CM 871

[Aussie Steve]

Hi
I think I"ll leave the injector cam timing as standard. I had thought a small advance might clean up the soot levels. Fairly strong advise not to for good reason so I've taken that on board.
With the injectors are we talking air in the system or cavitation?
I've had people tell me hear that they are setting the SOI at 3 & 2.4. They claim that these engines like SOI set at those numbers. I'm not so sure anymore. I will have to check those numbers today.
Even with new liner packs and a head the problems with this engine are only delayed.
I need to get it sorted out, I'm in disbelief that any engine will require the work that this one does after only 2000hrs.☹️

[Aussie Steve]

In reply to your question about the DFF Rawze.
The DFF has been entirely removed and replaced with a muffler that looks like a DFF. It's been made so that it resembles what was removed, even the sensors are reinstalled. I can only gauge it restrictiveness by the increase in exhaust note which is considerable over the DPF.

[AussieISX]

(08-28-2017 )Aussie Steve Wrote:  Hi
I think I"ll leave the injector cam timing as standard. I had thought a small advance might clean up the soot levels. Fairly strong advise not to for good reason so I've taken that on board.
With the injectors are we talking air in the system or cavitation?
I've had people tell me hear that they are setting the SOI at 3 & 2.4. They claim that these engines like SOI set at those numbers. I'm not so sure anymore. I will have to check those numbers today.
Even with new liner packs and a head the problems with this engine are only delayed.
I need to get it sorted out, I'm in disbelief that any engine will require the work that this one does after only 2000hrs.☹️

If the fuel pro is leaking air like ones I've seen in the past , half the stream of fuel exiting the filter and entering the IFSM will be full of air . As in a clear hose that should be full of fuel will be only have full with big gulps of air . With the HPI fuel system , timing is set with metered doses of fuel. So any air in the injector will compress and dramatically change the Soi . Injectors suffering the most end up with blue discolouration from heat . Not sure what your problem is but your symptoms closely resemble ones I've seen in the past due to the fuel pro . In the west Cummins went close to completely rebuilding a Cm871 due to a vibration and a harshness. I put a clear hose on it and showed the owner the problem. Chase the simple stuff first . As far as the timing , imo it's better to edit the table rather than add an advance to the entire table. Results in too much at higher trq and not enough cruising.

[Rawze]

(08-28-2017 )Aussie Steve Wrote:  ...
setting the SOI at 3 & 2.4. They claim that these engines like SOI set at those numbers.
...

Who is "they?". That sounds a bit on the retarded side of things at 1650 rpm and will likely produce some soot, cause EGT's to be slightly higher than they should be pre-turbo. Those numbers are more indicative to a CM2350 than that CM871. The CM871 is physically designed around early and late PCCI injection and "likes" about 4-6 degrees as the final SOI timing at the 1600 rpm range after all offsets and maps are added together and about 36-37 lbs of boost. 4 being conservative, 6 being lenient. 2-3 btdc would be more like the 1900 - 2000+ rpm range.

As far as the exhaust BP goes and that muffler,... It should have as little BP as absolutely possibe!. ANY restrictions will shorten the life of everything on that engine.

[Aussie Steve]

I was chatting to the fellow who did the work today. I have those numbers wrong.
I've got a lot of numbers running around in my head and probably the biggest is the $21K + repair bill. I have a copy of the file on a USB stick that I'll put on the computer tomorrow.
What is the best way to send it to you Rawze?

[Aussie Steve]

(08-28-2017 )AussieISX Wrote:  

(08-28-2017 )Aussie Steve Wrote:  Hi
I think I"ll leave the injector cam timing as standard. I had thought a small advance might clean up the soot levels. Fairly strong advise not to for good reason so I've taken that on board.
With the injectors are we talking air in the system or cavitation?
I've had people tell me hear that they are setting the SOI at 3 & 2.4. They claim that these engines like SOI set at those numbers. I'm not so sure anymore. I will have to check those numbers today.
Even with new liner packs and a head the problems with this engine are only delayed.
I need to get it sorted out, I'm in disbelief that any engine will require the work that this one does after only 2000hrs.☹️

If the fuel pro is leaking air like ones I've seen in the past , half the stream of fuel exiting the filter and entering the IFSM will be full of air . As in a clear hose that should be full of fuel will be only have full with big gulps of air . With the HPI fuel system , timing is set with metered doses of fuel. So any air in the injector will compress and dramatically change the Soi . Injectors suffering the most end up with blue discolouration from heat . Not sure what your problem is but your symptoms closely resemble ones I've seen in the past due to the fuel pro . In the west Cummins went close to completely rebuilding a Cm871 due to a vibration and a harshness. I put a clear hose on it and showed the owner the problem. Chase the simple stuff first . As far as the timing , imo it's better to edit the table rather than add an advance to the entire table. Results in too much at higher trq and not enough cruising.

It will hopefully be running sometime on Friday and I will ensure there is no problems in this area. Don't need any more drama with this engine, Cummins have wiped there hands of it.
I think the DFF replacement can/muffler was sourced from over where you come from Aussie ISX. This truck spent a lot of time in the west with the previous owner.

[Aussie Steve]

Sorry I'm still learning how to reply using the quote functions etc
I pulled a copy of the file today, its on a USB stick that I will load onto the computer tomorrow. How is it best sent?

[Rawze]

(08-29-2017 )Aussie Steve Wrote:  Sorry I'm still learning how to reply using the quote functions etc
I pulled a copy of the file today, its on a USB stick that I will load onto the computer tomorrow. How is it best sent?

I PM'd you.

[Aussie Steve]

The truck is back on the road. New head, pistons and liners, bearing roll.
Cummins even came to the party. Seems the cam timing was retarded by 12 thou.
It will be interesting to see how it performs