How long for rings to seat after rebuild?

That's the thing with an "inframe". Inframe, rebuild, overhaul... They really don't define anything. There are 100 different ways to rebuild an engine. Some guys only have the head and pan taken off, replace 6 liners, slap it together and call it over hauled. Other guys take the whole engine right out and strip it down to bare block, remachine and actually replace every single seal and gasket. These are the ends of each extreme with a LOT of gray area in between. One guy can spend $3500 on minimum parts and do the job himself, and the next guy spends $40,000 to do absolutely everything possible. Most average overhauls do not touch about 1/3 of the gaskets such as oil cooler, oil filter header, front and rear mains, front gear cover and so on.

 

mines stoped at 90.000..detroit 500 series 60 12.7 with new everything

 

I'll probably get some flak for this, but you should not have to worry about breaking in new rings. Years ago, cylinders honing was not what it is today and it took a while for hard rings to seat. Today they do what is called a plateau finish. The cylinder is honed to the proper final grit, then a much finer grit is used for just a few strokes to knock off the peaks. This gives a near broken-in finish, it doesn't take long to break-in. The rings should be set up before your first load.

The fuel system should be primed, excessive cranking on the initial fire is not good. Once it starts, keep the RPM up to over 1000 RPM, and rev it up and down for a for about 5 minutes. Double check for leaks and get it out for a test drive and give it hard throttle as much as you can (I don't have a dyno, but that's a better option). Once the engine is up to temp, drive it another 15-20 min.

I have yet to have an "oil burner", so I'm sticking with what's working. When the driver asks me how he should break it in, I say, Don't idle excessively and don't lug it, just drive it. I bring them back in after 2-3000 miles for a double check and to change oil filters, but I let the oil run out to a full change.

The biggest mistake I've seen was not priming the fuel system, so they crank and crank them to get them running. The second mistake I've seen was letting them idle until the were warmed up.

 

sorry after thinking, it was after my gear train rework that I got the leaks. the first load out I lost all my coolant due to some one not tightening up hose clamp under water pump.then oil spraying out, stopped at another local shop I deal with & turned to be a big -o- ring near the top front of engine, I think cam o ring they said. I still have the old ring it has a chuck out of it. shop said it was pinched while being put in. now water pump has to be resealed. I just picked up new seal from freightliner to be put in when I can have done without losing time off work.

 

My procedure is almost word for word like Grape Ape's. I tell my customer's break it in like you are gonna drive it, other than idling.

 

As long as your bumping it up not dead idle then no big deal. As far as getting the pyro up to a 1000 I don't really agree with whoever told you that. I tell my customers break it in exactly the way you are gonna drive it, except excessive idle or lugging it. I would back out of it about 900 or 950 due to it still builds heat for a second before it starts cooling down. Used to to get a set of rings to seat you got them a touch warm that is true. Even then we only did it the one time. The way they fine hone the cylinders these days I don't think it's nessacary any more. A good easy first start, and hard throttle stabs while it's warming up from different Rpms are important to me. I feel that the rings are seated in the first couple hundred miles. I don't like to see one running warmer or using more oil than it used to after an overhaul. I also use break-in engine oil.

 

I have about 35,000 on my C12 since it's inframe and it doesn't burn much oil at all, which is good I guess. What I am wondering about... Since my over haul the truck smokes under hard acceleration or going through the gears under load. It doesn't smoke through out the whole acceleration just a good puff once I get back on the throttle after a gear change. The funny thing is is that before the over haul I had no smoke at all and now I do.

any thoughts?

thanks nick

 

Boost leak will make it puff black smoke like that. Was the CAC checked for leaks? If it's good I'd go ahead and replace all the hump boots (if they're the old ones) and double clamp them on the ends. Use John3P's method of dawn dish washing detergent to lubricate them when installing to ensure the clamps seal the rubber boot really well when clamping force is applied.

 

Now why would you want to seal a joint up with corrosive soap?