Advice Breaking in rebuilt 6V92?

[bobk]

Engine had a coolant leak. Rebuild included kits, all bearings including mains, fresh and raw water pumps, etc. Also changed T-stats to 170 dgree as posted elsewhere. I have run about 20 hours so far mostly at about 1150 RPM, but the time includes running up to 1400-1500 for a couple of hours as well as 2000 rpm for maybe a half hour and some time at 700 and 1000 rpm in slow speed zones.

Any advice on oil change time and operating speed? Other things that I'm not smart enough to ask about?

Bob Kassal
Chateau de Mer
1981 48MY

[captddis]

I made a comment on another thread. Will say it again here. For the first 20 hours slow speed should be avoided as it will glaze up the liners. I guess it is a little late for that but try to run it up more on the rest of the trip. 1900 to 2000 is fine. Change oil after 10 to 20 hours. Reset injectors and valves after 100 hrs. Then use as normal.

[Canuck Dennis]

I thought these were supposed to be broke right after rebuild,,i.e. 8 hrs at varying rpm's under load including wot. ??

[Genesis]

Yep.

Run it long enough to know that it's not going to detonate right up front due to something dumb, then get a load on and get it good and hot, varying load and RPM within the "on boost" normal operating range.

Low-speed running should be avoided until you've got 20-50 hours on it if you can, as you need to make sure the rings seat properly and combustion pressure + heat helps with that a lot.

I'd change oil at 20 or 50hrs and then on a normal schedule. If you run oil analysis expect somewhat high numbers for the first 200hrs or so.

[krush]

I made a comment on another thread. Will say it again here. For the first 20 hours slow speed should be avoided as it will glaze up the liners. I guess it is a little late for that but try to run it up more on the rest of the trip. 1900 to 2000 is fine. Change oil after 10 to 20 hours. Reset injectors and valves after 100 hrs. Then use as normal.



Yep.

Run it long enough to know that it's not going to detonate right up front due to something dumb, then get a load on and get it good and hot, varying load and RPM within the "on boost" normal operating range.

Low-speed running should be avoided until you've got 20-50 hours on it if you can, as you need to make sure the rings seat properly and combustion pressure + heat helps with that a lot.

I'd change oil at 20 or 50hrs and then on a normal schedule. If you run oil analysis expect somewhat high numbers for the first 200hrs or so.

yeah.

[REBrueckner]

After experienced mechanics put in new 8V71TI liners, rings, pistons, and after engine warm up and leaving the dock....the boss wanted me to run my engines at WOT for an hour while they checked temps,for any leaks, etc..
I was told to run the engines nomrally no "babying" required......

These guys rebuild or refurbish at least a dozen two cycle DD annually....

[Boatnut]

yeah.


Yup, I agree with Krush

[bobk]

Thanks guys. I hate to push so hard ($$$ and I'm cheap) but if it makes long term sense, so be it.

Bob Kassal
Chateau de Mer

[Kiwipushrod]

The theory is to make WOT RPM's as soon as possible, because the increased ring travel at higher RPM's keep the rings from cutting a ridge in the cylinder wall, short of the pistons full, possible travel.

I learned why, about 20 years ago after boring a Chrysler 440 six-pak motor. After I started it and made some checks, I then inadvertently left the motor to idle for about 25 minutes. After a few thousand miles it began to use oil.

After the second teardown, I found the upper compression rings on three cylinders had chipps missing and scored their respective cylinders.

I would'nt be real worried about Your motor, it sounds like You did it close enough to right. . . Use it.

Kiwi

EDIT: And if Ddis told Me to "Change oil after 10 to 20 hours. Reset injectors and valves after 100 hrs. Then use as normal.". . . I would.

[Genesis]

Yeah, I'd check the injectors and valves after the first oil change at 20 or 50 hours, but if it was done right I wouldn't expect to find them out of spec. IF they are, fix it and check again at 100hrs. If it's out again SOMETHING IS WRONG.

[captddis]

Yeah, I'd check the injectors and valves after the first oil change at 20 or 50 hours, but if it was done right I wouldn't expect to find them out of spec. IF they are, fix it and check again at 100hrs. If it's out again SOMETHING IS WRONG.


With new heads the settings usually are still ok when checked. With rebuilt rockers etc it is not unusual to need readjustment. My experiences, YMMV.

[spartonboat1]

The theory is to make WOT RPM's as soon as possible, because the increased ring travel at higher RPM's keep the rings from cutting a ridge in the cylinder wall, short of the pistons full, possible travel.

