Turbo seal

On or around Sat, 17 Dec 2005 11:40:56 +0000, Steve enlightened us thusly:

are they likely to be a problem?

The air outlet (into the engine) looks wet with oil. And something wrecked this engine (before the rebuild).

Steve

Turbo seals are not 'seals' in the commonly understood manner. They will leak air.

As Austin suggests thay are not likely to be a problem.

The most important thing is to make sure that there is oil at the turbo oil inlet at start up. Prime the turbo by injecting oil after disconnecting the oil feed hose. Then prime the entire engine before permitting firing to occur.

There was another thread entitled 'turbo priming' here last week.

That was mine too, before I found the oil in the air outlet side. Now I wonder if the engine ran away at some point.

Steve

There's wet and wet!

Do you know the actual history of the engine before the rebuild? What sort of damage was present.

There's probably not much you can do to check the turbo without dismantling it (which is not usually a good thing). Check for any damage to compressor and turbine blades. Is there any evidence of either wheel contacting the casing? Check end float and radial play of the rotating assembly. Any noises when rotated by hand? Oil in the compressor outlet can be the result of excessive crankcase pressure (turbo oil cannot drain back to sump as intended), restricted turbo oil drain (draining problem again), high vacuum at compressor inlet (restricted air cleaner?

- oil is sucked out).

If the oil is only on the air side of the turbo it's probably a good sign.

Thats the issue - I haven't enough experience in this area to know what is happening.

No history, 'twas "running", but rough as a bear's arse - The main damage was knackered pistons, cylinder scoring in 2 and 3 - the rings were intact, but the ring grooves from the top and second ring were broken vertically to the piston crown. The crowns were unburnt. The valve guides were knackered on 2 and 3, and barely on spec on 1 and 4.

The head was warped slighly.

The exhaust valve tappet adjuster on 2 was bent.

Just about every seal face had been gashed up with black silicone sealant, and the water pump pulley plate was warped.

Project pictures soon.

You don't mean dismounting the turbines though, do you ?

I can measure that to a 0.0001 of an inch if necessary, but have you any ideas what is "OK" and what is "buggered" ?

Arghhh. There were no blocked galleries when we checked them, but then the block itself was being pressurised by the knackered pots.

Yes, theres none on the exhaust side. Its very clean in there.

Thanks for your comments Dougal. I am just being paranoid, but then there is about 500 quid worth of rebore, reworked head, reworked cam bearings, and a eyewatering amount of parts from Richard at BeamEnds in it, I don't want to fsck it up on the first run ! Cheers

Steve

It is possible for the oil seals to fail and in a simple turbo engine this would be unremarkable but in an intercooled engine there is the possibility of the oil filling the intercooler up, depending on entry and exit positions. In such a case there would be little warning until a critical point when the oil starts to be pulled over into the inlet manifold with critical consequences. I would get an exchange turbo and would remove the intercooler and wash it out with a special cleaner. Genkleen was the name of a solvent cleaner available for this purpose at one time I think. It should be possible for you to replace seals in a turbo yourself but getting the parts might be difficult. If the engine is a high miler then a repair or exchange by one of the many specialists would be the best bet. An exchange will probably set you back £400+ though.

Huw