149 Winter Tear Down.

[Ambush]

My 149 did its last snow clearing job a couple days ago and now it’s on the operating table for some work. It will be a complete tear down on the motor. I rebuilt it three years ago, but the rings never did seat good in the new .020” bore. And because of a misunderstanding at the engine shop, the valve guides didn’t get replaced either. I’ll balance the crank while it’s out too

I’ll also be adding a three spool hydraulic valve to the left side loader post. That will let me add front and rear ports plus I’ll run my rear lift cylinder from it. More pressure and volume than the present circuit from the charge pump and I can have a float position on the sleeve hitch. A few other plans as well.

It will take a few months in between other things, so updates will be sporadic. Also have to order a few parts after the engine is disassembled and that seems to be a slow process now.

[CubDieselFan]

I like your operating table. What is the plan on the bore? Can you take 0.010 more?

[ol'George]

Your gallons per minute is determined by the displacement of your charge pump, the only to way to increase GPM'S is a separate dedicated hyd. pump.
Your systems pressure is determined by the shims of your implement relief valve if using the charge pump, or your system pressure relief it using a seperate hyd pump.
Engine:
Its difficult to determine if a cylinders rings "didn't seat well" its possible the engine didn't receive the proper finish honing, or the cylinder was oversize, or the ring gap was not set properly, or synthetic oil was inadvertently used
during break-in or the breather cover was not assembled properly are just a
few reasons for abnormal oil usage after assembly.

Balancing your rotating assembly will not normally be noticeable at normal governed rpm's of 3600.
And it is not recommended to go much over that as going 4000 will get you into unsafe territory with a stock cast iron flywheel.
When they blow up it ain't purdy what the shrapnel will do to human body parts, or metal parts for that matter.
A 3 spool valve is a handy addition to your system.
just some things off the top of my head to help.
Luck!

[Ambush]

It was a aftermarket piston/ring set and possibly just poor quality. My hope is just deglaze and rehash. The block was machined and honed by a very competent shop that still has skilled guys that know what they’re doing. Rings were fitted to the bore. I used straight thirty weight, but not break in oil. Same shop on the JD 321 and aftermarket market piston set, but I did use break in oil. It’s doing great a season later. I’ll use break in oil again because I have it.

The aftermarket pistons all seem to have a much thicker walled wrist pin than stock too, which adds even more to the balance deficiency. Plus removing the balance gears. I did a K321 in a JD last winter and it did seem to be smoother anywhere above half throttle.

I have a dedicated hydraulic pump and plumbing for the loader system now and I’ll plumb through the new valve to the existing loader joystick . I’m running 1,600 psi on that system, whereas my charge pump output is 650psi. Having repaired hydraulic components for close to thirty years, I never run any system higher than necessary.

[Ambush]

I pulled the motor and pulled it apart. Bore is good with just a tiny bit of piston skirt scruff. A quick scuff should be all it needs. I always shoot for about .015” ring end gap and I probably did on this engine too. These rings have about 100 hours on them, but it did burn oil pretty much right off the hop.

Now my ring gaps are. .022” on the top, .065” on the middle and .050” on the oil control ring. I’m not sure how to explain the discrepancy? Poor quality?

It doesn’t look like the 3/4” on either side of the gap on the top ring even hit the wall. No wear marks.

[Ambush]

I had some time so I bushed the throttle shaft bores since they were pretty bad.

[Ambush]

Got a few things done on the engine. The flywheel had two fins broken off. I’m guessing one by accident and the other to restore balance. I remember crudely checking the balance when I rebuilt the motor. But I wanted to eliminate that as a source of vibration. I set it up on small bearings to balance it properly. I ended up drilling two factory balance holes a bit deeper and I’m now satisfied it’s as good as or better than the factory

[Ambush]

While I was in a balancing mood I moved on to balancing the crank. My new .020” over piston is 50 grams heavier the original, plus I left the balance gears out last time. I wanted to bring the counterbalance value up to just over fifty percent. There were two holes drilled into the crank lobes from factory balancing, one twice as deep as the other. I calculated how much lead I’d need to get my 50% plus and it would fill the shallow hole and half the deep hole which would keep the end to end balance even. It worked out that a 5/8” coarse tap fit about right, so I threaded the hole to keep the lead in place. I also put a dimple inside to prevent the lead plug from ever turning.

I heated the crank lobes with a heat gun and melted the lead then poured. After checking the balance now, it worked out to almost 52%. Originally from the factory it was 46%. And 44% with the previous oversize piston.

My new piston rings gap at .008” on the top and .004” on the middle. I’ll have to take those out to .010”.

[West Valley G]

Pretty cool stuff. I am impressed for sure.

Ken

[DSarow]

Keep this going,this is going to be an enjoyable and informative post