Do stock twins normally leak oil when the car is not running?
 

Hi,

As per the title, really. I have 2 sets of stock twins on the bench. I filled the oil cooling/lubricating channels with oil (so the shafts would be bathed in oil), and left them standing. When I came back, in one set I can see oil under the primary turbo exhaust compressor blades and in the other set, oil under the secondary turbo exhaust compressor blades. But NOT under both sets of blades in both turbos.

I had assumed oil seals were just that. And that they seal all the time. If they only seal under pressure, then when the car is not running should they both leak??

Do the above observations imply the oil seals are not working properly?

Thanks for any insights!!

I had the same experience with the BNR turbos. What Brian explained to me that if you lay the turbos on their sides (as on a bench) and fill them with oil the oil can leak over as the seal has a very small gap on the top side, similar to a piston ring gap. In my case too I only had oil leaking over one housing and not both.

When the turbos are in the normal operating position (as installed) the oil is supposed to drain fast enough from the shaft housing to prevent the levels from reaching that gap and leaking over.

Albert

Thanks for the reply! Very helpful!