I am doing an in-frame overhaul on my 95 U-240's Cat 3116 engine. This includes bore and sleeve all 6 cylinders back to standard, new pistons, rings, rod bearings, mains, new oil pump, rebuild my head. This brings to mind the procedure for break-in after the rebuild. I have read a lot of things about the process, but would like ya'll ideas and opinions. When do you quit worrying about doing it right? How long does it take to overheat the rings? How much do you have to vary the rpms?
Pat,
Is there a specific oil for break in??
My non diesel experience is to put a load on the rings immediately.
Go drive it up a small hill varying the rpms.
Probably why the original rings had blowby.
Never broken in hard enough.
Or the restrictive OEM muffler reduces the boost needed to seat the rings and causes overheating from excessive backpressure?
Probably both.
Several of us have noticed increased turbo boost and better mpg and less engine temps after a resonator install.
Went from 28.5 max to 30.5 boost.
For sure I would install a resonator
Pat,
Are you a member over on Diesel RV Club, an FMCA Chapter (http://forum.dieselrvclub.org/) ? That's Brett's technical engine discussion forum - might be a great place to get info beyond just FT folks with that engine.
Note - I don't believe you need to be either an FMCA member nor a club chapter member to participate in that forum.
Michelle
If you have a John Deere dealer nearby, consider getting this:
PMB Product: (https://jdparts.deere.com/partsmkt/document/english/pmac/5452_fb_BreakInOil.htm)
dino oil, don't idle it, run it with a good load. Drive it like you stole it!
Do yourself a big favor, talk to the people doing the rebuild, they will know better than any speculation.
I think running it like he stole it is why it needs rebuild,just don't let it get tooooo hot.
Do what Bill suggests, ask the rebuilder. Don't guess.
I had major engine work done on my Cummins ISM11. They followed a very specific breaking process on their dynomometer using controlled loads and RPM profiles. They monitored lots of engine data the whole time. I have a video of the process. I got a written report when it was all done.
Up 10 MPH for a mile, down 5MPH for a mile, up 10, down 5, etc. Then when attained desired top speed, slow down & stop. Let engine idle for a few minute. Then shut off, go somewhere & let the engine cool down all the way. Repeat entire procedure once more and you are good to go.
The thermal expansion & contraction caused by changing speeds/loads lets the engine season in and still lets the oil lube the cylinders, etc.
I have done the above procedure on every new car, snowmobile, and motorcycle I bought and ended up with the best running engines in our group.
It is well documented and proven that high cylinder pressures are required for proper seating of the rings and to prevent glazing of the cylinders in the very first minutes of running an engine. Glazed cylinders may or may not deglaze in the future. If they don't and rings don't get seated, the engine likely will use more oil and not have as great of compression.
Cummins ran it on a dyno for a reason....they wanted to put load on the engine.
There is lots of information about proper engine break-in put out by OEM, engine builders, etc.
I like the PMB idea.
I still would remove the restrictive muffler to allow more boost to seat the rings better.
In my unexpert opinion the restrictive exhaust caused the engine to run hotter and prevented the rings total seating.
Especially with a new, afraid to hurt the engine, Rv owner.....
How were these engines broken in on a new coach? If they were not run on a dyno or broken in somehow before assembled on
a coach then every engine on every coach has bad rings?Until he gets his head disassembled and they "mic" the cylinders
we still don't know his exact problem.
Yup, I'm still as confused (after thirty years of working on diesels) what happened to that, usually bulletproof, engine! :o
I bet cat runs them on a basically unmuffled dyno to get a baseline on condition.
The light weight u240 and an auto trans and a conservative driver and a restrictive exhaust would seem to be contributing factors to my mind.
Especially if mike says they are normally bulletproof in other applications.
My friend Steve lights failure matches this one. Same miles.
Being as the use is hard to change I would try to help this if it were mine by lowering the backpressure to reduce the heat and to help the ring seating and use the John Deere oil.
Engine manufactures spec the exhaust for a particular engine for maximum CFM for that engine, it is up to the end user to go by there specs.
I agree. I am not hard on any of my engines, but I am not afraid to work the engine. It has been WOT for 5-10 minutes before @2300-2400rpm in 3rd gear.
I agree that very speed and load at normal engine temp, but when do you stop this process?
Pat
I would be hard on it for at least 5000 miles. lots of acceleration followed by lots of varying of speed, minimal unloaded idle. I have always broken in engines by running them hard to push the rings, then periods of lighter load/varying load to cooldown those rings. I never take it easy or slow, and have never had a problem with an engine. Just read the John Deere page about the break in oil, and how they recommend doing so. It explicitly tells you to load it up, work it hard, and idle it as little as possible. That seems to be the key recommendation of most manufacturers.
My dirt engine break in matches the Deere ideas. Load then come to idle in gear.
Sucks any breakin products down into the pan.
I have every owner put a uphill load immediately after starting.
On a single ring single you have 15 minutes to seat the rings.
I would put a large load by towing something if no hill available almost put the toad brakes on and the cat
All the fancy wording on break in oils all are simply a non detergent oil, So just use a #30 wt Non Detergent oil, same results.
Do you know of Cummins has a written recommend break-in procedure for their new engines?
Cat 3116 and 31 series of the 90's have a pretty bad reputation in the boat world. I'm not informed in truck versions though.
Marine and on-highway expose engines to VERY different stresses.
Most marine Caterpillar 3116's were rated at 350 HP. On highway 100 HP less at 250.
Most marine engines of this size (read that, NOT in displacement hulls) are run at very close to rated HP RPM all the time. Again, totally different than on-highway.
So, while an engine could be good for both types of use, only one or neither, the fact it does not do well in one does not necessarily reflect on how it does in another application.
One thing I noticed in this conversation in post#16, this engine was run at WOT for 5-10 minutes @ 2300-2400 RPM in 3rd gear, I wounder if this had anything to do with the damage.
Bill,
Should not have done damage as long as coolant temperature was not excessive. That is within (just barely) the working RPM range of the 3116.
Sure, with any engine, the more you stress it, the more critical are operating temperature, oil, etc.