L175 Restore Thread

[gpreuss]

Fantastic job so far!! I used to do things like that to dirt bikes - fixing them was more than half the fun or riding... Keep up the great thread!! A lot of good ideas here!

 

[aquaforce]

Nice labor of love here Stumpy. Good job on the pics too.
When I did my engine I was so engrained in the work that I simply forgot to take pics at times and looking back on it I wish I had taken a lot more.

FWIW- the head gasket was not available from the dealer and the O.E. is discontinued throughout the Kubota networks. I tried to find some old stock for the original thickness but not such luck. If you have your original head gasket you can measure the thickness of it and the replacement gasket and then to keep the factory combustion squeeze and clearance mil the difference off the block deck.
If you mil the block deck ((((((( BE SURE TO AVOID THE MOUNTING AREA OF THE INJECTOR PUMP )))))))) !!!!!!!!!!!
The injector pump is timed with shims and if you change the height of the mounting then your installed timing is off and you will have to do the timing of the pump all over again. My timing, as factory installed, was good so I didn't mill the pump mounting part of the block deck.

Now that you have the tappets out you might be best built to replace them. They are cheap and starting with a new surface will help against cam lobe wear. This new oil that is govt legislated doesn't have everything needed, ZDDP, for machined running surfaces as in the years of these tractors production. For this reason I also run the GM additive to replace the ZDDP in the oil.

You will also find the block runs directly on the cam journals..... no cam bearings. This is another reason to keep the engine oil as close to the production requirements as possible and that is almost impossible to do off the store shelf.

Here is the link to my engine building when I found the head cracked in four places. http://www.orangetractortalks.com/forums/showthread.php?t=434&highlight=liner
Great job and continue to keep us posted.

 

[Stumpy]

Hello again everyone!

It's been a while. I kinda fell off the horse and haven't been doing much work on the tractor or visiting OTT but I've started working on it seriously again in the last few weeks and it's high time I came back here.

To recap I discovered in May that one of the cylinder liners had shifted when it was overheated and after some dithering came to the conclusion the only way forward was new liners and pistons. Unfortunatly with this design that means everything has to come off the block and it has to goto the machine shop. To that end I took the front end off again and removed the timing gear train. My last post removing the block.

With the block on the bench I removed the flywheel and rear main oil seal housing again and then took the flywheel housing off the block. I think I mention this in one of the older posts but this engine uses a strange design for the main bearings. The rear and middle bearings are traditional split bearings except they're housed in round housings a few inches in diameter. These housings fit into borings in the block. The front bearing is also unusual as it's a solid bearing that's pressed into the block. It's also got four oil holes as it's the point where oil is admitted to the crankshaft drillings. The middle bearing boring and front bearing are visible below.

So unlike most car engines there is a piece between the bearings and the block itself. The rear housing is held in place by the rear oil seal housing. The middle is held in place by two pins, one that goes through the oil gallery and another up from the bottom. With these removed the whole crank can then be carefully tapped out the back bearing housings and all. Since I'm down here I there's no reason not to replace the main bearings even though they have less than a thousand hours on them.

I built myself a puller out of some 12L14 steel pucks, a chunk of 5/8ths threaded rod, and some square tubing. I installed the puller and to expand the block and shrink the liner poured boiling water into the water jacked and ice water on top of the puck inside the cylinder. Unfortunately despite several attempts and putting enough force on my rig to start to strip the rod they refused to budge. Perhaps the overheating warped them or maybe I should have tried dried ice but rather spend more money and risk damaging the block I bought the bullet and paid a little more to have the shop remove and install the liners. I had originally intended to use the same rig to pull the front bearing but after this failure I decided to let them handle that too.

So after my pistons arrived I took put the block in my truck and took it to the same place that did the head way back last January. I left the pistons and book with them incase they had any sizing questions. A week and $300 later I came back and my rusty old block had two new liners, a new front bearing, and had had 0.006 of material taken off the deck. They did machine the injection pump mounting too but I ordered a few extra shims to compensate. The liners were finish honed with a standard flat stone and they hit the clearance dead on as far as I can tell with my calipers. They washed the dust out of every nook and cranny of the block I checked.

Next it was time to change the shell bearings and reinstall the crank but it's late and I'm not sure where those pictures are so I'll continue another night.

