| Author |
Message |
philip potter
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 12:48 pm: | |
Just taking out a different engine for the first time.
While sitting (idle or fast idle) lots of oil comes out the spit tubes - both sides (1/2 - 1 gal in an hour).
I also drove down the road for over an hour with no oil loss.
Anyone know what is going on? Why is there no oil loss while it is under load, but lots while it is idling? |
bowlingshoegiverouter
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 2:44 pm: | |
that's unburned fuel...the 2 cycle detroit should not be idled for over five minutes |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 3:12 pm: | |
Hopefully Geoff will chime in on this as he is one of the resident experts on DD's.
As I recall he says the primary cause of this is bad rings and I can not recall why it goes away when the engine is up to normal operating speed. He also definitely recommends against leaving the engine idle for long periods of time like this.
Also, are you using the proper oil? Multiweight will cause excessive oil consumption.
Richard |
David Dulmage (Daved)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 5:14 pm: | |
It's not bad rings, it's the result of excessive idling. It's best to run at fast idle, if idling is necessary and avoid unecessary idling.
FWIW
DaveD
(MC-8) |
Tim Strommen (Tim_strommen)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 5:40 pm: | |
I trick I use to determine what is coming out my engine is take a piece of blank white paper and let a drop fall on it. If it's diesel, a "halo" will spread to about twice the drop's original size within about 30 seconds. If it's oil, it'll take at least two minutes. Black liquid coming out of a 2-stroke's drain pipes COULD be a sign of bad rings, bad blower seals, over-sized injectors, bad injectors, too much idling (aka. "wet-stacking" - bad).
Find out what kind of fluid it is first (try the paper thing, and take a wiff diesel smells different than oil) then reply back here. 2-strokes weren't designed to idle, they were designed to run at load around 1800 RPM. Try to keep idling to about 1 minute (5-mins with fast idle) or about the same ammount of time you'd spend at a traffic light.
Cheers!
Tim |
Bob Vandawalker (Rav221)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 5:57 pm: | |
I could never understand why DD 2-strokes were so popular in fire apparatus which sits at times for many hours idling at emergency scenes. Also those long, slow parades. Most of them probably never developed problems due to lack of mileage/hours.
When I had a air box drain problem, the breather had become clogged. Cleaned the breather and it stopped dripping oil.
Bob V. |
Dale Waller
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 9:01 pm: | |
If you have to idle the engine alot, you need to fast idle. If possible you need to use the block heater also, because the engine will not build enough heat to burn off the fuel properly. That will cause unburned fuel drip |
Lew Poppleton (Lewpopp)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 10:30 pm: | |
Should the 8V92 be treated with the same idle time restraints as the 6V92? |
bowlingshoegiverouter
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 10:43 pm: | |
it's a 2 cycle |
philip potter
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 10:57 pm: | |
I was running it at fast idle to test new temp. gauge wireing. It is Oil. I'm using Rotella T 40W. |
John MC9
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 11:11 pm: | |
Bob-
I drove buses for a living... albeit, not recently.. But all the buses
I drove had 2 cycle Detroits. All the drivers idled their buses for
long periods of time.
On charter trips as well as line runs, the bus ran from the time
it left the barn, until it returned. During summer, it had to remain
cooled for passenger comfort, and in the winter...warm for the
same reason. The engines didn't seem to suffer, puddles of oil or not..
We did use the fast idle, however.. But we ran fast idle to keep
the batteries from being discharged with all the fans running..
And as far as I remember, that was the sole purpose of the fast idle.
They use 2 cyl detroits for generator applications that run 24/7
and idling for most of the time..
As far as I'm concerned, there's much ado about nuttin'. |
[philip potter
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, July 28, 2005 - 11:44 pm: | |
I have not cleaned the oilbath air cleaner after we swithed out engines this year. I'll check it out in the morning. Could that be causing this? |
John MC9
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 29, 2005 - 12:05 am: | |
Phil-
Make sure you're using SAE 40w in the crankcase. My MC9
was spitting and spewing oil like a PO'd Arab until I switched
to "the good stuff". The previous bus op owner was using the
el'cheapo' WalMart 10w30 at a gallon or more a trip. I made
a three hour round trip and used a quart. Oil -does- make a dif. |
Sean Welsh (Sean)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 29, 2005 - 1:39 pm: | |
Philip,
By "spit tubes" I assume you are talking about the airbox drains, and not the valve cover breathers.
The airbox drains have pressure-sensitive check valves in them. When airbox pressure rises to operating values, the valves close the drains. The drains are open when the engine is off, but also when it is idling. However, high-idle should generate enough pressure to close the drains. For that reason, I suggest you replace the drain check valves (and/or check your high idle setting, which should be at least 1,000 rpm -- check the specs on your particular engine).
Why you have so much oil coming into the airbox is a separate question, and there are many possible answers. However I would suspect the oil is blowing back into the airbox past the rings. You should open the airbox inspection covers and turn the crank until you see the rings through the intake ports. The rings have tattle-tale grooves in them -- if the groove is no longer visible, the rings are shot. Have a look at a brand new ring to see what the tattle-tale looks like. If the rings are gone, you probably need new cylinder kits, rod and main bearings -- this is typically required between every 250,000 and 400,000 miles. Rebuilding the turbo and blower would also be indicated at this time, and I would put in new injectors as a matter of course.
Some other possible reasons are insufficient viscosity (why multi-grade oil is unacceptable) or worn bearings (leaking oil) in the turbo (if you have one) and/or the blower.
HTH,
-Sean |