Piston Rings Worn Out, Time for a Rebuild

[Wildchild467]

What valve work has been done?

Nothing. The heads were fully assembled NOS heads. Completely brand new.

 

[Wildchild467]

The cylinders seem glazed. I'm tempted to just hone my cylinders and reinstall the pistons (new style with 2 compression rings) with the same rings to see if the break in was an issue, but that is taking a chance. Do I need need new rings though ASSUMING that a break in was an issue... lets just say that right now for conversation. Do people just hone the cylinders and install everything again? I haven't heard anything about rings glazing, its always the cylinders from what I have read.

74M35A2 brought up a good point. So what do I do with my new style pistons if I abort putting them in and just use my old pistons with new rings? If I put the new style pistons back in after I hone the cylinders and they are still not working, then what? Do I really want to pull it apart again for the third time? No so much.


I can go two ways from here:

Route one: Put these new style LDS pistons back in it after I hone the cylinders and hope that running 100% diesel fuel during break in was the only problem.

Route two: Hone the cylinders and put my original LDT pistons back in it (with new NOS LDT piston rings) and change my oil squirters back to the LDT style. If I did this right off the bat, I would not have had this problem.

I know Route two will be a proven good runner. I don't know about Route one and not sure I trust the new pistons.

Anybody that is rebuilding a deuce engine as a result to blowby, here is my advice. If you pull it apart because of blowby and your pistons look good with only broken rings, dont buy new pistons. measure all the parts to see if they are in spec, chances are they are. Buy new rings ($10 a hole), hone the cylinders with a 240 grit ball hone ($70 shipped to your door), New head gaskets ($120), new intake manifold gaskets ($40) and maybe a pan gasket ($20-$30). So for about $350, you can have it back up and going, running good as long as your valves and such are in good shape. I don't see any advantage of these new style pistons for our application. Don't run the engine over 1200 degrees EGT and I'm sure everything would be fine.

 

[rustystud]

That's a hard one Wildchild. I would almost go with the new pistons again and some new rings (check the gaps) . The old pistons could have some distortion you cannot see.

 

[Wildchild467]

That's a hard one Wildchild. I would almost go with the new pistons again and some new rings (check the gaps) . The old pistons could have some distortion you cannot see.

Distortion where?

So say I get new pistons, same ones I had before and put it all together. I basically have the same thing I did before. Now, how do I get it to have less than 10% leakdown after I hit the starter switch? Were the parts junk or was my break in procedure wrong? You look up a break in procedure of a diesel and you can get 100 different answers.

 

[o1951]

The cylinders seem glazed. I'm tempted to just hone my cylinders and reinstall the pistons (new style with 2 compression rings) with the same rings to see if the break in was an issue, but that is taking a chance. Do I need need new rings though ASSUMING that a break in was an issue... lets just say that right now for conversation. Do people just hone the cylinders and install everything again? I haven't heard anything about rings glazing, its always the cylinders from what I have read.

74M35A2 brought up a good point. So what do I do with my new style pistons if I abort putting them in and just use my old pistons with new rings? If I put the new style pistons back in after I hone the cylinders and they are still not working, then what? Do I really want to pull it apart again for the third time? No so much.


I can go two ways from here:

Route one: Put these new style LDS pistons back in it after I hone the cylinders and hope that running 100% diesel fuel during break in was the only problem.

Route two: Hone the cylinders and put my original LDT pistons back in it (with new NOS LDT piston rings) and change my oil squirters back to the LDT style. If I did this right off the bat, I would not have had this problem.

I know Route two will be a proven good runner. I don't know about Route one and not sure I trust the new pistons.

Anybody that is rebuilding a deuce engine as a result to blowby, here is my advice. If you pull it apart because of blowby and your pistons look good with only broken rings, dont buy new pistons. measure all the parts to see if they are in spec, chances are they are. Buy new rings ($10 a hole), hone the cylinders with a 240 grit ball hone ($70 shipped to your door), New head gaskets ($120), new intake manifold gaskets ($40) and maybe a pan gasket ($20-$30). So for about $350, you can have it back up and going, running good as long as your valves and such are in good shape. I don't see any advantage of these new style pistons for our application. Don't run the engine over 1200 degrees EGT and I'm sure everything would be fine.

Well, I hate working on engines in vehicle, so I would go route 2 with clean diesel and Deere break in oil. If nothing is cracked, I would not expect to be in that engine again.