I learned why, about 20 years ago after boring a Chrysler 440 six-pak motor. After I started it and made some checks, I then inadvertently left the motor to idle for about 25 minutes. After a few thousand miles it began to use oil.

After the second teardown, I found the upper compression rings on three cylinders had chipps missing and scored their respective cylinders.

I would'nt be real worried about Your motor, it sounds like You did it close enough to right. . . Use it.

Kiwi

EDIT: And if Ddis told Me to "Change oil after 10 to 20 hours. Reset injectors and valves after 100 hrs. Then use as normal.". . . I would.

Above reflects what I first heard in the 1970's, about building ridges. If a Hemi was re-ringed, "take it out for about 6 full bore runs" and they were seated for most part.

I believe that 2-cycle diesel rings are different from 4 cycle gas engines, in that the rings are pinned, so they will not rotate around the piston. Is that true? I do know that gas 4 cycle rings are reported to rotate around the piston at about 3 revolutions/minute per 1,000 rpm, as a function of each combustion cycle, which causes them to expand out to the cyl walls. So the rings are not static but very active in expansion, contraction, and rotation.

[captddis]

No pins on DD, have seen them on outboards.

[Kiwipushrod]

The only piston rings I've seen that are pinned, are to keep them from rotating and are on 2 strokes that stroke deep enough to pass thru cylinder wall porting. That way the ring gap can never get caught on a cylinder wall port.

Kiwi

[saltshaker]

I made a comment on another thread. Will say it again here. For the first 20 hours slow speed should be avoided as it will glaze up the liners. I guess it is a little late for that but try to run it up more on the rest of the trip. 1900 to 2000 is fine. Change oil after 10 to 20 hours. Reset injectors and valves after 100 hrs. Then use as normal.
Dave,
I have a 45min run at slow no wake speed then I usually run 1950-2000rpm. The first couple of times I ran her after the rebuild, I kept her under 2000 rpm. Only brought her up to WOT for about 5 mins. After that we ran her around 2000 rpm and short runs at WOT to check that all is well. Do I need to be concerned about the 3/4-1 hr run each way at idle speed? My mechanic also recommend a 10-20 hour oil change.

[krush]

There's lots of theory out there on break ins. The one I go with is that you need to run the engines somewhat loaded to build up enough combustion pressure in the cylinder to push the rings into the cylinder wall hard enough to let them wear in and seat. Otherwise they may glaze over--and this causes improper sealing which leads to blowby and excess oil consumption.

Flogg 'em!

[captddis]

Dave,
I have a 45min run at slow no wake speed then I usually run 1950-2000rpm. The first couple of times I ran her after the rebuild, I kept her under 2000 rpm. Only brought her up to WOT for about 5 mins. After that we ran her around 2000 rpm and short runs at WOT to check that all is well. Do I need to be concerned about the 3/4-1 hr run each way at idle speed? My mechanic also recommend a 10-20 hour oil change.


I would not loose any sleep over it. The idea is not to run for extended periods of slow running.

[saltshaker]

Thanks Dave.

[bobk]

With new heads the settings usually are still ok when checked. With rebuilt rockers etc it is not unusual to need readjustment. My experiences, YMMV.


The rockers were not touched, and my mech had the same thought.... check the injectors etc, but he does not expect anything to change. He sets the injectors with a dial indicator.

Be that as it may, what are the symptoms I need to watch for that will suggest something needs to be adjusted. I have a mech in Port St. Lucie who does DD work, but would prefer not to let anyone other than the re-builder touch it uintil I get back next year.

Thanks again for all the advice. I was going to change the oil this morning, but perhaps I ought to wait and get a few more hard running hours on it first???

Bob Kassal
Chateau de Mer
1981 48MY lying Hampton, VA

[Boatnut]

I know it's been mentioned before, it might be a good idea given you have a new rebuild, to have an oil analysis done when you change oil. Do an analysis everytime you change oil, it is worth it, it can tell when a problem may be developing.

We used to have analysis done on our heavy gears on the radar systems in Alaska, it was amazing how acurate the analysis was, and avoided a lot of unscheduled down time.

[Genesis]

I think you're fine Bobk. You won't hurt anything changing the oil "too often" other than your wallet.

I'd pull oil analysis for the first 500 hours or so on 100hr intervals (at oil changes) along with the first one at 20-50hrs. You SHOULD see high wear metals on the rebuild originally (iron and chromium in particular from the rings seating) but by 200hrs or so they should be within normal limits.

[SKYCHENEY]

Internet forums are interesting places. You tend to get all kinds of advice, some good and some suspect. In the case of engine rebuilds, I would tend to trust the advice of the guy who did the work. It's different than asking how to wax your hull as most of us have experience with that.

