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> Rod Bearing Failure, Probably?
torakki
post Apr 25 2023, 01:38 PM
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After a long, on and off, restoration (not the motor) I finally got the '74 on the road. Took a few test drives to the gas station, working out minor glitches and within 10 miles, I hear a knocking sound, like a rod knock but less consistent. Maybe broken rocker. I drained the oil and found a few tiny chunks of metal and the rest had a thin paper consistency. I believe it's the bearing material. Anyone?
Thanks for any input (before I pull the engine out.
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torakki
post Apr 25 2023, 01:41 PM
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rfinegan
post Apr 25 2023, 04:04 PM
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Old school:
Puling the plug wires one at a time was a way to find the rod knock. When the knock stops with a plug wire pulled you found the bad rod.

My knock turned out to be the cam thrust bearing. Knocked on cruise and idle. Then under load the knocking stoped
Mine too had long strips of babbit bearing material in the screen.
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torakki
post Apr 25 2023, 08:13 PM
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I think I'd be a little nervous about pulling plug wires that I may cause more damage. The knocking noise was pretty hard to ignore. It knocks anytime the engine was running.
I pulled off one valve cover and all pushrods seem ok. I think, I need to keep going on removing the engine. I restored the whole car, might as well do the motor too.
Thanks for the reply.
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Superhawk996
post Apr 25 2023, 08:27 PM
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At this point it doesn’t really matter what it is.

Time for an engine teardown to assess and repair. It will not get better with time and more mileage.
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mepstein
post Apr 25 2023, 08:27 PM
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QUOTE(torakki @ Apr 25 2023, 10:13 PM) *

I think I'd be a little nervous about pulling plug wires that I may cause more damage. The knocking noise was pretty hard to ignore. It knocks anytime the engine was running.
I pulled off one valve cover and all pushrods seem ok. I think, I need to keep going on removing the engine. I restored the whole car, might as well do the motor too.
Thanks for the reply.

If it needs an overhaul , pulling plug wires won’t hurt anything.
(IMG:style_emoticons/default/agree.gif) With superhawk a knock won’t fix itself.
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wonkipop
post Apr 25 2023, 08:47 PM
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QUOTE(Superhawk996 @ Apr 25 2023, 08:27 PM) *

At this point it doesn’t really matter what it is.

Time for an engine teardown to assess and repair. It will not get better with time and more mileage.


yep.

once the oil goes garry glitter its all over for the band.
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technicalninja
post Apr 25 2023, 09:55 PM
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"Garry glitter" is a new one for me. Sounds like a Vegas Elvis imposter.

Pulling (or shorting, this is easier) plug wires will not hurt an engine in any way, doesn't have to be bad already.

The only thing it might hurt is YOU if you're holding that wire when you pull it off.

I'll normally pull the boots on the distributor cap back and just use a test light to ground each tower. Works fine and no SPARKY.

Cylinder shorting is a common diagnostics procedure that has been around forever.

Don't try to do this with COP setup. Those can have enough ZAP to stop your heart.

Still will not hurt the engine however...

I am in agreement with the others.
It's done, time for teardown.

No need to shock yourself unnecessarily...
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wonkipop
post Apr 25 2023, 10:19 PM
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QUOTE(technicalninja @ Apr 25 2023, 09:55 PM) *

"Garry glitter" is a new one for me. Sounds like a Vegas Elvis imposter.



much worse. elvis was only fat and glittering but still had his majestic voice.
google GG.
he was extradited to UK from south east asia for bad things.

now his name has been translated into the aussie macquarie dictionary (mechanics edition) of terms to describe bad shiny things your engine is forced to make after its been abused.

(IMG:style_emoticons/default/beerchug.gif)

and apologies to @torakki
i don't mean to accuse you of abusing your engine.
although not driving it while it was laid up while the car was restored, combined with its age, combined with probably what amounted to being raised from the dead was a form of kindly abuse. especially if the old oil was left in it. best to drain an engine of the used oil before storing and then filling right up with fresh oil. often its that old oil in the engine that can do harm during a long lay up. take her apart. sorry to hear your joy was cut short. but i bet it was a fun drive while it lasted. enough i hope to help you face up to the rebuild. all good in the end when you are finished. (IMG:style_emoticons/default/beerchug.gif)
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930cabman
post Apr 26 2023, 10:29 AM
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Metal in the oil is never a good thing and does it matter which cylinder it is?

Hate to say it but it's teardown time
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