Bolts for turbo and manifolds, was Turbo cooling fan?

Post by **Macflai** » 18 Jul 2007, 21:59

Well it is supposed if the oil gets hot then will be more fluid and still lubricating the turbo bearings, and these bearings are ready for high rpm and high temps... is that correct?

Post by **andysimpson** » 18 Jul 2007, 22:03

Macflai wrote:Well it is supposed if the oil gets hot then will be more fluid and still lubricating the turbo bearings, and these bearings are ready for high rpm and high temps... is that correct?

Its not the bearing thats the problem its the oil it simply can't sit in such a hot housing, its fine when flowing.

Post by **andysimpson** » 18 Jul 2007, 22:07

Simon Baxter wrote:
andysimpson wrote:Turbos on almost every engine has a drain at 6 o clock so all the runs out and does not get baked, on a t25 the drain is about half past four and oil gets trapped in the turbo where it bakes and turns to a solid eventually restricting oil flow and turbo dies. Even letting it idle for 10 mins your still looking at over 100c turbo temp.

I often wonder about using a banjo bolt and a flexy hose to feed the turbo and try to get it to sit with the oil feed and returns closer to the vertical.

Infact, when i actually get time to build that AAZ up i may just do that.

I had similar ideas when i first did my td, it would work really well for a 2wd but would be problems on a syncro with the clearance between skid plate and trubo return pipe i had problems with the oil return pipe on mine at the stupid angle, it would of been worse at 6 o clock.

Post by **Macflai** » 18 Jul 2007, 22:25

Can you draw a solution?

Post by **HarryMann** » 18 Jul 2007, 22:40

Yes, the problem is 'coking' of the oil... carbon formation and thick deposits in the turbo CHRA

Despite not having a blower cooler nor oil cooler, and cooking the last engine when head gasket went, saw no evidence of 'coking' when I rebuilt the turbo, with very cheap diesel oil - but of course, very limted mileage (~5,000)

A fully synthetic oil will not coke as badly, they weren't avaialble for diesels in 1987/1990 AFAIK...

If you're sensible, and knock off the full throttle, full boost stuff 5 minutes from home, use a good semi or fully syntehtic oil, I reckon from that evidence you'll be OK, Mr MacFlai

I'm not running a turbo cooler now, and because I've got a similar problem to you, crappy KKK CHRA doesn't seal the turbine housing properly (they rust away as yours did?), might well be taking it off soon, so will let you know what I find if I strip it again.

I would not expect to find oil coking products inside...

PS. Cooking is what chefs do - heat things up..
Coking is what half of London do - stick powder up their noses

Nah, seriously Mac, it's a thick hard to remove sludge 'coke'

Simon's 'banjo' idea is a good one... DIY kits please Simon, would you like a pre-order deposit now?

Post by **andysimpson** » 18 Jul 2007, 22:46

Alot is down to oil quality, when 3b passats and audi a4 1.8 turbos first came out most were bought by lease companys, when in for service they would not pay for recommended oil so got nasty cheap stuff, eventually the oil baked in the oil feed pipe and seized the turbo, all cars that had proper oil were ok. VW did eventually come up with a fix by re routing a pipe but with proper oils this was not needed.

Post by **andysimpson** » 18 Jul 2007, 22:51

HarryMann wrote: Simon's 'banjo' idea is a good one... DIY kits please Simon, would you like a pre-order deposit now?

It can't work on a syncro well not with a decent oil flow out, also have the problem of sump level and turbo are still at same height, depending on parking angle sump level could be higher than turbo return. The only proper fix would be to relocate the turbo higher.

Post by **HarryMann** » 18 Jul 2007, 22:55

AH! Good story as I've read about always checking your trubo oil-feed pipes for 'coking' blockages... and that raises the point about the turbo feed line on the t25 then...

A steel oil-feed pipe VERY close to the exhaust manifold on the way into the turbo, though oil is moving at fair rate through it (but NOT when the engine is off as you both say)...