 

[gurn]

Looking good Matt and welcome back!

 

[Stumpy]

Thanks gurn.

Now we start the long climb back up. First the crank bearings need to be changed. I cracked open the bearing carriers neat as you please and while there was a little scaring they still looked acceptable and measured within spec. Popped the shells out gently with a screw driver and then hosed the carriers down with brake cleaner. The new ones were installed by placing them above the carrier like a spoon in a shot glass and then pressing them down evenly with a piece of wood to make sure they seated properly. I triple checked to make sure I had the bearings in the right way, i.e. the oil holes lined up. I heard of a multimillion dollar ship engine being ruined because they put a bearing in upside down.

Next we want to check the bearing clearance. They are not a tight fit if you aren't aware of that. There is a gap between the bearing and journal of a few thousandths of an inch that the oil fills when the engine is running. This allows the bearing to roll around on a cushion of oil and prevents most metal to metal contact. Journal bearings are curious things. They are capable of very high loads but are dependent on the velocity of the two parts to maintain the separation. This is why they say not to lug an engine. Highly loading an engine at low rpms exceed the bearing's capacity, the oil film breaks down, and you get that lovely vibration as the bearings and journals contact.

Anyway it's good practice to measure the main bearing clearance before assembly. Not much I can do about it here and it's just a tractor but good practice none the less. I don't have a hole gauge so I made do with the calipers. I measured the journal first and when I was confident of my reading I hit the incremental zero button. Next I assembled a carrier, bearings and all and torqued it to 30 ft\lbs as per spec. When measured I got the clearance which as you can see was .0025, right in the middle of the spec.

I oiled the journals with a 5W-20 motor oil to try and avoid attracting too much dust and assembled everything on the crank. They'll get the correct weight oil later when I prime the oiling system. The carriers have numbers cast on the side that faces the front of the the block so they can't be installed wrong. Once I was satisfied with everything I bent up the new set of tab washers I made, oiled the front bearing, and tapped the crank and carriers back into position.

I don't have any pictures of the next few steps but you've already seen most of it. The rear main seal was reinstalled gaskets and all, followed by the flywheel. Next the crank timing gear, idler gear, and fuel cam were installed in that order. A little heating was required to get the crank gear on. All the gears have numbers stamped into them that align with ones on the idler. The clutch was reattached and the block bolted onto the rear half again. I've also reinstalled the hydraulic pump pto housing and the starter. I'm using gasket sealer on all cases joints in a probably futile attempt to make the case a little more water tight. The next step is to install the pistons and connecting rods however I've noticed one of my pistons has a ding in it and needs to be returned so I'm awaiting parts at the moment.

Unfortunately I'm only going to be able to prime the oil pump as it's geared to the crank gear underneath the cover and the oil flows through the cover to the filter and then back into the block. I can't turn the oil pump with the cover on and I can't pump oil to the galleries without the cover on. I'll come up with something.

 

[pmhowe]

Quote "Unfortunately I'm only going to be able to prime the oil pump as it's geared to the crank gear underneath the cover and the oil flows through the cover to the filter and then back into the block. I can't turn the oil pump with the cover on and I can't pump oil to the galleries without the cover on. I'll come up with something."

Once you have it assembled and closed up, can you turn off the fuel line, then turn the engine over with the starter to pump oil through the system? I used to do that with old cars.

 

[Stumpy]

Yeah that was plan A. I've done it with engines that have sat for a while too. Pull the spark plugs so there's minimal load on the crank and turn it til I get oil pressure. That's still going to leave the valve cams and journals high and dry til the galleries and crank fill up though. I'd also like to run the rings as little as possible in the bore til I'm ready to start it the first time. It's also gonna quite a few turns to prime the fuel pump. I don't see to many other options though.

 

[Orange Tractors]

Matt,

When assembling gasoline engines, I have always used white lithium grease on the bearings (along with the cam assembly lube on the cam and lifters) and lubed the pistons and rings with 30 weight oil when I put them in. The theory being that the lithium grease would last long enough for the oil to get to the journals upon startup. It also doesn't run out if you take a few days to get everything together.

I don't know how that would work for a diesel, but it makes sense to me.

