Partial overhaul on Yanmar 3TNE88

[Domush]

Will this be your first diesel overhaul? If so, feel free to check out part 3 in my signature. It is nearly the identical tractor.

My gut reason is worn compression ring or simply rings with lined up notches. I don't understand how you are not getting blue smoke when burning that much oil. It is obviously going somewhere and not magically vanishing.

It seems mutually exclusive to have burning oil and blow by, yet high enough compression to burn cleanly.

Sent from my SCH-I500 using TractorByNet

 

[Mechanos]

Will this be your first diesel overhaul? If so, feel free to check out part 3 in my signature. It is nearly the identical tractor.

My gut reason is worn compression ring or simply rings with lined up notches. I don't understand how you are not getting blue smoke when burning that much oil. It is obviously going somewhere and not magically vanishing.

It seems mutually exclusive to have burning oil and blow by, yet high enough compression to burn cleanly.

Sent from my SCH-I500 using TractorByNet

Yep... that's what has me scratching my head. The excess vent gasses are quite blue in color and are leaving an oily footprint on the tie-rod below the vent tube.

 

[Mechanos]

Domush... I skimmed through the thread, but didn't try to read it all. Is there a Cliff's Notes for that thread? :laughing:

Anyway, our engines are quite a bit different. Yours had liners, mine does not. Yours appears to be indirect injection, mine is direct injection. etc. etc.

What I did read... after you got it running it was still smoking, just not as much? Did this ever get sorted out?

 

[Tx Jim]

Marvel mystery garbage!!!!! It won't fix anything, maybe mask some symptoms for a while. If you could put it on a steady load that puts it close to max output for several hours and run a slightly lower viscosity oil it may loosen the rings if that is the problem but more than likely there is permanent damage that only an overhaul will cure.

kuboman
Take a deep breath. I don't believe in "snake oils" as a magic overhaul in a can/bottle. But Marvel Mystery oil has been around for a long,long time AND might help loosen stuck piston rings. It's definitely worth a try. BTW won't adding MM oil to existing oil lower viscosity as you suggested???? Have a nice day,Jim

 

[Tx Jim]

All I did was price parts from JD. I think as I stated in my reply to kuboman that MM oil possibly could help loosen the rings. If rings are worn out or collapsed then replacement of them is the ONLY CURE.

 

[Mechanos]

A slow soaking rain all day yesterday turned my project site into a sloppy mud hole. Looks like I will have a few days to tinker with the engine a little and perform a compression and leak-down tests... that is, if I can get the injectors out. The Service Manual suggests using fuel line nut from an old fuel line, but I don't have an old fuel line. So, I need to figure out another way to pull the injectors.

 

[Mechanos]

Looking through the Yanmar TNE service manual there is a trouble shooting chart. One of the possible causes of excessive oil consumption AND escessive blow-by gasses is improper oil viscosity. The last time I changed the oil, I used Rotella T 15W-40. According to the chart in the TNE manual, it should be 20W-40. Wouldn't think there'd be that much difference between the two to cause the symptoms I'm experiencing.

 

[Mechanos]

I've been working the tractor pretty hard with my massive dirt moving project. I ran it for 8 hours today... and I noticed that sometime today, my hour meter quit working. The tach still works fine, it just stopping counting hours. Anyway, I'm starting notice the engine losing power. Under load, it's starting to look like it has two exhaust pipes... on off the muffler and the other one off the valve cover. :laughing: The vent tube is huffing and puffing a lot of blow-by gasses. Yesterday, it was about 35 to 40 degrees out and the tractor would not start without plugging the block heater in for a while. I'd say it definately has compression issues.

I was hoping to get my current project done and then get into the engine over the winter. Now, I beginning to wonder if it's going to make it. I plan to keep working it and keeping a close eye and ear on the engine. If I have to, I'll pull it out of service to deal with the engine and the project will have to wait.

My compression tester adapter showed up today, but I haven't received my tester yet. After looking at the adapter, I not sure that it is going to work with the coupler on the adapter. Seems like I just can't win on getting the right tools to diagnos this engine.

 

[Mechanos]

I lucked out and the tester I ordered is compatible with my adapter. Now I can find out just how bad off the old girl is.

 

[Mechanos]

Well, an overhaul is eminent... but I fear there's not going to be anything "partial" about it. Over the weekend I ran a compression test which showed about 300psi on all 3 cylinders. Spec for this engine is 498 +/- 14psi. Leak-down testing revealed that all three cylinders are passing substainial air past the rings and some leakage past the exhaust valve on No. 1 cylinder. So, the tractor has been pulled out of service and is parked in the barn awaiting a tear down.

I talked to my JD dealer to see who they use for machine work and then called that machine shop. He said he has done hundereds of these little Yanmar diesels. He said that it's been his experience that the vast majority of the Yanmar's he's worked on had either broken rings or broken pistons (collapsed ring lands) both of which usually take out cylinder walls. Since the only oversized pistons for this engine are 0.25mm (0.010in), which aint much, he usually has to overbore the block, sleeve the cylinders, and then bore the sleeves back to standard bore.

Assuming that this machinist is correct (I haven't torn the engine down yet), I called up my Yanmar parts distributor and started getting prices on parts... pistions/rings, rod bearings, main bearings, cam bearings, valves, gaskets etc. Again, if the machinist is correct, I'm looking at somewhere around $1,600 for parts and machine work.

My plan is to start by removing the head and pulling the pistons with the engine still in frame to do some inspection and/or measurement. I'll go from there depending on the results of the inspection.