Fiat doblo

[sooey]

Update on this. I sorted this out last week and was lucky enough not to have caused any damage, the engine was running lovely.....until yesterday when the belt must have jumped again, this time causing serious damage.
When I did it last week I fitted a new pump, another new belt and a new plastic pulley that the belt runs on between the crankshaft and the camshaft.
That pulley had been renewed in September as part of the kit, yet it was worn away to virtually nothing.
With that being the pulley between the crank and the cam, and with the belt jumping twice in just over a week am I right in suspecting the camshaft bearings?
My thinking now is that the plastic pulley has been subjected to too much pressure because the crank has been trying to turn a partially siezed camshaft. Although the cam seems to turn ok with a spanner on it, but that's when the engine was cold.
Anyone got any thoughts? Thanks in advance

 

[Burnerman]

In my years of doing timing belts, I've yet to find worn camshaft bearings....the odd fractured cam maybe (rattles like hell if it spins at all) but thats it.
However, a worn water pump causes the belt to run out of line, and causes the belt to run tight and then slack - this obviously gives any tensioners or guide pulleys a hard time.
On occasion, manufacturers change the spec of their plastic components to alloy ones and this doesn't always hit the after market suppliers in time (I can't comment about yours though, but if it was a kit by Gates or similar I'd be well happy).
As a hand tensioning guide, with the engine turned in the usual direction of rotation, you should just be able to twist the belt to 90 degrees on its longest run.
A slack belt flaps and a tight one whines, I find.
When the job is done, can you start up with any of the belt covers off, just to see how things are?
John

 

[Peter.N.]

... after having rotated it a few times with a spanner first

 

[sooey]

Thanks John & Peter, when I did it last week the pump bearings did have a bit of play in them but they were far from collapse, and I renewed it then.
The belt kit I put on was a Continental or Contitech which came with specific instructions on setting the tensioner. I'm as sure as I can be that I did that spot on.
So with a new pump, new pulley, new belt and the tensioner set right there must be another reason why it jumped again.
I find these engines hard to work on but after much messing about I managed to get the tappet cover off to find the top part of the engine is really minging.
I'm just waiting for an eleven mm allen key socket to take the head off and see what's happened, but I'm thinking recon cylinder head at this point.

 

[sooey]

By the way Peter, I used that link you provided to get a manual. It does cover the 1.9 D so thanks again for that.

 

[Burnerman]

The belt jumped because the tensioner became goosed....what ever it was that caused that
The top of the engine will be full of black gungy oil sludge, more than likely.....I suppose a dropped valve is next?
Be lucky - no one needs this.
John

 

[sooey]

Update on this, I finally got round to taking the head off and it seems that I was wrong to assume the belt had jumped when it started clattering.
It now looks as though a piece or pieces of foreign metal have somehow been introduced in to the no 3 combustion chamber.
Loads of damage on the piston crown and cyl head with small pieces of metal embedded in both.
All valves look ok and have not been interfering with pistons.
Has anyone seen this kind of thing before on a diesel? where can this metal have come from?
The only thing I can think of is the injector falling apart internally and dropping it's guts into the chamber, is that possible?

 

[Burnerman]

Its not uncommon on modern diesels to have a sort of butterfly arrangement within the inlet manifold - but I don't know if your engine has this system, favoured by BMW and Vauxhall I believe.
Failing that, maybe the turbo has thrown something, although I wouldn't have thought that would have passed through the intercooler.
I've never heard of a self destructing injector
John

 

[sooey]

Cheers john, I'm thinking now that it caused more damage than I'd originally thought when the belt slipped because of the worn pulley.
I'm thinking along the lines of the valve being hit by the piston and straining the valve stem seat causing it to crack, this has then broken away and fell through into the chamber.
I'll take the valves out tomorrow to check, but I think that's what's happened.
New cyl head time I think. (should have changed that bleedin pump)

 

[Burnerman]

Do keep us up to date about this one.....I've never had a valve seat crack (they are made from stellite and as hard as hell) but I have had a valve guide chip when a valve has bent.
Not all heads have guides of course.
It sounds like an expensive job, this one - but usually the pistons don't seem to mind being impaled by foreign objects!
John

 

[peterperfection]

fck fck fck why oh why didn't I change that water pump. I knew I shoud've but I didn't.
It's just gone, and it's took the belt off.
The only good thing about it is it happened just as I started the engine, ran for a second or two then just died. So hopefully won't have done too much damage.
Let that be a lesson to all...change the feckin pump while your at it.

 

[peterperfection]

Time for a new motor soozi.
ALWAYS Change the waterpump and ALL aux belts when you undertake such work..

Contitech belts are pretty bomb proof.
I use the same on My A6 TDI

 

[sooey]

Back on the road.
I put another head on it and it seems to be running OK (famous last words), I didn't bother stripping the old head (too minging) but I'm sure it was the valve stem seat that had disintegrated, I dug some bits of it out of the piston, and you could just make out part of the curved face that the stem runs in.
I'm of a mind to keep this motor for a bit so I'll keep hold of the old head and may get it reconned.
As for you peterpizzpot, change the record. No one gives a fck what you've got or haven't got, especially the ones on here who know your posts and know you're a self confessed liar.

 

[Burnerman]

Hells bells thats quite something......!
So it seems that a piston hit a valve, which then destroyed its own seat, and the bits of which became embedded in a piston......yep, thats pretty much par for the course, and the valve usually gets mashed beyond recognition too.
The good bit (you could do with a good bit, I feel ) is that the piston is unlikely to be too upset so long as the damage is away from the edge, and there's no damage to the aluminium above the top piston ring.
10/10 for effort mate - thats one hell of a job done. Here's to many more miles on the tarmac.
John

 

[sooey]

Cheers burnerman, and thanks for the help and encouragement.
Funny enough the valve looked OK, must have been bent slightly obviously, piston was a bit the worse for wear but I reckon it should be alright.
These modern motors are a pita to work on though, and I served my time on minis, though I reckon if I did do this again it would be easier. Though I'd still have to dismantle half the motor to do it, it's just the way they're made.