94' Kubota M7950DT engine??

[North Idaho Wolfman]

Well guys I dont have any easier way to say it...... the compression never changed. We did more atf in the cylinders let it sit 3 days. Today I put the torpedo heater on the bottom of the engine to try and add some heat into the block while the atf was still in there. Then got that stuff out of the cylinders and poured MMO into them let it sit about an hour and half with the heater on the block again. I then got that stuff pyked out of the cylinders. Then wiped everything off and did a compression test on the first two cylinder from the rad and still no change. If anything they were a tad bit lower. We did adjust the valve lash right about 0.10. That didnt make that much any change.
Idk now can I Re-ring this tractors pistons without pulling the whole engine??? Like could a guy pull the head and the lower pan to get to the caps and pop the pistons out through the top. Plan to re-ring them and maybe put a slight crosshatch on the liners from a ball Hone and put back together?? Im at a wall and wondering how far its gotta come apart?

Reringing that engine in frame is quite an undertaking.
You need to get the head off and measure bores.
If they are too large you'll need to re-sleave the engine and that will require a complete tear down.

 

[Orange1works]

Reringing that engine in frame is quite an undertaking.
You need to get the head off and measure bores.
If they are too large you'll need to re-sleave the engine and that will require a complete tear down.

Well I suppose I get some time again here i will rip that head off. Today was a busy day I was fixing stuff on my car trailer and mowing today. Im on afternoons next week so I will see if I get a chance earlier to take that head off to check the bore.

 

[Orange1works]

Well everyone Ive been pretty busy at work lately. House stuff kept happening as well. I finally got a chance to get the head off then tonight I got the back piston out. The result made me way happier. The only ring that was free and loose was the top ring! The 2nd ring and the oil ring they were stuck in on the piston groove. How's that for a surprise! We checked the bore looks to be stock bore and stock pistons. The bore comes very close to ref. Spec. I dont think much there will be needed once the new rings are installed. I was smiling because the amount of less work machining and money spending will work out for me.
I plan to pull the engine as planned rering the pistons buy new main cap bearings and con rod to crank bearings. Im just gonna leave the wrist pin bearings alone. Then get a gasket set check the injectors over and probably a new clutch and resurface the flywheel too. Im hoping to fire the engine up on the cement pad first before we throw it back in the tractor. What do you guys think soo far??? Do I stand to gain alot more compression with that 2nd ring new and doing its job once reinstalled???

 

[North Idaho Wolfman]

DO NOT resurface the flywheel, that is the worst thing you can do to these, it changes critical dimensions.

If anything just knock off any crud on the flywheel with 120 grit sandpaper and call it good.

I personally would see how much a complete rebuild kit (new pistons, rings, bearings and such) would run you, it would make a huge difference in the rebuild.

 

[Orange1works]

DO NOT resurface the flywheel, that is the worst thing you can do to these, it changes critical dimensions.

If anything just knock off any crud on the flywheel with 120 grit sandpaper and call it good.

I personally would see how much a complete rebuild kit (new pistons, rings, bearings and such) would run you, it would make a huge difference in the rebuild.

It will be alot more to include the pistons and the liners and wrists pins valvejob etc. Doing the kubota parts available from a dealer or even some discount parts online it will be close to buying a good used low hours engine. These engine parts add up quickly then machine work on the liners adds up the liners come unfinished you have to install them then bore them to the size of the new pistons. That little bit right there of using the press and doing the liners then a hone was gonna be a couple grand in my area.
The flywheel I will definitely take a good look at it before I do anything. I assumed a good resurface would be the way to go if it will still perform with a sandpaper touch up that will save some more money.

 

[North Idaho Wolfman]

It will be alot more to include the pistons and the liners and wrists pins valvejob etc. Doing the kubota parts available from a dealer or even some discount parts online it will be close to buying a good used low hours engine. These engine parts add up quickly then machine work on the liners adds up the liners come unfinished you have to install them then bore them to the size of the new pistons. That little bit right there of using the press and doing the liners then a hone was gonna be a couple grand in my area.
The flywheel I will definitely take a good look at it before I do anything. I assumed a good resurface would be the way to go if it will still perform with a sandpaper touch up that will save some more money.

I said use new pistons, rings, bearings, you said it's still in spec so you do not need not liners.
And FYI: You can not simply press the liners in, and hone them.
They must be machine bored to size to get it to the proper size and shape, I done a few engines so I know what it takes to build them.

So don't heed my advice "DO NOT resurface the flywheel", you will likely end up putting the tractor together then find out low and behold you cant disengage the clutch completely and you end up having to tear the tractor apart again to replace the now out of spec flywheel.

Every WSM for older Kubota tractors I've read, makes it abundantly clear and bold to DO NOT surface the flywheel only replace.

 

[Orange1works]

I said use new pistons, rings, bearings, you said it's still in spec so you do not need not liners.
And FYI: You can not simply press the liners in, and hone them.
They must be machine bored to size to get it to the proper size and shape, I done a few engines so I know what it takes to build them.

So don't heed my advice "DO NOT resurface the flywheel", you will likely end up putting the tractor together then find out low and behold you cant disengage the clutch completely and you end up having to tear the tractor apart again to replace the now out of spec flywheel.

Every WSM for older Kubota tractors I've read, makes it abundantly clear and bold to DO NOT surface the flywheel only replace.

I wasn't being aggressive on my reply of the flywheel. If thats the way it looked im sorry it looked that way. Im here to gain knowledge of what I own to keep something old going over wanting a payment and to gain some new friends along the way. Ive read about the liners I didnt mean to write hone. That's why I wrote about me knowing they come unfinished when they are new and you have to open them up to spec once installed. Doing the piston also I still have to then buy the new piston then the the wristpin its con rod bearing its just more expense I was trying to roll with what I have without more money in the engine than I absolutely have to.
I figured if the engine had compression I would never be changing the pistons or rings out. Since its the rings that got stuck from sitting a long time gunked up I can get away changing them out to put money elsewhere on the tractor.
The flywheel was just my thought on its buried in that tractor and if its not true nows the time to do it. If its a major contributor when its newer (low hrs) or used (6700hrs my tractor) to still not machine it i will leave it alone and just do a new clutch only.

 

[JohnDB]

@Orange1works thanks for sharing your project with us, it's interesting because there are some similarities with my tractor (dry liners etc) which I think is the prior model series to yours. I'm watching progress.