Engine / Gearbox Removal

[Jim Haseltine]

I tried. I got the normal nut and three of the long nuts off eventually, two of which wound the studs out as well. The last 4 nuts I couldn't shift when the engine was in place but came out fairly easy once I'd dropped it and pulled it forwards. It's the same with some of the breather pipes and a couple of brackets - you can't get to them until the engine has been dropped around 6". Turbos are rebuilt but I'm still waiting for Audi to supply some of the sundries. Exhaust manifold to block gaskets were supplied by a Lamborghini specialist next day delivery at about 2/3rds of Audi's price (only saved the price of a couple of pints but it all counts).

My 'oil tray', wish I'd thought of using it before I dropped the oil pump as it's going to take months to clean where the car has been standing.

[c3nturi0n]

I tried. I got the normal nut and three of the long nuts off eventually, two of which wound the studs out as well. The last 4 nuts I couldn't shift when the engine was in place but came out fairly easy once I'd dropped it and pulled it forwards. It's the same with some of the breather pipes and a couple of brackets - you can't get to them until the engine has been dropped around 6". Turbos are rebuilt but I'm still waiting for Audi to supply some of the sundries. Exhaust manifold to block gaskets were supplied by a Lamborghini specialist next day delivery at about 2/3rds of Audi's price (only saved the price of a couple of pints but it all counts).

My 'oil tray', wish I'd thought of using it before I dropped the oil pump as it's going to take months to clean where the car has been standing.

great post Jim.

Mind me asking, who is working on your turbo's (e.g. rebuilding them)? and in addition, what prompted you to engage on this activity?


Rgds

[Jim Haseltine]

Mind me asking, who is working on your turbo's (e.g. rebuilding them)? and in addition, what prompted you to engage on this activity?

I've pretty much covered this in the Turbos - options? thread. Basically, just about every time I started the car I got a cloud of blue smoke - sometimes for a few seconds, other times it lasted for minutes, sometimes miles and the amount of oil used and/or dumped into the inter cooler pipes was prodigious to say the least (750ml in less than 2 weeks). It took me until I had one of the turbos apart before I could identify the the model and spec for certain and then I couldn't find anywhere that could supply replacement CHRAs so I got hold of a couple of rebuild kits and tackled them myself. My first attempt was so tight that the turbine would hardly turn which puzzled me until I found that I hadn't pressed the retainer plate (maybe not the technical term for it) fully home. A job for tonight or later this week is to find a way to get some flow through the manifold to ensure that they spin up now they're fully assembled.

[welwynnick]

My first attempt was so tight that the turbine would hardly turn which puzzled me until I found that I hadn't pressed the retainer plate (maybe not the technical term for it) fully home.

Every turbo rebuild procedure is emphatic that you should liberally fill the turbo with oil (through the oil inlet) so that it's properly lubricated at start-up.

When you do this, you should be able to spin the turbos round apparently without any friction whatsoever. When I did mine, holding them horizontally and full of oil, the turbo is effectively floating in oil and has no static friction, only viscous drag.

So when you spin the turbo, it should slow down fairly quickly (the journal clearance is tiny) but as it slows down the rate of deceleration slows down, so the turbo spins slower and slower and slower without appearing to ever stop.

It's a weird thing and very satisfying.

Nick

[Jim Haseltine]

I've used an engine rebuild lubricant which is pretty much like treacle so there's a hell of a lot of drag but should protect things until there's some oil flow - remember the engine has been drained down for over a month now. One thing I found is that the oil inlet banjo bolt has a sort of restrictor valve built into it which means that when the engine stops there's a head of oil which doesn't drain through the turbos so that there's an instant supply of oil when the engine restarts. In the turbo replacement procedure there is an instruction to fill the oil supply pipe before reconnecting it to the cylinder head.
Once I've got everything back together I'm going to turn the engine over a few times with the rpm sender on the bottom of the engine disconnected so the oil gets circulated before I try restarting it.

[Jim Haseltine]

Having nearly completed the task, I think that putting the everything back together is a worse job than taking it apart. Even having made notes and taken pics there have still been points where I've ended up hunting around to find things that had dropped down or lodged in awkward places when the engine went back into place. And of course there's always a nagging thought at the back of my head saying that I've missed a hose connection somewhere.
There's 5 litres of oil in it and I've pumped in 11 litres of coolant and now I'm leaving it to see if there's a pool of anything under it tomorrow morning.

[c3nturi0n]

Well done Jim.

So grand opening (aka start) ceremony is scheduled for tomorrow?

Cheers and all the best !

[Pinkfoot]

Good luck and well done

[Jim Haseltine]

So grand opening (aka start) ceremony is scheduled for tomorrow?

