Engine/Transmission (1998.5 - 2002) High RPM: good for engine break-in?

[Hohn]

The reason I ask this is because I recently ran a little experiment.



Normally, I would cruise about 1500 RPM around town, and sometimes even lower. When I DID wind the engine up, it didn't seem to like it at all-- it felt "tight". I only ran the engine up to 2K on the interstate.



So for a whole tank of fuel, I decided to cruise at no less than 2000 RPM, and often ran at 2500 RPM (obviously not when engine was cold). I only ran about 400 miles this way, even cruising the interstate in 5th!!



This seemed to really free the engine up. It's seems to be smoother at high RPM and all other ranges now too. It seems to be a little quieter.



My SOP meter tells me that the engine is happier how that it's been worked a little harder. i don't have anything to tow, so what else can I do to make the engine work hard and break in better?



It seems that what everyone was saying is true: the CTD likes to work, and isn't happy loafing along.



Any more ideas on breaking this thing in? Even though it only has 8500 miles, it's starting to feel like it is ready for synthetic oil. I am watching my oil consumption to make sure (so far, it uses very little).



Hohn

 

[Rman]

Its not good to baby any engine when new. These diesels especially liked to be worked hard. The valve train must be "married" when you break in a new engine. The only way to do this is to use the motor across the full rpm band. Babying the motor and then saying its broken in, and then jumping in there and stomping on it will do more damage than if you just drove it hard from the get go.



The best way for these diesels to break in is just working it out. Haul some stuff, hell borrow it if you have to.

 

[Hohn]

I ran for a while with 1000 pounds in the bed to help. I now just have a Mopar 360 engine in the bed. It's only about 550#.



Funny how it took 1k in the bed to get it to ride smooth.



I am gonna see if I can hook to something heavy.



HOHN

 

[Scooby]

It sounds silly, but when my truck had about 2K miles on it, I rented a u-haul car hauler and put my other 4x4 on the back and towed it around on the interstate with some good inclines.



After I had 30K on the truck and loaded it up with a 4K lb camper and a (combined 7K lb) car hauler with a vehicle on it and then drove across country, the engine is noticably quieter and runs through the entire power band better. I think the x-country trip with all that weight finally broke the motor in! It is especially noticable on first starts, where the engine seemed much louder than other cummins (typically older ones) that had some miles (and fifth wheel hitches) on them. Clearly this is one motor that is happier after working hard.



So my advice is: Load it up and make it work - take a long vacation - maybe rent a travel trailer or put another vehicle in the bed or behind you!

 

[MAllred]

I agree - loading it helps but simply raising the rpm probably won't. Maybe semi-aggressive acceleration when you're able.



Skip the synthetic oil -- I tried it for 3 oil changes with Rotella synthetic at 80k and all it did was cost more, use more oil, "breathe" more, and make the rear main seal leak oil. Now that I'm back to using regular Rotella, all of the above symptoms have disappeared -- including the rear seal leak!

 

[Snow man]

Hohn, i agree with you,I rev my Cummins loyally,I hardly ever drop below 2000,and I have 4. 10 After a while I notice it seems to run better in the higher ranges. The engine is real smooth,and happy to be there. The side benefit is the trans,especially the auot,and 5th in the 5speeds,last so much longer at high RPM's. My oil samples confirm what ive been saying,they come back perfect every time,no wear metals high,all are very low. I run Shaeffers x2000 15w40 Moly supreme motor oil,and change at about 7000 miles,after 3 samples showed that at 7000 miles,the levels of contamination are still way under 1/2 allowable.

 

[Turbo Horseman]

Yup... gotta use the whole rpm range to break in that engine. Terrible side effect is (when bombed) crazy torque, lots of smoke and less time from intersection to intersection. With 151,000 km on my truck, I'm still trying to break in the engine... will I ever get there... hope not.

 

[MLee]

don't baby it

as the others have said, and don't baby it, BUT use some common sense in driving it also. the more it gets worked the better it runs. low RPMs is an engine killer, especially in a diesel.

just my penny's worth.



Marv.

 

[Tom G]

Me To - Work That Puppy

HIi Hohn:



I had about 15,000 miles on my truck before I began to believe it might be broken in. Pulled my 5er up the continental divide and then it really started running better.



I would agree with most here - work the truck and 2500 RPM will not hurt it. Changing your speed frequently during break-in is important. TRY and find something to tow up some hills. Get the operating temperature up to about 200 - 205 if possible then you will know she is working.



Check the color of your turbo [the silver part]. A well broken in engine should have a somewhat brownish color on the turbo instead of the bright silver color [I call it a sun tan]. This means that the turbo and other systems have been working at normal temperatures.



When your truck is properly broken in ONLY then go to syn lubes in the engine. If you can't find something to tow wait to at least 20,000 miles before switching over is what I would recommend. Using dino oil is just fine and most engines will make 300-400. 000 miles on dino lubes which is much longer than I will live LOL



300,000 / 20,000 miles per year = 15 years.



Anyway keep your trucks fluids clean [oil, fuel, coolant] and it will treat you right. I have found that it is very hard to overwork a Cummings. They are very different from the gas engine trucks I drove before.

 

[Scooby]

Adding to what Tom said, my turbo got a nice "sun tan" after that cross country trip with a camper and vehicle in tow. It really looks bronze now. I was a little worried about it at first...

 

[slo-ryde]

At 9,000 miles my engine is just starting to smooth out. I don't have anything to pull so moderate to hard acceleration up to near redline is what I've been using to "load" the engine.



The service department at the local Cummins shop says the best way to break in the motor is to hook up the truck to a moderate load and drag it around town for a few weeks.



I see some people have actually gone as far as renting a U-Haul trailer just for that purpose!

 

[Diesel Freak]

This is how I broke in my truck.



First oil change at about 1500 miles. Then hepled a buddy move. We loaded up his Nissan Maxima on a 20' flatbed trailer and drove from Portland Oregon to Colorado Springs Colorado in July 2000. Grossed at 14000#.

 

[DocStressor]

Hohn - I just came across this post. Your doing it right now. Use the full rpm range during break in. I think I explained why in the P/A section on the "Question on Synthetics" thread. You never want to lug the engine at low rpm during break in. Hydrodynamic lubrication (oil film strength) in parts of the engine such as bearing journalsi ncreases with rpm. Let the engine work hard, but let it rev free. Your breaking in many different parts of the engine at the same time, not just seating the rings.



How do you know when an engine is broken in? When oil consumtion, wear metals in the oil, fuel economy, and (if your nuts, rich, or both) hp and torque on the dyno all stabilize.