It depends, I don't know much about those 11.1 L detroits but I do know the 12.7L detroits like to idle around 1000 rpms.

Some engines are ok with a lower idle, like volvos. They're designed better so that they don't need a super high idle. Saves on fuel too.

 

Could be just the smaller engines can handle the "slober" thats what our mechs. call it. We have a M 11 engine in a truck... it's the yard truck :lol:
It's got a bunk, low miles, nice paint, chrome package... 03 ? Yep the yard truck... No offence ment, but we need power...

 

Yep...slobber is what Cat calls it too in the manual. Plus they say it causes carbon build up.

 

quote="silvan"]OTOH... At my old company, I just couldn't see running the engine this high at idle for the night, so I didn't. After a few months of this, it started drizzling oil out of the seams in the exhaust manifold, and my boss chewed my ass for not running it high enough at night.[/quote]


1000 is lots

the slober is NOT caused by idling under 1200, it's caused by running for long periods at low idle speed, more specifically; operating with a cold combustion chamber which causes incomplete combustion of fuel

 

?

 

What temp does your engine run at while idling?

new(er) engines (first 100,000) are most susceptible to ring seating and cylinder glazing problems. destroyit diesel used to be the ones i saw the most issues with

OTN ; some guys will NEVER experience this problem... well, at least for now

 

What I was getting at is two separate things on the Volvo:

1) The oil system is designed better, holds better pressure at lower rpms, and doesn't drop when the oil thins out(gets hot). For example, mine holds a steady 60 psi anywhere above 1000 rpms. Below that, even hot idle, doesn't drop below ~35ish.

2) The exhaust valve. It closes, creating a restriction in the exhaust, so that the engine has to work a little harder. This harder work creates a more complete burn.

 

i forgot that you have a volvo engine... that exhaust brake WILL load the engine and improve cold weather idling temps. does it open/close automatically?

 

It runs any time the engine is below 170 degrees. It doesn't care how cold it is out. It requires air to run. I guess it doesn't help with normal, at temperature idling. Cold weather performance on the volvos is far superior to any other engine I've ran.

They exhaust brake is also a problem on Volvos. The valve that controls the exhaust brake is $700, and the exhaust brake itself is $2000. I think both of mine need to be changed, they leak air. I might just to a rebuild.

Another thing, you cannot disable them. Well you can, but then you have to live with a code and no, I mean absolutely ZERO jake brake. I guess they did the jakes a little different from most manufacturers.

I have a completely open exhaust system, no baffles. I do have a muffler, but I'd hardly consider it that. Even with that setup, the jake is much quieter then other trucks with full-baffled mufflers.

 

yours is an exhaust brake. i would expect a butterfly or gate valve in the turbo down-pipe. most hd engine manufacturers use compression brakes... generally more power/noise