I'm not trying to discredit anyone here and most of what I hear corresponds to what I've been told in the past from my mechanics. I'm just curious as to who really has hand-on DD rebuild experience on this site. You don't have to brag yourself up if you don't want to and I can understand being reluctant to chime in, but it sure would be helpful. I know, anyone can inflate their resume, especially online. Just thinking out loud, I guess.

Hopefully I have many hours before I'll need to do this, but..........I'm listening because I know that day WILL come.

[REBrueckner]

Hands on rebuild experience is likely not much of an indicator....we should be following DD manufacturer recommendations on break in's as they have likely done the actual testing and engine breakdowns to determine what works best.....it's like multiweight oil...used widely in Nova Scotia (not recommended by DD) ...or synthetic oil (not recommended by DD)....what people do and their own experience may not be the best guide....

I guess that's why "factory trained" mechanics should know more than most of us....

[Kiwipushrod]

Hands on rebuild experience is likely not much of an indicator....we should be following DD manufacturer recommendations on break in's as they have likely done the actual testing and engine breakdowns to determine what works best......

OK. But then why would We need or read thru a forum, We could just have an online DD shopmanual and pay a dollar to read thru it.

Kiwi

[saltshaker]

Internet forums are interesting places. You tend to get all kinds of advice, some good and some suspect. In the case of engine rebuilds, I would tend to trust the advice of the guy who did the work. It's different than asking how to wax your hull as most of us have experience with that.

I'm not trying to discredit anyone here and most of what I hear corresponds to what I've been told in the past from my mechanics. I'm just curious as to who really has hand-on DD rebuild experience on this site. You don't have to brag yourself up if you don't want to and I can understand being reluctant to chime in, but it sure would be helpful. I know, anyone can inflate their resume, especially online. Just thinking out loud, I guess.

Hopefully I have many hours before I'll need to do this, but..........I'm listening because I know that day WILL come.
I follow the advice and recommendations of the mechanic who rebuilt my engine. I may check her to see what others are doing but can't imagine making serious decisions based on a post from someone who hasn't even seen the boat. The information received is only as good as that given, and that's a best case scenario. Bad information can be damaging and very expensive to those who take it as fact

[Boatnut]

Hands on rebuild experience is likely not much of an indicator....we should be following DD manufacturer recommendations on break in's as they have likely done the actual testing and engine breakdowns to determine what works best.....it's like multiweight oil...used widely in Nova Scotia (not recommended by DD) ...or synthetic oil (not recommended by DD)....what people do and their own experience may not be the best guide....

I guess that's why "factory trained" mechanics should know more than most of us....

The difficulty is learning who on the forum really has the experience. The guys in the know will tell you the right way, and it's uaually in line with the manu specs. Their has been a fair amount of misleading information on many subjects that has cost some people extra money. Of course if anyone points out this erroneous information, it strangely disappears. We all make mistakes even when, even when trying to help others, deleting posts correcting misinformation is not the answer.

[captddis]

The rockers were not touched, and my mech had the same thought.... check the injectors etc, but he does not expect anything to change. He sets the injectors with a dial indicator.

Be that as it may, what are the symptoms I need to watch for that will suggest something needs to be adjusted. I have a mech in Port St. Lucie who does DD work, but would prefer not to let anyone other than the re-builder touch it uintil I get back next year.

Thanks again for all the advice. I was going to change the oil this morning, but perhaps I ought to wait and get a few more hard running hours on it first???

Bob Kassal
Chateau de Mer
1981 48MY lying Hampton, VA

You did not do a valve job as part of the rebuild?

[bobk]

You did not do a valve job as part of the rebuild?

The mech DID do a valve job. He did say that they looked fine, but it made no sense to not do it right. The heads got new tubes that the injectors are mounted in too. It's running like a dream. No more oil in the crap can either. I did change the oil today!

Bob

[krush]

I'm just curious as to who really has hand-on DD rebuild experience on this site.

Some people on this site do this stuff every DAY for a living. Their posts are the product of many years of experience. Other people on this site just quote manuals and try to talk it up.

It's up to you to figure out which is which.

[mobilemn1]

Karl,,,,,"Genisis",

I see on here for two years now that when it comes to engines,,,you seem to be an expert, with what always seems to be quoted from somewhere,,,,,Just out of curiosity on my part,,,,,,How many engines of any kind have you torn down and rebuilt from scratch yourself,,,,,,and the reason I ask is that some of the advice you give is sometimes not what you find in the real world.....and before I take advice from someone online,,,,I kinda like to know that they have done more than change oil, tighten a bolt, replaced a hose,,,,well you know what I mean......So please elighten me on your real world knowledge.