That's one reason, failing to shiled the pipe last time, I made up those stainless exhaust manifold heat shields... goodness knows what the temperature is inside that cocoon, but at least it's not radiating straight at the turbo bearing assembly, the oil pipe, or for effcieincy, the compressor

PS. Cleaned my oil feed pipe out during last rebuild, did not find evidence of sludge or any coke in it... despite that £5 litre non turbo-rated 20-50 diesel oil from GSF.

Have you checked your oil-feed pipe Mr Macflai... ? Worth rinsing it through and wiggling a wire down it

Post by **HarryMann** » 18 Jul 2007, 23:02

The only proper fix would be to relocate the turbo higher.

After much thought and sketching angles and things, head scratching,

ideas of float pipes in sump etc.

... came to the same conclusion. Turbo must be higher!

I bet they didn't even think it would survive 10,000 miles until they tested it and found it would work... every turbr book says that low design won't work...
I'm now only getting oil run-on under the most severe of circumstances and much milder when it does happen... can't quite beieve it myself, conslusion... either the windage tray in sump OR the new seals in the turbo. But I'm

about that one!

Website · Post by **syncrosimon** » 19 Jul 2007, 11:31

Just love my 2.1dj. !!!!

Simple is best. (sometimes)
Just had such a great drive from London down the A303, that extra fuel consumptions so worth the smile factor. (much less than a tenner I bet) It's quite amazing the speed these lumps will go.

P.S. Saw a very nice looking white double cab syncro with canopy or something on the back at around 1000am near Ascot en route to Legoland wednesday morning.

Clive it never fails to astound me on your knowledge of the diesel engine and all things syncro. I love to read all your post, but understand them, well I dont Know.

Simon.

Post by **Macflai** » 19 Jul 2007, 13:01

Well, the problem I had was this one... typical broken bolt...

http://es.youtube.com/watch?v=f8l73bWTXPI

Post by **andysimpson** » 19 Jul 2007, 14:08

HarryMann wrote:AH! Good story as I've read about always checking your trubo oil-feed pipes for 'coking' blockages... and that raises the point about the turbo feed line on the t25 then...

A steel oil-feed pipe VERY close to the exhaust manifold on the way into the turbo, though oil is moving at fair rate through it (but NOT when the engine is off as you both say)...

That's one reason, failing to shiled the pipe last time, I made up those stainless exhaust manifold heat shields... goodness knows what the temperature is inside that cocoon, but at least it's not radiating straight at the turbo bearing assembly, the oil pipe, or for effcieincy, the compressor

PS. Cleaned my oil feed pipe out during last rebuild, did not find evidence of sludge or any coke in it... despite that £5 litre non turbo-rated 20-50 diesel oil from GSF.

Have you checked your oil-feed pipe Mr Macflai... ? Worth rinsing it through and wiggling a wire down it

Coked oil feed pipes happens more with flat running pipes, the t25 is downhill into turbo so the hot oil should drain away quickly.

Post by **HarryMann** » 19 Jul 2007, 14:10

Even without the broken bolt, those KKK's have such a naff cast ledge to locate the turbine section onto the bearing housing, they can give trouble anyway... mine is, very annoyed with it

Simon, Any knowledge I might have has usually been earnt with tears, fits or tantrums or just been stolen from others - much easier

Coked oil feed pipes happens more with flat running pipes, the t25 is downhill into turbo so the hot oil should drain away quickly.

Right, so it certainly feeds in nicely when upright, so maybe best to not park like this immediately after a long blast up the motorway...

[img:640:480]http://www.club80-90syncro.co.uk/pics/D ... cn0917.jpg[/img]

... when the supply to the turbo tends to be from both ends!

Mind you, a very daft piece of driving led to that rare angle

Post by **Macflai** » 19 Jul 2007, 14:18

http://www.aa1car.com/library/turbo_repair.htm

Post by **andysimpson** » 19 Jul 2007, 18:15

Centre sections rarely come loose on diesels because of low egt's, more common on petrols so a diesel coming loose is a sign of high egt or sudden temperature changes which they are prone to on t3 because of low down postion of turbo, go through a big puddle and turbo will cool to quick, different bits cool at different rates and things distort.