Scraping sound from front of motor

.
Spun rod bearing.

-G

...Could be a spun Rod bearing. When I spun a Bearing...it started out as a Tick, as in a Exhaust Leak or Lifter and advanced into a 'Rod-Knock'. Could be the #1 MAIN Bearing.

My Guesses: The sound seems to be Pulsating/Intermittent.

1. Water Pump Bearing. Perhaps we're hearing the Idler Pulley Bearing. Or the WP Impeller is Rubbing against the Plate, because the bearing has worn-out.

2. Distributor Shaft Bushing and/or the Dist. GEAR is Not getting adequate Lubrication and is Eating itself up against the Cam. Or the Wrong Dist. Drive gear is just now starting to fail.

3. Which brings us to Timing Chain and Sprockets. When these chains 'Slack', they can rub against the water-pump PLATE. Especially if they are the factory 'Nylon covered Teeth' type.

4. Fuel Pump 'Eccentric' has no lubrication against the Pump Arm. Or the Fuel Pump Itself.

5. The 'Oil-Slinger' is Rubbing against the 'Cover', if installed backwards and has Now, slipped into contact.

BEFORE You start tearing things apart, First, get a Mechanics' 'Stethoscope' and try your best to Pin-Point the Cause of the Noise...Most Caution for the Alt Belt.

MJ     

Thanks George and Marlin.

The alternator belt was off when I took the video and it is out of the loop.

I removed the balancer and there was no change in the sound.

The sound is much more of a scrape than a knock.  I am leaning towards the timing chain at this point.  It is not much more work at this point to pull the timing cover and perhaps find the problem.

Marlin,

It is a new distributor with a melonized gear.  It is supposed to be compatible with my hydraulic roller cam.  I went ahead and pulled the distributor.  The gear looks healthy although some of the black coating is worn off on the top half of the gear as you can see in the photo below.

My experience tells me that a bad rod bearing sounds just like how many describe it "rod knock" which emanates from deep inside the engine. From your video it sounds more like a scraping sound. Marlin's advice of using a stethoscope to help pinpoint the noise is a great option. If you haven't used one before you will be impressed with what you will hear. It sound like something has shifted enough to scrape part of the rotating assembly. Many something around the timing cover or windage tray.

Your harmonic balancer may have unbonded and the outer ring could be dragging on the block

...I'am looking at the Distributor Gear...I do Not see One Bit of Lubricating Oil!! That Gear should be 'Dripping' with Oil! Not only is the Phosphor Coating gone (normal), the teeth look to be fairly Worn-In. The Cam gear can be expected to be Dry, also.

With No Oil, THAT will make your 'Scruffing'...Chafing Sound. I heard this same Sound before. I performed the operation where you drill a .030" Hole through the Opposing Oil Gallery Plug. This shoots a continuous Stream of Oil Directly onto the Drive Gear Teeth. I have Not heard the sound again, during all these years.

In Normal use, the timing chain is supposed to Splash/Throw Oil up onto the Gear. But, if the Chain is Running DRY, The Drilled Hole Guarantees Lubrication to the Gear!!

Here's a Test you can pull. Pack-Goop-Up the Gear well with Moly-Di Grease, re-install the Distributor, Set the Timing and Fire the Engine Up. If the Sound is GONE for awhile...You have found the Source. You might have just pulled the Damper for Nothing. Did I say First get and Use a Stethoscope!?

MJ

Thanks Marlin.

When I pulled the distributor the gear was completely coated and dripping in oil.  I thoroughly wiped it down to inspect it and to take its picture. I am getting a stethoscope this morning.  The next thing I might try is removing the fuel pump.

Thanks JT,

The harmonic balancer is off the motor and it looks healthy.  I test ran the motor with it off and the scraping sound persisted.

On my laptop the noise sounds like scraping. The frequency of the noise is not consistent and has no relationship with the steady engine speed. Are you sure the noise is coming from the front of the engine? Does the engine have a mechanical fuel pump?

@stevebuchanan posted:

The sound is much more of a scrape than a knock.

Like a bearing shell scraping a rod journal.

I've run across that sound before. I recognized it as soon as I heard it. And a spun bearing is what I found when I opened up the engine.

I was getting ready to use my new stethoscope and the scraping sound is no longer there.  Since the balancer is removed I am going to replace the seal and clean up the front of the motor, and then put it back together.  I hope the engine makes it through Drive Your Pantera Day which is next Saturday, 8/27.

My hunch is that the problem will come back soon and I will try to locate the source of the sound with the stethoscope.

The balancer, pulleys, and belts are back on the engine and it is running well.  I used the stethoscope and it was impressive to hear the different sounds from the engine block, water pump, alternator, etc.  As was mentioned above, I should have been using it at the beginning of the problem.  The scraping sound is not there now.  I might have able to pinpoint the problem with a stethoscope when it was happening.  My best guess at this point is that the sound was coming from the fuel pump.  I have a new one on hand just in case.

