'93 1fz-fe engine knock. Main bearings = toast = cracked crank (2 Viewers)

[mudgudgeon]

I noticed an odd growl from my 80 in the past few days when RPM was approaching 2500-3000rpm.
At first I thought it was an odd exhaust note.
I spent a week camping and offroad a week ago, so figured maybe my exhaust had cŕapped its pants. (I had made some field repairs to fix a rattle and a leak)

Anyway, yesterday after a 30 minute drive, I parked my car. When I came back to drive away, as I pulled away, the previous growl was clearly a knock.
I stopped and popped the hood to listen, and it was knocking around 2000 RPM upwards. Sounded like possibly big end bearing, but not conclusive.
I tried to baby it and drive it, but the knock got louder fast! It also stalled when I slowed to stop.

I had it towed, as oil pressure gauge was also lower than usual (oil level good) I didn't want to risk a total failure.

Today I started it, and idled it up a little, and listened to the engine with a long extension bar as a stethoscope from above, and from underneath.
There's a definite rythmical knock that was loudest around pot 4 or 5, and it seemed loudest in the bottom end.

I decided to pull the sump and check big end bearings.

Oil pick up screen had a bit of crud in it

The sump had quite a bit of metal in it. It all looks like bearing metal, or possibly aluminum. A few pieces looked distinctly like swarf.
There was soon longish thin strip's, about 5/8's which i thought was odd.

When I got big end caps off, to check bearing shells, all the shells look to be in really good shape. Not perfect, but I would have been happy to let them ride undisturbed for a lot longer.

All big end crank journals look good too, no scoring, no transferred bearing metal.

I pulled plugs too so I could turn the engine over easily by hand.
All plugs look spot on. Dry, pale grey. Consistent in every pot.
The engine has been running great since I replaced a head gasket a few thousand kms ago.

So, now I'm stumped. Not sure what to look at next.
In thinking of pulling main bearings one at a time, but don't want to disturb the crank if not necessary.

I think tomorrow, I'll remove the rocker cover and check the top end.
The metal in the sump looks a little like aluminum swarf. I'm wondering if I failed to torque something up when I put the top end together. Wondering if a bolt head may be scraping the timing case.

Also wondering if a valve retainer may have come loose, and a dropped valve is a possibility. The knock was definitely louder around cylinder 4 or 5.

Looking for suggestions / feedback on my troubleshooting process.

Any help appreciated.

 

[mudgudgeon]

Additional info

Head gasket failed at cylinder #1, and was changed a few 1000 km ago.

Engine has done approx 250k km, 160ish k miles.

Cylinder bores looked excellent when HG was done

Cam bearings all looked good, minimal wear when HG done

Bottom end appears to have never been touched. Sump was sealed with grey FIPG, and it had clearly seen a lot of years service.

I'm a competent shade tree mechanic. Careful and clean and systematic in my approach, but not OCD or analy retentive. Carpenter / builder by trade.
There's really no part of a car i haven't had apart at some stage over the years.

This ain't my first rodeo, just a little stumped on trouble shooting, and what next.

 

[wesley993]

I’m stumped too? I have a 93 also. Hopefully one of the forums fzj80 ninjas chime in. Following.

 

[azngarage]

Most likely is the main bearing. probably Cyl # 5 and 6

 

[Shipwreck]

^^^
That's exactly where mine failed.

When you replaced the head gasket, did you place and then remember to remove the service bolt for the camshaft gears? ...An easy thing to forget, and has caused issues for other Mud members.

 

[mudgudgeon]

^^^
That's exactly where mine failed.

When you replaced the head gasket, did you place and then remember to remove the service bolt for the camshaft gears? ...An easy thing to forget, and has caused issues for other Mud members.

99.99% sure I got that right. Gonna pull the rocker cover today and look at the top end.

Most likely is the main bearing. probably Cyl # 5 and 6

Mmm, I was hoping I wouldn't need to disturb main bearings.
Listening to the knock with a sold bar, it was definitely more pronounced in that area.


