Only running on 3

[chrisw]

Ok, Going up the Gateway Bridge this morning a bit of a louder knock (than normal) develops and the presence of blue smoke is noted out the rear (300tdi 130 defender). Get down to the tolls and the things smoking heap's and running very rough, smoke settles down a bit when acelerating and at higher revs. Get home and startings no drama, back off the injectors in turn and sure enough nothing happens on #3. Swap the injectors around- Still #3 no change in rev's. No broken valve springs or obvious signs of dammage to the rockers - although is hard to tell with the oil spraying around. So im picking sticking or burn't valve or perhaps crook rings. Blow by doesn't feel excessive on the breather but thats subjective I guess. Either way the head's got to come off so thats whats happening now. However any other idea's and tips greatfully accepted.
Cheers
chrisw

1996 130 defender
4-71 Detroit
6-71 Detroit
16V92 Detroit

[Trout]

Before you pull the head off take the injectors out and have a close look. I had similar symptons. Turned out to be an injector that had broken and dropped bits inside the cylinder. You may still have to take the head off to retreave the broken bits. Mine made a loud expensive sounding noises that I thought was a dropped valve.

[Blknight.aus]

first things first, is the pump firing that injector? crack the union with the engine running and then crack #2 and make sure that they are both dribbling the same amount and at about the same pressure.

next warm the engine up stop it and pull the #3 glow plug. turn the engine over by hand untill #3 is on its compression stroke then put it in gear.
remove the air filter
remove the dipstick +replace the rocker cover if you had to remove it to work out the compression stroke
remove the coolant expansion tank lid
have someone listen to the exhaust (a film of soapy water over the tail pipe works really well)

Now put compressed air into the glow plug hole

if the air comes out the air box youve done the inlet valve
out the exhuast the exhaust valve
out the coolant expanstion tank and thats the head/gasket
and out the dipstick tube and its the crown or the rings.

[chrisw]

Well the head came off and #3 exhaust has a chunk of the side which of course is stuck in the bottom of the head - probably the best place for it considering. Pushed up there by the piston. It seems a but odd to me that the side of the valve has gone- unless the valve and the piston were in the wrong place at the wrong time- which makes me wonder if the timing belt (which I may have been a bit lax with) has slipped. But there is no other damage, I did drive 30ks with it missing and it still started easy... so mi no save...

So a new head (No second hand ones around), another piston, new rings + a timing belt = $2k in parts...

[chrisw]

Well the head came off and #3 exhaust has a chunk of the side which of course is stuck in the bottom of the head - probably the best place for it considering. Pushed up there by the piston. It seems a but odd to me that the side of the valve has gone- unless the valve and the piston were in the wrong place at the wrong time- which makes me wonder if the timing belt (which I may have been a bit lax with) has slipped. But there is no other damage, I did drive 30ks with it missing and it still started easy... so mi no save...

So a new head (No second hand ones around), another piston, new rings + a timing belt = $2k in parts...

[rick130]

Ouch.

How many km ?
It'll be interesting to see if there is any belt damage when you get to the front of the engine, or it was just a fatigued/dodgy exhaust valve.

Curious, has the fueling been increased at all ?

[chrisw]

280K. The local guru's said that it was unusual but they had seen it before, pretty much the same. The timing belt is in good nick and all the marks line up. So its just down to fatigue/overheating or something. I wonder if a dirty injector with a bad spray pattern could cause uneven heat/overheating of the valve. However they tell me that the injectors are throwaways and cannot be checked because they are two stage...

[Blknight.aus]

usually it will be carbon loading that causes it..

and dicey injectors can do it.

the injectors can be checked and adjusted but its a very fine and time consuming art requiring expensive equipment.

most places will do a basic pattern/dribble check and reccomend replacement.

rule of thumb for me is...

your injectors are good to 100K Km and should be pulled and checked, probabley replaced at that distance and not on time...