HDJ81 Died (1 Viewer)

[gerg]

Be nice to add one "how to"to replace the pulley and or timing belt as it seems this isn't the first thread ive read with a catastrophic failure on this engine that seems to be preventable with a Saturdays worth of care.

 

[mudgudgeon]

Yes. I see now the bolt is missing that secures it to the block. Yes?

I'm pretty sure that hole is supposed to have a locating pin only, not a bolt. (Long time since I did a t belt on 1HD-T) the 8mm hex bolt with the flange end holds the tensioner in place.

View attachment 1627329

In this pic, the idler pulley looks badly on the piss, did the central bolt let go, or has something bent?

Was the tensioning spring new?

Its got me puzzled, how did rubber seal get caught up in the t belt

 

[carbon60]

I think the idler pushed the cover away from the gasket enough for the gasket to fall in.

 

[roscoFJ73]

doh!

 

[roscoFJ73]

Be nice to add one "how to"to replace the pulley and or timing belt as it seems this isn't the first thread ive read with a catastrophic failure on this engine that seems to be preventable with a Saturdays worth of care.

Its such a simple job. It just needs to be checked before the cover goes on. The last thing I do before I put the cover on, is put a big bar on the crank nut and spin the engine by hand to make sure all the marks line up as they should.
In the 15 years Ive been on MUD, I can only remember a 1or2 failures and they seem to have been belts that have done 200000klms over their 100000klm change interval and failed.
They are fool proof as long as fools are kept away.

 

[gerg]

Ahhh k

 

[mudgudgeon]

This is about a 1hr, job at most, maybe 2 hrs if you've never done it.
Certainly not something a shop should F-up


The FSM covers it fairly well, but goes further than needed.
e.g. FSM says to remove camshaft pulleys, but gives no reason why, and it's not needed.

There's always going to be some catastrophes, even with the simplest things. I've definitely read about a few t belt failures. Seems to usually be related to the tensioner, or idler pulley.
I've always changed the tension spring ($14 OEM), and in my newer 1HZ, the hydraulic tensioner (closer to $100 from memory). Pretty sure I changed the pulley last time too. It's definitely on the "must do" list now.

 

[roscoFJ73]

e.g. FSM says to remove camshaft pulleys, but gives no reason why, and it's not needed.

I think they borrowed the directions from getting the water pump off.

 

[roscoFJ73]

Louis Skebo (haven't seen him on MUD for awhile) has already made an excellent video. He removes the cam pulley because he is doing the water pump as well.

 

[Diesel Cruiserman]

My favourite little tool is some type of liquid locking product on the threads even if it does not call for it, before I torque..

I would for sure pull the head and inpsect.

And check the BBs to spec.


Louis has a , new focus.

 

[Mighty690]

I think they borrowed the directions from getting the water pump off.

Yeah, I haven't done the belt replacement yet, but when reading that section of the FSM I was like, "Why do you have to pull the pulley and, thus, the valve cover?!?"

 

[AlbertoSD]

Yes. I see now the bolt is missing that secures it to the block. Yes?


View attachment 1627329

There is not a missing bolt there. The timing belt plate has two Dowel pins (one on each side on the top) that guide the timing belt tensioner in place (I think the belt tensioner only occupies the upper right one). The only two bolts that secure the belt tensioner to the plate itself are the bolt on the center of the pulley and the Allen head bolt next to it. Maybe the timing belt cover gasket jammed things enough to move the tensioner pulley out of center? Hard to say.

Here are some photos of when I replaced the timing belt on my HZJ70:

Louis' video is an excellent guidance on how to do this (as Rosco @roscoFJ73 mentioned).

 

[carbon60]

There is not a missing bolt there. The timing belt plate has two Dowel pins (one on each side on the top) that guide the timing belt tensioner in place (I think the belt tensioner only occupies the upper right one). The only two bolts that secure the belt tensioner to the plate itself are the bolt on the center of the pulley and the Allen head bolt next to it. Maybe the timing belt cover gasket jammed things enough to move the tensioner pulley out of center? Hard to say.

Thanks for clarifying that!

 

[mudgudgeon]

@AlbertoSD very helpful pics. That matches my memory.

 

[carbon60]

I like the paint markings on the bolts. There must be a convenient pen, for that?

 

[IanB]

I like the paint markings on the bolts. There must be a convenient pen, for that?

Paint pen, available at most hardwarestores/parts houses.

 

[AlbertoSD]

I like the paint markings on the bolts. There must be a convenient pen, for that?

I use this thing called "Cross Check Torque Seal" made by Dykem. It is a paste rather than just paint. The paste will break if the bolt rotates making it easy to spot loose fasteners.

You can see on the above picture that it meets airliner manufacturer codes (Boeing Specs), which should be good enough for our Land Cruisers . I bought it at Amazon for $7 a tube:

https://www.amazon.com/Dykem-Tamper...36004&sr=8-3&keywords=cross+check+torque+seal

I used to use paint, but then found this and liked it MUCH better.

Disclaimer: I am not affiliated with the company in any shape or form. Just like the product.

 

[carbon60]

After getting the truck into a nice warm, and well lit, garage, I’ve come to the conclusion that the root cause of the failure was the timing belt cover gasket.

There is dirt in the bottom, which indicates that the gasket was not sealing correctly. Furthermore, the gasket was jammed into the gears and tensioner.

I suspect the gasket was not correctly sitting in the muddled plastic cover, and may have been pushed into the housing during a water crossing.

 

[carbon60]

Pulled the head, and there is lots of damage.

Cam shaft has many damaged lobes, most of the intake valve shims are slaughtered.

 

[IanB]

Dislike. That's awful, I'm really sorry to hear this.