of the holes maybe

-B
 
Someone got them in there, has to be a way to get them out....try some different brands of socket - as was said earlier, thinner walls...
 
JNickel101 said:
Someone got them in there, has to be a way to get them out....try some different brands of socket - as was said earlier, thinner walls...
Click to expand...
X2!

They went in, they've got to come out.
 
5-90 said:
Failing that, you could also try getting a rubber strap and a metal or plastic "loop" buckle and grabbing the porcelain part. You can also try pliers, but that would be a 'weapon of last resort' - and you'll want some sort of soft covering so you don't scratch the glaze (and compromise the strength of the porcelain.)

But yes, all the listings I've seen for 4.0L plugs have been for the 5/8" "peanut" plugs, so they're probably wrong. I didn't think they made 13/16" hex plugs with the 14m/m thread tho - they're usually 18m/m.
Click to expand...

Japanese cars and even GMs used 13/16" with 14mm threads. You can get a lawnmower plug socket that fits in really tight spots.

Fords used 18 mm plugs.
 
carnuck said:
Japanese cars and even GMs used 13/16" with 14mm threads. You can get a lawnmower plug socket that fits in really tight spots.

Fords used 18 mm plugs.
Click to expand...

Figures. Just when I think I've got a handle on things, something screwy comes up...

Whatever happened to standard parts?
 
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