Thanks guys

 

[Kernal]

Might not explain the stalling, but could the timing chain be loose,
grinding away at the timing chain cover??

 

[mudgudgeon]

Thinking about this more this morning. With the drop in oil pressure, I think it's pointing to the bottom end.

Oil pick screen is partly blocked, but I don't think enough to cause pressure loss.

 

[mudgudgeon]

Well, spend more time on this today. I now know where the problem is.

4 of 7 main bearings are toast!

Crank journals all look pretty good. Theres a small amount of bearing material galled onto a couple of journals.

I'm going to pull the engine, remove the crank and linish it as needed. I'll replace Big end and main bearings.
I have a new clutch kit sitting in a box, so pulling the engine will let me replace the clutch, machine the fly wheel, and refresh the rear main seal too.
I'll probably pull the head too to make doing big end bearings easier. Undecided on that. May leave it.

I think the damage to bearings started after doing the head gasket. I ran the engine for a few minutes before I changed the head gasket knowing I had water/ coolant contaminating the oil due to busted head gasket. Circumstances kind of left me without an alternative. I knew I was rolling the dice and contemplated opening the bottom end to check bearings, but decided against it.
I guess it didn't pay off.

 

[azngarage]

The main bearings damage is due to low oil pressure. Most of the time the last 3 cylinder because it's furthest from the oil pump. If you're going to pull the motor, i think it's best to do a complete rebuilt. Also make sure to check the oil pump when you do the tear down.

 

[Shipwreck]

The main bearings damage is due to low oil pressure. Most of the time the last 3 cylinder because it's furthest from the oil pump. If you're going to pull the motor, i think it's best to do a complete rebuilt. Also make sure to check the oil pump when you do the tear down.

Oil pump and bearing wearing is a chicken and egg scenario. Which comes first? I've always been taught that the oil pump just produces oil flow. The tolerances in the bearing journals, passages and bearing clearance creates resistance to that flow and thus produces pressure. If you have excessive wear in the bearing tolerances, oil pressure will drop.
But, as @azngarage mentions, a worn oil pump can also produce reduced flow, which may result in reduced pressure.

Either way, I agree that a full rebuild would be the best action. You're already in there, and have most of the engine torn down. Might as well do the whole thing and not have to worry about it in the future.
...Or you might want to look into a factory short block. In my case, machining costs were so expensive that for a few hundred more I bought a factory block from Mr T. Good Luck!

 

[mudgudgeon]

I've always been taught that the oil pump just produces oil flow. The tolerances in the bearing journals, passages and bearing clearance creates resistance to that flow and thus produces pressure.

I agree with this.

I'll definitely be checking the oil pump.

My thoughts are running it with water in the oil caused some galling of the bearings. Once it starts, wear increases exponentially. Oil pressure drop as the bearings failed makes sense to me

At this stage it'll most likely be getting new bearings and buttoned back up. Unless I find anything more concerning.
When the top end was apart, everything was in great condition.

A full rebuild is not really an option right now. If I have no alternative I will swing it, but not easily.

 

[Kernal]

Sorry about the bad news.

 

[AussieHJCruza]

Ouch, this has gotta hurt @mudgudgeon - hopefully a quick polish and the crank is OK

 

[DivByZero]

Since you're pulling the crank after a bearing failure, make sure you inspect it for any cracks while you're there. If you don't know what to look for, take it to someone who does for a lookover. I was rebuilding a Toyota 3L diesel from a LN106 Hilux after a bearing failure. Crank looked fine, but I decided to take it to a specialist to inspect and polish. He spotted a crack in about 30 seconds. Plain as day when he pointed it out, but until you know what to look for they're hard to spot.

 

[Snowy105]

I'm in a similar situation with the 1FZ in my 105.
No water in the oil at any point I've owned it but......Park it facing slightly downhill and there is audible knocking coming from the bottom end.
I was going to leave the engine in and just do connecting rod bearings but now I'm thinking I"ll pull the engine out and do the main crank bearings also.
I would hate to go to all that trouble and not actually fix the issue and have to pull the engine out anyway!

