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MikalCarbine 06-10-2013 09:42 PM

My 4.0 rebuild/replacement thread
I figured I'd make a build thread out of this, I'm either going to rebuild, stroke to 4.6 and rebuild or simply replace my current 4.0 with a junkyard engine

Long story short, I did a few water/mud crossings, got stuck in semi deep mud twice, probably enough to sink the oil pan. My RMS/oil pan had been weeping prior and apparently it was enough to pull water/silt into my crankcase resulting wacky oil pressure readings and this

I changed the oil but was still getting strange readings. I bought a mechanical gauge and verified that at cold start my pressure started at 30 psi but would slowly drop to 0-2 psi at hot idle. At this point I decided it was time to open her up. Inside the bottom of the pan was an inch or so of muck

Nice copper shine on this one

The pump pickup screen didn't look clogged but I opened it up anyways. It did show some signs of wear, including a few places inside the pressure relief bore

With the pan off I decided it was time to check out the RMS as well, here are two shots of the bearing and main journal

I also pulled #5 and #3 rod bearings, both looked like this

The score in the journal was deep enough to slightly feel with my skin, definitely with my fingernail. I also pulled the #3 main, it didn't look too bad but was similar to #7 by the RMS. Plastigage showed the rod bearings at 0.003 (spec 0.001-0.003) and the main bearings at 0.002 (spec 0.001-0.0025).

After talking with multiple people I decided I was going to pull the engine and go from there

With help from my buddy Pat we began the process last Saturday. We started with pulling the grill with radiator and condenser in place. I understand it's doable without it but this made it a hell of a lot easier

We disconnected everything, labeling all connectors with sharpie and tape and bagging bolts that couldn't be reinserted into their homes

We managed to get the dreaded E-12 transmission bolts off with ease, overall everything went super smooth and total wrench time was about 5 hours

On Sunday I pieced together my new harbor freight engine stand

Pat's buddy Justin was kind enough to lend me his engine hoist. Me and pat were ready to use his winch, a snatch block and tow strap on a tree branch, we figured this would be a little safe haha

Hoist all set up, I used two 3/8" grade 8 bolts to hold the chain, one on the top most alternator bracket hole on the block and the other on the rear uppermost intake/exhaust manifold bolt, this balanced perfectly

MikalCarbine 06-10-2013 09:42 PM

We had some minor trouble getting the engine to separate, turns out I forgot two small bolts holding the cover plate. We wound up pulling off the motor mounts so we could lower the engine a bit to help get it out (1" MML was installed)

Here she is freshly pulled

My clutch fingers were toast, even the remaining ones were paper thin
[img width=450 height=600][/img]

The clutch and flywheel were dirty but in good condition, clutch definitely has some meat left on it but I'll be replacing it anyways. My throwout bearing is in tact but feels like 3 muddy bearings are all that's left haha

After that I called it quits, another 5 or so hours in on Sunday, totaling about 10 hours. This was my first time pulling an engine. Overall everything went super smooth and I think it was easier than some other stuff I've done (installing HPD30 alone)

I'm going to pull the mechanical fan, timing cover and take a peak inside at everything. I don't have the belt installed, can anyone recommend how to get the mechanical fan off? I've read a 36mm spanner wrench will help

Here are some photos of the internals, any experts care to comment

My lifter push rods all had something coating them at the same height, I'm thinking this was water/oil residue, it wiped off no problem

Some of the same muck that was in my oil pan was floating on top of these bolts

Here's a bunch of shots of my cam lobes, this will largely decide what kind of build I am going to do if it can't be resurfaced

The wear looks funny and some of the cam lobes look like their starting to flatten, I don't know to which extent is normal

Something doesn't look entirely kosher with my oil pump drive gear, it looks like a few teeth on the camshaft side gear are chipped

MikalCarbine 06-10-2013 09:43 PM

Reserved for potential stroker build specs

Rubi513 06-10-2013 09:49 PM

That sucks. My CJ5 met the same fate.

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