Thread: I brokeded it ... 97 300TDi engine

Originally Posted by shack

A "lean" state in a diesel will have no bad implications whatsoever, in fact it's the best possible state for them to run.

Rich however is another issue altogether, I have a feeling you are thinking of a petrol engine.

A melted piston top is a sign of overfilling, if it is only one, it is probably a dodgy injector.

Some rotary injector pumps can start to overfuel as they get older/wear.

In one of your pictures though the damage looks to be collision damage not heat.

If the lash caps haven't been replaced, it's quite possible one broke, then got pushed down by the rocker and released the collet on that valve.

Have you found them all?

If they are all ok, it could also have been a failure caused by the rocker being massively out of adjustment.

You may also never know what caused it.

Thanks Shack,

Yup I am thinking of Spark ignition engine, I know very little about oil burners.

If it was over fuelling wouldn't you get black smoke?

Either way im learning on this old girl and will be taking time on a stripdown and hoping to get away with a head, piston and conrod n some new shells on the crank obviously with new parts on the valve and rocker assembly.

The collets are all intact based on my brief inspection but I might Pop out and take a pic or 2 of the top of the head.

before the rocker assy was removed the rockers were all tight bar the dud cylinder but when the push rods were pulled from the block they were all clicked in their seats but again im new at this oil burner stuff.

Either way theres a bit of stuff to check and replace with the Pump and injectors to make sure it doesnt grenade again.

Originally Posted by tony66_au

Thanks Shack,

Yup I am thinking of Spark ignition engine, I know very little about oil burners.

If it was over fuelling wouldn't you get black smoke?

Either way im learning on this old girl and will be taking time on a stripdown and hoping to get away with a head, piston and conrod n some new shells on the crank obviously with new parts on the valve and rocker assembly.

The collets are all intact based on my brief inspection but I might Pop out and take a pic or 2 of the top of the head.

before the rocker assy was removed the rockers were all tight bar the dud cylinder but when the push rods were pulled from the block they were all clicked in their seats but again im new at this oil burner stuff.

Either way theres a bit of stuff to check and replace with the Pump and injectors to make sure it doesnt grenade again.

It will blow black smoke if it's overfuelling, the amount depends on how much it's overfuelling.

I very much doubt that injectors or injector pump has anything to do with your failure, it looks to be simply a mechanical failure on that valve.

What are the lash caps like?

If the collets look ok, where did you find the 2 that were off of the dropped valve?

Originally Posted by shack

If the collets look ok, where did you find the 2 that were off of the dropped valve?

Post #10 makes it sound like the head has come off the stem, and that the stem and collets were still in place.

All the best with it Tony.

(another) Tony

Originally Posted by TonyC

Post #10 makes it sound like the head has come off the stem, and that the stem and collets were still in place.

All the best with it Tony.

(another) Tony

Ok thanks, I must have misunderstood.

So that is possibly from a quality control issue on that valve.


The other possibility is that many (particularly early) 300tdi engines suffered from snapped or damaged timing belts due to incorrect tensioning and a lack of retaining guides on the timing gears.

This was rectified with an update kit.

If the belt has previously broken, the valves and pistons will have hit, this will leave a mark on the piston crown, you can usually get away with replacing the broken rockers and bent push rods.

The catch is that it could also have damaged any of the valves that hit.

I'm not saying this is what has happened, just that it could have.

Originally Posted by shack

It will blow black smoke if it's overfuelling, the amount depends on how much it's overfuelling.

I very much doubt that injectors or injector pump has anything to do with your failure, it looks to be simply a mechanical failure on that valve.

What are the lash caps like?

If the collets look ok, where did you find the 2 that were off of the dropped valve?

The Collets were still in place and apart from sitting about 1/3 of an inch higher it looks normal.

Originally Posted by shack

Ok thanks, I must have misunderstood.

So that is possibly from a quality control issue on that valve.


The other possibility is that many (particularly early) 300tdi engines suffered from snapped or damaged timing belts due to incorrect tensioning and a lack of retaining guides on the timing gears.

This was rectified with an update kit.

If the belt has previously broken, the valves and pistons will have hit, this will leave a mark on the piston crown, you can usually get away with replacing the broken rockers and bent push rods.

The catch is that it could also have damaged any of the valves that hit.

I'm not saying this is what has happened, just that it could have.

Well initially that's what I thought the issue was, Timing belt or component failure as my initial inspection with the rocker cover removed showed it was all seemingly okay, nothing tight or bound and everything in place and id already received the Late Timing kit hoping it was a simple fix of someone else's half hearted work but as the timing marks lined up and it was all intact we went on to dig deeper and found the issue when the rocker assembly came off and saw the valve stem sitting higher than the rest along with the Injector well and truly stuck in the head and the glow plug coming apart as we removed it to try get a bore scope to check the thing.
At that point I knew it was Head time............

Originally Posted by tony66_au

Well initially that's what I thought the issue was, Timing belt or component failure as my initial inspection with the rocker cover removed showed it was all seemingly okay, nothing tight or bound and everything in place and id already received the Late Timing kit hoping it was a simple fix of someone else's half hearted work but as the timing marks lined up and it was all intact we went on to dig deeper and found the issue when the rocker assembly came off and saw the valve stem sitting higher than the rest along with the Injector well and truly stuck in the head and the glow plug coming apart as we removed it to try get a bore scope to check the thing.
At that point I knew it was Head time............

I can't quite see from the pic, but are the lash caps ok? As in are they still on top of the valve or is that the top of the valve stem I can see?

By the by, its a late Post MA Vin MF7VA729390 and the engine number 18L19944A I believe corresponds with the Vin and she's a tad over 480k on the clock.

The heads been off the thing before and the Gasket wasn't leaking plus there were no leaks and the intake and exhaust ports were surprisingly clean and even nor were there any leaks behind the timing cover although it is due for a new one.

I haven't dumped the oil yet but it was reasonably clean still and was changed with filter about a month before I bought the Disco although I had planned to change it again with a genuine filter and do the Breather at the same time as I fitted the Pyro and turned the fuel up to remove the factory fuel lag setting in the pump although I will keep it clean of black smoke (Pet hate).

The when? It'll be a while and with qualified help.
Had a TIA (Stroke) 7 Months ago and there's bits missing memory and skills wise which is annoying but I figure a nice project is what the Doctor ordered and when complete the old girl should give me another half million km with care and attention.

Other things that need love is the R380 (I have one to go in) and a transfer case refurb as it leaks and im sick of topping it up with 80/90 and the R380 has gear oil in it as well as being worn and id like to go back to ATF with the replacement as that's what's in it and the old box is a bit niggardly on cold mornings with the 2-3 shift although its still a delight compared to the LT94 4 speed combo in my RRC :-)

All in all?
I'm enjoying the Disco, its simple and effective plus so much like the Classic Rangie in so many ways I feel at home driving her.