300 Tdi Rebuild

Goc3k said:

Forgot to reply earlier, but were the bits metallic / magnetic in the end? or seal material as suspected?

Had another thought earlier in the week as well, did you ever check in the top of FIP boost compensator for oil? Can't remember if it was mentioned before. That'll deffo be full of oil if the turbo is leaking

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All the bits were seal material apart from the one tiny piece.
No! I haven't looked in the top of the FIP. Looking forward to that.

Took the other three pistons out this morning. Rain stopped play before I could take the top off the FIP or take the turbo off completely. It's been lashing it down ever since.
Here are some piston pics from piston No2 onward. (piston No1 was posted above last week)

On this piston you can see a band of carbon build up down the side with nice straight edges
It looks like the carbon build up is allowing the piston skirt, between the rings, to brown/scorch.

Piston No3

There is carbon build up on 50% of this skirt (ie around this side)
This is the other side of piston No3

No carbon on this side and between the rings is less brown/scorched. Fairly normal I'd say.

Piston No4

Carbon distributed around the skirt on this one. You can see sections where the carbon has rubbed off or not built up. Thick carbon on the crown may have been protecting those strips?
Big end bearings don't look great for 30K miles (IIRC that's how many she's done since engine rebuild)
No1

No2

No3

No4

A bit of polishing on all of them and some radial scratches. Don't know what's been in there to cause the scratches. First recon turbo was very iffy. When I sent it back and told them it was carped they claimed they could see tiny metallic pieces when the took it apart. Claimed it was off the engine boring. They might have been making that up to excuse the carped turbo! The block was washed after machining.
Oil pressure valve held no rogue bits. The spring is 48mm long, so it has lost 20mm since I put it in. Unlikely to be the cause of the high pressure I noticed.

So, where is the carbon coming from? Burning oil coming in through the inlet manifold from the turbo? Or, burning oil that's coming up past the piston rings? Burning oil coming down the valve guides. They are worn, but I was advised that this wasn't an issue so long as new seals were put on.

Those shells looked well shagged for 30k miles, I might be totally mistaken though and it might completely normal for a 300tdi to do that ? Hopefully someone with more experience than I can comment.

Carbon down the piston skirt suggest a lot of blow-by ? But really ? on a freshly honed cylinder with new rings and pistons ? seems unlikely

I haven't got the foggiest what wrong with your engine but i'm interested to see what the problem is and after all the work you've done I'd have to assume you are too !

Have you done 30K since the rebuild?

Blimey time and mileage shirley does fly.

Cheers

windy81 said:

Those shells looked well shagged for 30k miles, I might be totally mistaken though and it might completely normal for a 300tdi to do that ? Hopefully someone with more experience than I can comment.

Carbon down the piston skirt suggest a lot of blow-by ? But really ? on a freshly honed cylinder with new rings and pistons ? seems unlikely

I haven't got the foggiest what wrong with your engine but i'm interested to see what the problem is and after all the work you've done I'd have to assume you are too !

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Aye, the shells don't look the best.
The turbo is passing oil in to the air inlet, I've not been convinced that the turbo seals leaking were the sole cause of the oil consumption though. starting to think it is now as honing looks ok.

neilly said:

Have you done 30K since the rebuild?

Blimey time and mileage shirley does fly.

Cheers

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Engine went about 170k it's done over 200k now
Mrs daily drive to work, so mileage soon clocks up.

Why didn't you just buy a brand new turbo just to see if it was the case ? mainly to avoid doing all the work you've done

windy81 said:

Why didn't you just buy a brand new turbo just to see if it was the case ? mainly to avoid doing all the work you've done

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Because I was told it was the honing and not the turbo. A new turbo is £500. If you haven't spent anything yet it doesn't sound very much. If you've all ready spent about £6k it's adding to a large amount, especially if you're told it's not that.

In for a penny in for a pound. Just, if it is the turbo, and you've done all that work I'd be gutted. Good time for a VNT upgrade
Best upgrade ever for an old Dino engine like the 300tdi. Transformed my 200tdi so I'll vouch for it.

