Did You know this 'Can' happen to a diesel (Death by oil)

Sorry I still haven't had time to read all posts, basically 1st and last page only.

I suspect the overfilling with oil is a red herring. I have seen 300 Tdi reving there tits off while standing nearly vertical trying to climb dry waterfalls also nearly flipping over tail or nose with no affect from the oil concentrated at one end of the sump.

When the piston was holed the sump might pressurise enough to blow considerable oil from the crankcase vent line into the turbo inlet, then to the inlet manifold leading to runaway and residue in the inlet system.

I can't help thinking faulty injector, and after my previous post also considered a faulty oil cooling jet to #2 piston as Dave has posted.

What I am also thinking.

An EGT gauge post turbo won't show up one cylinder overfuelling.

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Originally Posted by Dougal

What I am also thinking.

An EGT gauge post turbo won't show up one cylinder overfuelling.

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Depends how much it is overfuelling - but probably not under most conditions.

It is strange that there are 2 HS2.8's mentioned in this thread which have "run away" - yet I have not heard of it in (much more plentiful) 300 Tdis.

On a slight tangent - you may find this interesting:
http://www.aulro.com/afvb/showthread...12#post1630012

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Originally Posted by wrinklearthur

Thanks Serge, the info in your previous post was what I was after .


I had a interesting read of that thread and well, that kept me quiet for a while.
I'm sorry Serge, but the seat of the pants dyno you used, in hindsight wasn't the way to go and I am thinking the initial damage ( No 2 injector ) was done even earlier when you had the trouble with the arm that faulted, to what extent that damage was done, is lost now with the motor run away episode.

Where I posted about a excessive amount of combustible material being fed into the motor, still stands.
Air boost pressure didn't rise enough to burn the fuel correctly, causing the piston to melt with the increased temperature.
It's debatable whether the runaway started with the oil being picked up and fed into the induction of the motor, or over fuelling by that injector being damaged and feeding a large amount of diesel directly into that cylinder.
.

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not sure where you are coming from with regards to the "seat-pants-dyno". I only used that and the term as a gauge so to speak. When the actuator rod pin fianlly broke off, it was VERY noticable. Not only a fair power loss, But it co-incided with an increase in boost/turbo whistle noise. I could "feel" straight away it was down on power. So after a quick look and not finding anything obvious, I left it as it was going to the mechanic in 2 days anyway. I drove it very little between then (say 3km) Then to said mechanics. Then home via truck parts and then finding the problem was not resolved, got about fixing it myself. Yes, about 30-40km in total from when it failed.

Now in saying that, there is evidence that it did not just fail (from a perfect working condition) The hole in the actuator rod was "wollowed" out. So even if the pin wa still perfectly in place, there would be some discrepency in its working due to the actuator having to travel further to take up the "slack" in the hole before it started to adjust the vanes.

So maybe that was the start of it, then the 5 days and 30-40km of driving without the vanes moving at all was the big nail (remember I noted double normal EGT's but still under a dangerous max of 550 post turbo.., or so I thought :()...then with piston melt, blow by was pressurizing the crankcase and forcing the now over filled oil up the breather (there is pretty good evidence of that) and into the intake for it to feed on....

just a WAG

Quote:

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Originally Posted by isuzurover

Depends how much it is overfuelling - but probably not under most conditions.

It is strange that there are 2 HS2.8's mentioned in this thread which have "run away" - yet I have not heard of it in (much more plentiful) 300 Tdis.

On a slight tangent - you may find this interesting:
http://www.aulro.com/afvb/showthread...12#post1630012

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Ben and Dougal, Im wondering if your points re the placement of EGT sensor probe quite relivent. Lets say that at a given normal rpm/load that the post turbo EGT be 200, could we say that each cylinder was 50 (4x50). Now turbo is failing and due to the physical design of intake #2 gets the majority of problem. Now Post turbo EGTfor the same rpm/load shows 400, but really #1, #3 and #4 are say 70 and #2 is 120....so it suffers the most and starts to fail.

these numbers are just used as an example and yes it is probably way to simplified.....

Just a stab in the dark

Ben, I looked at your link, but I think its in Chinese :D

regarding the 2 2.8tgvs running away, have you got the numbers on % of idiots that own the 2.8tgv vs the 300tdi.........:eek:

btw Im not sure that #2 had actually got a hole in it?? but am assuming with the ring and bore damage that pressure could have got past these to pressurize the crankcase....

I went back to the workshop today to pick up the turbo, Injection pump and injectors. I have dropped the IP and injectors off to be tested. Turbo will be taken to Brisbane on Monday for a going over. Nothing else major found yet...mechanic has said that most stuff is looking very good.

here are a couple of pics:

timing gears, only because the mechanic says they are so much nicer than the 300tdi type.

Cam shaft: he thinks it in very good condition. (no wear)

So, to those that know, what parts would you replace as a matter of good practice in a engine rebuild?

Im not talking about what is, or may be broken. Rather what parts you just dont use again and replace with new.

I need to order some International specific stuff and only want to do 1 order if possible.

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Originally Posted by uninformed

given normal rpm/load that the post turbo EGT be 200, could we say that each cylinder was 50 (4x50).

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It doesn't work like that. The EGT is an average of the individual combustion chamber output temperatures, not an accumulation.

I must have missed something about the position of the EGT probe. Isn't common perception is that it should be pre turbo?

Please, correct my if I'm wrong anyone.


James