Valve Lash Adjustment B9200 (PIC)

[npalen]

Been putting off checking the valve lash and finally got "arountuit" today. It was interesting in that three of the valves were excessively loose in the neighborhood of 0.025". These three were near the "radiator end" of the engine.
The three farthest from the radiator (at number 1 and 2 cylinders) were a hair snug so loosened them to get the 0.006" feeler gauge to slide easily. I used the mark on the flywheel to verify that the number one and then the number four cylinders were top dead center when adjusting according to the WSM.
I'm wondering why so loose on some and snug on others. The rocker arm jam nuts were all tight. I did check the rocker arm assembly mounting bolts to make sure they were tight.
Looking forward to working the old girl to see if setting the valve lash makes any difference.
Any ideas why so much variation?

 

[North Idaho Wolfman]

Been putting off checking the valve lash and finally got "arountuit" today. It was interesting in that three of the valves were excessively loose in the neighborhood of 0.025". These three were near the "radiator end" of the engine.
The three farthest from the radiator (at number 1 and 2 cylinders) were a hair snug so loosened them to get the 0.006" feeler gauge to slide easily. I used the mark on the flywheel to verify that the number one and then the number four cylinders were top dead center when adjusting according to the WSM.
I'm wondering why so loose on some and snug on others. The rocker arm jam nuts were all tight. I did check the rocker arm assembly mounting bolts to make sure they were tight.
Looking forward to working the old girl to see if setting the valve lash makes any difference.
Any ideas why so much variation?

The only reason the valves would be off that much is if something is very worn, or someone set them wrong.
With the valves were off that much it should make a huge difference in power.

 

[npalen]

I don't know the history of the tractor prior to the six years that I've had it.
I saw no evidence of the valve cover having ever been off. Makes me wonder if the lash was set correctly at the factory some 30 years ago.
Just seems odd that some valves would have so much more slack than others. I suppose worn cam lobes could cause that but why would some wear so much more than others.
The tractor seems to have good power handling a 5 ft roto tiller well.

 

[North Idaho Wolfman]

I don't know the history of the tractor prior to the six years that I've had it.
I saw no evidence of the valve cover having ever been off. Makes me wonder if the lash was set correctly at the factory some 30 years ago.
Just seems odd that some valves would have so much more slack than others. I suppose worn cam lobes could cause that but why would some wear so much more than others.
The tractor seems to have good power handling a 5 ft roto tiller well.

I've never heard of these engines wearing cams at all, and that would also be the first one that I've ever heard of that the factory was off that much.

When i set the valves on these engines, I watch the valve train and you can see when they drop to their lowest point and I run them around three or four times just to make sure.

If your valves were that loose they should have rattled like mad and you should have lost at least half the power out of the cylinders.

 

[npalen]

I'm not a mechanic by any stretch but tried to follow the WSM exactly. Some of the valves were definitely in the area of 0.025" gap.

It seems odd that the first two or three valves at the back end of the motor were very close to correct where the rest of them varied all over the place.

Attached is the WSM page showing which valves are adjusted when the #1 piston is TDC and the ones when #4 is TDC. Sorry for the "sideways" on the pic.

I do appreciate your feedback.

 

[npalen]

Try this for the pic.

 

[North Idaho Wolfman]

Don't get me wrong, I'm not saying you did it wrong!
I just saying that someone having adjusted them wrong in the past is a far more likely event that anything else.

I look forward to hearing how it starts and how it runs for you.

 

[whitetiger]

Been putting off checking the valve lash and finally got "arountuit" today. It was interesting in that three of the valves were excessively loose in the neighborhood of 0.025". These three were near the "radiator end" of the engine.
The three farthest from the radiator (at number 1 and 2 cylinders) were a hair snug so loosened them to get the 0.006" feeler gauge to slide easily. I used the mark on the flywheel to verify that the number one and then the number four cylinders were top dead center when adjusting according to the WSM.
I'm wondering why so loose on some and snug on others. The rocker arm jam nuts were all tight. I did check the rocker arm assembly mounting bolts to make sure they were tight.
Looking forward to working the old girl to see if setting the valve lash makes any difference.
Any ideas why so much variation?

Number 1 cylinder is the one closest to the radiator. Maybe why you have such a variance in the lash.

 

[npalen]

Wow! Thanks for that info! That puts a whole new "twist" on it and more than likely explains the wide variances.

I'm guessing that I will find the rest of the valves are "loose" as well--the ones that checked near the correct lash because of them being at other than TDC.

Makes sense that #1 would be at the front but I mistook "gear case" as meaning the transmission instead the timing gears at the front. Rookie mistake.

Thanks again and will report back.

 

[npalen]

OK--got the valves readjusted with number one cyl at the front end (radiator) of the engine.

Got a question:
Will the lifter (tappet) necessarily be at the lowest point on the cam when the piston is at TDC? Reason I'm asking is after setting the lash to 0.006" at TDC I'm finding a lower point on the cam (more lash) after turning the engine to a random point in its rotation.

The engine starts and runs fine but this additional lash thing is throwing me.

 

[North Idaho Wolfman]

Like I said earlier I would not go by the TDC rules, they are too confusing.

Just turn the motor by hand, then when you see the valve start to compress, back it off a little and set the valve, do this a couple of times to confirm the lash is right.

And thanks to Whitetiger for catching what I had missed with you having the direction of #1 wrong.

 

[npalen]

I've never heard of these engines wearing cams at all, and that would also be the first one that I've ever heard of that the factory was off that much.

When i set the valves on these engines, I watch the valve train and you can see when they drop to their lowest point and I run them around three or four times just to make sure.

If your valves were that loose they should have rattled like mad and you should have lost at least half the power out of the cylinders.

End of saga, I hope.
I found that your method here is the only way I could get the lash adjusted "properly" and it purrs like a kitten.
Trying to use the markings on the flywheel simply did not work for me as I apparently don't understand them fully and could never be sure when #1 cylinder was at TDC or I was off by one revolution.

Here are the markings on the flywheel:
1.4/FI and then another 10 degrees or so 1.4/TC
then another half revolution
3.2/FI and then another 10 degrees or so 3.2/TC

I'm sure that TC means "Top Center" but not sure about FI.
Perhaps it means "Fuel Inject"?
Would make sense, I guess, that fuel inject occurs just before top center on the compression stroke.

Maybe you guys can enlighten me a bit of some of this.

 

[npalen]

Thanks to Wolfman and whitetiger for your help. Without it I would probably still be fighting the great lash struggle.
The old girl is purring like a kitten now and happier than a clam ready for another thirty years of work.

Edit: She blew out a huge puff of soot when starting the first time after the valve reset. Probably hadn't that much "air in her lungs" in a long time.

 

[North Idaho Wolfman]

Thanks to Wolfman and whitetiger for your help. Without it I would probably still be fighting the great lash struggle.
The old girl is purring like a kitten now and happier than a clam ready for another thirty years of work.

Edit: She blew out a huge puff of soot when starting the first time after the valve reset. Probably hadn't that much "air in her lungs" in a long time.

Excellent to hear!