New 4.0 engine: What else to replace?

[guapo79]

Hey folks,

My son's 2002 TJ with a 4.0 (manual transmission) had a piston skirt break into chunks (found em in the oil pan), so we're going to swap it out for a crate engine. My question for you all is, what components would you recommend replacing at the same time?

Here's what I am thinking, not sure if its overkill or I missed anything:

• Water Pump and Thermostat and housing
• Motor Mounts
• Idler Pulley
• Crankshaft Sensor
• Spark Plugs
• Serpentine Belt
• Belt Tensioner
• Fuel Injector O-Rings
• Gaskets for the oil pan / Valve cover / and timing cover

On the fence on the 4x o2 sensors, since the old ones seemed to be fine.

Also on the fence on the exhaust manifold. It's the two piece system, neither one seems to have any cracks in them, but I've heard mixed opinions on stock vs getting something that has expansion joints in them.

Also, any recommendations on which oil to use for break-in?

Thanks!

 

[GoldenGorilla]

Unless there was a serious issue, the thermostat housing is probably fine. Just clean it.
I'd see if the fuel injectors themselves are swollen and cracked on the sides. You'll also need the intake/exhaust manifold gasket.

 

[mrblaine]

Unless there was a serious issue, the thermostat housing is probably fine. Just clean it.
I'd see if the fuel injectors themselves are swollen and cracked on the sides. You'll also need the intake/exhaust manifold gasket.

The reman we got from S & J came with break in oil and a Felpro gasket set. So far, it has had ever gasket we've needed. Even had a complete set of injector o-rings. Granted, I've had some gasket preferences where I bought different ones but only due to personal preference.

 

[macleanflood]

Crank pulley if it's checked. Anchor motor mount and transmission mount set... about $30 on Rock Auto. Robert Shaw thermostat from Flowkooler. Pcv elbow grommets. Idler pulley, tensioner, belt.

When I did my 4.6 stroker I moved most of my stuff over from my existing engine...most of the stuff had less than 5-10k on it.

-Mac

 

[OilSpot74]

Crank pulley if it's checked. Anchor motor mount and transmission mount set... about $30 on Rock Auto. Robert Shaw thermostat from Flowkooler. Pcv elbow grommets. Idler pulley, tensioner, belt.

When I did my 4.6 stroker I moved most of my stuff over from my existing engine...most of the stuff had less than 5-10k on it.

-Mac

Two thumbs up on the water pump and thermostat.

 

[MikeE024]

Also on the fence on the exhaust manifold. It's the two piece system, neither one seems to have any cracks in them, but I've heard mixed opinions on stock vs getting something that has expansion joints in them.

I’m not aware of that being an issue for the two piece manifolds. I have headers and don’t think you’re missing anything noticeable.

I’d probably do the o-rings, tensioner/pulley, idler pulley, and harmonic balancer as well. I upgraded those items along the way and have no regrets

 

[Edgar Marton]

Thermostat... there's a big discussion here about which thermostat is good... I can only say that I've now installed my sixth thermostat... Robert Shaw Flowkooler. It works really well... cheap $10 thermostats (Gates, Crown, aftermarket) are not recommended... they usually break after six months.

The Robert Shaw 195 thermostat has been installed for six months now. It's the best thermostat I've installed in the last 20 years. Anything else is not recommended.
(Gates, motorcycle, etc.).

Today, in a four-hour "operation," I removed a water pump (which had only been in the Jeep for six months, US Motor Works, the own gasket was already broken – it's junk...) and reinstalled the same water pump (old version) with a new FelPro gasket (new version). For everyone's information: it fits perfectly because the four mounting holes in the gasket are identical. I used Dirko HT sealant on the top and bottom, and everything works great. No more leaks.

The broken seal from US Motor Works:

 

[GoldenGorilla]

Same, I bought a felpro water pump gasket rather than the one that came with my flowkooler pump. The felpro has some sealant material built in to the design.

But as mrblaine says, if the motor comes with a Felpro engine rebuilt kit, you won't need any one offs.

 

[mrblaine]

But as mrblaine says, if the motor comes with a Felpro engine rebuilt kit, you won't need any one offs.

I sorta said that. I would have hunted down the Mopar gasket and did. That's just me though. I also prefer the Mopar thermostat housing gaskets for no other reason than of the 40-50 I've installed, I've never had a single failure. Superstition or experience, I tend to use what I've had perfect success with. That also means I'll continue to use the Mopar thermostats until I have a problem.

 

[guapo79]

Thanks for all the info everyone. I like the idea of doing the harmonic balancer too.

I'm narrowing my supplier down, and I'm looking at one of these three:

S&J: https://www.sandjengines.com/product/2002~JEEP~Wrangler~1323
Fraser: https://fraserengineco.com/4-0l-jeep-options/#jeep40-options
Mabbco: https://www.mabbcomotors.com/catalo...28ab-no-core-required-1-year-limited-warranty

All three seem to come with the rebuild gasket sets, so that's a plus. Anybody have good or bad experience with any of these?

Should I worry at all about the head on the reman being the 0331 non TUPY version?