At least my curiosity would be satisfied,,,,

Thanks and waiting to hear"

[captddis]

Hands on rebuild experience is likely not much of an indicator....we should be following DD manufacturer recommendations on break in's as they have likely done the actual testing and engine breakdowns to determine what works best.....it's like multiweight oil...used widely in Nova Scotia (not recommended by DD) ...or synthetic oil (not recommended by DD)....what people do and their own experience may not be the best guide....

I guess that's why "factory trained" mechanics should know more than most of us....


He, he. Those manuals are full of things they DON'T tell you. Factory trained means they went to a few day course. I will take the guy with the beat up tools and grease under his fingernails any day.

[Avenger]

Hands on rebuild experience is likely not much of an indicator....we should be following DD manufacturer recommendations on break in's as they have likely done the actual testing and engine breakdowns to determine what works best.....it's like multiweight oil...used widely in Nova Scotia (not recommended by DD) ...or synthetic oil (not recommended by DD)....what people do and their own experience may not be the best guide....

I guess that's why "factory trained" mechanics should know more than most of us....Problem is.... there's no "factory trained" mechanics on this forum that I'm aware of. Probably because they can't make enough money to buy a Hatteras by working for some of the cheapskates that live here.

[q240z]

He, he. Those manuals are full of things they DON'T tell you. Factory trained means they went to a few day course. I will take the guy with the beat up tools and grease under his fingernails any day.HA! I second that! lol

[saltshaker]

He, he. Those manuals are full of things they DON'T tell you. Factory trained means they went to a few day course. I will take the guy with the beat up tools and grease under his fingernails any day.
1000% accurate. I do my own maintenance and some engine work. When it comes to the major issues I call the mechanic. The best mechanics always leave the big shops and go out on their own. Take a look at who is working on the commercial guys boats. Not likely to be the local Detroit dealer unless the engines are under warranty. When you see the dealer mechanics, they show up with the laptop, plug it in and then have to come back a few more times to figure out what to do. Most have no idea what to do with our old Detroits.

[Kiwipushrod]

1000% accurate. I do my own maintenance and some engine work. When it comes to the major issues I call the mechanic. The best mechanics always leave the big shops and go out on their own. Take a look at who is working on the commercial guys boats. Not likely to be the local Detroit dealer unless the engines are under warranty. When you see the dealer mechanics, they show up with the laptop, plug it in and then have to come back a few more times to figure out what to do. Most have no idea what to do with our old Detroits.

Then, They replace the wrong part for $1800, but it helps them in the diagnosis of whats really wrong, lol

After they swap out the $300 part and it's fixed, they blow smoke up Your a$$ and tell You it needed that $1800 part also. Why. . . Because the manual told them so. I've seen it quite a few times, from the inside.

Kiwi

[rsmith]

I always listen to the EX SPURTS

[saltshaker]

Then, They replace the wrong part for $1800, but it helps them in the diagnosis of whats really wrong, lol

After they swap out the $300 part and it's fixed, they blow smoke up Your a$$ and tell You it needed that $1800 part also. Why. . . Because the manual told them so. I've seen it quite a few times, from the inside.

Kiwi
I had a car that had a intermittentt starting problem. Every now and then the starter would do nothing when you turned the key. Ten minutes later it would start fine and not do it again for several weeks. The dealer kept changing sensors because the computer had a fault code for it. I let them change what ever they wanted since it was still under warranty. After 5-6 failed attempts to fix the problem, I got them to put in a new starter. Had that car for another 4-5 years and never had a starting problem again.

[Boatnut]

After experienced mechanics put in new 8V71TI liners, rings, pistons, and after engine warm up and leaving the dock....the boss wanted me to run my engines at WOT for an hour while they checked temps,for any leaks, etc..
I was told to run the engines nomrally no "babying" required......

ThesREBrueckner
Senior Member Posts: 3,254
Join Date: Apr 2005

Re: Advice Breaking in rebuilt 6V92? - Yesterday, 11:41 AM
--------------------------------------------------------------------------------
Hands on rebuild experience is likely not much of an indicator....we should be following DD manufacturer recommendations on break in's as they have likely done the actual testing and engine breakdowns to determine what works best.....it's like multiweight oil...used widely in Nova Scotia (not recommended by DD) ...or synthetic oil (not recommended by DD)....what people do and their own experience may not be the best guide....

I guess that's why "factory trained" mechanics should know more than most of us....

e guys rebuild or refurbish at least a dozen two cycle DD annually....

