Yanmar 3GM30F Random Ticking Noise - Need Advice

[four winds]

I'm feeling some anxiety today, can't afford repairs I can't do myself. I've rebuilt many types of gasolene engines but totally new to diesels. I can fix anything on old cars and motorcycles.

Help me diagnose this issue if you diesel gurus here don't mind. I would appreciate it greatly.


I have a random ticking noise occurring every few seconds. Imagine holding a marble sized steel ball and tapping it against a steel plate. It's definitively a “tick” or “tick-tick” each time it occurs, randomly but regularly. Cold or hot, at idle, 1500, 1800, 2100 rpms, in gear or neutral.


Yanmar 3GM30F fresh water engine with 1790 hours since installed in 1989. I've put 40 hours on it since purchasing in mid summer last year.


I'm not concerned about the rods or mains, it's just not that type of noise. It almost sounds external to the engine but I spent several minutes looking, hoping, to find something external with no luck. It's a classic “tick” like a loose tappet on a solid lift cam would make, but it's not regular. A singe “tick” or double “tick, tick” each time with a second or two or three between ticks.


Tick..........tick,tick,.....tick................. .......tick.................tick,tick....
...tick.................................tick...... .........tick,tick.......
......tick,tick.....................tick.......... ............................tick,tick.....


.....as my anxiety level rises.


I ran it about 30 minutes this morning, decided not to go out for a sail on the bay. Strangely, the interval and rapidity of a “tick-tick” doesn't seem to increase in proportion to an increase in engine speed. It does increase slightly so this may be a red herring statement.


The only smoke I see is a very small puff just as engine speed is increased. Raise the throttle slowly and maybe no puff. Raise it quickly and a short puff occurs. Color is grey looking to me, sometimes darker grey, sometimes lighter grey. I don't think I saw any smoke in the past, but not sure I looked as closely as I have now.


Here's an important point, this started after a soft grounding last month. I ran the engine hard getting it off the bar. Not over revved, but 3100-3200 for several minutes at a time. Maybe four to six minutes then a few minutes at 1800 or sometimes idle while I evaluated the results. Then back to 3000+ for a few more minutes. It started to move the boat so I did this about four times I would guess. Finally got off when I took the weight of the anchor and chain off the deck. I notice the noise on the way back to the marina and I'm sure it wasn't doing this before the grounding. This engine has spent most of it's time at 2200-2300 RPMs while underway I would guess.


Engine runs smoothly and strong, offering no clue something is wrong except the tick. I've only recently realized it's OK to test full engine RPM at the dock and this engine will do about 3300-3400 wide open. I've done this once. Should do 3600 but it might be the condition of my throttle cable, it needs replacing. I'm not convinced it's capable of pulling the proper stroke length.






My plan right now is to change the oil since it needs it anyway and adjust the valves. Hoping it's just a loose rocker. I'll look carefully for a broken valve spring as well, but it runs good to have a broken spring unless its just the top or bottom coil.



I think about the governor assembly on my old Ford 800 tractor and wonder if the governor could have a problem.


I think about how little I know about injector pumps and wonder if there is an issue there.


Any advice the members would like to offer is welcome.


Thanks.

[motion30]

Could be many things If related to grounding mayb a crack in the drive plate. I use a shot length of broom handle held next my ear, move it around to see if you can find it

[four winds]

Kanzaki KM3V v-drive in a '78 Pearson 323.

In the factory shop manual the page with the transmission exploded view is full of greasy fingerprints. An arrow has been drawn to the input shaft oil seal. I assume it has been pulled to replace that part. Or maybe loose bolts.

I'm not familiar with the drive plate. Studying the book now.

..............


I see an unlabeled part that looks a lot like a car clutch disc at first. Then I see it bolts to the flywheel and splines in it's center to the input shaft of the transmission. I'm sure this is the drive plate, just not labeled. Has several springs to absorb shock. I could believe one of them knocking around in the bell housing could make the noise. Even though I had the sense it was not coming from that area.

Going to do the long wooden dowel or screwdriver to the ear test next time I start it.

I put a beer in the cooler, I think I'm going to need one.

Keep it coming guys, please.

I was planning on moving the boat several days up the coast soon.


edit,..... it's worth mentioning the shift cable housing is probably well worn. Much slack in the cable motion. Takes a few seconds to shift in and out of gear. I'm sure many times in the past the revs came up before gear engagement. Especially when needing to slow quickly, like when a boat pulled out of it's slip in front of me. Also when a small flat bottom fisher appeared suddenly from behind the end of the pier with the operator looking the other way. With a clunk into gear of course. Could be the drive plate has taken a beating and the grounding didn't help.

[four winds]

The bell housing has some slots in it just below the Kanzaki name plate that allow me to see two of the four springs right now. I can rotate to inspect the others. Can see down to the splines as well.

What's the easiest way to rotate this engine by hand?

