Engine noise help

Fireguyfire

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So when I bought my 70 300 convertible last fall, the previous owner mentioned there was a tick sound on the top of the engine which had just arrived. When I drove the car a couple of times and moved it into my shop for the winter I could tell it was a top end “tic” but didn’t sound deep, and could even be the water pump or alternator.
This winter I pulled the engine, took it apart and found it had been recently rebuilt and bored 30 over, and everything looked excellent inside. I installed a new engine gasket set, replaced some fuel lines etc and then freshly repainted the engine and dropped it back into the freshly restored engine bay.

Anyways, I’ve recently recorded the engine and am about to get to tuning the 440, and the sound is still there, which I could best describe as a fairly loud “tic” on the top end. By ear I was thinking it sounded like the alternator, but using my engine stethoscope it actually sounds like it might be the top front of the intake, just to the right of the distributor.
My plan is to remove the belts for the alternator and PS pump and quickly fire the engine which would eliminate the PS pump, water pump and alternator. If I still have the tic with the belts off, that will tell me it is the engine itself.

Does anyone have any guesses on what this tic might be if it’s not an ancillary item?
It seems very localized to the top enter front of the intake in a small area.
Any suggestions or tips for further diagnosing the sound would be appreciated!

I don’t want to get too deep into setting up the timing and the carb until I figure this one out first.
 

75LandYacht

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Did you check the valves springs? If a spring breaks, May be hard to see initially when just looking, pull the valve cover and take a hard look, but will make that Tic sound .. or even a flat spot on the Cam smacking the lifters.. just my 2cents.
 

MONC440

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With the stethoscope are you hearing it on the intake itself or below that. Did you insect the lifters when you had it apart?

Also do you have a single bolt or 3 bolt camshaft? The 3 bolt needs a button on the front. If the button is missing it could be walking in and out causing a noise.
 

Fireguyfire

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I can’t remember if it’s a 3 bolt or a 1 bolt camshaft but I will check.
I had all of the valves out of the heads to check the seats, but I didn’t remove the lifters
 

Fireguyfire

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Yes I did; inspected timing chain and gears, and installed a new cover gasket and front crank seal
 

Fireguyfire

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I spun up the distributor on my Sun machine before I dropped it in and it seemed good, but it’s easy to pull and check again for sure.
 

413

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Also do you have a single bolt or 3 bolt camshaft? The 3 bolt needs a button on the front. If the button is missing it could be walking in and out causing a noise.
Not according to the factory service manual. You are thinking of a roller cam, they have a button on the front For thrust.
 

Pertti K

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If possible, run the engine without valve cover and push each of the valve lifters firmly with your thumb, wooden block or equivalent. You should hear a change in the noice or "feel" it when you hit a faulty lifter, spring etc.
 

MONC440

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Not according to the factory service manual. You are thinking of a roller cam, they have a button on the front For thrust.
413 your right, been a long time since I built a stock engine.
 

CBODY67

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What about a cracked flex plate. I know, not at the front of the engine, but the sound might be telepraphing to the front. I had one that broke and it seemed to take forever to find it as it sounded like it was from the middle of the engine.

Just a thought,
CBODY67
 

MONC440

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What about a cracked flex plate. I know, not at the front of the engine, but the sound might be telepraphing to the front. I had one that broke and it seemed to take forever to find it as it sounded like it was from the middle of the engine.

Just a thought,
CBODY67
That's a good point. I bought a duster cheep because the guy thought the engine had a rod knock. I brought it home and when I was backing it off the trailer may dad said it was the "flex plate" and he was always right.
 

thethee

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Front and center of the intake, have you checked the oil pump intermediate shaft? Just thinking out loud.
 

Fireguyfire

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What would I look at regarding the oil pump shaft?
With the stethoscope on the rocker covers they are quiet; it is definitely located high on the front of the engine.
I’ll remove belts tomorrow and hopefully it’s the alternator or water pump, although the water pump sounds pretty quiet with the scope, the alternator has a bit louder sound, but if I put the tip of the stethoscope probe onto the top of the engine to the right of the distributor it’s obvious.
 

Wildbunch02

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Has the factory insulation pad been removed from under the intake? Depending on the severity of the noise this could be normal. They are usually not replaced during rebuild.
 
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