I found the source of the scraping sound and it is the eccentric for the fuel pump arm.  After removing the the eccentric from the cam gear, I cleaned it and tested it by spinning the outer ring on its base.  The sound it made is the same as in the video at the top of this thread.  I ordered a new eccentric that seems better made.

...Thank You! For Proving Me Correct! Along with Others Here. Experience!

I'am very happy you discovered the Problems!

MJ

P.S. That drilled oil plug I recommended earlier, would have lubed that eccentric and prevented it from 'Running-Dry'. About that eccentric...I run a Electric Fuel Pump, while reassembling the Engine from a rebuild, I had a thought, maybe I could Leave it Off...I decided to leave it On, because it is 'Suppose' to be in that Position.

'If' I Had Left it Off, it would be: Because-OfCourse...the eccentric is Mechanically Off-Center, and therefore 'Out-of Balance' to rest of the Engine. How much of a Possible Vibration are We feeling? Has anyone Here rebuilt their Engine and Left the Fuel Pump Eccentric OFF? Don't mean to hi-jack the thread...but we were on the subject.

Thank you all for your help with this and my other engine problem with the cam and lifters.

After this problem happened I disassembled the engine for a different problem and there was no oil slinger in front of the gear for the double row timing chain on the crank.  Perhaps they had trouble fitting it when they built the engine.  I will try to fit one on there when I reassemble it.  The timing chain was well oiled when I disassembled it but not enough oil was not making to the fuel pump eccentric.

Dear Steve,

          Thanks for the reminder that the thin, flimsy, trivial and lowly oil slinger is actually a functioning and purposeful part of the Cleveland symphony.  I always use one, but I have questioned how beneficial it is. 

              Warmest regards, Chuck Engles

@cengles posted:

Dear Steve,

          Thanks for the reminder that the thin, flimsy, trivial and lowly oil slinger is actually a functioning and purposeful part of the Cleveland symphony.  I always use one, but I have questioned how beneficial it is.

              Warmest regards, Chuck Engles

...I'am going to tell All of you, what the Benefit of this 'Trivial' Part Is.

First of all, a question. "Would FORD add thousands of dollars to the cost of Manufacturing the 351 Cleveland Engines, by adding this one Piece, just because it 'Looks Pretty'...and it does Nothing ?"

...On this Forum, Where is the 'Vision'? The 'Imagination'?? Most owners, here, Need to 'Read a Book', The Books.

The Oil Slinger is there, Duh, to Throw Oil through/over the Timing Chain, the Gears and other parts. But THAT is a Bonus Aside to the very Reason it is actually There, to 'Guard' Against Crankcase 'Pulsating' Pressure (caused from the Rotating Assembly and Pistons with Blow-By) from forcing Oil Out through the Forward Crankshaft Oil Seal. The Slinger Prevents 'Most' oil from ever reaching the Seal, by Throwing it 'Out' Centrifugally, as the Oil runs twisted around the crankshaft Towards the Seal. NO Oil, NO Oil Leak.

...To All, If Your Forward Oil seal IS leaking, your Slinger is either Missing, OR You have Capped/Plugged Both Valve covers, where there Must be Breathers...in which case Both front and rear Oil Seals will Leak from failure. You have 'Blown-Out' the Seals.

MJ

...It was said, you removed the Damper and re-installed it. Perhaps the Slinger was pressed back into position, and the Sound therefore has ceased. If You have Not installed a Cloyes TRUE roller Chain and Gears (Recommended)...does the Engine still carry the original Timing Chain along with the 'Aluminum' Cam Sprocket with 'Nylon' Coated Teeth, which ages, cracks and breaks off??

MJ

Thanks Marlin

After removing and reinstalling the damper, new and unrelated problem happened with a pair of hydraulic roller lifters.  They got under their dog bone retainer and rotated in the bores.  I had to replace the cam and both lifters.  

When I disassembled everything there was no oil slinger.  I guess some people leave them off.  I am now starting reassembling things.  I just installed the new hydraulic roller cam and checked its degree.  The engine already had a nice double roller cam chain and gears.  It might be Cloyes.  In any case I am reusing it.  The photo below shows it with the new fuel pump eccentric and its nice Grade 8 bolt and thick washer.  It will get an oil slinger next week.

...Good to know, You're doing it Right! I would put Moly-Di (or other) Grease Inside the Two Pieces of the Eccentric, just so it does Not Start-Up Dry. It looks as if You Did That.

Before you put the cover back on, pour some Oil All Over the Chain and Gears! Remember, Timing Chains DO NOT 'Strech', they Ware-In and then Ware-Out.

MJ

P.S. When installing a New Cam, the Usual procedure calls for Replacing ALL lifters with new. Replacing just the Two Lifters, does not account for the Debris that 'Could' have entered the Needle Bearings of the Rollers, on remaining Lifters. I Pray You are Lucky and "the Gods of Internal Combustion and Wind in the Face", Smile Upon You. And don't forget the Oil and Filter change!