I have an 82 300SD turbo which may be similar. The big plastic "U" that connects the air cleaner to the turbo has rubber seals at both ends and it's not hard for one of these to "fold under" or "push out of position" when you reinstall the "U". This condition causes a bad seal that can let dirt in and turbo noise out. The problem is more likely with an old seals. It may be worth checking if you hear unexplained turbo noise.
If you are concerned about boost function, you can temporarily install a plastic "tee" at the switchover valve and feed a pressure gauge to monitor boost while driving. I usually just tape the gauge to the outside of the windshield vs running the hose into the passenger compartment. This pressure is the boost signal to the injection pump. Turbo boost produces almost no extra power unless the injection pump adds more fuel (via ALDA) to burn in the extra air. Boost pressure is limited by the waste gate that dumps excess pressure and also an electrical overpressure switch that vents the boost signal to the ALDA (via the switchover valve) if the boost pressure is too high. Higher boost is not good; it only puts more stress on the engine. The transmission also has a circuit to the switchover valve to reduce boost signal to the ALDA (less fuel/engine torque) during shifts. Back in the Marshall Booth era, 617 turbos almost never failed unless abused. Scott > -----Original Message----- > From: Mercedes [mailto:mercedes-boun...@okiebenz.com] On Behalf Of > Curt Raymond via Mercedes > Sent: Thursday, September 25, 2014 4:50 PM > To: Karl Wittnebel; Mercedes Discussion List > Subject: Re: [MBZ] turbo update 82 300td > > Why bother replacing the turbo? A bigger turbo isn't (by itself anyway) going > to make more power and is going to take longer to spool up... > > -Curt > > > ________________________________ > From: Karl Wittnebel via Mercedes <mercedes@okiebenz.com> > To: Andrew Strasfogel <astrasfo...@gmail.com>; "mercedes@okiebenz > com" <mercedes@okiebenz.com> > Sent: Thursday, September 25, 2014 4:44 PM > Subject: Re: [MBZ] turbo update 82 300td > > > The transmission is new. You guys helped me get it rebuilt by the Sun > Valley guy. > > The u-shaped hose seems tight on the air cleaner. Not sure where else it > could be leaking. Manifold obviously but it all looks fine. Maybe a soap > bubble test is in order. In any event it does not appear to be "bad" > functionally. > > For new turbos, if I could find the holset he200vg it could be truly > modern. Anybody know what cummins motor that turbo came on? > > Thanks, > Karl > > > > Whiney transmissions can go on and on too... > > On Sun, Sep 21, 2014 at 12:22 PM, Karl W via Mercedes > <mercedes@okiebenz.com > > wrote: > > > Then mine (85 tdt) has been bad for the last 100,000 miles. Who knew? > > Drives fine and is not slow. I am planning to put an hx30 on there anyway > > so maybe it was meant to be. > > On Sep 12, 2014 7:00 AM, "Peter Frederick via Mercedes" < > > mercedes@okiebenz.com> wrote: > > > > > If you can actually hear the turbo whine and the air cleaner is > > installed, > > > you have a bad turbo (unless you have a leak between turbo and intake -- > > > check the 0-ring). MB turbos are usually silent, unlike the Volvo, where > > > it sounds like a police siren a couple blocks away..... > > > > > > > > > Peter > > > > > > _______________________________________ > > > http://www.okiebenz.com > > > > > > To search list archives http://www.okiebenz.com/archive/ > > > > > > To Unsubscribe or change delivery options go to: > > > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > > > > All posts are the result of individual contributors and as such, those > > > individuals are responsible for the content of the post. The list owner > > > has no control over the content of the messages of each contributor. > > > > > _______________________________________ > > http://www.okiebenz.com > > > > To search list archives http://www.okiebenz.com/archive/ > > > > To Unsubscribe or change delivery options go to: > > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > > All posts are the result of individual contributors and as such, those > > individuals are responsible for the content of the post. The list owner > > has no control over the content of the messages of each contributor. > > > _______________________________________ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > All posts are the result of individual contributors and as such, those > individuals are responsible for the content of the post. The list owner has no > control over the content of the messages of each contributor. > _______________________________________ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > All posts are the result of individual contributors and as such, those > individuals are responsible for the content of the post. The list owner has no > control over the content of the messages of each contributor. _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com All posts are the result of individual contributors and as such, those individuals are responsible for the content of the post. The list owner has no control over the content of the messages of each contributor.
