DiegoR

Hello Rennlisters,

not long ago I rebuilded (preventive service) my K24's with a 360º degree bearing and stepped rings to get better seal. All went good and the shafts/compressors were balanced. I even was in the turbo shop when they did all this and took away the turbos the same day I stoped by them (I wathced all the procesess)

I did service the car, drained the 10w-60 oil and filled up the V-Twin 20w-50 Mobil. After all, the car fird up and all was good. Took it for a spin, it boosted perfect, no smoke, no oil leaks, no nothing.

Car rested for about 2-3 weeks and then I took it for a spin, noticed it didn't smoke anymore at the tailipes like it used to do when is stopped too much time as many other 993tt's out there that suffer from this condition.

I garaged the Porsche again. Went back to the car after 3-4 weeks to take it for a spin but before I got in, noticed the rear left portion (belowthe LH muffler) some oil on the floor.....strange!

Decided to start it and the tailpipe smoke was huge and wouldn't stop, BUT only the LEFT side will smoke as a result from the RIGHT SIDE turbocharger. Right side tailipe wasn't smoking at all, was perfect.

Then I lifted the car and found the culprit. Right turbo was dry the compressor housing but the turbine housing was with oil , as well the whole right side exhaust including the CAT inside, a nice new bath of oil was covered and Left turbo is dry at the turbine side, but compressor side had a ton of oil in the intake pipe (very bad).

I'm scratching my head right now as what it could be the cause? I took off the metal return oil pipes and they were free of flow, installed them back to the scavenage pump and I tried to push some air to each pipe (with the mouth) and found the Left side will flow a bit better vs right side that needed more effort to push the air, however both return oil lines exhibited some restriction to pump some air with the mouth (starnge test but I just wanted to give a try) and wouldn't flow freely. (keep in mind the rear cover that is actually the scavenage pump had to be taken off to be able to change the timing chain gasket seal while servicing the car).

So the question is, would be the return lines/scavenage pump the culprit of this situation? Shoudl flow air free with out any major restriction through the scavenage pump or is normal to have some mid/heavy restriction while pumping some air inside (again with only the mouth and huge lungs) ??

Photos

Oil return pipe/lines turned backwards and testing the flow




Any help is very appreciated.

-Diego

Kevin

Send your right side turbo back in to check the rebuild.. If they really installed a stepped gap ring, you shouldn't see the wet turbine.

DiegoR

Hi Kevin,

thanks for yor reply. Tha's what I'm thinking as well, but the left turbocharger, the HUGE and massive leak in the compressor housing is something really weird. But taking the turbos myself and go back to the turboshopp where I got them assambled/overhauled I would like to know more about the return lines how restricted are when the engine is OFF you try to blow through it and if it's normal to sense some mid/high resistance...this is something I keep thinking if could be the culprit or not.

rlme36

You may want to purchase the upgraded lines from Kevin. No affiliation just a happy client. Just saying can't hurt and is the right solution that the factory adopted for later iterations.

Rob

Kevin

How are you going to blow thru a line that is connected to a 3 geared scavenge pump?

When I see that much oil coming out of the turbine wheel/turbine housing>90% of the time we have a breached turbine seal. If the oil was pouring out of the passenger inlet vs the drivers side, the diagnostics would be different.

Another two questions..

1) Where is your oil level when the temp is pointing at 9:00

2) What oil filter is on the engine right now?

ronnie993tt

Hint: Above 1/2 and Mahle are the wrong answers............

DiegoR

Hi Kevin,

right side turbocharger seems to be something related to the turbine seal you mentioned before, so I'm taking it to the turbo shop to get a inspection, hopefully we can find something wrong there.

But the left turbocharger worrie me a lot...there was excesive oil in the compressor housing. I couldn't see much inside of the intake pipe to see if that could come "somehow" from the top piping but it was dry where is bend the tube and go up (can't think how oil can get in there except from the turbo oil feed line).

Answering your questions:

1) Where is your oil level when the temp is pointing at 9:00

I really can't remember exactly, but when I drained the almost new Edge10w-60 in favor of the VTwin20w-50 oil I didn't change the pretty much brand new oil filters because I wanted to "wash" the previous oil with the new one, run for a bit and drain again and install new filters and new 20w-50 again. When it was at normal temp ( I think it was a 9:00 the needle) I checked the dipstick and it was at the middle of both marks

2) What oil filter is on the engine right now?

Always genuine Porsche oil filters, never aftermarket. I read few threads regarding how important was to use genuine oil filters in these cars. I have a brand new set of oil filters ready to go with the new VTwin 20w-50 but found this problem of leak.



-Diego

DiegoR

So I installed back the turbos, didn'tfind anything wrong with them. Cleaned all and then I checked my recently engine oil change I made, level on the dipstick was over the top mark of the machined section. So I kept draining the oil in small quantities until it was left at arround 3/4 mark of the machined section of the dipstick. I think all in all, was added like 1/4 over the max allowed.

Could bee this the main problem? Overfill. So far after few runs and all in all seems to be pretty much dry, no smoke whatsoever and nothing wrong from what I can tell.

Mike J

Keep your oil level, with the car fully warmed up and idling on a level surface, maximum 1/3 up between the marks on the dipstick. There is a lot of oil in the system, so you can run the oil lower than that even with no impacts, and that allows lots of room for the oil to expand when it gets hot. I keep mine between the bottom mark and 1/3 up.

An oil change, with both filters changed, draining the tank while hot, case and turbo reservoirs, and dropping the main oil feed line to the engine, should take about 9.5 - 10 litres fill to hit that spot. If you are over the "machined section" (assuming you mean the section between the two marks on the dipstick), that is an issue for sure, you can see smoking happen, but not sure if it would soak one of the turbo's.

Not sure what "1/4" over the maximum allowed is - its 1.5 litres between the marks on the stick, so that would be possibly 1/2 to a full litre over - yes too much!

Cheers,

Mike

zweistein

Usually the left turbo is wet after the car was sitting a long time. No need to rebuild anything,it is just a slow backflow of oil from the carter to the turbos.

See below, unfortunately I do not fabricate any more as I am busy with other challenging things.
Best regards
Andreas

http://www.zweisteintrading.eu/993_turbo_oil_lines.htm

badabing

I had the same symptoms. Overfill was culprit. Even after removing intercooler and all turbo air plumbing and cleaned thoroughly I would still get some smoke but only after exhaust heated up. Not on start.

This was due to oil soaked muffler packing heating up. I drive around for awhile (several weeks) hoping it would all burn out but it never did and I eventually replaced the mufflers.

All good after that.

I did send the oil soaked muffler and a mate to be made into Fisters which are now on the car.

BIGRICH805

I had oil in my muffler from a failed turbo and eventually got rid of it by baking it on high at 700 degrees in my BBQ.

DiegoR, before starting your car after not using it for several weeks, it is a good idea to pull your DME relay and crank the engine over for 30-45 seconds in order to make sure the turbos have plenty of oil in the bearings before you start the engine.

DiegoR

Thanks for the suggestions guys. The car is slowly getting rid of the "burn oil" smell the more I use it. It's all good now. I will give a inspection later at the intake of each turbo to see if there is any significant oil accumulation in there and/or in the intercooler. No smoking whatsoever and not smoke at the start up after some good time parked w/o running the engine anymore thanks to the V-Twin 20W-50 oil and perhaps the rebuild of the turbos.