Ah, no. I'm waiting for a hose and until I get that it's a waste of time fitting the PCV breathers.
Tomorrow will be the rest of the oil & coolant, the PS fluid, torquing the drive shafts and fiddling about double checking stuff. Cleaning a few month's worth of rust off the brake discs would be an idea too.
Although it's been chucking it down here for the last couple of hours so my plan for leak checking has been washed out.

[Jim Haseltine]

There is a phrase that rhymes with 'clucking bell'. I didn't get around to adding anymore oil, so he car is still on stands with some bits & pieces still to be fitted and as mentioned above, has had 5 litres in it since last Saturday. Last night (Thursday, so 5 days) I noticed a small patch of clean oil under the car which on investigation I found to be very slowly draining from the front of the rh turbo down the outlet to the intercooler, even though the engine and hasn't been run.
I've been wracking my brain to try to work out why and now have a complicated theory but it might be way off.
There was, I believe, a modification made at some point to deal with smoke from the rh turbos which I believe (but may be wrong) inserted an oil reservoir in the rh turbo oil return line - something that hasn't been done to my car. One of my thoughts is that maybe this reservoir is there to absorb a volume of oil that gradually drains back to the pump from the oil tank when the engine isn't running. As fluids should find a level through a system and the oil tank is higher than the turbos I think that this level (without the additional reservoir) might well be above the centre line of the turbo shafts so there's a head of oil in them that can gradually leak past the seals. With me so far? Now, with only 5 litres instead of the 7 or so that I usually put in when changing the oil I wouldn't expect this level to be reached except for one thing - the system was pretty much completely dry, including the oil cooler and the cooler pipes which I'd estimate would hold a good couple of litres, possibly more - and I think still will be dry because the oil thermostat will be closed.

So, does that sound sensible or am I just clutching at straws?

[welwynnick]

According to SSP431, the turbo oil doesn't drain into the bottom of the engine like everything else (though I don't see what's wrong with that). The oil extraction pump has a port specifically for the turbos (not sure if its one port of two).

The complication is that in order to reduce the oil pump scavenging at high speed, air from the air cleaner is admitted to the oil return line. This is what the study guide says:

The turbochargers are supplied with oil from the oil pressure ports on the cylinder heads. The return oil does not return to the engine block as before, but is drawn off by a separate extraction pump. The suction pump is integrated directly in the oil pump module and pumps the extracted oil internally into the oil reservoir via the feed pump and the oil thermostat.

Flow control

At high engine speeds, the high suction capacity of the extraction pump is reduced by means of the intake air. The suction pump creates a so-called Venturi effect at the connection between the oil return pipe and the air pipe, whereby air is drawn out of the air filter and into the oil extraction flow. This air/oil mixture is fed internally into the oil reservoir by the feed pump, the elements again being separated inside the oil reservoir cyclone. The extraction pump has a high suction capacity due to the high engine speeds. Without volumetric flow control, the oil could be drawn off before reaching the lubrication point in the turbocharger.

It's a complicated beast isn't it?

Nick

[Jim Haseltine]

Complicated? It's beyond me sometimes.

Two extraction ports for the turbos but both on the left side of the pump. Not all the oil drains down but a lot does. Drive your car and then check the oil level is correct (following the procedure of waiting the correct time) and then don't drive it again for a day or so. Then before starting the engine put the dip stick - the oil will be way down. Start it, run it, recheck the level and it'll be correct again.
Adding the return line reservoir isn't simple 'cos they changed the design of it. The first ones were simply a two port (in/out) container inserted in the return line but then it was redesigned to move the air feed connection from the metal line near the turbo to feeding in to the reservoir. I'm figuring that when the engine is running the pump scavenges all the oil from it.

I'm going to have a chat with the RS techs at my local dealers tomorrow and pick their brains.
Added to this, I'm currently struggling to fit poly bushes to the roll bar links - what a pain. I have 1 fitted, the others seem to be much happier ricocheting around my garage.
Anyway, when I get home this evening I'm going to drain a load of the oil into a clean container and not fill it again until I'm in a position to run the engine.

[Jim Haseltine]

5 litres in, 4 out. All came out of the tank to pump pipe drain point, with all the other drains being dry as a bone.

[Jim Haseltine]

Added to this, I'm currently struggling to fit poly bushes to the roll bar links - what a pain. I have 1 fitted, the others seem to be much happier ricocheting around my garage.

After a week of a couple of hours each evening and a couple of hours this morning I got nowhere with the other 3 then got all of them in place in half an hour tonight.

[welwynnick]

Sometimes you have to stop and do something else, and come back to it later. I've been wrestling with an oil cooler leak for weeks. I fixed it three times and each time it leaked. Then a few minutes ago I fixed it again, started the engine, and no leak. Sometimes it goes well and sometimes it's a nightmare. That puts me off doing this for a living, as you have to be sure to get it right first time (only thing is, I don't think professional mechanics get it right first time either. The more I find out about cars and garages, the more I realise they're no better than me).

All the best Jim,

Nick