I have always thought the rings will scuff/seal during the recommended 20 minutes for the cam to break in; and the old recommendation of taking it easy for (pick one) 500, 800 or 1,000 miles was for people to get used to having a more responsive engine than the old worn out one.

Robert

 

[rsluss3]

Stumpy, great job so far. I just found this site yesterday and searched L175 (since I just got one) and found your thread. I've learned a lot already. My steering shaft was missing on my tractor so I searched around, when you get to that part on your build you might want to check out ebay. There's a place on there that sells a rebuilt unit you just bolt on for about $385 delivered. I know you pretty much build everything yourself but it is an option. The pitman arm on the one they send isn't the same but other than that it seems to do fine. Yours will bolt right on though.

 

[Stumpy]

I do have some assembly lube that's designed to do the same thing. I've never heard of using lithium grease but I don't doubt I'd do the same thing. It's sticky as honey and I doubt it'll last longer than a day or two. I'm also a little wary of using it on the journals but that's probably what I'll end up doing.

Breaking an engine in is a long process though it's much quicker if you use a ball hone to add the final hone on the cylinders. But you're right, the majority of the metal is removed in the first run up to operating temp. Here's the theory I subscribe to.

Thanks rsluss. After what I paid for just the new steering case I probably should've gone that route. At the moment it's sitting on the back of the bench with a fresh coat of paint and no guts. Once I've got the front end back on and the engine running or close to it I'll put it together.

 

[Orange Tractors]

Your link made sense to me on the break-in procedures; although I hadn't specifically thought about letting the engine cool to ambient temps between running periods.

One thing they mentioned was oil changes: I have always regarded frequent oil and filter changes as cheap insurance. Its not that the oil gets worn out; the filters get clogged/ or fail, and for low capacity systems (less than two gallons) it isn't cost effective to run an oil analysis vice changing the oil and filter.

Robert

 

[lsmurphy]

Interesting thread..........thanks.

 

[Stumpy]

Agreed on the frequent oil changes. More certainly doesn't hurt anything. I do the mower once a season even though it only gets about 20-30 hours on it and the cars about every 5000 miles. The oil does get worn out though, it thins as it accumulates hours and the detergents and acid neutralizers get used up.

Got quite a bit done last weekend. Started by removing the pistons from the connecting rods. Simple wire clips help retain the piston pins, needle nose removes and installs them handily. Drift out the pins with an appropriately sized socket, pop the old bearing out with my fingers and here we are. Ugly huh? I don't think they came out that way so they apparently rusted a bit sitting on the shelf, probably from the salt my truck tracks in. Odd considering I never wiped the oil off but easy to fix. A quick run through the wire wheel on the bench grinder (best tool ever) has them looking good again.

Clapped the connecting rod in the vice with a rag and applied some heat to the wrist pin end of the rod. The bearing drifted out with a socket and a little persuasion with a ball peen. The new one pressed in on the drill press fairly painlessly though heat was required again. Installed the new pistons, pins, retainer clips, and bearings. I did order new rod bolts, they're highly loaded and were $2 a piece, cheap insurance. They've changed the bolts a few times as you can see, old one is on the left, new on the right. I measured them and they're nearly identical dimensionally despite the different appearances.

Next I installed the rings. Do yourself a favor and use a ring spreader to install the rings, they're very easy to snap. I found it easier to remove the backing wire from the oil control ring and install that in the groove before the ring. The middle and top rings are difference sizes so they cannot go in the wrong grooves. They all go in with the lettering facing up. I torqued the rod bolts and measured the clearance like with the main bearings. I had to use my verier caliper so I'm not to sure of the measurement but the clearance appeared to be 0.003 which is right where it should be.

I turned the crank to BDC and after lubing the bearing, journal, cylinder wall, and piston with engine oil dropped it into the cylinder with a ring compressor. The bearing shell dropped out of the rod the first time around and a gentler hand was required. The shell shifted a little and I used a flathead to gently push it back into position and then put the cap on finger tight.

Rinse and repeat and viola. Torqued everything to 30ftlbs, looked everything over and bent the tab washer on the middle bearing retainer. Then I install the oil pan and it's 40 bolts. It's easier on the wrist to get them started by hand and then use a 3\8th drive adapter on the drill to run them down.

