YM226D Project

[winston1]

Should be 27 ft lbs. page 20-05-5 226 manual.

 

[bmaverick]

Big night tonight. I installed the pistons with new bearings and rings, got the oil pan back on, new oil filter, new head gasket and installed the head. Everything went super smooth up to this point - I used a bunch of assembly lube and triple checked torque specs before closing things up.

After torqueing the eight head bolts and 3 head assist bolts down I put the pushrods and valve wear tappets back in place and dropped the rocker arm shaft assembly on. The final step to secure everything was to tighten the rocker shaft assembly down using the brass looking nuts on the three stepped studs. I screwed the studs into place by hand and went to secure the nuts following the 40 ft lbs spec from the manual and ran into problems. The nuts started to snug down and then started spinning. The nuts appear to be stripping out on the studs and when I went to remove the nuts the entire stud came out instead. The nuts are now stuck on the studs and I can tell the nut or stud is stripped. Any thoughts on what went wrong?

I'm glad it's just the studs/nuts because that is easy enough to replace (I also have a spare set from the other tractor) but I'm not convinced if I were to try it again I would get different results. Is the 40 ft lb spec wrong? Is there a special technique that is required and I don't know about it?

The closest Service Manual I have is the YM169 of the 3T72 engine, It's close to your 3T75.

So, those rod bolts are near Winston's value (27) coming in at 20.2 ft-lbs.


You would need the Service Manual of

 

[tc197]

Well that's dumb. I was following along on page 13. Thank you Winston, at least it's an easy fix moving forward.

BMaverick, I think in your manual the part I'm referencing is the rocker arm support at 45-52 ft lbs, no?

 

[tc197]

Went with the 27 ft lb spec and got the rocker shaft assembly secured. Went ahead and adjusted the valves, they were extremely loose and I almost made another big mistake. Similarly to the 40 ft lbs vs 27 ft lbs, the valve adjustment in the manual had a typo and said .080” instead of .008”. I thought it seemed off and sure enough on another page in the manual the correct spec of .008” was listed (also confirmed by the sticker on the valve cover).

Installed a new belt and hooked up all the radiator lines. Added coolant and noticed a small leak along the new head gasket and a small leak at the bottom of the radiator. The leak at the head gasket has me confused. I did some searching online and people suggested retorqueing the head bolts after running the tractor for a bit. The leak is extremely small, and I’m wondering if it just needs to set properly after being run/heated for a few minutes. It’s definitely coming from between the block and head and not running down the side from somewhere else. Not sure where the leak at the bottom of the radiator is coming from yet. That one is a drop every 5-10 minutes or so.

 

[bmaverick]

... Similarly to the 40 ft lbs vs 27 ft lbs, the valve adjustment in the manual had a typo and said .080” instead of .008”. I thought it seemed off and sure enough on another page in the manual the correct spec of .008” was listed (also confirmed by the sticker on the valve cover).

rScotty over the years pointed out this problem with many of the manuals. Yanmar issued Tech Service Bulletins to correct these problems. The big trouble is, the people selling the manuals today don't give you the those TSBs to cover the discrepancies. So, doing all that work can and could get messed up badly.

It's a shamed that those TSBs for the YM Series are not made public anymore. How are people ever going to know ???

 

[tc197]

It’s surprising how many mistakes there are to begin with. It’s forced me to slow down and try to really understand what I am mechanically about to do instead of blindly following directions. Can’t say that’s a bad thing.

Tightened up a lower radiator hose and stopped the slow drip leak from the bottom of the radiator for now. If it starts up again I’ll get new hoses or swap out radiators. Still signs of coolant ever so slightly seeping out between the head gasket.

When I started tackling the second tractor I separated everything into old tractor parts and new tractor parts so nothing got mixed. As I re-assembled the new tractor I referenced the old stuff and slowly worked through the piles of bolts, nuts, and parts that came in a box to determine where everything belongs. I am now down to about 3 bolts, 2 washers and a nut that I am unsure of where they belong. I have a new valve cover gasket, exhaust gasket, and air intake gasket due in tomorrow - at which point I should be able to complete the assembly. I will then spend a decent amount of time attempting to figure out a use for the extra parts. Today I flipped through the entire manual looking at the diagrams and trying to pin point where they go without much luck. I will post pictures of anything I can’t figure out in case someone has an idea.

 

[tc197]

Parts are delayed, not sure what the deal is but they haven’t arrived yet. I have a few “spare” parts. Does anyone have any thoughts on where these items would go? It’s also very possible they have nothing to do with my tractor and just fell into a box while sitting in the previous owners garage.

 

[California]

I suspect you're going to get some wise-ass answers to that post!

 

[tc197]

I suspect you're going to get some wise-ass answers to that post!

Better than nothing . Worst case they stay in a box to the side and we see what happens

 

[ponytug]

Ok, full confession, reassembly with leftover parts is a recurring nightmare of mine.

I'd love to tell you that is an old style nylon Kimura seal backer for the main engine seal just to see the expression on your face, but the reality is I have no clue.

All the best,

Peter