My rebuild thread (1 Viewer)

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Joined
May 26, 2018
Threads
11
Messages
328
Location
Portland, Oregon
1992 HDJ81 0017607 (just to get that out of the way so we all know what my truck has)

Finally getting around to the rebuild. I'll use this thread to document my findings, feel free to contribute!

Back in august, I took a vacation to southern california to visit friends / family. Drove 1000~ miles from Portland, Oregon, allllll the way down to the LA area. the truck was absolutely perfect. had been for the 6 months of me owning it prior to vacation, too. Nice smooth sailing at 65-70mph.

I'm staying in Crestline in a cabin up on the mountain. I had to detour down the back of the mountain to get to Rancho, no big deal. Warm the truck up, hop in, start driving. I get a good 5 miles outside the cabin, I am coasting downhill in 3rd gear going probably 25 mph.

BOOM. truck all of a sudden sounds like someone turned the volume up from 5, to 11. My initial thought is OH s*** I LOST EXHAUST! and I stop and check while it's idling. everything seems intact. truck still revs, is still idling semi decent. i continue coasting a few 100 yards to a flat place where I am safe and blah blah I wait for tow truck etc. truck has no power, revs but sounds like dog s***, is dead.

I'm thinking injectors because I roll coal now. either that or a valve is toast. first things first, i'm pulling the intake to inspect the turbo, and the valve cover, to see whats up top.

I had to wait to work on it due to contractors and other lame reasons. I'm glad to hopefully get her up soon. I miss that truck.

here's two videos of it idling. I just charged the batteries since it's been sitting, silently taunting me.




 
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Don't run it anymore. I be dropping the oil pan and check for play in the bottom end. If that's ok then move onto a compression check to isolate which cylinder(s) it could be.
Sorry man
g
 
Small update. I checked the turbo for shaft play, absolutely none. that's a huge relief. it feels fantastic.
I checked my timing belt again (when the truck broke i just peeked under the cover) and it's great. I don't think I skipped a tooth.
Pulled the valve cover off and everything there looks much better than I expected, to be honest. so that's great!

My next step is to pull my injectors, and test them. if those are good, I'll move onto the bottom end.

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Judging by the movie clips you have posted, I would say the timing is off.
Looking at the pic showing your timing belt, it seems to me that the camshaft timing pulley is not aligned with the pump pulley. The teeth of the timing belt are coming outside the camshaft pulley. Maybe the woodruff key of the camshaft pulley is gone and your pulley span around the camshaft. Timing can go off in many ways, not only tooth belt skipping.
Before doing anything else, I would rotate the crankshaft pulley to OT and check that every other pulley shows the same position.
 
That is a fantastic Idea, I think I will give that a shot! if that was the case, it certainly would explain a majority of the issues.
 
Did you do big end bearings on this motor? Did you remove the cold start advance mechanism (ACSD)? I don't think those are the problem here, but both are known to fail with various consequences on these motors.

The motor sounds uneven to me. Meaning the problem could be related to one or two cylinders.

Does the engine start as easy as normal? Is there a huge power loss? Is there unusual smoke out the exhaust at idle?

Open your oil filler cap while the engine is idling and look for blow-by. If someone messed with the tuning and the truck has run high EGT's, it's possible a piston has cracked.

Try cracking one injector at a time and see if one cylinder is contributing more issues than another.
 
Pulley's appear to line up. keyway is not damaged.

got the injectors out, they're all in one piece, so they will be flow tested soon.

Pulled out my glow plugs, they're all in one piece as well.

Did you do big end bearings on this motor? Did you remove the cold start advance mechanism (ACSD)? I don't think those are the problem here, but both are known to fail with various consequences on these motors.

Does the engine start as easy as normal? Is there a huge power loss? Is there unusual smoke out the exhaust at idle?

Where is the ACSD? I did not remove anything. I've done pretty much nothing to this other than oil changes.

when my batteries are charged, it does start just as fast as it always did, pretty much when the first cylinder gets compression. It's always started very easily. from sitting I think it drained them, so they are going to be replaced.

it does smoke slightly at idle now, yes. It did not before, after it warmed up. when cold it barely smoked prior to this.

