TO30 Z129 click diagnosis

Jeremy in DE · Mar 3, 2019

TO30. Runs and works well. But it has had a minor tick/click for years. Worse when cold. Mostly gone when fully hot.

My mechanical experience is limited, but not zero.

A friend with more knowledge than I thinks it's one of the tappets clicking.

I've had it running on an auxiliary fuel tank with the valve cover off to adjust the tappet clearance according to the manual. That doesn't change it. I briefly adjusted "wrong" to hear that sound. It's a different sound.

A hose in the ear will not identify a specific location of the sound. But I agree with my friend it seems cam/valve/tappet related and probably on the cam shaft side. Not in rocker assembly.

Questions:
A. I've pulled the push rods to examine them as the manual suggests. I don't see scoring or wear, but then again my experience with push rods is limited to this engine. What is normal wear vs time-to-replace wear?

B. Can the tappets be removed to inspect them with the engine mostly together? The manual just says to "replace" them if worn and doesn't say how to remove them from down in there (or precisely what wear justifies replacement).

C. Would it be as likely to be cam shaft itself? How would I diagnose that? My friend thinks not, but then again he also stressed he doesn't know these engines specifically.

pomester · Mar 3, 2019

"What is normal wear vs time-to-replace wear?" If you observe galling associated with either end of the rod it's time to replace - short of running without oil they pretty much last forever -

"Can the tappets be removed to inspect them with the engine mostly together?" no - they are basically the first thing in when assembling an engine and the last thing out when disassembling

"Would it be as likely to be cam shaft itself?" I'd say not likely - if you can't change the sound by adjusting the valve lash, I'd look elsewhere - if you pull the pan you can inspect the camshaft and could observe if a lobe was chewed -

the frequency of the 'tick' is a key - tappets/rocker arms actuate every second revolution, crankshaft moves at twice the speed altho the power stroke is every other revolution - possibilities of a 'tick' at tappet frequency include the governor and the cam/crank gear tho that would be an unusual sound for either to make - a loose valve seat could be a possibility, but I'd expect that situation to destruct rather than being chronic over a number of years - wrist pin is a possibility, but has a 'deeper' sound than valve train -

if it were me at this point I would adjust the valve lash down to zero with the engine idling and see if I could change the sound/make it go away -

good luck -
David

Bruce(OR) · Mar 3, 2019

A bad cam usually will produce a rhythmic popping sound out of the exhaust or through the carb, especially under acceleration
You dd not mention a pooping noise under acceleration, I do no believe you have a bad cam.
Inspecting flat tappets requires removal of the cam. Installation best done on an engine stand, upside down.
Push rod wear can be a problem with a lack of oil changes. Measurement might also be a good option.
A 3/8 hose in ear will tell you if the noise is on top of the engine or the bottom. Did you check the genny, etc?
A running hot valve adjustment can be very messy.
A slight amount of excessive clearance on a tappet is not a problem as the valve stays seated longer and has longer to dissipate heat.
A tight valve remains seated longer and can eventually burn as it is NOT seated long enough to dissipate heat.
A loose valve will reduce engine performance as it is not opening far enough to let in/release fuel vapors.
Next time you fire it up running with the V/C off, place your thumb on each rocker while running.
You might be able to isolate the culprit.

Steve@Advance · Mar 3, 2019

If you can't change the sound by adjusting the lifters, chances are it's not valve train noise.

Something to try, pull one plug wire at a time, see if one changes or stops the noise. If it does, could be a loose wrist pin bushing, cracked piston skirt, or loose piston to bore clearance. That is a common symptom to be worse when cold.

Could also be a chipped timing gear tooth. The governor ball cage failure is a common problem on that engine. Sometimes a piece of the cage will run through, or get embedded in the timing gears.

If it's been that way for years, and not getting worse, and no loss of oil pressure, I would ignore it until a better reason to go in.

Jeremy in DE · Mar 4, 2019

(quoted from post at 13:36:31 03/03/19)
the frequency of the 'tick' is a key - tappets/rocker arms actuate every second revolution, crankshaft moves at twice the speed altho the power stroke is every other revolution

It was the frequency of the sound that made my friend guess tappets. But I'll admit to my ear it's hard to hear the frequency differences between various engine noises. I appreciate the other suggestions of items that might be at a similar frequency.

Thanks so much for the quick answers to my questions. The manual is very nice, but sometimes it assume more experience than I have.

John Deere D · Mar 4, 2019

Stethoscope:

This tools, has assisted me many time in narrowing down the location of a questionable "NOISE / SOUND"

Bob...

