Hello all who read this. Sorry for it being such a long read.  I have an 08 6.7 2500 4X4 at 448,000 miles standard shift. I am almost stock as in I did a cal delete with the smarty race me pro. I keep it set at the 0 setting for fuel economy and that has worked out well. I went with a dual disc clutch when the stocker failed and started to slip under load. I also am using a K&N air filter in the stock airbox.  I use my truck for moving travel trailers and a daily driver. The truck developed a vibration some time ago. First thought it was the drive shafts had them rebuilt tires balanced. Used to it would only vibrate on the road now it vibrates sitting still. I can look at the engine running and see it shaking just a little and as I increase the engine speed I can feel it in the whole truck sitting still. The vibration was there long before the new clutch so that is not the issue. I have been told maybe a harmonic balancer or motor mounts. However looking at the cost of those items I don't want to just throw parts at it. The injectors are quiet but I guess they could be going out with this many miles. I run the Howes fuel additive on almost every tank of fuel. On occasion when I have neglected to use Howes the injectors would rattle a little. Sounds kinda like lifters tapping. When that happens I just crank up the smarty to 3 for a little while to increase the fuel pressure along with some Howes and that seems to silence them.  I keep up with the maintenance myself as in I do all my own work. The oil and filter is changed every 7-10,000 miles  I don't use the dealer for anything other than warranty or recalls. This is my first diesel so I am new at learning about them. I am a very good mechanic as far as gasoline engines. Not real sure as to where to begin researching the vibration on a diesel. The motor has never been broken into other than front and rear main seals, valve adjustments along with a couple water pumps and one of them was under the 100,000 mile warranty. I am hoping to make a million miles before rebuild (fingers crossed). I understand that stock injectors have a specific number that has to be programed into the computer of the truck for it to run properly and the dealer is the only one with the ability to do that (not positive on that). I have read many post on here about 2 cycle oil and aftermarket injectors. I just want to clear up the vibration. I know if I take it into a dealer for diagnostics they are going to look at the miles and tell me a set of injectors or possible valve job. I know there are good dealerships and bad ones. A few yrs back I kept getting a check engine light so I stopped into a dealer ship while I was on the road and they told me they thought it was the turbo. I could see the tech guy pecking on his computer and ever so often look over his shoulder at my truck. Dead give away he did not have a clue. LOL Anyway I passed on the new turbo. Turns out the map sensor was bad and was throwing the turbo code. As far as the 2 cycle oil what flavor and how much per gallon of fuel? What about the aftermarket injectors? Which ones would you use?  Sorry about rambling on. Any suggestions as to where to start on the engine vibration? Thanks.

a harmonic balancer would be easy to visually look at and see if the rubber is deteriorated at all.  Can you see movement at the motor mounts when the engine is running?

Check out what he^^^^^^^ said.

 

Tranny bolts to engine, and tranny X-member support would be guesses in addition to Hawkez as far as "hard" parts go.

 

I wouldn't rule out injectors at all.  Not with that many miles on them.  Do you run a "rail pressure" gauge??

 

Unless you've done the "deletes", I would not use 2 stroke oil in your 6.7.

 

 

Edited March 16, 20169 yr by dorkweed

On 3/16/2016 at 8:17 AM, mark402001 said:

I have an 08 6.7 2500 4X4 at 448,000 miles standard shift.

I would look at the injectors as well. Poor functioning injector can create a poor spray pattern and not ignite the fuel very well either making it rough. Excessive return flow could also bring rail pressure down making all the injectors fire poorly. The average life span of injectors is about 150k miles and most vendors would suggest having them bench tested. Rail pressure gauge or a scan tool that can read rail pressure is very handy. I would suggest OBDLink LX being its on sale now. Good quality scan tool and cheap in price.

I would also check the dampener for wear. The rubber on mine was protruding out both sides and my alignment marks were off by ~1/16". I went down to Rocky Mountain Cummins and picked one up...noticeable difference in how much smoother it is!

