Piston ring/engine break in procedure
10-25-2020, (Subject: Piston ring/engine break in procedure ) 
Post: #1
Piston ring/engine break in procedure
So it's time. I think it's about dead. 900k and 25k+ hours will do that on a truck that was fleet maintained the first half of its life.

She has tons of blowby, takes lots of boost to do anything, is low on power, started burning oil (2 1/2 gal from Savannah to Chattanooga on 75), I can hear the pistons rattling when hot at an idle, mileage is in the ground, etc...over 15 lb of boost she smokes, can't maintain minimum speed loaded on 75, and plugs filters. I'm sure I've got some broken rings in it too. Exhaust detent clearances are all under .026, a couple at .021. Can't even do a leak down test on it, compression is too low. No sense in running it into the ground at this point. At least the mosquitoes stay away when it's running...

I was fortunate enough to get my hands on the same counterbore cutter that rawze uses for about 1/2 price. Score!

So I need to ask a few questions first.

-How are you guys going about breaking in the piston -rings? Using what oil? I've been considering a non detergent oil for the initial break in.
-First oil change intervals? I still have a bypass filter even though it's been @m*m^2'd.
-If I remember correctly, Rawze mentioned in his video he didn't have a core because he bought a new head, not a reman. Everywhere I looked wants a core even if I dig out a new head from their reman stack. Rawze, where did you get yours?
-how many times can you retorque rod bolts before they are junk? I did a bearing roll and new cooling nozzles a couple years back, but I do have some reman cummins rods on hand.
-are you guys using stainless or brass liner shims? Do they get 'stacked', or just the one shim?
-my valve cam started to flake again thanks to some crappy rocker arms I found a couple months back. I'm just going to replace both. Are these cummins reman cams worth a damn, or should I insist on new, like the head?
-can anyone explain to me again how to identify a new head by the packaging? I'm aware of how to identify one by the numbers on the head, keep forgetting the packaging differences.

I've been considering using another engine that is laying around and building it so I can just swap them out. That way I can address the flywheel housing gasket/clutch/team main/trans at the same time. 13 is on its way out for an 18.

I'm sure I'll have some more questions once she is torn down. I'm working on a contract deal locally right now (bad timing), but I've got another set of wheels temporarily. Looking to do this between Thanksgiving and Christmas.

This will be using all OEM parts.


User's Signature: 2010 T2000, CM871, 13spd, 977k, tanker yanker
Overhauled @ 927k
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10-25-2020, (Subject: Piston ring/engine break in procedure ) 
Post: #2
RE: Piston ring/engine break in procedure
No reman parts if you can help it, especially the head/cams. And, a new head comes in the big crate, the reman come in the skinny crate. If it is a reman, it will have rx on the head, welded at the backside of it. Just order a new head, that way you are sure of what you are getting, and when I bought mine at the dealership down at Rawze's house, there was no core required.

Break in, drive it like you stole it!

The oil, we poured in the oil that originally came out of the motor and added a few gallons to top it off. We also used a pump to pump the oil into the motor down by the oil filter, we waited to see the oil coming up into the head, and then we topped off. We then drove it around for a bit, and then took her down to Speedco and had them change the oil, I used what I always used, regular old Rotella. I drove it for around 4,000 miles and changed it again, and then went to normal service intervals at around 15,000 miles.

No clue on the rod bolts, quick serve should have the answer. If in doubt, get new ones.

The head bolts are stretch bolts, I replaced all of mine prior to installing the new head.

Rockers, just get new ones, don't gamble on this stuff.

New wrist pins too, do not skip those.

I would put new piston cooling nozzles in too, you are in there, do it right. One of those older ones break or fail... Not worth the gamble.

You said you had the tool to cut the ledges, but do you have the tool to measure the liner heights? You will need one of those too. The shims, we used brass, some use stainless and yes you can stack them. If you need a certain thickness that is not available, a good machine shop should be able to make up a set for you.


User's Signature: 2008 ProStar, OEM 600hp CM-871, 18spd, 3:42, in framed in Rawze's driveway. Every day is a fresh new episode of, "The Twilight Zone"... Rod Serling lives rent free in my head. I can smell the Chesterfields.
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 Thanks given by: dhirocz , JMBT
10-25-2020, (Subject: Piston ring/engine break in procedure ) 
Post: #3
RE: Piston ring/engine break in procedure
i beleive hagg has his rods sent out to a shop to be remanned i think they are shotpeened to strengthen them and remove any defects. new head as waterloo says comes in big box reman in skinny the new ones box is made of sturdy plywood you could jump ontop of it drop is off the truck whatever it wont break whereas a reman comes in a box that might just implode if you look at it wrong.

otherwise just replace all the replaceable parts with OEM new parts where possible.


User's Signature: 2010 Lonestar - CM871 - 13sp - 3.70s, 2016 T680 - cm2350 - 13sp - 3.36s - skateboarder
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 Thanks given by: dhirocz
10-26-2020, (Subject: Piston ring/engine break in procedure ) 
Post: #4
RE: Piston ring/engine break in procedure
I guess the 'less than sturdy' boxes remans come in are the ones made of particleboard not plywood then?

I'm kind of leery on rocker arms...the last 2 I replaced when my cam went flat at 685k were both duds, neither had the oil passages drilled for the followers. Cummins, of course, when I told them this, ensured me I was wrong. When I offered to send photos, they declined. I'm sure they would rather avoid it so they weren't on the hook for a valve cam. I did luck myself into a box of rocker arm bushings, and I have a press...

I was planning on rebuilding the jake rockers again, including detents, and replacing the rocker shafts as well.

Liner height tool, I'm guessing it's like a deck bridge? Got one.

As far as breaking it in goes, I can certainly do that. A loaded trailer back and forth across the talmadge bridge a few times would do that, as well as some in town driving loaded after the initial break in. Both things I can do.

If I build an identical replacement out of frame, which is an option, I may send the crank off to see how far out of balance the stock crank is. I would be willing to bet, quite a bit.


User's Signature: 2010 T2000, CM871, 13spd, 977k, tanker yanker
Overhauled @ 927k
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10-29-2020, (Subject: Piston ring/engine break in procedure ) 
Post: #5
RE: Piston ring/engine break in procedure
Dhirocz, sounds like you have a fun project ahead of you. I am not far behind you man, I will probably be doing mine next year sometime.


User's Signature: Anti-seize EVERYTHING, Except injectors...Use Petroleum Jelly!!!
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