Were these guys factory trained DD mechanics, and was their break in done according to the DD recommendations?

[krush]

GE makes big turbines. They have year long "factory training". GE used to be GREAT...until all the great people that made them great gave the bean counters and Jack Welch the finger.

Now the running joke is,: "GE, we probably aren't the best, but you can be sure we're the most expensive!" and "GE, Imagine it works."

The small biz guy can't afford to have unhappy customers. DD "factory shops" can afford to piss off customers. It's pretty simple.

[Boatnut]

Along the same line, when I worked for GE, the saying was, you can buy better,but you can't pay more.

Now the people voted but they couldn't elect worse.

[rsmith]

GE makes big turbines. They have year long "factory training". GE used to be GREAT...until all the great people that made them great gave the bean counters and Jack Welch the finger.

Now the running joke is,: "GE, we probably aren't the best, but you can be sure we're the most expensive!" and "GE, Imagine it works."

The small biz guy can't afford to have unhappy customers. DD "factory shops" can afford to piss off customers. It's pretty simple.


I'm with krush on this one. Now old jiffy jeffry Imelts giving all the stockholders the finger

[SKYCHENEY]

One good thing that can be said for the DD dealer is that if you use them for a rebuild, you DO get a warranty and they WILL honor it. Some of the little guys may warrant their work, but they may not have deep enough pockets when everything goes to hell.

Example: I had a big CAT engine in a 100K lbs front-end loader rebuilt by CAT. On the second day after getting it back, it put a rod through the side of the block. As it turned out, someone forgot to torque the rod bearing caps. The end result is that Cat put in a new rebuilt engine. I have no idea what this cost, but I'm sure it wasn't cheap.

Obviously, the chances of having this kind of a problem from a big shop with several mechanics working on the same engine is higher than with the one man show. But, what would happen if you had a major failure like this under the warranty period for your rebuild on the boat? And what if it ruined the block and it was documented to be the rebuilders fault that caused it, AND it was in a MY that had to have the side of the hull cut out to get the block out? What then? I'll tell you what. They had better have some deep pockets and some good customer service.

Sometimes the cheapest price is not the only thing that matters.

[Kiwipushrod]

One good thing that can be said for the DD dealer is that if you use them for a rebuild, you DO get a warranty and they WILL honor it. Some of the little guys may warrant their work, but they may not have deep enough pockets when everything goes to hell.

Example: I had a big CAT engine in a 100K lbs front-end loader rebuilt by CAT. On the second day after getting it back, it put a rod through the side of the block. As it turned out, someone forgot to torque the rod bearing caps. The end result is that Cat put in a new rebuilt engine. I have no idea what this cost, but I'm sure it wasn't cheap.

Obviously, the chances of having this kind of a problem from a big shop with several mechanics working on the same engine is higher than with the one man show. But, what would happen if you had a major failure like this under the warranty period for your rebuild on the boat? And what if it ruined the block and it was documented to be the rebuilders fault that caused it, AND it was in a MY that had to have the side of the hull cut out to get the block out? What then? I'll tell you what. They had better have some deep pockets and some good customer service.

Sometimes the cheapest price is not the only thing that matters.


Point taken, but that's the reason for shop liability insurance. I'm sure the Cat dealer used it in Your senario.

Only two men should be responsible for one rebuilt motor, the builder who should also be the installer and the machinest. To Not torque rod bolts is inexcusable, I find it very telling to know just who that tech worked for.

Kiwi


EDIT: Another thing, that tech should have sold his tools, because the only tool he'd need at his next job would be a microphone headset, saying "Would You like Me to Supersize that order?"

[REBrueckner]

Do Detroit Diesel manuals have advice on break in after rebuild??

I don't believe I ever checked and my manuals went with the boat.

[Boatnut]

Do Detroit Diesel manuals have advice on break in after rebuild??

I don't believe I ever checked and my manuals went with the boat.

OK, where the mechanice DD trained? I just had to ask.

[Pete]

Just to add to the discussion of factory trained versus experience taught, here is my story. When I decided on the boat I wanted (48 LRC), before finding and buying one, I went to the 53 series DD "factory training center" at Covington Diesel in Greensboro, NC for their 53 Series rebuild class. Completed the class, got the Certification Certificate. Finally found the right boat, year later decided to rebuild the 453 engines and hired a small business guy who had been doing Detroit rebuilds for 25 years to do it. I was his helper, learned a lot, engines have run 10 years without a single problem. Trust me, you would rather have this small business guy do your rebuild than me, I made that same decision, and I was "Factory Trained and Certified".

Pete