Keen to hear how your bottom end adventure turns out!

 

[mudgudgeon]

Since you're pulling the crank after a bearing failure, make sure you inspect it for any cracks while you're there. If you don't know what to look for, take it to someone who does for a lookover. I was rebuilding a Toyota 3L diesel from a LN106 Hilux after a bearing failure. Crank looked fine, but I decided to take it to a specialist to inspect and polish. He spotted a crack in about 30 seconds. Plain as day when he pointed it out, but until you know what to look for they're hard to spot.

Yeah, good call. I will be taking my flywheel to get machined. Thinking I'll get the crank linished and size new bearings to suit.

 

[Spdstr280Z]

This doesn't help your situation any, but those big aluminum shavings and black (plastic?) crud look like what I found in my oil pan too. All of my bearings showed some wear, but nothing that would not have kept going for long time. What I discovered is that early 1FZ's had a timing chain guide / tensioner issue, and some of them failed early on. The guide was redesigned a couple years in. My belief is that mine failed, and all the aluminum and plastic in the oil pan was from the guide. Mine had the original design part, so I assume it was replaced early in its life under warranty, and they didn't bother to pull the oil pan for a thorough cleaning, so that crap had been riding around in the pan for most of the trucks life.

Crap in the oil pan post from my build thread...

Jason

 

[Snowy105]

Well, spend more time on this today. I now know where the problem is.

4 of 7 main bearings are toast!

View attachment 2751590

View attachment 2751591

Crank journals all look pretty good. Theres a small amount of bearing material galled onto a couple of journals.

View attachment 2751592

View attachment 2751593

I'm going to pull the engine, remove the crank and linish it as needed. I'll replace Big end and main bearings.
I have a new clutch kit sitting in a box, so pulling the engine will let me replace the clutch, machine the fly wheel, and refresh the rear main seal too.
I'll probably pull the head too to make doing big end bearings easier. Undecided on that. May leave it.

I think the damage to bearings started after doing the head gasket. I ran the engine for a few minutes before I changed the head gasket knowing I had water/ coolant contaminating the oil due to busted head gasket. Circumstances kind of left me without an alternative. I knew I was rolling the dice and contemplated opening the bottom end to check bearings, but decided against it.
I guess it didn't pay off.

Quick question on pulling out the engine,
did you have to leave the transmission connected and pull that out with the engine?
or were you able to disconnect the engine from the transmission in the car and just pluck out the engine by itself?

 

[mudgudgeon]

This doesn't help your situation any, but those big aluminum shavings and black (plastic?) crud look like what I found in my oil pan too. All of my bearings showed some wear, but nothing that would not have kept going for long time. What I discovered is that early 1FZ's had a timing chain guide / tensioner issue, and some of them failed early on. The guide was redesigned a couple years in. My belief is that mine failed, and all the aluminum and plastic in the oil pan was from the guide. Mine had the original design part, so I assume it was replaced early in its life under warranty, and they didn't bother to pull the oil pan for a thorough cleaning, so that crap had been riding around in the pan for most of the trucks life.

Crap in the oil pan post from my build thread...

View attachment 2752542

Jason

Thanks. I'll check tensioner too then.

At this point, main bearings are obviously toast, but looking at other potential issues too

Quick question on pulling out the engine,
did you have to leave the transmission connected and pull that out with the engine?
or were you able to disconnect the engine from the transmission in the car and just pluck out the engine by itself?

I left the transmission bolted to the cross member, slung a ratchet strap around the chassis rails and under the bell housing, and cracked it tight to support the gear box, then yanked the engine only.

I took the radiator out, but left AC condensor and radiator support in place.

I used a couple of long extension bars to undo bell housing bolts. The top two took some stabbing in the dark, but wasn't too bad.

Hopefully it goes in as easy as it came out