Piston Rings Worn Out, Time for a Rebuild

[Jeepsinker]

Alright good to know. Just don't want to ventilate a brand new block.

 

[welldigger]

If you spin a bearing or throw a rod you either had a faulty part or did something wrong. Either way it was going to happen regardless.

 

[Wildchild467]

Start it and see if you have any leaks, noises, screw ups on assembly. Idling is what kills a new engine. How far is it to the dyno?

If it were in my hands, run 1 gear down, 50-60 hp at say 18-2000 rpm til the stat opens, put a little bit more power on it, 75-80 hp and run there for 5 min, pull the rpm down to peak torque and put your foot to the wood increasing 100 RPM every 5 or so mins to rated speed. Done. Be careful when using a dyno, it is WAY different than driving and it WILL find any issue you have in the engine, cooling system or drivetrain.

Just put a load in the bed and drive it on the highway for an hour.

We are going to towbar it to the dyno. So the first time it will fire up is on the dyno. We can even get the rollers spinning ahead of time so soon as it fires, its game on. Maybe when it is running the initial lighter load, I can check for leaks then.

So what was the idea behind how the TM says to break in a new engine? Theirs is a lot more in depth and has more steps to get up to the full power load. What was the reasoning they had for their process?

 

[o1951]

Sounds like a plan!
Since you have use of dyno, I would follow TM. Don't see how you can hurt anything doing that.
Absence of specific instructions, we all have our own ways of breaking in a new or rebuilt engine. Obviously some methods are better than others. I was never one to fire it up and jump on it. I went thru a gradual procedure similar to what tm says, but not as involved. I used either break in" oil or an inexpensive oil and changed out oil and filter immediately at conclusion of break in. Always had good results, but most of my rebuilds were gasoline engines.

 

[daytonatrbo]

We are going to towbar it to the dyno. So the first time it will fire up is on the dyno. We can even get the rollers spinning ahead of time so soon as it fires, its game on. Maybe when it is running the initial lighter load, I can check for leaks then.

So what was the idea behind how the TM says to break in a new engine? Theirs is a lot more in depth and has more steps to get up to the full power load. What was the reasoning they had for their process?

In my understanding, the "gentle start" is to seat bearings and the other components. Then you have to get on it before you glaze the walls and while you still have a cutting edge on the rings.

For the rings, its better to get it going right off, as long as you have oil flowing and the oil is warmed up.

The rest of the engine needs a gentler wakeup, so you end up with a compromise.


However, modern oil, and better manufacturing processes lessen the need for both (when speaking of more modern engines.)

 

[rustystud]

In my understanding, the "gentle start" is to seat bearings and the other components. Then you have to get on it before you glaze the walls and while you still have a cutting edge on the rings.

For the rings, its better to get it going right off, as long as you have oil flowing and the oil is warmed up.

The rest of the engine needs a gentler wakeup, so you end up with a compromise.


However, modern oil, and better manufacturing processes lessen the need for both (when speaking of more modern engines.)

If you used a good assembly lube on all the bearing surfaces and cam lobes then after you get full oil pressure it's OK to get on the engine and make it go. Remember your crank and rods are actually riding on a layer of oil, not the bearings themselves.

 

[mark salanco]

I tore my deuce engine down the other day, I was surprised to find the 12 point rod bolts in it. The rebuild Tage said 6-1-98.
Did they start replacing the rod bolts back then?

 

[o1951]

Good practice to replace rod bolts at every rebuild.

 

[m715mike]

This thread epitomizes everything I like about the SteelSoldiers website! Someone enjoying the hobby (at least he was when he started this thread) had a desire to document a major project and share the information for others to learn. There has been camaraderie and support the entire way in the form of help turning wrenches, ideas and suggestions from experienced people all over the world, use of equipment, and even Gimp's offer to donate an engine if things go south on the dyno. The amount of information and data shared in this thread is, in my opinion, invaluable. Also, the bits of humor sprinkled in added to a really good read. Now all we need is a happy ending.


A desire to purchase new rod bolts and bearings for my multifuel engine and the search function lead me to this thread. After finding what I needed and reading a few pages, I flagged this thread to read when I got more time. That was today. I just finished reading this entire thread! Wow! My eyes are about to pop out, but I have learned a ton.

Also, Tom, thank you again for taking the time to answer my questions via PM. That was a big help! I'm pulling for you and (staying positive) looking forward to hearing about the excellent results you have breaking your engine in on the dyno.

 

[cattlerepairman]

Not to side-track, but I will have to break in my engine the normal way - by driving. After install, I will need to idle the engine to ensure it runs reasonably well, compressor builds air and that there are no leaks before I get going. How long of an idle period is acceptable before the engine gets loaded?

 

[mark salanco]

I am in the process of rebuilding my engine, I was looking through the TM for additional information. TM9-2815-210-34-2-2, page 142,
It's list's 2 different cylinder liners. Each liner has a different OD.
Liner Y OD is 4.7516 to 4.7520
Liner Z OD is 4.7511 to 4.7515
Anyone replacing liners, better make sure they get the right ones.
All of my liners are Z.

 

[rustystud]

Not to side-track, but I will have to break in my engine the normal way - by driving. After install, I will need to idle the engine to ensure it runs reasonably well, compressor builds air and that there are no leaks before I get going. How long of an idle period is acceptable before the engine gets loaded?

Use your shop air to fill the tanks. That way your not waiting on the compressor. As soon as you have good oil pressure start driving it. You can drive conservatively until the engine reaches operating temperature, then get on it hard !

 

[o1951]

Wildchild- any updates?

 

[ShawnIfert]

The newer industrial diesels I have seen lately like a C15 does't have a long skirt and have two compression rings and make 600 hp with 30 psi boost. Like you had said, the newer martials used make a difference. The thermal dynamics of the new alloys keep the pistons and rings tight in the bore at operational temperatures.

 

[o1951]

The newer industrial diesels I have seen lately like a C15 does't have a long skirt and have two compression rings and make 600 hp with 30 psi boost. Like you had said, the newer martials used make a difference. The thermal dynamics of the new alloys keep the pistons and rings tight in the bore at operational temperatures.

How many total rings?

 

[WillWagner]

Cummins is using 3 on all the product since from around 1995 . The rings on the 15l fall off the piston...they are larger than the piston before a compressor is installed

 

[ShawnIfert]

one compression one intermediate and a oil ring. three. They run all day long on site get about 2.6 mile to the gallon if they were going down the road fully loaded. I have pistons the size of old big coffee cans here from the engines with two compression ring. The ldt and lds are not a race car like the engines here, just a design from the 50's/60's.

 

[ShawnIfert]

I have a funny story about that. My old boss years ago told me he had one **** of a time putting liners in a ldt. He pressed them in. He was the head of maintenance for three continents and I asked did you read the manual, he said no. I then told him there are two liners available for that engine and he pressed Y liners into a Z block!! it ran fine he said!! lol He asked me if I had a problem. I told him no, they dropped in and I put the correct liners for my engine in !! lol

 

[o1951]

Thank you for the information. I believe ring tension would have to be much higher with only 3 rings.

 

[ShawnIfert]

No it would not. The newer materials would have a greater tension when at temperature with the combining influence of the piston exaptation and the rings staying nominal. So what I am saying is the piston closes the gap the rings stay the same and that the piston adds tension.