The v drive is staring me in the face under the sink. End of the prop shaft sticks out the back. The "front" of the engine is accessible through the cockpit lockers.

I think I'll make a sandwich and drink that beer.

[four winds]

Ran the engine again. Sound just doesn't seem to be coming from the transmission end of the engine. Cant' see any signs of loose metal flailing about against the drive plate springs. The ear to broom handle test hasn't helped yet.

But when I'm at the water pump, injector, side of the engine the noise just seems to be staring me in the ears, so to speak. When I'm at the alternator side, it still seems to be on the water pump side.

Could this possibly be the water pump">raw water pump?

I was thinking how could it be, it would have to be a ball bearing to sound like that. Then I look in the book and discover there are two ball bearings in the water pump. I wonder if water lubricates these bearings, that would be strange to me. Or maybe they are sealed ball bearings.

Water out the stern is present, but spurts out, not so steady, always been like that. Of course the impeller pumps, so a bearing going bad wouldn't have to effect that until it seized.

I'm going to pull the belt off tomorrow to find out. Have to clear the locker for access and it's beer-thirty or close enough now.

[daddle]

The raw water pump is usually a "lubed for life" ball bearing assembly. By "life" they mean about a year. Could easily fail and make odd random noises as the corroded balls flail around.

[four winds]

I believe it daddle. I noticed the oil seal when I looked at the book again, but no oil supply.

It sounds like a bad ball bearing, I've heard that in the past. Plus, I probably spun it faster than it has been in quite some time getting off the sand bar last month.

I'll find out tomorrow when I take the belt off.

[perchance]

Valve lash? " a tappy valve is a happy valve"

[four winds]

I was going to adjust the valves anyway, before this came up. I don't have diesel ears yet so it's hard for me to hear the valve lash. I was going to adjust for peace of mind.

Lash is .008 in. on intake and exhaust. If it's lash it would have to be at least .040 in. or better to make this noise. It's not a regular tap like loose lash would be but that was one of my suspects anyway.

Can't hurt to adjust them, and take a good look at the water pump and put a new impeller in it at least. I have three spares now.

[capngeo]

Originally Posted by perchance

Valve lash? " a tappy valve is a happy valve"

Changing (tightening) valve lash is an issue with overhead cam engines, not so much with push rod engines.

• Does the "tick" correspond to engine RPM?
• Is the tick uniform or does anything have a profound effect? (like putting in gear)
• Oil pressure in spec?
• did you overheat during your ungrounding?
• pullys tight on alt and WP?
• output flange bolts tight to prop shaft?

[four winds]

In reverse order.

Output shaft is tight, and noise occurs in neutral and in gear at any rpm.

I'll check the pulleys tomorrow when I pull the belts. Didn't think to give them a tug or two today.

No over heating, though I only have a warning light and it works. Runs cool enough to put my hands on the engine when I get back to the dock. On the way back after the grounding I was hearing the noise and my first thought was "it's hot". Thought I may have plugged the raw water intake. Checked for flow, no problem, laid hands on at the dock, same as always.

The tick is not a uniform tick, tick, tick. It's a tick or two spaced at random intervals of may one, two, or three seconds. I've described that in the first post with spaces to simulate the timing of the ticks if read at a normal pace.

I does seem to increase in frequency slightly with rising rpm, though not really proportional to the increase. It's not louder either. Just seems to decrease the interval between each set of ticks. In other words, at lower rpms it might go three or four seconds between a tick or tick,tick. At higher rpms one or two seconds between them.

After learning the water pump has ball bearings I'm thinking that is the most likely suspect. Actually looking forward to checking further tomorrow.

This sound can almost be masked be the normal sound of the diesel running. It's the random nature of it that allows it to be detected more easily. Maybe that makes sense.

Thanks for the input everyone.

[Sailmonkey]

Once you've got the belt off, try running the engine for 5-10 seconds and see if the sound is still around. Our engine becomes strangely quiet when the belt breaks.

[DeepFrz]

Adjust your valves, that way you eliminate a high probability item.

[jrd22]

A random tick can be a bugger to track down. The good news is that since it doesn't seem to increase directly with an increase in rpm's it's probably not something internal. Use a long screwdriver and put it on different parts and put your ear on the handle, you can identify where it may be coming from, and eliminate where it's not coming from. Keep us posted.

[joey69]

Sounds to me like you have an exhaust leak.There is a donut shaped gasket about a half of an inch thick where the exhaust pipe bolts to the manifold.I have had this problem in the past myself.The gasket is a ceramic fiber and can get too hot and crack.I know this sounds crazy,because the exhaust pipe gets hot anyway but it does happen.It makes that "ticking" noise because it is sucking in air.I almost replaced an engine once thinking a rod was knocking.A friend told me about the "donut" gasket and when I unbolted the exhaust pipe from the manifold it fell out in pieces.It is made of the same material as brake pads.It is worth it to check,as they are only about $5.00 each.