K341 build

[Gregor 4,846]

The parts for my other project are still at the media blaster, and I have no clue when I will get them back. Could be a week, could be 6 weeks. I needed something to do, so I decided to at least take the K341 off of my brand "X" tractor, and get started on it. I have already replaced the carb, coil, plug, points, condenser, and all fuel lines on the tractor just to get it running. I don't know if it needed all that, but I did it anyway. It didn't seem to run too bad, but like I said, I need something to do.

 

I have said before, every time I work on another engine, I learn something new. I learned a lot today. Before I took it off the tractor I stripped off the muffler, carb and linkage, coil, condenser, valve cover, and a few other incidentals. I wanted to do a leak down test. This is a shaft driven, hydro-static tractor, and I thought it may be easier to hold the crank in place, while still on the tractor. I got the motor to where I thought TDC would be, and checked through the little peep hole for the timing mark. Didn't see any. I thought this would be a good time to watch a video. I found 2 EXCELLENT videos on performing a leak down test on a Kohler. I believe the videos are actually put out by Kohler.

Leak Down Test

 

Understanding A Leak Down Test

 

These videos are both well worth your time, if you have not seen them. In the past, one of the problems I had trying to do a leak down test, was holding the motor at TDC during the test. The first video explains, IF you actually have you motor at TDC you don't have to hold it. It will stay there by itself. Whooda thunk? I found this to be true. There are no vice-grips, wrenches, pipe wrenches, or any other device holding this motor at TDC. But don't jar anything too much, because it will take off on you, even at 20 psi.  It also explains that the key way in the crank shaft will line up parallel with the cylinder, IF you are truly at TDC. I found this to be true also. Again. Whooda thunk?   Once I had the motor at TRUE TDC, the timing mark was clearly visible.

Here hare the results of my leak down test.

With a pressure of 80 psi from my compressor, my cylinder showed 74 psi. This calculates to a drop of 8%. I think that's pretty good. I don't see any reason for a complete overhaul of this motor. I will however open it up and remove the balance gears. (I think) Is it possible to remove the balance gears without removing the rod and crank?  I may also lap the valves but then again, like they say, "If it aint broke, don't fix it"' I will replace all the gaskets and seals using ONLY OEM Kohler parts. I've had enough of those ebay kits.

This is as far as I am going today. Tomorrow I will yank it off the tractor, and get it on my stand. I'll remove the head, and see what I can see. There appears to be red RTV Silicone on the valve cover gasket, which leads me to believe someone has been into this motor before. I'll find out just how far they have been, tomorrow.

[oliver2-44 9,764]

1 hour ago, Gregor said:

Is it possible to remove the balance gears without removing the rod and crank? 

Yes sort of!!  I recently removed the balance gears from a K301. You need a good snap ring pliers with 99 degree points. The 1st gear came out Ok. The 2nd gear I just could not quite get off the shaft due to the crankshaft counter weights. I took a sharp cold chisel and gave the narrow section of the cast iron gear with a hammer. It broke and came right off

 

The K341 has thicker counter weights so I suspect you will need to do the same

[Jeff-C175 7,202]

@oliver2-44

 

Oliver, I know you posted this over in my thread also but I figured I would ask here...

 

Did you have any 'symptoms' that the balance gears were 'in trouble'?  Was there a 'rattle' at any particular RPM range that led you to believe the gears were about to 'grenade'?

 

 

[ebinmaine 67,671]

Excellent post with great timing. 

Having just gotten hold of another K341 I do need to (at the very least) replace the head gasket. 

I'd like to do leak down tests on several engines we have here.  

 

What's the source of your Leak down tester?

 

 

[Gregor 4,846]

15 minutes ago, ebinmaine said:

What's the source of your Leak down tester?

https://www.harborfreight.com/cylinder-leak-down-tester-64918.html

[ebinmaine 67,671]

Is there a specific reason you bought that particular one instead of a less-expensive one? Better variety of adapters? Is there something different about the tool?

[Gregor 4,846]

At the time I bought it, no. It was simply the one I grabbed. Now I'm glad I got the more expensive one.
In the first video the technician explains how to check your gauges, before hooking them up to the motor. His set had a 5 psi discrepancy.

On the cheaper, ($25.00) set, the second gauge does not show psi. It simply shows percentage of leakage. I guess this would be fine IF in fact the 2 gauges showed the same psi before the test. On the cheaper one, I don't know if there is a way to test this.

 

Edit  Also, if you notice on HF web site, the less expensive set is being sold at a "Clearance" price. To me, this means once they sell out of these, they won't be selling them any more. I have to think there is a reason for that.

Edited November 2, 2021 by Gregor

[oliver2-44 9,764]

@Jeff-C175

That engine came to me on a parts tractor so I never ran it before I opened it up.  It was missing the dipstick so I opened it to clean it out.  The bearings and shaft defiantly had some wear.  
 

I recently bought a $100 NOS K301 that I’m on the fence about opening up and removing them. 

Edited November 2, 2021 by oliver2-44

[Gregor 4,846]

I have decided to pull the crank, rod and piston, and also remove the balance gears. If I can get the magnetic clutch off.

There just doesn't seem to be a good way to get a good hold on this thing to pull it. Looking at the balance gears, there is some slop, but I am not familiar enough with balance gears to know if it is excessive or not, so I will just yank them out. I don't believe there is any way to do it with the crank and rod in place. Also, there is less than .002" end play in the crank. Maybe this isn't really a problem, but it's less than the book calls for. I don't intend to remove the cam or valves. I don't think I can improve on the 8% leak down, so I see no reason to.