My balancer does not have a rubber in it. Mine is the solid type. I did all the deletes. I do not have any pressure guages or egt temp guage. I apologize for not getting back sooner. What type of 2 cycle and how much should I use? Thanks 

26 minutes ago, mark402001 said:

What type of 2 cycle and how much should I use?

Any 2 cycle oil will work. Preferred to be petroleum and not synthetic. 200:1 ratio is normal for CR engines.

27 minutes ago, mark402001 said:

I do not have any pressure guages or egt temp guage.

I highly suggest you at least get a boost and pyrometer gauges. Rail pressure would be a good too but you can get that with a live data tool like OBDLink LX or similar.

Mark you being down there in Texas heat means you should use 2 cycle all the more. For  as long as everyone has been doing it I've dumped in a full qt. per fill up. Might leave an ounce of residual in the qt bottle so I'm not standin there waiting for every last drop, but, I reuse the same qt. bottles every time. I found some with good caps and threading to hold tight when stored behind the seat.

I'm not yelling but want to........ Mark please get rid of that K&N Filter. That is the worse thing on a Cummins.

Edited March 20, 20169 yr by JAG1

6 minutes ago, JAG1 said:

For  as long as everyone has been doing it I've dumped in a full qt. per fill up.

@JAG1 Your a 2nd Gen 24V vs. 3rd Gen CR. Ratios are a bit different since they have pre-injection phase.

Edited March 20, 20169 yr by Mopar1973Man

2 minutes ago, Mopar1973Man said:

@JAG1 Your a 2nd Gen 24V vs. 3rd Gen CR. Ratios are a bit different since they have pre-injection phase.

OPPS Thanks for the correction there boss.

I've been putting in 1/2oz. of 2 stroke oil per 1 gallon of diesel in my '04.5 for years now.  Usually fill up with 31-32 gallons, so right around 16oz. is what I dump in.  I'm not real scientific about it either.................if an ounce more or an ounce less gets added, it's not a big deal.

As the OP pointed out he has a different harmonic damper that doesn't have the rubber ring. It's a viscous damper that is solid. 6.7 on the left  

 

Thats a lot of miles on CR injectors and would be my first thought with Internet troubleshooting. 

 

I agree on ditching the K&N.. They are called turbo killers for a reason, simply pure crap. 

 

I am not sold on 2 stroke on CRs and wouldn't reccommend it. Mine didn't like it, and the more I think/study it I just don't think it's a good idea in diesel fuel at all. 

 

Edited March 23, 20169 yr by AH64ID

15 hours ago, AH64ID said:

I am not sold on 2 stroke on CRs and wouldn't reccommend it. Mine didn't like it, and the more I think/study it I just don't think it's a good idea in diesel fuel at all. 

 

Care to elaborate on this??!!!  Lets get a discussion going!!

 

yeah adding lubricity into a fuel is bad? I think not. the beauty about the diesel engine is it was design to burn OIL regardless. peanut oil would even work. as long as it's clean enough for the fuel system, and doesn't build up an ash, or high carbon, Which we all know the proper TCw3 does not do. then it will not harm your engine. mine runs noticeably quieter, weather it's the lower ignition point, or just the lubrication it adds i like it. it's not like the government EPA or the fuel companies care about the quality of fuel you burn.

Yes our engines are more modern the the OLD cat's of days past, but the engine is more or less the same as it always has been, just the fuel system has changed, the compression may have changed. but the old design of the diesel still in tact.

one has to think of the after treatments systems on the newer trucks but for the most part ours should be safe.

Look at the flash points and specs of 2 stroke. At low load/combustion temps a complete burn is unlikely. 

 

When I ran it my exhaust got a sticky residue to it and my exhaust brake would stick. Since I stopped running it those issues are gone. 

 

Nothing wrong with added lubricity, but I would use something designed for diesel. 

