ACL rod bearings after 150k kms.

[powermad]

I'm not sure what you mean by "debris on the backside of the shell" There was nothing trapped between the bearing and the rod.

A piece of dirt on the back of the shell will make a raised spot and look like that.
You would see it embedded into the back of the shell if that was the case.

Bearing fatigue is generally caused by lugging the engine hard at low RPM's for extended periods. It can also be caused by detonation from an improperly timed fuel system.
Which can be kind of hard to hear on a rod knocker.

Cavitation and fatigue can sorta look like same kind of damage.
Kind of hard to tell from just one picture and not seeing it first hand.

 

[gerg]

It is kind of weird that it's on a rod bearing. I've never really heard of this on a 1hdt. Always the BEBs.

 

[Dougal]

I'll call it hardly definitive. An obscure paper that you did not provide a link to that mentions 6cyl engines (the 1HD-T must the only one ever made!) and may have had a Toyota engineer help write it. Please.

Doesn't mean you're wrong, you may very well be right. You'll have to do better than that though.

I've posted the link here before, your comment sounded like you'd read it and didn't agree.
But what you really wanted was a link to the paper.

http://www.tytlabs.com/english/review/rev401epdf/e401_036aoyama.pdf

 

[gerg]

Now that is a neat paper Doug. It speaks of exactly the main bearing grooves cut that I referenced, or at least similar. Course I was actually referencing some massive generator that suffered this somewhere in the English speaking world. They solved their problem in a very similar manner.

 

[roscoFJ73]

and 35psi oil pressure at hot idle.

.

That's seems too much to be healthy. I thought under 15psi would have been the norm for a good engine.

 

[ozwallaby]

It is kind of weird that it's on a rod bearing. I've never really heard of this on a 1hdt. Always the BEBs.

I'm not understanding something here...........

 

[Locked79]

I'm not understanding something here...........

As in rod bearing is a big end bearing?

 

[crushers]

BEB = big end bearing of the con rod
thanks for posting up the thread. i will fall into the category of those that didn't know you had to change out the BEB on HDT on a regular basis.
since this is the case then i would suggest that if you turbo your 1HZ you should at least inspect the BEB every 100K to 150K to be safe.
the paper is an interesting read but the main bearings don't show the cavitation where as the BEB do. the paper talks about cavitation in the mains, maybe i missed it, but where in the paper did it talk about the BEB delamination?

 

[roscoFJ73]

BEB = big end bearing of the con rod

Yes and the other bearing down there is the mains bearing which hold the crank to the block

thanks for posting up the thread. i will fall into the category of those that didn't know you had to change out the BEB on HDT on a regular basis.

Really ,we must have discussed this 500 times on MUD Its not in the manual ,its just something Toyota Australia may have suggested to customers while denying there was ever a problem.

since this is the case then i would suggest that if you turbo your 1HZ you should at least inspect the BEB every 100K to 150K to be safe.
the paper is an interesting read but the main bearings don't show the cavitation where as the BEB do. the paper talks about cavitation in the mains, maybe i missed it, but where in the paper did it talk about the BEB delamination?

I don't remember seeing anything about delamination last time I read it either
The paper is quite ambiguous and we don't know for sure if is the 1HDT is is referring to, but I don't know of any other Japanese diesels suffering the same probs.

 

[crushers]

Rosco,
yah, really. i know some had suggested doing an inspection every 150K but i had not seen any delamination results till this thread.
enlightening.

 

[Gareth]

A piece of dirt on the back of the shell will make a raised spot and look like that.
You would see it embedded into the back of the shell if that was the case.

Bearing fatigue is generally caused by lugging the engine hard at low RPM's for extended periods. It can also be caused by detonation from an improperly timed fuel system.
Which can be kind of hard to hear on a rod knocker.

Cavitation and fatigue can sorta look like same kind of damage.
Kind of hard to tell from just one picture and not seeing it first hand.

There was nothing on the back of the bearing shells, IP was properly timed, as for how the previous owners drove it I have no clue.

I'm not looking for a diagnosis on how the bearings failed, It's clearly the same reason the oem ones failed.

I'm posting this because there is a lack of "second set of bearing" posts and quite a few people believe that replacing them once is enough.