I did not do BEB's, nor do I have any idea if they have been done. The PO in Japan owned this for 15 years according to his posting, but I wasn't given any history on it, nor can I probably get it anymore, either.....
 
tomorrow I plan on draining the oil and going from there. I'll snag a new filter if anywhere has them in stock and cut the old one open.
 
Gotta agree with gerg.
Don't run out, do some investigating first.
Running it right now is possibly causing more damage.

Something is not right with your timing belt, it should not be sitting proud of the cam shaft pulley.
 
I would check to see if, while cranking/running the engine, the pump pulley runs true. I've seen where if the pump is misaligned, it will wobble a bit.

Also, pull the cold start device off the side of the pump. If you need a step by step, Im sure there is a thread on it.

Check that the ball has not broken off the shaft.
If it has, there are likely bits of steel in the pump and it will need to be pulled apart and cleaned at the very least.
If it hasn''t, you should delete it anyway for piece of mind.
 
I noticed the belt seemed a little off, going to do some more investigating into that as well. It doesn't look off in comparison to the tensioner or the IP pulley to me, but it could be! It wont be running for a while, I can't get the injectors to the shop for about a week. With the injectors out I cranked it over and everything seemed to be rotating correctly. according to the timing belt cover, and the condition of the belt, it had been replaced shortly before I bought it.

I'll look into the ACSD tomorrow. I can machine a block off plate or buy one but i can't find much info on the removal process due to Photobucket deleting old things, or the dowel pin needed to go in to stop the pump timing from retarding? I may have to machine that as well if I can figure out what's needed. probably will make more sense when i stick my face down there and look at it all. I had no idea these were a common point of issue, in fact i didn't even know it existed. lol.

Coworker is stopping by tomorrow with a compression tester, and sunday I'll get the boroscope to look into each cylinder.
 
Removed my oil filter and drained oil out of it - no bearing debris. I reinstalled filter temporarily until I make it to the store to buy a new one. I intend on draining the oil, removing pan and inspecting bearings after my injectors are tested so I can for sure rule that possibility out. one step at a time :)

I ended up doing the compression test before the borescope just due to the nature of timing and my coworker bringing it over.

my lowest was 475 PSI, my highest was 500 PSI. I want to do it again with a different gauge because the gauge had a right angle adapter and cylinder number 4 had a hard time "keeping" the pressure, but the gauge's fitting was barely able to hit the quick connect due to fuel lines being in the way. I can't rule it out as being a faulty gauge unless I prove it lol.

At some point this week I am removing the ACSD. After a little research I feel Yota is right and I should just remove it regardless if it has failed or not. Just need to do more searching to make sure I remove it correctly.

Onto the camshaft / fuel pump pulley. My coworker noted the placement of the belt, and we both saw that as look at the camshaft pulley, you can see a very faint mark from where a belt used to be riding. Now, the belt / tensioner has pretty obviously been done recently, so he asked if it was possible the camshaft pulley may have been put on backwards. Does the pulley show a TDC mark on both sides? Is the pulley offset differently so if it was flipped one way or the other, that it might "stick out" further? The camshaft has not moved. it is seated neatly against the holder.

Progress is being made!

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Glad to hear your bearings are ok and compression is ok! This is becoming a less expensive problem....
 
Cam shaft pulley well only go on one way. It has a tapered connection on the cam. Would take a "talented" mechanic to get it on backwards.

If no4 still doesn't hold compression, squirt a couple of teaspoons of engine oil into the cylinder, and try again. If it hold compression with oil in it, it suggests bad rings, if it does not it suggests a cracked piston, or ****ed rings
 
I'd add a full inspection of the timing belt and idler pulley set up to your list, but check other stuff first.

Idler pulleys can fail in multiple ways, and can fall off.
Also check the tensioning spring. They can be stretched if not fitted carefully. It's a 15 dollar part that should be replaced, but often isn't. FSM has a measurement specification so you check if it has stretched
 

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