1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks Discuss the Early Eighties Bullnose Ford Truck

1983 F150 4.9L 300 Engine hum/whine

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Old 12-12-2011, 12:04 PM
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1983 F150 4.9L 300 Engine hum/whine

Issue: hum/whine in the engine.

I have:
Replaced water pump and harmonic balancer, fixed oil pump bracket in oil pan, checked 1, 2 and 4 main bearings (some unusual wear, but nothing out of spec. limits), checked 1 and 2 rod bearings (again, some wear but nothing out of spec. limits).

Still have the same sound/issue.

Any thoughts on culprit/repair? It's driving me nuts and I want my truck back!
 
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Old 12-12-2011, 01:12 PM
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Air pump, power steering pump?
 
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Old 12-12-2011, 01:23 PM
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The sound comes from the front of the engine mostly, which is why we took 1 and 2 main and rod bearings apart.
 
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Old 12-12-2011, 02:47 PM
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Most likely gear noise from the cam drive gears. No chain, it's gear to gear. Some steel gears are known to whine....
 
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Old 12-12-2011, 04:00 PM
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Would the gears just start up having not whined before? Looked at the timing gears and they look great (no cracks, breaks, etc.).
I've had suggested a flex plate or push rods, thoughts on that?
 
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Old 12-12-2011, 07:47 PM
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Originally Posted by Rogue_Wulff
Most likely gear noise from the cam drive gears. No chain, it's gear to gear. Some steel gears are known to whine....
All the 300 equipped trucks I've had over the years have had a little gear type noise from the front...it's the nature of the beast. How loud are we talking here? Are you able to upload a video...or even just sound?
 
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Old 12-12-2011, 08:03 PM
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Originally Posted by custom1106
All the 300 equipped trucks I've had over the years have had a little gear type noise from the front...it's the nature of the beast. How loud are we talking here? Are you able to upload a video...or even just sound?
Me too. My 300 has an almost electric sounding "hum" to it sometimes, that tracks engine speed. I'm not sure a "hum" is a bad thing. Is a "whine" just a higher-pitched "hum"?
 
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Old 12-12-2011, 09:09 PM
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I suspect my 300 has the hum/whine from the cam gears. Can't hear it over the whine from the C6.......
I know the 300 has steel gears, as they were listed on that reciept the car lot didn't find. I know they didn't find it, or I couldn't have bought the truck for $300 less than the total spent on the engine rebuild 2 years earlier.......
 
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Old 12-14-2011, 09:47 AM
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Did you take off the accessory drive belts and run the engine? Ford power steering pumps are known for being noisy (I hate it when I hear a parts changer say that "they all do that", but most ford PS pumps do make a whine) and that could be the source of your noise, as could the alternator and water pump.

Next time you replace the front crank seal, look at the cam and crank gears. Your 83 should have steel gears (not the fiber ones), and they can be a little noisy. With the timing cover off you can check to see that the timing set isn't rubbing the cover ( a sure sign that the thrust plate is loose), and that the cam thrust bolt is tight; but just check it for tightness-the thrust plate is brittle and easy to break, so don't tighten it more unless it's loose (unlikely).

Good luck.
 
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Old 12-14-2011, 09:53 AM
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Originally Posted by Wyowanderer
Your 83 should have steel gears (not the fiber ones), and they can be a little noisy.
What year did they stop putting those steel gears in and start putting the fiber ones in?
 
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Old 12-14-2011, 10:34 AM
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Originally Posted by Wyowanderer
Did you take off the accessory drive belts and run the engine?
Next time you replace the front crank seal, look at the cam and crank gears. Your 83 should have steel gears (not the fiber ones), and they can be a little noisy.
We have run it without the belts on and it has a new water pump. Last weekend we had the timing cover off and ran it and heard a noise. I'm tempted to button everything back up and just see if it is the timing gears humming. The only thing I am worried about is that it hasn't always done it, just in the last two months.

Any thoughts on it starting up recently?
 
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Old 12-14-2011, 10:39 AM
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Originally Posted by custom1106
All the 300 equipped trucks I've had over the years have had a little gear type noise from the front...it's the nature of the beast. How loud are we talking here? Are you able to upload a video...or even just sound?
I'm not able to hear it after it has run for a bit and my heater is on. I believe I'm able to work on it this weekend and I'll see about a video/audio clip. It sounds like extra tension somewhere is making it tough to spin, even with the belts off.
 
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Old 12-17-2011, 09:45 AM
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On a 300 L6 Ford it is normal to have a low whirring sound coming from the timing gears. It isn't a precursor to something going wrong. Simply it is an oiling issue, the engine gets enough oil to lubricate the gears but not enough to keep them quiet. If you don't want the whirring you can drive a small roll pin into the oiling hole above the gears. This acts like a straw and extends the oil passage so the oil falls directly on the timing gears. I believe HP Books has a pub on the 300 and the procedure.
 
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Old 12-17-2011, 09:49 AM
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Originally Posted by nosub4CID
On a 300 L6 Ford it is normal to have a low whirring sound coming from the timing gears. It isn't a precursor to something going wrong. Simply it is an oiling issue, the engine gets enough oil to lubricate the gears but not enough to keep them quiet. If you don't want the whirring you can drive a small roll pin into the oiling hole above the gears. This acts like a straw and extends the oil passage so the oil falls directly on the timing gears. I believe HP Books has a pub on the 300 and the procedure.
Cool tip. I had never heard this before, but it sure sounds logical.
 
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Old 12-17-2011, 07:42 PM
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Originally Posted by Grubbworm
What year did they stop putting those steel gears in and start putting the fiber ones in?
I can't give you a definitive answer, but my best guess is '83-84. I've read that '83 was the last year for steel gears, but my '84 came with them too.
Maybe I was lucky...
 

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