4.2TDi sudden death

[Joe2.0E]

Thats a disaster, would a used engine be an option.
It’s likely to be cheaper than rebuilding yours.

[erubus]

Originally Posted by Joe2.0E

Thats a disaster, would a used engine be an option.
It’s likely to be cheaper than rebuilding yours.

The cheapest engine I've seen so far was £3'500!

I've decided I'm going to rebuild the engine. I've got a (horrendous) Peugeot 407 2.0hdi to run about in just now. It cost very little which was handy given that's how much money I had! It's the worst handling car I've ever driven but so far it seems to only need to be shown fuel to run... Which is nice. Going to need a timing belt etc though as there is no history with it.

My plan with the A8 is to turn it round in my work shop first off. Easier said than done due to slopes and available turning space and a generally big car.

Once it's pointing towards the door I'll get it up as high as possible on axle stands and disconnect everything underneath then disconnect everything from the top and lower it down onto a trolley of some sort which I'll need to make.

Once the engine/transmission/subframe combo is on the ground I'll lift the front of the car as high as possible with the front loader of the tractor and hopefully have enough room to roll the engine out to the side for stripping down.

I've found complete febi timing chain and tensioner kits for £550 online and should be able to get them cheaper through my dad. Valves cost about £7 each. Guides are about the same.

The problem would be if the head itself is cracked, or if pistons are cracked. Rockers and hydraulic tappets could also be broken and hard to source.

That's all an unknown until the engine is out though which will be challenging enough! I'll keep you all posted with plenty of pics.

Gill

[MikkiJayne]

I assume technical data for this venture is either in the tech dump or online somewhere, but if not ping me and I'll look up what I can

A pallet truck is very handy for pulling the drivetrain free once it's on the floor.

[Mechcanico Lee]

Don’t take engine out yet !!
You say it does not sound any different cranking over ? This is indicative of it not bending valves , you can hear the engine off when you crank it if it has bent valves

Seen on loads of diesels with broken cam belts sometimes it just breaks rocker arms or if it’s hollow cams knocks the lobes round .

Remove injectors and rocker cover and inspect , it may be rockers or buckets, im not sure .

I realise that if it’s an engine out job to do the chains , well so be it ....but have a look first , is the toothed segment that the cam sensor picks up off part of cam or a separate bolt of section .

Have a look first before you commit to dropping the lump out

[snapdragon]

Terrible news and you are expecting the worst but maybe you need to hope for the best and do a little digging. If you remove the screws around the black // shaped cover that the injector is inserted through, you can prize them up and rotate it 90˚ and see the valve gear. You can do 1 to 4 depending how much you want to see and then use your endoscope and get someone to crank. See if the rockers are broken which thankfully seem like mechanical 'fuses' on these protecting the other stuff.

[erubus]

From what I've seen, the lobe that the cam sensor reads is cast in one part with the rest of the camshaft. It has roller rockers supported on hydraulic tappets so yeah, they could have gone rather than the valves but it's still an engine out job to change the chains anyway.

That's interesting about the covers round the injectors. I had assumed that was how the injectors were clamped in and didn't want to undo them and risk unseating an injector and dropping a sealing washer into a cylinder.

The engine sounds normal when cranking but with the microphone on the endoscope inside the engine there is a distinct ticking noise which could well be pistons hitting valves. I'll try and post the vids. Will post the vids from down into the sprocket housings too.

If I can avoid dropping the engine that would be amazing and I'll go down any avenue that helps!

[snapdragon]

Originally Posted by erubus

That's interesting about the covers round the injectors. I had assumed that was how the injectors were clamped in and didn't want to undo them and risk unseating an injector and dropping a sealing washer into a cylinder.

After you rotate the covers, it exposes two larger nuts holding down a ~1CM thick spring clamp and it is these that hold the injectors in, the spring clamps, nuts and the seals on the injector bodies should be replaced upon refitting. The covers sometimes weep too (after refitting) at the rubber seals that seal against the valve cover.

[erubus]

She, good news then. That will allow me to get rid of that final 0.5% of doubt and might give some insight into the damage in the head. Thanks

[Joe2.0E]

Brand new cylinder heads available for €700 on eBay.de
Example attached, obviously dependent on your engine code.

[erubus]

Originally Posted by Joe2.0E

Brand new cylinder heads available for €700 on eBay.de
Example attached, obviously dependent on your engine code.

Ouch! better than i imagined mind you! Now I realise that is a right hand bank head in your pic but if you look at the lower camshaft in the pic, right at the left hand side you can see a little semi-circular cutout. That is exactly what I can see through the cam sensor hole.