Intermittent Whine

[lat 64]

I read the whole first post this time
I can't offer much more than the others anymore except to say that one time I was involved with an engine that squeaked. It turned out to be the bronze valve guides we put in it. We honed then to a slightly larger clearance and the squeak went away.
Just yesterday I went driving in a '61 chev truck with a 235 stovebolt six. The engine started to squeak as it ran out of gas. I poured in some 50:1 two-stroke gas to get home and the squeak went away on that too. I think it was the fuel pump running dry.??????

Russ

[hanleyclifford]

Sounds like metal on metal grinding.

Have you localized the sound? Is it from front, back, or middle.

Sound reminds me of sharpening a knife on a grinding wheel.

Jim - Please look at post #25 and comment on the picture. Thanks, Hanley

[jpian0923]

I see worn gear teeth on the front of the gear.

Question is: Is that wear or is that normal?
What is causing that wear (if it is wear)?
Could that be causing your whining?

Don?

[Don Moyer]

Jim, you can read post 27 for my attempt to relate Hanley's whining to our historical experience with the idler gear (where I came up rather empty-handed), and post 29 for his own very thorough analysis of the various forces applied to the idler gear. By the way, thank you Hanley, I hadn't looked that closely at the opposing forces on the idler gear before. Although the opposing forces might be expected to be rather constant at any given RPM, the lack of precision of the gear itself in terms of diameter and shape of the teeth would be very consistent with a "clicking" sound as the gear completes each revolution.

Bottom line, Jim, while I hate the feeling of swimming upstream on this diagnosis, I can't get very enthusiastic over the prospects of his idler gear causing the whining sound. In fact from the photo and his measurement of the end play his idler gear appears to be better than normal (remembering that "normal" is sloppy).

[hanleyclifford]

In the picture at post #25 follow an imaginary line drawn thru the slot of the water pump shaft slot to the idler gear and go up one tooth. What do you see?

[Mo]

Is that seated there flush Hanley...looks like it might be off a bit which would put wear on one part of it....or it just might be the photo. Re #25

[jpian0923]

All I see is what looks like wear.

[Don Moyer]

Hanley, I can certainly see wear on the tips of the teeth, but I'll have to think about that for awhile. I don't recall anything immediately forward of the idler gear that would easily explain the wear. You might stick a small thin magnet in through the 3/4" pipe threaded opening in the top ledge of the oil pan (under the carburetor) and troll the bottom of the oil pan for metallic filings.

Meanwhile, a couple generic questions; did the whine start all of a sudden? Did anything unusual precede it's manifestation? Since it's now present in both neutral and forward (instead of just neutral), is it getting progressively worse? Is the oil pressure being affected?

I regret that my old ears couldn't hear anything but the roar of the engine from your sound bite.

[hanleyclifford]

Don - Yes, the whine is getting progressively worse and did start as a very intermittent event. Speaking of filings and magnetism, can anyone see the cluster of iron filings gathered on the end of teeth? Oil pressure has not been affected and remains 40 psi at cruise. The only event that preceded this issue is that I have been running the engine faster than I ever have (2500rpm). This is a very old engine, 1967 I believe, and is one of the earliest late model engines, I think (see snapshot of engine behind #4). It was used in a work boat at Edgartown Marine for most of it's (hard) life. Curiosity is going to compel me to open it up (in a week or so as soon as the hurricanes settle down) and see those gears while I simultaneously prepare another engine.

[domenic]

Take off the plate that's over the gear, and see if there are marks on it. The plate could be lose, or not set even. If it is a bearing...bearings often go flat on one side, and will stop rolling now and then. (When they are on the flat side.)
I don't think you have a major problem. Start with easy, and work toward hard.

The A4 hand book from Universal says;RACING THE MOTOR. Do not race the motor when not under load. This practice is harmful to the motor, and unnecessary.
Driving the boat at high speed before the motor is "warmed up" may result in scored pistions, and cylinder walls.

[Don Moyer]

Hanley, sorry, but I'm not seeing any filings on your gear photo. However, on closer look, it appears to me that the most profound grinding of the teeth is limited to the ones you have identified with red arrows. Moreover, it seems that the damage to the teeth lessens dramatically on either side of the arrows and, in fact, disappears within the scope of the photo. In my opinion, the limited duration of this damage (less than one revolution of the gear) makes it a more convincing witness mark of a one-time destructive event (perhaps an invasion of some foreign object) than it does as the source of a steady whining sound.

[hanleyclifford]

Here is a photo of the same view of a gear thought to be good alongside the first picture from #25. I am quite certain I see metal filings hanging on the tooth just opposite the "R" on the gear in the second photo.

[Mo]

I am thinking it's ....

Hi Hanley,

Trying to get my head around this here. That gear looks OK to me; yes it has some wear but it certainly has not worn enough to cause catastrophic failure. I listened to the video of your engine (I can hear subtle heart murmurs so I'd like to suggest something before you haul it apart)....I'd like to suggest suck out that 30 weight oil and throw some 15w40 diesel oil in it and see what happens. I think it might make all the difference in locating the sound. It will quieten the engine down somewhat..

[Don Moyer]

Hanley, you could well be correct about seeing a small collection of metal filings on the tooth you're identifying, and I can understand that circumstantially the whining sound and the presence of the filings (should they be confirmed) might logically seem to be related. But even in face of all those assumptions, I'm simply unable at this time to connect the dots between the wear marks in the #25 photo and the whining sound using historical data, at least not with the evidence thus far presented.

Another question comes to mind; does the whining noise sound like the reverse pinion gears in the gear cage assembly when you race the engine in reverse? If so, it would seem go a long way to support that it is in fact the idler gear and its neighbors that are the perpetrators; whether or not we can figure out how they're doing it. Also, do you have one of those stethoscopes that enables you to listen very selectively at various places on the engine?

[hanleyclifford]

Don - I have to agree that this thing does not add up based on what has been presented thus far. Yes, the noise does resemble the noise made when revving in reverse. I do not have a stethoscope. I am going to attempt to make some better audio/videos in the next few days. Mo - I have no experience with the 15w -40 diesel oil but based on your suggestion I will give it a try - nothing to lose. I must delay the removal of the gear case cover in any case since I cannot disable the boat on a mooring with hurricanes lurking.