You have a LOT more patience than I have ----- the thought of a 3rd teardown and rebuild would make me consider explosives.

 

[Plane Fast]

Before you put it back together. You need to find where that coolant was coming from!

You'll have it right in no time.

 

[Wildchild467]

Before you put it back together. You need to find where that coolant was coming from! View attachment 607308

You'll have it right in no time.

When I took off the rear head, the nuts didn't seem to be as tight as the fronts, but there was not any sign of leakage on the gasket or the head. I am going to assume that isn't the cause of any problem right now. A possible cause of this sludge is the large amounts of blowby in the number 2 cylinder. At 95% blowby, that is a lot of exhaust gasses which carries moisture. When I drained the oil from the pan (it was sitting for a couple weeks), I did not see any coolant at all come out when I pulled the plug.

 

[Wildchild467]

Well, I hate working on engines in vehicle, so I would go route 2 with clean diesel and Deere break in oil. If nothing is cracked, I would not expect to be in that engine again.

You have a LOT more patience than I have ----- the thought of a 3rd teardown and rebuild would make me consider explosives.

I agree. These engines are not crazy complicated and I pay very close attention to detail. I have my buddy helping me and with two experienced heads and 4 eyes looking things over, we would catch something. With everything we see and the DATA we have, the piston/rings/cylinders is where all the blowby is going. The valves are seating great and are not causing the blowby. All the blowby is going past the rings. How nuts is it though that it has 95% blowby and has rings on the piston? It blows my mind how that can even happen.

 

[Plane Fast]

Man.. I would look the heads over real good. Did you use the magnaflux dye? I know they are new, but may have a defect.

 

[rustystud]

View attachment Scan0064.pdfView attachment Scan0065.pdfView attachment Scan0068.pdfView attachment Scan0069.pdfView attachment Scan0070.pdfView attachment Scan0071.pdf

Distortion where?
So say I get new pistons, same ones I h
ad before and put it all together. I basically have the same thing I did before. Now, how do I get it to have less than 10% leakdown after I hit the starter switch? Were the parts junk or was my break in procedure wrong? You look up a break in procedure of a diesel and you can get 100 different answers.

Hope this helps.

 

[gimpyrobb]

I wouldn't take out the dual squirters, they will help keep the piston cool with high egts.

 

[WillWagner]

When I took off the rear head, the nuts didn't seem to be as tight as the fronts, but there was not any sign of leakage on the gasket or the head. I am going to assume that isn't the cause of any problem right now. A possible cause of this sludge is the large amounts of blowby in the number 2 cylinder. At 95% blowby, that is a lot of exhaust gasses which carries moisture. When I drained the oil from the pan (it was sitting for a couple weeks), I did not see any coolant at all come out when I pulled the plug.

Negative ghost rider. Blow-by past rings does not carry moisture, unless the head gasket is failed and allowing coolant into the cylinder. The only way moisture gets into the crankcase to show what you have under the valve covers is from something failed, like a cracked casting, an oil cooler, but you will see oil in the coolant because oil pressure is greater than block pressure except at hot shut down, a failed head gasket...you stated the nuts didn't seem as tight on the rear head...a coolant cooled intake, or exhaust manifold. Rain water will do the same.

Did you pressure check the intake manifold?

 

[74M35A2]

I disagree. One of the two primary products of combustion is water. The other is CO2. Did not do any separate coolant leak checking beyond the 7psi pressure tester. He may do more upon reassembly, but he is not going over 7psi on the radiator per cap rating. He is going to hone the new cylinders, installing new rings on his old pistons, and put it all back together with new gaskets and such. Flush the WMO out completely all the way to the injectors, and replace with clean diesel, then we are going to tow it up to my work, lash it down, and break it in on the chassis dyno exactly how the manual states, 15hp for 30 minutes at xxxxRPM, followed by yyyy, etc..... He may pressure test the long block at a higher pressure before connection to the radiator, but at what point is there concern to blow out other components such as the oil cooler plates, etc....? Some people pick 20psi, but where does that number come from, especially if it is impossible for the cooling system to reach that? Not picking a fight, but just trying to gain from other's experience.

 

[daytonatrbo]

I disagree. One of the two primary products of combustion is water. The other is CO2.

Can't argue with that.