So button it all up and install new turbo is the name of the game now ?

windy81 said:

In for a penny in for a pound. Just, if it is the turbo, and you've done all that work I'd be gutted. Good time for a VNT upgrade
Best upgrade ever for an old Dino engine like the 300tdi. Transformed my 200tdi so I'll vouch for it.

So button it all up and install new turbo is the name of the game now ?

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How much did your VGT cost?

Al2O3 said:

How much did your VGT cost?

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1k from Turbo Technics [<--click me] but I was 'all in' so to speak so went for it, as I'd done a load of other mods to the engine too. Cherry on the cake for me.
It has power any time now whenever I decide to peg it vs the bogged down std 200tdi scenario. Brilliant so it is.
If you were closer you'd be more than welcome to try it and see for yourself

Forgot to say I did pay 1k but they are a bit cheaper now than they were.

light polish on shells is probably o-k after 30k, but the scratches arent great - probs the shrapnel mentioned when they took the first turbo apart from the bearing chewing itself up, as it was tight. Wouldn't worry about carbon on the sides of the crown as long as the skirts themselves are clean, shows the rings are sealing well enough.

Time to nip out for a late night visit to the FIP if you ask me! Should be full of oil ontop of the compensator diaphragm and that'll string the turbo up red handed as the prime culprit. i'd check that before taking the turbo cartridge out for a look

Goc3k said:

light polish on shells is probably o-k after 30k, but the scratches arent great - probs the shrapnel mentioned when they took the first turbo apart from the bearing chewing itself up, as it was tight. Wouldn't worry about carbon on the sides of the crown as long as the skirts themselves are clean, shows the rings are sealing well enough.

Time to nip out for a late night visit to the FIP if you ask me! Should be full of oil ontop of the compensator diaphragm and that'll string the turbo up red handed as the prime culprit. i'd check that before taking the turbo cartridge out for a look

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I'll put new big end shells in when I put it back together.

Good point about the rings sealing well and so carbon not building up between the rings. That gives me more hope that it's not the honing!

Still lashing it down here, so haven't been back out. Didn't do a late night visit in the rain either However, because I knew no better at the time, I didn't take the top off the FIP after the run away 30K miles ago. So, oil in the top of the FIP could be from then or the current turbo

I've been looking back through past pictures and the old pistons were brown between the piston rings too, so I'm not so worried about my new ones in that respect.
Not a great picture.

The old pistons crowns were in much better nick, they just looked as though they had been painted satin black, nice and smooth with no carbon build up. Apart from piston No4 which was melting

Did you hold onto good old slightly melted piston No. 4 as a keepsake? Got to have a few trophies in the shed.

Even if you didn't clean the top of the pump out originally, it can be checked and cleaned now at least and will show results in only a few hundred miles at the rate you're using oil

Goc3k said:

Did you hold onto good old slightly melted piston No. 4 as a keepsake? Got to have a few trophies in the shed.

Even if you didn't clean the top of the pump out originally, it can be checked and cleaned now at least and will show results in only a few hundred miles at the rate you're using oil

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No, put it in recycling bin for some reason
Funeral and other things to do today. Might get top off FIP tomorrow if it's not raining.

@Goc3k

Just took the top off the FIP. Oil glugged out.




Of course I don't know if it's off original turbo, this turbo or both.

Spacer for EGE controller fell in half

a definitive result. I bet your glad you know whart the problem is

Al2O3 said:

No, put it in recycling bin for some reason

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Probably been made into a whole wedge of beer cans by now then!

Looks quite fresh that oil, would expect less if it had had 30k of new turbo to evaporate. Might be a good sign. You going to whack it all back together with new shells and see if any more builds up after cleaning it? Fair old bit of legwork been done over the last few weekends pulling it all apart it seems, fingers crossed this'll be it for a good 150k!

windy81 said:

a definitive result. I bet your glad you know whart the problem is

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I don't for sure, that's the problem. That oil could have been there from the runaway I had that carped the engine in the first place. I never touched the FIP when I rebuilt the engine. You live and learn.