DD60 Idle

[jello_jeep]

Howdy,

I read in the book, that when you fire up your engine, it should run at idle for five minutes before you put a load to it, and also when you are stopping, it should idle for five minutes before you shut down.

Is this idle at the normal idle, or with the "fast idle" switch on?

Is it ok to idle for long periods if you have that FI switch on??

Just curious..

[Jon Wehrenberg]

Others will likely weigh in on this topic also, but as a practical matter when embarking on a trip it is unlikely you can get moving quicker than five minutes so you are likely to observe that practice anyway. By the time you start the coach, air it up, check the lights, hook up the toad, go to the bathroom one last time you are way past the recommended idle period.

Once underway, if you stop for lunch when you restart you will just fire it up and go.

As far as the five minute cool down, it is always recommended, but it is highly unusual for you come from a high speed uphill run to a dead stop in seconds and then shutting off the engine. Typically, a long deceleration such as a coast down from highway speeds to a rest area, and then a slow drive to the parking spot, plus a minute or two leveling it is more than adequate. I think your coach has pyrometers, and a good guide is when the pyros are at the bottom of the scale, regardless of how much time has elapsed you can shut down.

Upon reflection you probably have the series 60 and no pyros, so just observe the above as far as a gradual cool down. Use fast idle when starting and at any time when idling, but go to slow idle before shifting and before shutting down.

[jello_jeep]

Thanx Jon... Much appreciated..

[Jon Wehrenberg]

Warren,

The cool down of five minutes was and is intended to allow the turbocharger to cool down. Once you shut the engine off, there is no more oil passing through the bearings, and if the turbo is still extremely hot, the oil there will "coke" or burn. Once the turbo has cooled down if you were working it hard (your turbo boost gauge will tell you that) you can shut it down. If I have been driving relatively slow, like winding your way to a camp site when you turn it down does not matter because the turbo is cool.

This holds true for planes also, but like the bus, before landing the power has been pulled back for quite a while so it is unlikely the turbo is hot enough to be damaged.

[jello_jeep]

Makes sense Jon, I remember in the Hughes 500 (Loach), you had to run at flight idle for 2 minutes before shutting down, for the same reason.

[BrianE]

We just may have a ROTOR HEAD in our midst. Be very careful of this guy!

BrianE
94Liberty XL

[jello_jeep]

Someone order a bucket of rotor wash, this thing needs a bath!

[Jon Wehrenberg]

Us fixed wing guys use prop wash.

[jello_jeep]

We could all use a spool of flight line

[win42]

Cool Down; Back when Lew and I were youngsters we had to walk the horses to cool them down after we raced them to school.