8V92 STARTING

[JIM KELLER]

Jon, So after starting your engine how long do you wait before hitting High Idle ? Do you wait longer when the engine is cold vs hot or do you go right into High Idle.

[Jon Wehrenberg]

Good question and I don't have a good answer.

Usually I start it and wait about 30 seconds or so before going to fast idle. Right after starting I am scanning the instruments to make sure they are all coming alive and are in the proper range. Then I go to fast idle.

Keep in mind however the bus rarely sees cold temperatures so it is very rare the engine is cold soaked. If it is cold out, the Webasto has been used and the engine is warm.

I have heard coaches start and immediately go to fast idle, and I am presuming the owners are just leaving the fast idle switch "on". I don't think that is good. I have had planes a lot longer than I have had the buses, and when starting the planes it is always my practice to start the engine and allow it to run at the lowest practical idle speed until I am sure oil has fully circulated, usually at least a minute or more, and to never exceed 1000 RPM until the cylinder head and oil temps are in the green.

We don't have a set of gauges in our buses with limits or gauge markings to denote normal range, but I like to see the coach temp gauges move off the peg before I get up to highway speeds. Fortunately most of the time, whether moving from home or from a campground I can idle slowly for some distance before getting above 1200 or 1300 RPM.

[rfoster]

I have recently been diagnosed with CRS, but I do recall that question was asked at United Engines Facility, OKC were the food was real good. I just don't remember the exact answer but I think it was wait two minutes before fast idle.

I must confess that I do not always follow those recommendations but I do try to wait at least one minute from a cold start.

Maybe someone who has not been infected yet can fill in the correct answer.

[truk4u]

I think starting an 8V or a series 60 once a week just to run it without getting it hot and up to temperature would be the worst thing you could do. When I have done it, I put them on high idle and let it run until normal temps are reached. United Engine said you could run it all day at high idle without any adverse effects.

[dale farley]

I usually do very similar to what Jon says he does. I start it and look at the gages a few seconds and then go to high idle. If I am starting cold, I make sure I wait a little longer. I am reasonably sure the manual says wait one minute before going to high idle. The main thing is that the oil has had time to reach all surfaces.

[James]

My operators manual states:

"After starting, run the engine at
slow idle for two minutes to allow lubricating oil
to reach the turbocharger. Then run the engine
at fast idle. Let oil pressure reach normal
operating range before driving."

Of course that is for the 2002 Series 60 and may not apply to other engines.

[Will Garner]

Wait a minute. What was Woody's question? I think it had something to do with starting an engine not with prelube procedures (are there really any?). Didn't he have some dead batteries?

Woody, I had a similar problem three years ago. The new batteries that came with the coach, yes they were only three months old, turned up dead one morning when Carole and I were going to exercise - the coach that is. It was a pleasant day so we sat outside the bus barn and watched as three Coach-Net service outfits came and went. "What, 24V,system, that is not what Coach Net said. We don't have anyway to jump start that engine." Well the fourth guy was determined to get the coach started, and get paid by Coach Net, so we removed the cables and found one of the batteries totally dead. Took it to Advance Auto where it was load tested and failed. So we went back with four new chassis batteries, replaced the cables, and off we went. That is we closed the bay doors and went home - too late to go crusing. Shortly after that experience I added a Guest #2611 battery tender so I would not have that experience again. So far so good. I'm looking at putting one on my house batteries to keep them charged also. You see, I don't have a 50 amp outlet in the bus barn (its not mine) and even if I did that would do absolutely nothing for the chassis batteries. It would only cover the house batteries on my coach.

Trukman has a wiring schematic to do the installation. It is really easy, so take your time and enjoy getting to know your 8V92 a little better.

Now as for the fast idle thread drift, I watch the oil pressure gauge and don't go to fast idle until there is 50-60 psi cold pressure. I have built many gas engines over the years and if you don't go to fast idle on an 8V92 you will see the oil pressure drop like a rock to about 10 psi. I'm told that is normal for this engine. On the engines I built, using speciality after market oil pumps, 50-60 psi was normal for a hot engine. Obviously 8V92 diesels are really different beasts from high performance gasoline powered engines.

[jack14r]

I wonder if the series 60 takes a little time to lube the rocker arms and if going to high idle too soon could create a problem in this area?

[rahangman]

As a newbie, I asked a couple of Drivers of tour buses, they seemed to think it to be a good idea to let my 8V idle normal for a couple minutes at least to allow belts,lube to "stretch" just like I should before working out! Just a thought

[Ray Davis]

I don't remember exactly where I heard this, but the word was that most busses which have had crankshaft damage was due to going to high idle too quickly. 2-3 minutes is the time I use.