GEN1 LWB 6G72 12V Engine Refresh
- Thread starter chadzeilenga
- Start date
chadzeilenga
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Thanks, took longer than I wanted but glad it’s done And I’m glad I was able to go through that whole assembly and torque everything to spec which I know isn’t what was done by the previous owner
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I know that feeling of wanting everything sorted out properly. This summer was a big one for my Gen1, as I had the infamous KM145 transmission rebuilt. While I was under there I took care of a whole bunch of other things and made sure everything was done right. I just finished putting in a new water pump, fan clutch, and all new hoses simply to make sure everything was up to spec.
chadzeilenga
Active member
Well, I finished up installing Pass valve cover. Went pretty smooth. Started up and I still had some noise coming from engine at idle. Oil pressure closer to 60psi with Mitsubishi filter installed (not sure if that matters). It sounds like the VLA’s and then goes quiet when I hold RPM at 2-3k, but comes back at idle.
It sounds a little like a tractor. I checked timing marks after a few revs during belt install and all were aligned. Have a good spark going to each cyl.
Also, I seem to be getting a little contact between PS and SERP belts.
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It sounds a little like a tractor. I checked timing marks after a few revs during belt install and all were aligned. Have a good spark going to each cyl.
Also, I seem to be getting a little contact between PS and SERP belts.
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chadzeilenga
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chadzeilenga
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Work has been pretty busy, so I haven't had much time to mess with the Montero now that it is running and out of the garage. I have taken it on a few short errands, and the VLA's do appear to be quieting down. My next order of business is to sort out where the noisy bearing is on the front of the engine. I'm going to start the process of elimination to track down the pulley that is giving me an issue, but once found how do I ID the bearing to replace? In all of the pulleys I've looked at there doesn't seem to be a bearing # to order a replacement from. My suspicion is that the cooling fan bracket bearing is the culprit.
Also, for those of you who have serviced these bearings, how did you do it?
Also, for those of you who have serviced these bearings, how did you do it?
chadzeilenga
Active member
Ok, a long awaited update and finally some time out in garage.
I ran engine with all accessory belts removed, and harmonic balancer was wobbly. I removed and found this:
Looks like the key started to eat into the pulley. The crank bolt was definitely tight when I removed and I torqued to 120ft-lb when installed.
The pulley was newer and from bad engine. Marked with MD141486
The key appears undamaged and I’m going to install the balancer from new engine and torque to 135ft-lbs (found that in TSB for new bolt)
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I ran engine with all accessory belts removed, and harmonic balancer was wobbly. I removed and found this:
Looks like the key started to eat into the pulley. The crank bolt was definitely tight when I removed and I torqued to 120ft-lb when installed.
The pulley was newer and from bad engine. Marked with MD141486
The key appears undamaged and I’m going to install the balancer from new engine and torque to 135ft-lbs (found that in TSB for new bolt)
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chadzeilenga
Active member
Installed the other balancer and torqued bolt to 135ft-lbs. The crank washer is loose which doesn’t make sense to me.
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Last edited:
chadzeilenga
Active member
Took the bolt out and I think I found my problem.
The bottom thread is galled up pretty bad. I think the threaded hole in crank is not drilled deep enough so the REV 3 crank bolt does not fully compress the washer and balancer.
This engine previously had a REV 1 crank bolt installed and if I can find will compare the thread length. I ordered a bottoming tap 14mm-1.5 and will clean out the threads at bottom of hole and ensure bolt will fully thread.
Based on the damage of 1st balancer, I’m not sure if I had the key in the slot as the point of my woodruff key is worn
New parts are on order, does anyone know if key can be removed without taking the timing belt & sprocket off?
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The bottom thread is galled up pretty bad. I think the threaded hole in crank is not drilled deep enough so the REV 3 crank bolt does not fully compress the washer and balancer.
This engine previously had a REV 1 crank bolt installed and if I can find will compare the thread length. I ordered a bottoming tap 14mm-1.5 and will clean out the threads at bottom of hole and ensure bolt will fully thread.
Based on the damage of 1st balancer, I’m not sure if I had the key in the slot as the point of my woodruff key is worn
New parts are on order, does anyone know if key can be removed without taking the timing belt & sprocket off?
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chadzeilenga
Active member
Argh, really? I should have checked the p/n on it before I used it. I got this from previous owner. A dumb mistake that could have been avoided. At least it didn’t progress any further and cause damage to crank, thanks for the heads up though.
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chadzeilenga
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Winner winner, chicken dinner
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chadzeilenga
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I got everything back together tonight and started up and everything was good. Thanks to all for the helpful pointers, I would not have suspected I had the wrong bolt and who knows what would have happened...
My lifters are all quiet now and overall the engine idles really smooth. I have a few items that I need to troubleshoot now:
- My idle is ~1500 RPM, I cleaned out the IACV and it didn't seem to make a difference
- My temp gauge is very slow to rise and when it does it only gets to the low mark. I've double checked all my connections and nothing yet
- Very rarely I get a hiccup and it feels like a stumble but then resolves.
I'll probably drive it around here a bit and see what I can figure out with the list above and the FSM troubleshooting guide.
My lifters are all quiet now and overall the engine idles really smooth. I have a few items that I need to troubleshoot now:
- My idle is ~1500 RPM, I cleaned out the IACV and it didn't seem to make a difference
- My temp gauge is very slow to rise and when it does it only gets to the low mark. I've double checked all my connections and nothing yet
- Very rarely I get a hiccup and it feels like a stumble but then resolves.
I'll probably drive it around here a bit and see what I can figure out with the list above and the FSM troubleshooting guide.
chadzeilenga
Active member
Spent a little time on it tonight. I got the IACV cleaned and brought idle down to ~900RPM by also adjusting the stop screw. Set the shift linkage and will test drive Monday.
I think that my random hiccups are a fuel delivery issue. There wasn’t an issue before so I’m assuming the fuel filter/pump are good for now. Maybe some dirt got in fuel rail or there is an issue with FPR? I haven’t investigated much yet.
My temp gauge is still slow to rise and registers low, so I need to check the sensor is in range and maybe swap one from old engine.
I’m currently running an aftermarket fan clutch from previous owner which I’m unsure of the performance. I have an OEM unit I pulled from yard, but front is covered in oily dust. Are the seals on the fan clutches serviceable? Seems to be same unit as Land Cruisers so I can order new silicone as I’ve seen done by others, just don’t want to add only to have it leak out again.
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I think that my random hiccups are a fuel delivery issue. There wasn’t an issue before so I’m assuming the fuel filter/pump are good for now. Maybe some dirt got in fuel rail or there is an issue with FPR? I haven’t investigated much yet.
My temp gauge is still slow to rise and registers low, so I need to check the sensor is in range and maybe swap one from old engine.
I’m currently running an aftermarket fan clutch from previous owner which I’m unsure of the performance. I have an OEM unit I pulled from yard, but front is covered in oily dust. Are the seals on the fan clutches serviceable? Seems to be same unit as Land Cruisers so I can order new silicone as I’ve seen done by others, just don’t want to add only to have it leak out again.
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