Diesel RVs: Re: [diesel_mercedes] (NSFADQ) Not So Frequently Asked Dumb Questions (but have to ask anyways...)

I agree with Bobby on the fast idle but........don't rev it too much. One of my pet peeves is starting a turbo charged car and then revving it too high before the oil gets a chance to become viscous enough to take the spinning turbocharger.

If it's really cold out you need to let it warm up enough that the oil temperature comes off the peg before taking off and goosing the engine at high rates of RPM. What happens there is if the oil is still cold ( and therefore VERY stiff) you will superheat the thin layer around the bearings, burn the oil, and then have carbon issues.

I used to fly a supercharged Beechcraft 18 with radial engines, and in extremely cold weather we had to really baby the oil/turbochargers. In fact we even had a method of injecting gasoline into the crankcases to dilute the oil so it would work properly in cold weather starting. After we started we just idled the engines until the gas evaporated and went on our way.........

Randy

--- On Wed, 9/28/11, Bobby Yates Emory <liberty1@gmail.com> wrote:

From: Bobby Yates Emory <liberty1@gmail.com>
Subject: Re: [diesel_mercedes] (NSFADQ) Not So Frequently Asked Dumb Questions (but have to ask anyways...)
To: diesel_mercedes@yahoogroups.com
Date: Wednesday, September 28, 2011, 3:55 AM

Barton, For #2 - my guess would be to go with the fast idle. Part of
my reason is to keep the engine from "strugglling" which it will do
sometimes when it is cold. I feel that the slightly higher RPM helps
the oil pump build up pressure better. Also, MB wants us to - that
is why they provided a fast idle. Bobby

On 9/28/11, Barton <barton.fiske@gmail.com> wrote:
> Some of this may not be Mercedes Diesel specific, but then again, mebbe it
> is....
>
> 1). After 280k mi, is it harmful to park in park? i.e. should I *always* set
> my park brake and make sure the cable and system get regularly used? Does
> resting on the transmission in park on an incline "hurt the car"?
>
> 2). On a cold start, i.e. hasn't run in more than "n" hours and the oil is
> fully drained and at ambient temp (i.e. "thick")...is it better to let it
> idle at whatever RPM is wants to idle at, (i.e. < 600RPM), or is it better
> to hold the accelerator just enough to quiet the "diesel rod knock" that
> accompanies the well worn but still strong engine? No more than 800-900 RPM
> until I'm reasonably sure things are "moving smoothly"?
>
> thx in advance!
>
> -Barton
>
>

--
Toward freedom,

Bobby Yates Emory