And an installer to put it on.

The HB bolt may too short to draw the HB onto the crank snout, my 95's and earliers have been.

My low buck installation tool is a bolt of the same thread diameter and pitch but way longer, a nut and a few washers.

The method I use is run the nut up the bolt to the head, grease between the washers then slide them on the bolt and lightly grease the bolt from the nut down leaving the first couple inches ungreased.
Put the HB on the crank snout, screw the bolt into the crank by finger until it bottoms out then back it off a turn.
Hold the bolt still with a wrench and run the nut down with another wrench pressing the HB home.
Remove the low buck tool, install the HB washer and bolt. Torque to speck.

YMMV

 

update:
New HB installed!
no change in knocking- but it was pretty shot anyways so I guess it was worth it (if I can solve the knock and actually drive the thing)

I also changed the sparkplugs, cap, rotor and wires. I had bought them a while back for a tune up so I figured might as well.

there are 2 major things I still haven’t done to find the knock and that is
-check compression
-check oil pressure

and yes yes I know this should have been done first thing when diagnosing. Bought a compression test kit that didn’t have the correct thread size adapter so still solving that. Not so easy where I live to get the correct stuff. Let’s just say it would’ve been easier if I had a Volvo.

oil pressure- I figured it was ok looking at my gauge, but now I know I need to get a test kit for that.

After removing the valve cover and inspecting the rockers I could not find anything wrong.
can you guys please have a look at this clip and see if everything looks fine and dandy to you?

 

One of the many revisions Jeep made for the 1996 model year to address Harshness Noise and Vibration was different pistons.

The old design was suceptible to skirt shift at high milages resulting in piston slap.

 

What is skirt shift? I tried googling the term, but only got photos of models wearing skirts. Not a bad outcome, but I'm still curious about what you mean by skirt shift.

 

A dimensional change in pistons skit. A shift or "colapse" reducing the skirts diameter a few thousandths of an inch. Not entirely uncommon in high milage pre 97 4.0 engines.
Especially if it's been run hot and hard under load for extended periods of time.

 

ok, so what does that mean, that the piston skirts break? The jeep has 124 k miles on it and has mainly been driven on the highway as a company truck for a clothing salesman in Germany. It had some towing alterations so I think it used to pull something. The last 10 years or so it has mainly been sitting, and I have not been able to drive it hardly at all so I suspect a lot of gunk/carbon in the motor. I am a bit hesitant towards driving it since I’m not confident if it’s a broken piston or just carbon build up.

From what I’ve learned so far the earlier models has less issues with cracked pistons, but that might just be wishful thinking for my side?

and no I have not done a compression test yet 😊

 

Broke skirts are more common on late model XJs that have lighter pistons. I would be concerned about that sound if its always present. You said you checked the flex plate bolts? Have you considered using a stethoscope?

 

Flex plate and bolts seems fine.

knocking seems to be appearing after reaching operating temp. Changed the oil to Rotella T6 and the engine got more quiet overall, but knock reappeared. No debris in the oil from what I could see.

the knock seems to be more loud at low rpms at idle and disappearing when revving. Have not had the chance to drive it much so hard to diagnose more.

The plan is to 1. Compression test 2. Steam clean DIY

spark plugs where really black and full of carbon but I guess that’s a different case

 

I would only drive it as necessary to diagnose the issue. Definitely do a compression or leakdown test. You may want to consider dropping the pan to look for broken/cracked piston skirts. Or possibly a borescope might work for finding piston skirt issues. I think I saw a YT vid where someone used a borescope.

 

update!

so I finally got around to dropping my oil pan.
i found some stuff there as expected but not sure exactly what it is:
stone like to the touch
Brown/redish colour on one side of the chunks
with clear arched edges as from being shaped in a circle
2-3 mm pieces
Piston head?
old carbon build up?


I have also checked the rod bearings and the journal bearings where worn down to the copper.
i couldn’t feel any play side to side or up/down though
Can that wear still be enough to cause a knock?

thanks alot

 

First guess is that its part of an old seal, ASSuming its plastic/rubber...
Theres not much plastic in these engines: Front seal, Rear Seal, and timing chain wear pad are the only things I can think of.

You could plastigauge a couple rod bearings to see what the clearances are. This could be your knock, but Im still thinking piston skirt.

 

it feels hard and crumbles when trying to squeeze it but I guess it could be something old and dry

this is my bearings fresh out the jeep
i guess plastigauge is the new word I’m learning today
these would knock right?

 

My guess (based on what it looks like and has be something that could find it's way into the sump)
​​​​​​ Sometime in the last quarter century someone got really carried away with some sort of gasket cement on the valve cover iand the globs that ended up on the inside broke off and washed into the pan.
what do I win if I'm right???
​​​​​​
I've seen worse bearings, at least it didn't spin. But a ton of embedded junk....ever change the oil? What does the crank journal look like?

 

Now THAT is a solid theory! Reminds me of Chat GPT hallucinating and giving me links to made up jeep forums (actually happens)


When this story is over you might win a 1990 XJ in need of an engine…

 

Ive seen seals that crumble like that. But I like the sealant theory too, could be big globs of aviation permatex or something.
Yes I think those would knock.

If it was mine, and depending on what the crank looks like/how brave youre feeling, I would try slapping a set of bearings into it and see what happens. Best case it runs forever, worst case you would have had to pull the engine anyway.