Next I decided to clean the injectors and prime the pump. It took a remarkable amount of force to break the injectors apart. I couldn't break it loose even cranking it in my best vice and using a breaker bar. I finally had to break out the impact gun to get them open and then found out why they were so hard to open. It was good and rusty in there as you can see but the wire wheel and a 1\2" pipe brush cleaned everything up nicely. I took care not to touch the ground surfaces.

A new set of copper gaskets and aluminum washers on the fuel return fittings and we're good to go. I then filled the pan through the drain holes in the cam tunnel with some old 5W-30 gas engine oil I had sitting around. It'll only be in there for the first run up and the bearings will only see idle load on so it should be fine. I attempted to install the oil pump but the gear was such a tight fit on the new shaft I had to take it off and press the gear on using my drill press (and a hammer). It was a bit of a pain to tighten the bolts with so little clearance but it worked. Before installing I fill the pickup passage with oil and dribbled some into the pump rotors.

I primed it with a drill before I realized the gear wasn't going to go on so to prime I was going to have to spin the crank. I decided to use the starter but first I installed the fuel pump and filter and used a bottle to fill the pump through the filter. A little oil on the fuel cam bearings and lobes, a borrowed battery out of the lawn mower and it cranked til I got oil out of the pump's exhaust port and good fuel out of both pump nozzles. It was amusing to see the fuel drops jump out of the pump like a fountain. I'd have shot video but I couldn't hold my phone and hold the wire on the solenoid lead at the same time.

I also removed the idler gear and reinstalled it to reset the timing (it would have taking a lot of revolutions to get all the marks to line up again). I lubed the valve cam journals with oil and the lobes with some Permatex Engine Assembly Lube. The stuff is like honey and while I don't think it's going anywhere I'm a little concerned it will degrade before I can start the engine. We'll see.

 

[Stumpy]

I also took apart the throttle arm cover to clean it. The bushing that seals the oring was some sort of fiber board and was pretty far gone so I drilled out some 3\8ths washers to replace it along with a new oring.

The next step is to reattach the gear cover. Popped out the damaged front seal I installed from last time and pressed in a shiny new one with the drill press to make sure this one went in straight. I managed to do something useful with the cylinder sleeve puck I machined at least. When I went to reinstall the oring that seals the crank behind the front oil seal I realized the oring I installed last time was too big and didn't allow the metal retaining ring to contact it's backing plate. The oring would have had to take the entire 150+ ftlbs of the retaining nut and would've probably failed after a while. 3\32ths orings are to thick and 1\16ths is too small, I need a 2mm thick oring. I found a store on ebay that sells single orings with free shipping, $4 gets me two orings. I await the postman.

 

[gurn]

You're getting there Matt. You have a knack at making this a very enjoyable read.

 

[Orange Tractors]

You're getting there Matt. You have a knack at making this a very enjoyable read.

Agreed.

It sure is a lot more fun when things are going back together, isn't it?

Robert

 

[Stumpy]

Thanks guys. I do what I can.

And yes it is! I'm starting to see the light at the end of the tunnel. I'm getting ahead of myself but I really want to take this thing for a spin!

 

[gurn]

Thanks guys. I do what I can.

And yes it is! I'm starting to see the light at the end of the tunnel. I'm getting ahead of myself but I really want to take this thing for a spin!

After all this I hope to see a video of that days first spin.

 

[quinka]

Hi Stumpy,

My hats off to you, can't even leave your posts, sooo interesting explanations. I am toolmaker by trade and the machining you have done with what you have is beyond the best. Thanks for the info and pics as well as the write ups. I am sure we all envy you as I do to take on such a task. I would have gone with another engine (lazy I guess). I am going to put power steering on my L245DT soon (I hope) I took a part time job programming computerized (CNC) machines, so I don't have the time I used to have. I have a mill drill like yours that I just converted to 3 axis CNC machine. Going to build FEL on my B7100HST soon also and put power steering on it as well.

I would never have the courage to do what you are doing though. Thanks for all and I wish you the best with this project. Look at the satisfaction you will have when it's done. Don't look back, your doing a superb job. I envy your attitude and patience as well as your immense knowledge.

Best to you,

Frank

 

[Stumpy]

Ahh but this is so much more fun than an engine swap! As for having the courage it certainly is a leap of faith. I sometimes wonder if it's going to work at all or more correctly what critical part I've put in wrong that's going grenade the engine 20 hours in.