 

[Wildchild467]

I just want to say that even though we seem to be throwing around ideas, I appreciate hearing everybody's own wisdom and experience. Even if somebody has one idea that may not be right, it may clue us in to something else, etc. The idea is to learn from this so I can help out the next guy and give as much data (numbers) as I can. I can say it had low compression or lots of leakdown, but how much? That is why giving numbers may help out the next guy. I know this for sure, If I had to do this again, I wouldn't have put these new style pistons in. The main reason is lack of knowledge of them. Say the rings on the new pistons are made of something else that requires more breakin or a different procedure... Where do we find that data and procedure? I haven't seen it out there. I do know the procedure for the old rings and parts, so that is what I would go with. One weekend and having all the parts, you could swap in new rings for about $300 as long as no other parts are bad. I'll be keeping a close eye on the blowby when I have it on the dyno.

I have spent so much time and money on this engine to try and give it the best parts so it lasts a long time. Money does not always mean the best running machine. Its therapeutic driving it and it such a stress reliever, I cant wait to be back behind the wheel.

Hopefully the correct hone arrives today. I ordered one and the one that came to my house was an 3.5 inch hone instead of a 4.5 inch and it looked like somebody used it once already. I cant get a break working on this thing. I ordered head gaskets and one of them had a dented fire ring, so they sent a replacement. Its always something, but hopefully this weekend I can get pistons in and heads bolted down. That would be fantastic.

Again, thank you everybody for the support. It helps a lot when you are burned out with a project.

 

[Wildchild467]

Negative ghost rider. Blow-by past rings does not carry moisture, unless the head gasket is failed and allowing coolant into the cylinder. The only way moisture gets into the crankcase to show what you have under the valve covers is from something failed, like a cracked casting, an oil cooler, but you will see oil in the coolant because oil pressure is greater than block pressure except at hot shut down, a failed head gasket...you stated the nuts didn't seem as tight on the rear head...a coolant cooled intake, or exhaust manifold. Rain water will do the same.

Did you pressure check the intake manifold?

We did not pressure check the intake other than when we pressurized the cooling system with 7PSI at the cap. What are your thoughts behind the intake?

How would an exhaust manifold cause moisture in the crank case?

Thank you for ideas.

 

[74M35A2]

You may be one of the only members here to spool it up on a dyno. TM specifies break in procedure, and the final step of that is 64hp @ 2800rpm for a specified time. That is from the manufacturer and instructed to do from the military. WC wants to skip that step or reduce it to a different value that he is more comfortable with. I disagree, and say if it is specified, then it is a necessary step, it can hold it, and not blow up. He typically will not exceed 2100rpm (49mph) on the freeway out of fear his rod bolts are crying from the mass of the solid wrist pins. The 2800rpm was specified with the original rod bolts, of which he has since upgraded to the later and stronger style. They specify a specific break in procedure to maximize the longevity of the engine after. I could use some help by having a few others please chime in that their 465's have not flown apart at this RPM, and that if we are going through all the trouble to tow the vehicle up to my dyno, lash it down, and follow the TM procedure to an exact letter right from the initial start, then it doesn't make sense to skip any steps. Engine coolant temp, oil pressure, oil temp, and EGT will all be monitored continuously, in addition to a high speed frontal cooling fan. We will fix the RPM by locking in each dyno rolls speed as a fixed value, and then increase the engine load by adding throttle with a linear actuator until the target kW (hp) is reached for each step of the process, exactly how the procedure states to do so. Huh, sounds a lot like the stress test I went through a few years ago....

 

[gimpyrobb]

We did not pressure check the intake other than when we pressurized the cooling system with 7PSI at the cap. What are your thoughts behind the intake?

How would an exhaust manifold cause moisture in the crank case?

Thank you for ideas.

I forgot the intake manifold is water cooled. Have you had it checked for flatness? Coolant could leak into a cyl if not.

Would coolant cause the rings to glaze over? I would think it would hydro lock the motor, but I guess it could bypass the rings if there is an issue, right into the crankcase.

 

[gimpyrobb]

I have driven my truck at 2500rpm for many miles.

 

[74M35A2]

Thanks. The break-in procedure he gave me says 2800r's, so we are going 300r past that. I found one member say he drove for 300 miles @ 2900rpm the entire time on the governor, and his engine is fine. Now if I see a poster say all the rods flew out the oil pan on their engine at 2700rpm for no reason, I'll be concerned. But, I have yet to find such story. 64hp is nearly 50% engine load, and max rpm. This is probably to keep the liners from glazing!