collapsed oil pump pulley.(big pic warning)

[bob-monk]

Hi folks,
Has anyone got any ideas what's caused this ?

As you can see, the oil pump pulley has collapsed.
Also, the back metal "belt guide ring" on the crank pulley is loose and bent.
The timing belt stayed in one piece, but its shredded (under all the loose bits you can see)

At first, i thought the oil pump had seized up and caused it, but it still spins nicely.

I've read somewhere that the valves "shouldn't" hit the pistons if the belt snaps,
so am i gonna get away with not taking the head off?

Apart from the loud bang when it happened, there's been no odd noises from the engine at all.

(sorry for the big pics, but i have no photo editing software)

 

[GrimJack]

Yikes! Never seen that before... You are right about the valves, this is a non-interference engine, so you should be able to replace the pulley, timing belt, and be done with it.

 

[bob-monk]

Well, that certainly sets my mind at rest,
but i'd still love to know what caused it.:icon_conf

I've now got all the bits out, and the only wear i can see on them, has been caused by the crank pulley ring whilst it's all been sitting at the bottom of the timing cover(my next pic will explain). It is from a 140,000 mile engine, i suppose it could just be fatigue.

For the record, the belt was changed approx 2500 miles ago.

 

[Joel W.]

Wow, I would also guess the pump siezed for a second.. :dunno:
What do the fracture lines where the pulley came apart look like?
Are they all the came colors?
Any rust in the cracked areas suggesting a past fracture?

 

[mrg]

Was the engine under load when this happened?

 

[bob-monk]

Here's some pictures of the bits, and yes, there's a couple of parts that look a bit suspect. (the middle of it's still on the car.)

mrg: I'd been cruising for a while at about 60mph, but yes, it was when i put my foot down to overtake. (not excessively, as the rain was pouring down). probably about 1/3rd throttle.

 

[IJ.]

Bob: Did you have the top plastic cover on?

 

[bob-monk]

Yes. i'd never dream of running with no top cover:nono:

 

[IJ.]

Just checking as many do!

 

[3p141592654]

Any damage to the teeth of the pulley? Could something have got wedged into the spokes?

 

[bob-monk]

As you can see in one pic, there's half a tooth missing from the big piece, but from the very firs pic in post 1, it looks to me like the tooth might have smashed off when it all reached the bottom of the case.


IJ: if it wasn't my car, i'd have been asking the same question:naughty:

 

[IJ.]

The pully is made from sintered iron and maybe it was just it's time to fail

I bought a new one for my build!
(after seeing this I'm glad I did)

 

[JustAnotherVictim]

Wow, never seen that before.

 

[Joel W.]

It looks like the last picture in your #6 post has some discoloration in the "spoke" of the far right and left chunks.. But it's hard to tell for sure.. IJ is probably right, It was just time...


Edit: Has anyone ever had a oil pump sieze on a 7m before? I know it's common on say a Ford, but I have not heard of it happening in a Toyota?

 

[werewolves182]

Wow, thats really weird. Ive got one for you if you want. Just pay shipping and its yours.

 

[IJ.]

I did a scrap metal run this morning and chucked 2 used ones out!

After seeing that no way would I risk it!

 

[Adjuster]

Totally strange.

I tried to powder coat the pullies and they did not take to that very well at all. (The metal actually released gases at 400f that caused bubbles in the powdercoat...)

Then had to thermal coat them, and so far, no problems.

I've had an oil pump pully damaged by an idiot with a pry bar using it as a leverage point. (nope, in that case, I was not the idiot in question...) It actually gouged a tooth pretty badly.

I've had to machine down the oil pump drive shaft since it was hitting on the shoulders of the Pauter rods in my stroker motor. (I've worried about it ever since, but there is no other choice, actually hitting the shaft did not more damage on the first motor.... )

Never seen these pullies shatter like this. Never seen them crack actually, just teeth damage.

I was going to say that the belt looked new. I wonder if when it was changed, something was not put back right and that caused stress on the pump drive?

Check your pump drive too. there is a pressed on bearing, and I've seen them come loose, and let the pump drive pully out into the front case, causing wear and noise. That could have allowed your pully to get caught, and shatter? (Nothing there to catch on, but the pully does wear out into the front lower cover.)

Bad part is, to remove the pump drive, you have to pull the front second cover so you can remove the bolt and retainer for the pump drive. (Pull the head and everything while your at it, the front cover also forms the front edge of the oil pan, so your taking the motor apart at this point IMHO.)

Good luck, I hope it's just a pully that failed, and your pump and pump drive are fine.

 

[bob-monk]

werewolves: that's a mighty kind offer, but i've already got another one........ thanks.


I've also got a spare motor, which i was going to rebuild over the next year or so, i'm just hoping nothing else got damaged so i can keep this car on the road till the other motor's ready.

Is it possible to check if the oil pump is still working while the belt is off?
(because i'd hate to get it all back together and then starve everything of oil.:nono: )

 

[johnathan1]

Maybe pull the EFI fuse, and crank until you see pressure on the guage?

 

[Joel W.]

Or, try hooking a right angle drill up to the oil pump drive shaft with the key on and spin the drill while someone verifies oil pressure at the gauge?

Not sure this will work, just an idea..