Some one has been in here before. Of course I don't know if it was 3 years ago, or 30.

The piston is .020" over. I can't say about the crank. I will hone the cylinder and reassemble with the same rings, as long as they are in spec. There was virtually no carbon build up on the piston or valves. I'm guessing whoever was in here before knew more about what he was doing than I do, so why mess with anything I don't have to.

Oddly enough, There was a 3/8" lock washer laying in the bottom of the pan. No idea where it came from, but it was definitely there. Should I replace it with a new one? I don't think so.

I think I may have put my garden hose and power washer into winter storage, a but too soon.

[richmondred01 2,237]

Make sure you measure the piston too. The cylinder may be within spec however, I’ve seen several aftermarket piston and ring sets, out of the box, .002 and .003 off. If it wasn’t mic’ed prior to being bored then this will cause an issue. 
Also check your valve seats and lap in the valves. 
 

Edited November 2, 2021 by richmondred01

[953 nut 55,325]

4 hours ago, oliver2-44 said:

I recently bought a $100 NOS K301 that I’m on the fence about opening up and removing them.

The bearings on the balance gears are the common failure item. With a NOS engine you pave several hundred hours of operating time before there should be any concern.               

[Achto 27,609]

To remove a magnetic clutch, there should be a threaded hole in the end of the shaft for the clutch. Run a bolt into that hole and it should bottom out on the crank shaft. Keep tightening the bolt, this will push the clutch off from the crank. 

[Gregor 4,846]

1 hour ago, Achto said:

To remove a magnetic clutch, there should be a threaded hole in the end of the shaft for the clutch

This is not a Wheel Horse tractor. This is brand "X". I'm afraid I have no such hole, but I did manage to remove the piston /rod, and the bearing plate. Then I could simply drive the crank through the clutch with my dead blow hammer. Came out quite easily that way.

After checking the crank pin, I believe the crank has been turned .010". It measures 1.4875. Stock is 1.5000. That's a difference of .01250. If I am reading the book right, that is not ideal, but it is what it is. All this motor has to do is drag my butt around, so I think it should be good enough for that. 

As usual, keep in mind these are not top of the line instruments.

 

Back to the leak down test.

While doing the leak down test, I checked the valve lash to be certain the valves were indeed closed during the test., and they were, but.............

I also noticed while the cylinder was under 80 psi pressure, the valve lash was much tighter, than when no pressure was applied. Is this normal? Has anyone else experienced this? Does it mean the valve springs are weak? With a 92% seal rate, I have to believe the valves are sealing very well under compression, but it left me wondering something. Should valve lash be set while the cylinder is under pressure? I have never seen instructions like that in them manual. I guess I will continue to do it as I always have, but I thought it was interesting anyway.

For the record, of the 8% loss I was experiencing, some was coming through the intake valve and out the bore where the carburetor would normally be, and some past the pistons, and out the oil fill tube.I am not replacing the rings, but I will hone the cylinder just enough to get rid of the shine, and get a cross hatch pattern. When I put this thing back together, I'll see if I maintain the 92% seal rate. I actually expect it to drop some, until the rings seat themselves in. All KOHLER gaskets and seals are ordered.

[oliver2-44 9,764]

17 minutes ago, Gregor said:

After checking the crank pin, I believe the crank has been turned .010". It measures 1.4875. Stock is 1.5000. That's a difference of .01250. If I am reading the book right, that is not ideal, but it is what it is. All this motor has to do is drag my butt around, so I think it should be good enough for that. 

As usual, keep in mind these are not top of the line instruments.

The .0125 clearance seems a little large, but maybe the machinist ground it to the actual rod size.  It might be good to get some Plastigage and verify that your your rod clearance is not too large.  

 

[Gregor 4,846]

1 hour ago, oliver2-44 said:

The .0125 clearance seems a little large, but maybe the machinist ground it to the actual rod size.  It might be good to get some Plastigage and verify that your your rod clearance is not too large.  

 

Actually, I have Plastigage. Maybe I should learn how to use it.

 

I watched "Eric The Car Guy". I watch him a lot. Simple explanations without a bunch B*******. Here are the results of my Plastigage test. Rod cap torqued to 17 ft lb. Doesn't seem like much, but that's what the book says. Hard to get a real clear pic, but it's between .0015 and .0020  If I am reading the book right, this falls within spec.

Edited November 2, 2021 by Gregor

[Snoopy11 5,714]

11 hours ago, oliver2-44 said:

I’m on the fence about opening up and removing them

I don't like balance gears, as they rob power. BUT... I have never removed any without going with stronger rods... so... 

 

Don

[Gregor 4,846]

Seems every time I clean and paint parts for a motor, I think I'm done, but there's always one more piece in the bottom of the bucket. I think I got them all. Normally, I would not paint a motor gloss black, but if things go as planned, I expect EVERYTHING on this tractor to be shiny.

[Gregor 4,846]

The K341 is back together and breathing after it's balance-gear-ectomy. I performed another leak down test after it rand for 10 minutes. The video I watched suggested doing the test on a warm engine. All I did to this motor was remove the balance gears, adjust valve lash, hone the cylinder, and replace gaskets and seals. I also removed and sealed off the fuel pump port, as this tractor will get an electric fuel pump, eventually. K341The leak down test showed 85% seal rate (15% leak down) on a warm engine. I still think thats pretty good.

 

 

K341 Video

[ebinmaine 67,671]

15% is perfectly respectable

[Fordiesel69 263]

So you did replace the rings after the cylinder hone job right?

[Gregor 4,846]

18 minutes ago, Fordiesel69 said:

So you did replace the rings after the cylinder hone job right?

No, I didn't.