I may have to lay off for the next week or two, got some tests coming up but I made good progress this weekend.

This was unfortunately the best picture I got of a series (just got a new camera phone) but you may be able discern a healthy sheen of rust. We had a sudden warm spell last week, it was almost 60F. The first two days I noticed condensation on my truck's exterior (parked in the barn with the tractor) but thought nothing of it. Between the persistent wetness and the salty air from the truck every exposed steel surface rusted. Thankfully the head and gasket provided enough of a seal that most of the deck and head didn't rust.

Unfortunately one corner was apparently propped up slightly and though it's hard to see in the pic the forward most lifter bore rusted all the way down. The cam and journals were coated with motor oil so they're fine. I pulled the cam again and made a little tray with paper towels and then went at the bore with scotchbrite. It cleaned up fairly easily to my relief and I'm confident I caught most of the scotchbrite particles. Hopefully any that escaped will pass through the oil pump without too much of a fight. I did learn that my assembly lube turns sticky after a while and while would probably be fine I'd prefer at add it the same day I start it so final installation of the head will be one of the last things I do.

To ensure I don't end up doing that again I reinstalled the valve cam with a new tab washer, smothered everything in engine oil and dropped in the lifters. I got four new lifters because as mentioned before two of the old lifters showed abnormal wear patterns. The old lifter on the far right shows normal wear, it was rotating properly. 2nd from the right shows concentric scoring probably a result of excess valve load because of the overheat. On the two new ones to the left you can see the very slight taper ground into the lifter (larger dull area). When the cam lobe starts raising the lifter this results is a small turning force to rotate the lifter. The point of this is to even out wear on both the cam and lifter and more importantly to allow oil into the contact point. They tend to be touchy and are sensitive to proper break in, roller lifters are superior in every way except for cost which is one reason they are used on the fuel pump.

I was never thrilled with the way the new gasket fit so instead I used an instant gasket maker a friend told me about called Hylomar. After application it dries to a tacky film within a minute or so and upon installation the pressure causes it to flow into the gaps. It has the advantage being reusable, I can take a part off, and reapply without issues. I did a few test installations of the gear case to test this and it worked fairly well. I also learned that you can't reliably install the spacer the front oil seal runs on from the front. It almost has to be inserted from the inside and then slid over the end of the crank as the gear case is installed otherwise you risk the spring popping out of the seal.

I discovered I made a slight boo boo. This is the end of one of two helical gears that drive the tachometer. It fits into a slot in the end of the fuel cam and apparently it was misaligned during one of my test fits. It's bent and the tip is indented in two spots. I wet a rag, wrapped the gear and then heated the end with a MAPP gas torch and beat it relatively flat again. I then locked it in a vice and straighted it as best I could and ground the edges straight. It's not great and I'll have to check it after the initial break in but if it doesn't work I just take out the gear til I can get a used part (new not available).

I didn't get a chance to an after pic as everything was covered in white lithium grease shortly after but I installed the gear case tach drive and all. My new key didn't fit into the slot in the crank due to interference from the oil seal spacer but a little grinding and it squeezed into place. Locked the pulled down with my homemade "wrench" to a torque of about 10 hammer blows. Heh, I'm thinking I got around 150 ft-lbs on the nut. I used the old lock washer tab but on this one I had to option of bending a different section of the tab.

I think I showed this before but it's rather confusing so its worth repeating. These are the governor springs. The little one attached to the right arm (from this perspective) is called the start spring by Kubota and attaches to a stud on the gear cover. I believe it adds more fuel at cranking speeds to aid startup but I'm not positive on that. The larger one on the left attaches to the throttle arm as serves to counter the force generated by the fly weights behind the fuel cam gear.

I dropped the head in place, attached the intake and exhaust manifolds and put the valve cover in place just to remind myself how an engine is suppose to look. The head still looks a little rusty but that's mostly a trick of the camera.

Finally I reattached the front axle and put her down on all four feet again. Now I'm back where I was in April. Next I need to reinstall the radiator, refill the transmission and install the shifter plate, finish rebuilding and install the steering box followed by fuel tank, dash and wiring. After that I can finally install the head, check the injection timing, prime the oil pump, install the exhaust and fire it up assuming nothing else comes up.