4.0 Piston skirt replacement
Thread Starter
Junior Member
Joined: Mar 2013
Posts: 46
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From: North Vancouver
Year: 1996
Model: Cherokee
Engine: 4.0 Litre HO
Heard a pretty loud ticking noise coming from the rear of the engine, louder from underneath. Under further diagnosis after pulling the oil pan, I found pieces of the #5 piston skirt laying in the pan. So Pull the valve cover, pull the head and intake and push the piston up from underneath. Luckily the bore seems really good and the bearing seems decent. Take the old piston to get replaced and use the old rings. Another 5 hours and the cost of the piston and gaskets and she'll be back together... Hopefully haha
CF Veteran
Joined: Aug 2010
Posts: 8,357
Likes: 103
From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
Did you have to use a ridge reamer to get the piston out?
How many miles on the engine?
Where are you going to get a replacement piston, and what size piston do you need?
Did you use a cylinder bore gauge to determine what size piston you need?
Are you going to deglaze the cylinder wall with a hone?
How many miles on the engine?
Where are you going to get a replacement piston, and what size piston do you need?
Did you use a cylinder bore gauge to determine what size piston you need?
Are you going to deglaze the cylinder wall with a hone?
CF Veteran
Joined: Dec 2012
Posts: 4,169
Likes: 6
From: York, PA
Year: 1998
Model: Cherokee
Engine: 4.0
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I was glad to see the OP didn't see the rod hanging there.
I think it's WAY easier to pull the head without the manifolds on.
Thread Starter
Junior Member
Joined: Mar 2013
Posts: 46
Likes: 0
From: North Vancouver
Year: 1996
Model: Cherokee
Engine: 4.0 Litre HO
Gonna take it to a buddy at Jeep Thrills. Was thinking of honing the bore but if I use the same rings I shouldn't have to. Didn't need a reamer at all as the top was nice and smooth. no ring at all.
Was super easy to leave the manifolds on. Just disconnect the exhaust and make sure you got a buddy to help lift it out cause its pretty heavy.
Soon as I get some cash together ill post more pics of the reassembly and what it cost to do it. Its a bandaid fix but ive seen those run for 200k+ km
Was super easy to leave the manifolds on. Just disconnect the exhaust and make sure you got a buddy to help lift it out cause its pretty heavy.
Soon as I get some cash together ill post more pics of the reassembly and what it cost to do it. Its a bandaid fix but ive seen those run for 200k+ km
Thread Starter
Junior Member
Joined: Mar 2013
Posts: 46
Likes: 0
From: North Vancouver
Year: 1996
Model: Cherokee
Engine: 4.0 Litre HO
So piston went in without a hitch. Heads back on and she purrs like a kitten
Piston was about $100
Rings about $85
Gaskets about $150
Oil and misc tools about $100
I rehoned the bore, put a ring compressor on the piston and pushed her in. Re connected the bearing and torqued the bolts. Gaskets oil pan and head back in. I reused the same head bolts as I'm a broke *** but they army stretch bolts anyways. Rods back in their original slots and all rockers torqued back to specs. Connected spark plugs and fuel injector wiring. Throttle body and power steering. Serpentine belt. Filled it with oil and she started up on the 2nd time cranking over. Mass airflow sensor will need to be cleaned to sort out any rough idling but she sounds amazing. Would never know such a critical engine component disintegrated without destroying the engine.
Stoked on the result. I should've taken more pics during the rebuild but I forgot. If it happens to anyone out there my suggestion is to just do it. As long as you don't have engine damage. Under $500 and prob a weekend of wrench time. Just have a buddy to lift the head out cause its heavy and awkward.
Piston was about $100
Rings about $85
Gaskets about $150
Oil and misc tools about $100
I rehoned the bore, put a ring compressor on the piston and pushed her in. Re connected the bearing and torqued the bolts. Gaskets oil pan and head back in. I reused the same head bolts as I'm a broke *** but they army stretch bolts anyways. Rods back in their original slots and all rockers torqued back to specs. Connected spark plugs and fuel injector wiring. Throttle body and power steering. Serpentine belt. Filled it with oil and she started up on the 2nd time cranking over. Mass airflow sensor will need to be cleaned to sort out any rough idling but she sounds amazing. Would never know such a critical engine component disintegrated without destroying the engine.
Stoked on the result. I should've taken more pics during the rebuild but I forgot. If it happens to anyone out there my suggestion is to just do it. As long as you don't have engine damage. Under $500 and prob a weekend of wrench time. Just have a buddy to lift the head out cause its heavy and awkward.


