Cam sprockets discolored. Need to replace?

GeoJD · **Posted:** Wed Jun 23, 2021 10:09 am

Update time! I got the injection pump pulley off. I removed a bit of material from the shoulders of the sprocket tool feet with a dremel, and they slipped right in.

Then, I attached the puller tool, tighten and tap, tighten and tap... and the 3rd or 4th time, pop! Off it came.

Getting the pump out was not super easy. I cleaned up the area pretty well , especially the pump shoulder. There was a good deal of buildup, as you can see. To drive the pump out, I rearranged the pieces of the factory puller tool so the square "holder" would be in contact with the pump shoulder, and with the main cylinder of the puller over that to pound on so the force would be distributed over the face of the shoulder. Then, I heated up the surrounding bracket with with an electric heat gun, applied freeze spray to the pump, and pounded on my driver contraption with a plastic dead blow mallet. It took several cycles, but it finally walked out. I will clean up the inside of the bracket with a bit of sandpaper and apply antiseize when I reassemble, just in case.

I've been cleaning the grease from the outside of the block, and the carbon from the deck and piston crowns, which are looking pretty good. I pulled the balance shaft assembly, which appears sludge-free, and the jets, which I was able to spray cleaner through without any problem. I'll be replacing those, just in case. Looking down the bore where the turbo oil line attaches, the areas I can see also look pretty clean.

I pulled the rod caps one by one. The rod journals on the crank all look smooth and bright.

Rod journal 1:

Rod journal 2:

Rod journal 3:

Rod journal 4:

The rod bearing halves look somewhat less bright, though I'm more concerned about the scoring on #2:

Rod bearing 1:

Rod bearing 2:

Rod bearing 3:

Rod bearing 4:

Since this is a tunnel crank, there's no way to look at the main bearings without pulling the whole crank. I was hoping I would get away with not doing that. Now I'm not so sure.

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

I hate to say it, but I think I'd be pulling the crank - #2 rod is the worst, but #3 and #4 don't look far behind. I would be concerned about the mains at this point. Pulling the rear carrier isn't hard, and that gives you access to #5. Maybe a place to start?

CATCRD · **Posted:** Wed Jun 23, 2021 4:11 pm

GeoJD wrote:

Rod journal 3:

Out of curiosity, when you pulled the balance shaft assembly off, were the o-rings around its oil feed dowels smashed flat and split?

GeoJD · **Posted:** Fri Jun 25, 2021 10:16 am

No, mine looked fine - which is good (for me), because they, too, appear to be discontinued.

I got my pistons out last night. I've ordered new rod bearings and main bearings too, because if I'm pulling the crank, with the mileage I'm putting in new bearings no matter what they look like.

GeoJD · **Posted:** Sat Jun 26, 2021 6:46 pm

Well, I've now spent 2 days trying to get the crankshaft sprocket bolt out. Yesterday I applied Blaster and heat from the electric heat gun and hammered with my 20v impact gun (in the correct direction for left-hand threads!) until the battery went dead. Today I picked up a corded version and went at it again, but I'm a little scared to really "put the spurs to it", because I'm not sure what I would do if I rounded it off. Any suggestions for getting that bolt out?

In other news, my new ultrasonic cleaner showed up, and it's awesome

GeoJD · **Posted:** Sun Jun 27, 2021 7:05 pm

Ha! Got it! The shop I’m working in has a compressor, so I went and exchanged the electric impact wrench for a serious air gun. I heated up the bolt for a while with the electric gun, until a bit of water on top of the sprocket started to steam. Then, I applied a MAP gas torch to the head of the bolt, 30 seconds on, a minute off to let the heat travel, until the water on the sprocket started to sizzle a little. Then, I put the impact gun on and let it hammer. After what seemed like forever (probably less than a minute) it started to move a little, then out it spun. As a bonus, the sprocket slid right off too. The nose of the crank was cool enough to touch almost right afterward. I’m going to declare victory for the day and celebrate with a frosty beverage.

WWDiesel · **Posted:** Sun Jun 27, 2021 9:33 pm

My general rule; if it dont move, get a bigger or stronger impact. Something has got to move or break.

Hot wrench is always my last resort when all else fails...
But very glad you finally got it off. :BANANA:

GeoJD · **Posted:** Fri Aug 13, 2021 5:15 pm

Well, here it is - the heart of the beast:

After I got the crank bolt out, I continued with disassembly. I took off the front cover, and took some close-ups of the sprockets in case the oil pump or vacuum pump needed to be timed. (They don't as far as I can tell.) Then I pulled the sprockets and pumps.

On the back end, the air wrench popped both the flex plate and flex plate adapter with ease. That left just the rear seal and main bearing carrier, which pushed out with a couple of the front cover retaining bolts.

Which finally brought me to the part of the job I'd been dreading since reading Captain Dean's thread: pulling the crank assembly itself. I got some short bolts and fender washers as cheap insurance to keep the sleeves in, inverted the block, and used the factory slide hammer tool to pull the retaining pins.

Then I attached the load leveler chains to the motor mount holes on the sides and to a couple of transmission adapter mounting holes, removed the stand and hoisted the block. I used the factory crank removal tool to give it a couple of taps, and it started to move. I was a little surprised and greatly relieved at how easily the assembly came out. Then (after snapping the first photo in this post), up on the bench and off came the carriers.

I'm glad I kept going. The coatings are gone on these too. Journals look good, though.

I took the rear carrier to a local machine shop, where they pressed the rear main bearing out of/into the carrier for me. I did the front one myself. I warmed up the block and used the factory tool to push the front main bearing out. It took a couple of beers and a little time to figure out how to configure the tool, and a nervousness-inducing amount of tightening, but it broke loose with a pop and slid out pretty easily. After cleaning everything up, I grabbed the new front main bearing out of the freezer and used the tool to press it back in. It was so easy, I did it twice! (I had the oil hole a little misaligned on the first try.)

Back on the bench, I put the new bearing halves into the carriers and put them back on the crank with ample assembly paste. I put the carrier bolts in dry and torqued them to spec.

The crank slid back into the block as easily as it came out. I made sure everything was properly aligned and replaced the pins. I used the old rear seal cup and a plastic mallet to install the new rear seal and got the rear carrier, washers, adapter, and flex plate back on using Permatex Orange on the adapter bolts and flex plate mounting bolts. The FSM claimed that the flex plate bolts were only torqued to 35 ft-lbs, which seems crazy to me, so I also went a bit tighter on those. I got the pumps and sprockets back on the front, and got the front cover on.

At this point, I was scrambling to get everything together, as I was hoping to use the reassembled Liberty to tow a camper on vacation in a few days, and I figured I was on the downslope. I got the first two pistons in with the new rod bearings and tightened them lightly.

But on the third one, I was rushing things, and struggling with the cheap ring compressor I had bought, and the entirely predictable happened. It turns out sadness looks exactly like a broken oil control ring:

So, there we are, I'm back from vacation, and I suppose I need to order a set of new pistons unless, by some stroke of luck, the oil rings didn't change when the pistons did. Anybody know? Either way, there was a little light scoring on the paint on a couple of the piston skirts (the dingleball honer removed any trace of such on the sleeves), so I suppose now I have time to get new wrist pin bushings pressed in.

MtnClimber · **Posted:** Sun Feb 05, 2023 11:49 pm

@GeoJD whatever happened to the rest of your tear down and reassembly?

DieselJeepLuvr · **Posted:** Tue Feb 07, 2023 11:23 pm

Right? It's like reading a good novel and finding out the last half has blank pages!

Cam sprockets discolored. Need to replace?

Who is online