 

[Gareth]

That's seems too much to be healthy. I thought under 15psi would have been the norm for a good engine.

Just because the minimum spec is 4psi doesn't mean its "good" to have that little oil pressure. If you haven't already you should hook up a mechanical guage and check yours.

Manufacturers will generally set specs like that to avoid having to do warranty work.

Look at chrysler's spec for dodge 1ton ball joints for example their maximum allowable spec is what most people would consider dangerously unsafe. They changed it after being flooded with warranty repairs, and loosing lots of money.

 

[powermad]

It's not just smaller diesels that suffer from cavitation.
Here's a set of Volvo 13 liter rod shells. 620K miles.
High counts for low oil pressure and high oil temps.

 

[gerg]

That's seems too much to be healthy. I thought under 15psi would have been the norm for a good engine.

Id have to agree rosco. 35 psi hot seems to be quite high. I would be suspect that somewhere in that engine somethings getting starved of oil. What weight are you runing? Running a lower weigt oil will net you more flow with less pressure. Their is a direct relationship.

I mistakenly thought BEBs were the crankshaft end bearings... am I way off? I think we might be using similar words but talking about very different bearings.

Those bearings on that Volvo are from starvation and cavitation from high temps? That sort of makes sence as the damage is quite spread out. The 1HdT bearing has very localized damage which is why I suspected crank whirl. That is where the crank can begin to rotate in the opposite direction in the bearing space and hammers at the 5 oclock position which is normally where the crank sits when running. This reverse oscilation can cause very high pressures specifically in that area with high temps that can cause the cavitation as well as over come the fluid film and cause metal to metal wear. Ill see if I can find a link for that whirl but im at work right now. Its not that uncommon.

 

[powermad]

This particular engine also had cavitational erosion on the cylinder liners coolant side. It ate away enough that coolant ran into the cylinder and then coolant went into the basement.
It was noticed when the #1 hole hydro locked and split and bulged the liner.
That the was caused from improper coolant maintainence.
Coolant in the oil will cavitate the bearing when the oil temps are in the 250 F range. Add in low oil pressure and away they go.
The coolant flashes and causes little explosions that starts the pocking.

 

[BC40]

I mistakenly thought BEBs were the crankshaft end bearings... am I way off? I think we might be using similar words but talking about very different bearings.

.

Believe you are thinking bottom end bearings (main bearings) instead of big end bearings Greg.

Interesting discussion...

 

[Gareth]

Id have to agree rosco. 35 psi hot seems to be quite high. I would be suspect that somewhere in that engine somethings getting starved of oil. What weight are you runing? Running a lower weigt oil will net you more flow with less pressure. Their is a direct relationship.

Not trying to be a dick and start an internet argument, but there's no way you've spent any time around engines if you think 35psi at idle is too high.

You'll notice that the posted specs by toyota are minimumand always state "or more"

 

[gerg]

So im thinking BEBs are at either end of the crank shaft, as in the ends of the crank. The mains are in the middle and rods are well... on the rods.

250F is a very low temp. I had no idea it could happen at such a low temp. Id have to think most engines run that or close to that in the shell.

It would make sence for the 1HDt if is it is predisposed to cavitation from whirl, then cavitation damage would differ from engine to engine based on fuel/coolant contamination, but the whirl would also errode the bearing eventually causing them to fail even with carfeul maintanace. I guess that is how you could get some bearings packing it in early and in such a bad way where as if maintanance is strict and the enigne is loaded up more regulalry then the bearing could last much much longer.

Im quite interested in this problem cus its pretty much the only thing stoping me from getting one of these engines. If I cant solve this personally then its a no go. Changing bearings more frequently than your timing belt is not a solution im willing to accept.

 

[gerg]

No I dont think your a dick, and Im not a mechanic at all. I jsut wrench as a hobby, but it just seems high thats all. Its a bit of a red flag.

 

[Gareth]

No I dont think your a dick, and Im not a mechanic at all. I jsut wrench as a hobby, but it just seems high thats all. Its a bit of a red flag.

I am a mechanic (13 years exp Red Seal certified) 35 psi at idle would be considered normal for most vehicles, and good for a truck with 310k kms.