[3FE] Main crank pulley keeps walking, time for engine rebuild? (2 Viewers)

[TheElegantFox]

Hey all,

I've had a time keeping the 3FE in my FJ62 chugging due to the crank pulley nut walking off. Here's the thread from when it originally happened: FJ62/3FE sheared one of the serpentine pulleys - https://forum.ih8mud.com/threads/fj62-3fe-sheared-one-of-the-serpentine-pulleys.1261525/

Since then it's been ok for a few miles or so but it recently walked off on me again, the nut was literally resting on my sway bar this time, got mega lucky. I had my local shop torque it down and use some thread locker only for the nut to get loose within 10 miles of engine time. They mentioned it's likely a bent crank causing some harmonic vibrations that are walking the nut off. A replacement/repair would end up being an engine rebuild basically with dropping the power plant out of the truck and sending it off to the machine shop for the pros to asses what needs rebuilding.

Does an engine rebuild sound like the next possible step? Other than the crank, the block is holding compression fine and general performance is good for the 242k miles on the truck.

 

[OSS]

Maybe from the wobbling in the past, the fit is no longer snug. Wore down a tad.
Since you’re going to want to get a new harmonic balancer with a rebuilt engine anyway, why not buy a new harmonic balancer now and mount it on the existing tired engine and see what happens? I bet it won’t come loose.
Then the rebuild can be put off.
Also buy a new crank HB nut from Toyota.

 

[TheElegantFox]

Maybe from the wobbling in the past, the fit is no longer snug. Wore down a tad.
Since you’re going to want to get a new harmonic balancer with a rebuilt engine anyway, why not buy a new harmonic balancer now and mount it on the existing tired engine and see what happens? I bet it won’t come loose.
Then the rebuild can be put off.
Also buy a new crank HB nut from Toyota.

The original harmonic balancer cracked so I sourced a used one from a forum member and it seems to be fine. Could it still be an issue with the used part fitment? I thought the crank nut was NLA.

 

[Lead Head]

You should be able to detect a bent crank just by watching the pulley. Does the pulley fit snug on the crank, or is there a lot of slop?

Clean the threads thoroughly on both the crank and the nut, apply loctite and tighten it. The torque-spec on the 3FE crank nut is EXTREMELY tight. It is 253 ft-lbs! You realistically are not going to get that bolt tight enough without using a 3 foot bar and absolutely heaving on it. Plus, then you need to make sure you have a way to hold the engine from turning. We ended up jamming something in the ring gear to tighten the crank bolt on my 3FE.

 

[TheElegantFox]

You should be able to detect a bent crank just by watching the pulley. Does the pulley fit snug on the crank, or is there a lot of slop?

Clean the threads thoroughly on both the crank and the nut, apply loctite and tighten it. The torque-spec on the 3FE crank nut is EXTREMELY tight. It is 253 ft-lbs! You realistically are not going to get that bolt tight enough without using a 3 foot bar and absolutely heaving on it. Plus, then you need to make sure you have a way to hold the engine from turning. We ended up jamming something in the ring gear to tighten the crank bolt on my 3FE.

The shop said there wasn’t visible wobble on the crank and did lock-tite and breaker bar the nut to about that spec which is why this has me scratching my head over all this.

 

[OSS]

I thought the crank nut was NLA.

Maybe not?

Toyota 90179-22010​

Nut
1988-1993 Toyota Land Cruiser 9017922010

90179-22010 Genuine Toyota Nut

ToyotaPartsDeal.com offers the great deal for genuine Toyota parts 90179-22010 (9017922010) Nut for $32.81. All parts are backed by the Toyota's warranty.

www.toyotapartsdeal.com

 

[TheElegantFox]

Maybe not?

Toyota 90179-22010​

Nut
1988-1993 Toyota Land Cruiser 9017922010

90179-22010 Genuine Toyota Nut

ToyotaPartsDeal.com offers the great deal for genuine Toyota parts 90179-22010 (9017922010) Nut for $32.81. All parts are backed by the Toyota's warranty.

www.toyotapartsdeal.com

Could a new crank nut bite the threads better than the used one? I was talking to another car friend and they said crank nuts can be something like one use where they only truly lock once after being torqued to spec.

 

[pithicus]

I had a 3f nut unscrew itself twice. The pulley was loose in the the keyway too. I took a gamble and torqued it back to over the recommended spec, cannot remember how much over sorry, was years ago. It stayed on for years after that, never unscrewed again. Might be worth a try.

 

[TheElegantFox]

I had a 3f nut unscrew itself twice. The pulley was loose in the the keyway too. I took a gamble and torqued it back to over the recommended spec, cannot remember how much over sorry, was years ago. It stayed on for years after that, never unscrewed again. Might be worth a try.

I need to check the exact leak point this time, but the first times it walked off it chewed up the seal causing the oil to deluge out. Did your unscrew instances chew through the crankshaft seal?

 

[Michael Hanson]

Hi, Keyway worn out? Mike

 

[TheElegantFox]

Hi, Keyway worn out? Mike

The keyway didn’t show any signs of wear last time the balancer walked off so we assumed it was fine to drop a new key in.

 

[pithicus]

Did your unscrew instances chew through the crankshaft seal?

Didn't seem to. Although it started to leak there years later. By this time it had done 700,000 kms.

 

[TheElegantFox]

I cleaned around the area today and it seems to be dripping from right where everything connects to the oil pan.

 

[TheElegantFox]

Ok, managed to grab some decent video of the crank with the truck running. It’s not leaking during idle, so I’m wondering what’s changed.

 

[OSS]

That oil leak is normal and to be expected on an engine with that many miles

 

[TheElegantFox]

That oil leak is normal and to be expected on an engine with that many miles

I wonder if potentially the remaining oil spray from the 2nd walk off combined with that existing leak might’ve fooled me into thinking it was walking again or had chewed off the seal.

I should probably drive it around a bit and see if I get any new oil leak lines after hitting it with some gunk degreaser.

 

[Lead Head]

Tighten the absolute snot out of the nut, and then mark the pulley and the nut with a white or silver line from a paint pen. Drive it a bit, check for movement. Rinse, Repeat.

 

[TheElegantFox]

Ok, marked the nut and pulley and it hasn’t walked on my drives today but as soon as the oil got to temp it started spewing out pretty healthily and dripping above this metal hose.

 

[TheElegantFox]

Maybe the crank has already chewed through the new seal?

 

[roadstr6]

Was the seal replaced when you replaced the HB with the used piece? The HB and the front seal tend to “wear in” as a set. If the “new” HB has even the slightest wear in a spot that the seal can’t cover, it’s going to leak some. If it were me, I’d inspect that HB real close for wear, install a Speedi-sleeve if necessary, and push in a new seal. Torque the nut to spec and see if your leak goes away.