Jeremy in DE · Mar 4, 2019

(reply to post at 13:43:13 03/03/19) PostPosted: Sun Mar 03, 2019 12:43 pm Post subject: Re: TO30 Z129 click diagnosis
A bad cam usually will produce a rhythmic popping sound out of the exhaust or through the carb....
A 3/8 hose in ear will tell you if the noise is on top of the engine or the bottom. Did you check the genny, etc?
...Next time you fire it up running with the V/C off, place your thumb on each rocker while running.
You might be able to isolate the culprit.

No rhythmic popping. It runs smooth and works hard when needed.

I have tried the hose in ear trick. But I must admit failure to get more than a very general idea. Not at the bottom of the engine I don't think. No sound at the governor cover. It seems something in the valve cover area, but it's all vague. I hear it most distinctly just standing on the left side of the engine (side with distributor). The hose gives me individual noises but nothing that quite says "aha, that's the noise I'm looking for and it comes from this area."

I'll try again with the Valve Cover off someday when I have time to fiddle. The thumb idea is good. And you're right it is messy. Oil splashing around unless I get it at very slow idle--about 350 by the tach.

Fairly sure not the alternator (generator has been replaced with an alternator) or water pump. I even briefly ran without the belt to verify.

Thanks for the comments. I learn a lot from people on here.

Jeremy in DE · Mar 4, 2019

(reply to post at 00:22:11 03/04/19) ...Something to try, pull one plug wire at a time, see if one changes or stops the noise...

...The governor ball cage failure is a common problem on that engine. Sometimes a piece of the cage will run through, or get embedded in the timing gears...

If it's been that way for years, and not getting worse, and no loss of oil pressure, I would ignore it until a better reason to go in.

I have tried pulling plug wires. No change in the tick/click that I can discern.

I did have governor problems a couple years ago. That is fixed now. The sound in question never changed. When I had the cover off I didn't see any metal pieces stuck in the gears, or any damage to the gears, but maybe I should have checked the gear teeth more carefully. But the hose in the ear doesn't sound like it's coming from the governor cover, although perhaps the sound would get transmitted back though the mechanical system rather than being noticeable at the cover...

Fairly good oil pressure from my understanding-- 25-30psi when fully hot and running about 1200rpm, 8-10psi at fully hot idle of 400rpm. And the sound has been unchanged for years. I use the tractor quite regularly--weekly or better except in winter, though total annual hours are not really all that high. Except last summer when it dug me a pond and it got a couple hours work every day for months. I usually ignore the sound, but every once in a while it grates on me and I try to hunt it down again.

With everything else running pretty good, that one click bugs me.

I have assumed the right Fergie genius would know immediately if he stopped by my place and listened. But I'm not that man.

Tom H. · Mar 4, 2019

I think others mention already, but, it may just be the valve adjustment. You?ll need to take off the tank to get at the valve cover. Otherwise fairly easy
job.

54FergieTO30 · Jun 17, 2019

(quoted from post at 07:43:17 03/03/19) TO30. Runs and works well. But it has had a minor tick/click for years. Worse when cold. Mostly gone when fully hot.

My mechanical experience is limited, but not zero.

A friend with more knowledge than I thinks it's one of the tappets clicking.

I've had it running on an auxiliary fuel tank with the valve cover off to adjust the tappet clearance according to the manual. That doesn't change it. I briefly adjusted "wrong" to hear that sound. It's a different sound.

I have a very similar problem with a 35. Old mechanic I know thinks it could be wear on the camshaft. There are no bushings or bearings to replace on the cam. So mine is just going to continue to make that ticking noise. It runs great, just an extra noise.

A hose in the ear will not identify a specific location of the sound. But I agree with my friend it seems cam/valve/tappet related and probably on the cam shaft side. Not in rocker assembly.

Questions:
A. I've pulled the push rods to examine them as the manual suggests. I don't see scoring or wear, but then again my experience with push rods is limited to this engine. What is normal wear vs time-to-replace wear?

B. Can the tappets be removed to inspect them with the engine mostly together? The manual just says to "replace" them if worn and doesn't say how to remove them from down in there (or precisely what wear justifies replacement).

C. Would it be as likely to be cam shaft itself? How would I diagnose that? My friend thinks not, but then again he also stressed he doesn't know these engines specifically.

TO30 Z129 click diagnosis

Jeremy in DE

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pomester

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Bruce(OR)

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Steve@Advance

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Jeremy in DE

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John Deere D

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Jeremy in DE

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Jeremy in DE

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Tom H.

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54FergieTO30

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