 

There was a thread recently that had a different study on lubricity and 2 stroke did not get the praise many want it to have. It is intended to be an aresolized libricant and not a extreme pressure one. 

How do you plan on getting the score value back into the proper range and not causing premature wear?

Do you have another product that has a tested result on scoring values?

Edited March 25, 20169 yr by JAG1

He bought a third generation.   That's his plan, haha.  

4 hours ago, CSM said:

He bought a third generation.   That's his plan, haha.  

The mandate for "ultra low sulfur" fuel came after the the 3rd gens initially came out IIRC.

On March 24, 2016 at 11:49 PM, AH64ID said:

Look at the flash points and specs of 2 stroke. At low load/combustion temps a complete burn is unlikely. 

 

When I ran it my exhaust got a sticky residue to it and my exhaust brake would stick. Since I stopped running it those issues are gone. 

 

Nothing wrong with added lubricity, but I would use something designed for diesel. 

 

There was a thread recently that had a different study on lubricity and 2 stroke did not get the praise many want it to have. It is intended to be an aresolized libricant and not a extreme pressure one. 

John, you're one of the very few that has had issues.  I dunno??!!!

11 hours ago, JAG1 said:

How do you plan on getting the score value back into the proper range and not causing premature wear?

Do you have another product that has a tested result on scoring values?

 

I use Amsoil Diesel concentrate every fill up; however, additives are not what keeps the lubricity high enough to prevent failures. 

 

Think about it. There is a very very small percentage of people who use additive, and even smaller who use 2-stroke. Based on the doom and gloom on this website everyone who doesn't should have a failed pump, yet thst simply isn't the case. 

 

It is true that when ULSD first came out there were additive issues and lubricity issues but those have long since been fixed... Or trucks would be failing at an alarming rate. 

6 hours ago, dorkweed said:

 

John, you're one of the very few that has had issues.  I dunno??!!!

 

IIRC you aren't running an exhaust brake or a drive pressure gauge, which means you wouldn't be able to see the issues I was having. I made the assumption that if my exhaust brake was sticking that incomplete combustion was occuring. There were no other overly obvious signs but I quit using it pretty quick. 

 

 

1 hour ago, AH64ID said:

 

I use Amsoil Diesel concentrate every fill up; however, additives are not what keeps the lubricity high enough to prevent failures. 

 

Think about it. There is a very very small percentage of people who use additive, and even smaller who use 2-stroke. Based on the doom and gloom on this website everyone who doesn't should have a failed pump, yet thst simply isn't the case. 

 

It is true that when ULSD first came out there were additive issues and lubricity issues but those have long since been fixed... Or trucks would be failing at an alarming rate. 

 

IIRC you aren't running an exhaust brake or a drive pressure gauge, which means you wouldn't be able to see the issues I was having. I made the assumption that if my exhaust brake was sticking that incomplete combustion was occuring. There were no other overly obvious signs but I quit using it pretty quick. 

 

 

I would counter that by saying that if I had "incomplete" combustion, that my mileage would suffer.  That is not the case at with my truck.

 

Now granted;  I don't tow as heavy as you, but I tow a lot more than you.  Just saying.  I would guestimate that near 1/2 of the miles on my truck are towing miles.............................

Yeah only about 36% of my miles are towing over the last 3-4 years. 100% this week. I've been hauling road mix to build a side driveway and shop. 12K empty to the gravel pit and 24-26K GCW home. These trucks handle weight so nice! It's also amazing how effortlessly they can move 25K at 65 mph when it's a dump trailer vs a travel trailer. 

 

That at being said the time for incompete combustion is at low rpm and low load, especially on a cold engine. So idling or very high fuel efficiency (50mpg type downhill). Your diesel would still burn and get the fuel economy but the 2-stroke may not and you would get deposits. This is very common on 2-stroke engines, just look at what happens to spark plugs when they aren't ran with a heavy load. Granted 50:1 is a lot heavier concentration the oil will still react the same way. 

Edited March 26, 20169 yr by AH64ID