Leaking turbos after overhaul

[INTERPRO]

(03-05-2023 )Rawze Wrote:  The program needs an update. It should not be only set at 18% at idle.. as this alone has since been known to cause it to pull a vacuum on the face of the turbo and suck oil out of it. The turbo needs positive pressure on it at all times for it not to bleed oil. You might have gotten lucky with the turbo not bleeding oil in the past at such low idle positioning, but it cannot be relied on.

Most engines have to be set to about 48% or higher at idle to get proper positive pressure at the intake.

you also did not mention what kind of engine it is either. CM871?. CM2250?. CM2350?... you did not mention this.

It also should not have changed boost levels so radically from one turbo to the next .. unless you changed turbo models or something. Something did not add up there.

(a simple validation) ...
To check for a vacuum at the intake.. remove the IMAP sensor from its hole on the intake side of the engine without unplugging it. Crank the engine and feather the throttle a few times hard to get everything settled and running good. - Then place the corner of a sheet of paper over the hole with the engine running at idle .. and see if it mostly wants to suck the corner of the paper up into the hole or not.

If it mostly tries to get sucked into the hole .. then the turbo is not spinning fast enough at idle to keep up and has a high chance of bleeding oil.

If it mostly only flutters up and down and does not really want to get sucked in.. or blown up away .. then it is about right.

If it mostly wants to be blown up and away with some positive force from the hole .. then it is spinning a bit too fast for idle... and is costing fuel consumption at idle unnecessarily.

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NEXT: .. if there is any restriction whatsoever in the crank case ventilation system.. the crank case filter is dirty, clogged, etc.. then it will also cause the turbo to bleed oil out of its face (plus cause significant harm to the engine too). It being a fresh inframe.. and likely having some extra blo-by until it gets broke in good.. this may be part of the issue too.

make sure the crank case filter is 100% hollowed out or is one of the maintenance free ones.

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Thanks for the reply.

I have the CM871 engine @m*m^2 485hp overlay.

I did the paper test and it does have a vacuum (it constantly sucks the piece if paper). I can't remember where actuator percentage was before the overhaul.

I replaced the ECM in 2020. I backed up the original ecm and restored it into the new one. Would this change anything on the commanded actuator percentage?

I already have 8k miles on tha tractor after the overhaul. How long would I need for it to be considered broken in?

I am using a maintenance free breather insert instead of the filter.

This is the old turbo
   
This is the new turbo