What is this sound?

[Fran Blacker]

Just turn the engine enough that you can run your fingers along the back of the block's lower web, or get a hooked wire and do the same...

There so many random nicks Remcharge and dadsbee said something bouncing around up there.

 

[khryslerkid]

Here's a guy who had a loose tq bolt and it grabbed the starter dust shield.

https://moparforums.com/forums/f62/75-6-225-starter-shim-flexplate-17623/#post121943

 

[69 Sleeper Bee]

But it’s a banging sound. Frequency of the bang goes up with rpm.

I agree with you and also @dadsbee as it can only be what he stated unless something got in there that shouldn’t be which is unlikely with inspection cover in place.
And by the sound in the video it is something backed out and maybe there are pieces breaking off and causing the fresh nicks we are seeing.

 

[moparedtn]

See post #35... no point going forward here in the guessing game until you do that. There's a bolt or nut sitting between crank and starter that's beating that flex plate. Gotta be.... or the camshaft block plug is sticking out, there's nothing else..

Yep. Perhaps the aforementioned carburetor nut in post #34??

 

[Babyblue66]

Just drop the tranny and look.

 

[Don Frelier]

Phone boroscope

 

[RemCharger]

Phone boroscope

What's this??

 

[Fran Blacker]

What's this??

https://www.amazon.com/s?k=cell+phone+borescope&ref=nb_sb_noss

 

[Don Frelier]

They sell boroscope cameras that you can view using your phone. It's a little wire mounted camera for looking inside pipes and small dark places.
They work pretty well and are fairly cheap

 

[RemCharger]

Thanks guys,, I'm in!! And they're not stupid money!

 

[BB BELLA]

I have one that connects to laptop General DCS050 was cheap and works great!

 

[chillbill]

I have a digital one as well. It didn't seem like there was much space between the flex plate and block but I'll give it a try.

 

[SublimeSixpack]

Did you resolve this issue? Just curious.

 

[chillbill]

Sorry for the long delay. We finally found out the issue: the power steering pump. The pump pulley has a lot of back and forth play and hits the pump body. Tightening the belt got rid of the sound. I am 75% that was the issue :sweat_smile:

I checked around the flexplate, used a digital scope as well, and couldn't find anything. I think I was wrong in assessing the marks. They're probably old...

I'll be driving it some more to see if the sound comes back.

 

[Will-Fonkjam]

Oh, I'm adding this to my knowledge base. Gotta love the BBO forum!