GEN1 LWB 6G72 12V Engine Refresh

[GrantC]

I removed the rockers from the heads and confirmed that they are done. Note the cam journals.

Ouch. I don't think I've ever seen anything that bad.

At least now your path forward is unambiguous. Hope the junkyard heads are good!

 

[chadzeilenga]

Yea, I can’t catch the journal grooves with my fingernail, but they are definitely there. Probably the same reason I have 120psi since I got it and ~20-30 psi gage pod oil pressure. Now is when I wish I had gotten around to taking a real reading at the oil pressure switch.

I was right in that the upper bolts are much easier to remove with heads off, but the starter was a bear. Took me a while to realize I also had to remove the engine/trans bracket with it.

I can’t seem to figure out how to get the flywheel bolts loose. Should I just put it in park to stop the rotation?


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[chadzeilenga]

I can’t seem to figure out how to get the flywheel bolts loose. Should I just put it in park to stop the rotation

I can’t believe I said this, haha, must have been a late night.

The good thing is I figured it out:

Tomorrow night I’ll get the oil pan off and mic those crank journals....



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[chadzeilenga]

Pan off tonight, made a few discoveries:
1. I don’t think these are factory welds on my oil pickup tube (looks like a washer)?

2. Main bearings and crank journals appear to be pretty scored. I measured 59.99-60.00mm OD on main journals. I’m no expert in these, so would like to get input from those who are. Planning to visit machine shop tomorrow.

Oil pump also showing some wear, will get measurements but I doubt this will pass. Also, based on the Phillips bolts stripped and generous RTV, looks like someone was here before:

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[GrantC]

Sorry your first Montero is proving to be such a PITA!

 

[chadzeilenga]

It's part of the process I suppose. At least now, I know things are done right.

Quick question, does anyone know if the engine harness (Alt, temp sensors etc) that goes to engine passes through the firewall or is there a disconnect at the firewall junction?

 

[chadzeilenga]

Hi All,
After tallying up the parts, machine work required as well as sourcing another set of heads I decided to look for a donor motor.

I found a motor out of an 89 Raider SWB with 91k certified miles that ran. Brought it home and am starting the assessment. So far there doesn’t appear to have been any work done to it. There doesn’t appear to have been prior oil leaks. The cyl walls still have decent cross hatching.

So far my plans are:
- Front & rear main seals
- crank bolt update
- inspect oil pump for wear? (not sure on this one, might leave alone)
- new timing belt, water pump & water tube O-ring
- front and rear cam seals
- 3mm VLA’s
- valve stem seals?
- gaskets-oil pan, valve covers, exhaust,
- new rubber hoses
- get starter rebuilt
- misc tune-up items

Does anyone have additional suggestions on what to refresh while I’m in there?


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[evomaki]

How are these 12v motors on valve stem seals and lifters? Sounds like you've taken the heads off the new donor motor, or did you look with a bore scope? If heads off, worth having a machine shop check those out since they are out? New oil pump a good idea or leave well enough alone?

 

[chadzeilenga]

The valve stem seals & valve lash adjusters (lifters) are on my list and I can service those without removing the cylinder heads. I'm trying to leave as much of the original factory assembly intact and only focus on the known items that are worn/out-of-spec, so I'm planning to leave the head gaskets alone. I don't see any evidence that they had previously been removed.

I'm even debating about the Front and Rear main seals! I know that I "should" do them since they are buried so deep within the engine, but the rear one looks perfect (I have flywheel bolts in the way of viewing the seal)

 

[Toasty]

Do the rear main, been in that exact place and two times I've gambled with newer engines with perfect looking seals and lost both times. I hate leaks.

 

[GrantC]

Toasty is a wise man. An '89 with only 91k is going to need seals everywhere. Might as well do them now while it's easy (personally, I'd worry a whole lot less about the starter than the seals.)

 

[Montynv]

I would do the front main as well, better to have fresh seal than too have motor installed and have the mains leak. I would also suggest you get the Viton valve seals, just a better quality for longer life.

 

[chadzeilenga]

Thanks guys, yea seals are on the list. Crank, cam & valve plus all the o-rings. I’ll be updating my list tonight and hopefully getting everything on order.

I need to identify what tools I need to hold crank pulley and cam gears. Will start searching for those as well. Luckily my old motor has a new OEM harmonic balancer from when the PO failed the crank bolt.

Is the updated crank bolt reusable?
Did oil pan originally use FIPG?


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[chadzeilenga]

Well all of my parts are starting to come in and my rear main showed up today, so it’s time to get started. One question:
What tool works to hold crank in place for the bolt torque and the can sprockets in place to torque and for timing belt install?

Strap wrench with piece of old belt in pulley?


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[chadzeilenga]

Just an FYI, the Carquest cam seals (B45682) on RockAuto are same brand & PN as OEM. NOK - EZ295B and package says made in Japan, only difference is they are $2

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