Strange Clicking Noise 383 Engine

[glrestomod]

Hello! I have an odd issue I was hoping to get some help with, as this forum has been super helpful every time I’ve posted!

I have a 1970 383 4bbl in my 1969 Dodge Charger. I’ve been driving it a lot and it’s been running great all spring and summer. However, I start it up a few Sundays ago and it starts making a loud clicking noise form under the engine bay.

I shouldn’t have, but I drove it up the block and back. If the noise wasn’t there you wouldn’t notice anything different in how it ran and would think all is well.

Today, my cousin Josh and our friend Kenny came over to help diagnose it.

We took the valve cover off and nothing is loose or missing. We even turned the crank and checked all of the rocker arms, etc. with and without load. We then left the valve cover off and put cardboard between the cylinder head and the exhaust manifolds and started it. When we did that there wasn’t any noise at all! It went away completely!

We reinstalled the valve cover and the noise is back. It’s never done that before. We even used a stethoscope type tool to listen to the engine with the valve cover one and it sounded the same everywhere. It was much louder when placing it in the exhaust manifold (factory exhaust manifolds, no headers), but it was consistently the same type and rhythm of noise no matter where you placed the stethoscope.

Baffled as to why when the valve cover is on, it clicks. When the valve cover is off it doesn’t ‍

Any help would be much appreciated! Thanks in advance for any help you can offer

 

[Don Frelier]

Take a look inside the valve cover.
Maybe one of the rockers is hitting it somewhere?

 

[DeltaV]

My best guess is it's an exhaust manifold leak and the noise was blocked by the cardboard you slid in between the cylinder head and exhaust manifold.

Try it again same as before with the cardboard, but then pull out the cardboard and listen for the odd noise.

 

[BLK 68 R/T]

I think the valve covers have a sheet metal baffle that is spot welded inside? Maybe one came lose and hits a rocker arm?

Or maybe a chattering PCV valve?

 

[PurpleBeeper]

My best guess is it's an exhaust manifold leak and the noise was blocked by the cardboard you slid in between the cylinder head and exhaust manifold.

Try it again same as before with the cardboard, but then pull out the cardboard and listen for the odd noise.

I’ve got $5 on exhaust manifold gasket to win

 

[Don Frelier]

I’ve got $5 on exhaust manifold gasket to win

Yes but remember originally they had no gasket just the exhaust manifold to the head.
So it might need one now that it didn't have when assembled.

 

[WileE]

My best guess is it's an exhaust manifold leak and the noise was blocked by the cardboard you slid in between the cylinder head and exhaust manifold.

Try it again same as before with the cardboard, but then pull out the cardboard and listen for the odd noise.

Exactly my thought, you mind reader !

 

[dadsbee]

Torque converter bolt...

 

[PurpleBeeper]

Torque converter bolt...

Oooooo……not crazy

 

[Don Frelier]

Maybe it needs a new cardboardreter?

 

[Macdon221]

Had this before...is was the transmission cover....the bolts were striking it ever so slightly. Remove it to try.

 

[glrestomod]

I think the valve covers have a sheet metal baffle that is spot welded inside? Maybe one came lose and hits a rocker arm?

Or maybe a chattering PCV valve?

Check that, nothing is going on there‍♂, but I see why you would mention that though!

 

[glrestomod]

Maybe it needs a new cardboardreter?

 

[glrestomod]

Had this before...is was the transmission cover....the bolts were striking it ever so slightly. Remove it to try.

I’ll definitely look at that! However, when we remove the valve cover it goes away, so who knows. I’ll try this week and get back with an update. Thanks!

 

[glrestomod]

My best guess is it's an exhaust manifold leak and the noise was blocked by the cardboard you slid in between the cylinder head and exhaust manifold.

Try it again same as before with the cardboard, but then pull out the cardboard and listen for the odd noise.

I appreciate your response, this makes a lot of sense to me! I’ll try this week to check it out and report back! Thanks again!

 

[glrestomod]

Is this the part I need? I realize from the feedback and reading in other threads in this forum that there is no gasket between the manifold and the cylinder heads. I may replace both sides if it’s only $8 per gasket. Here’s the link: is it an exhaust manifold flange gasket I need?

https://www.classicindustries.com/product/mp700212.html

 

[BLK 68 R/T]

Is this the part I need? I realize from the feedback and reading in other threads in this forum that there is no gasket between the manifold and the cylinder heads. I may replace both sides if it’s only $8 per gasket. Here’s the link: is it an exhaust manifold flange gasket I need?

https://www.classicindustries.com/product/mp700212.html

View attachment 1757962

That’s for the downpipe to manifold connection.

 

[BLK 68 R/T]

And while those will probably be a good idea to have on hand if you install the other gaskets between the head and manifold.

This is one brand of the manifold to head gasket.
Fel-Pro 1414 Fel-Pro Performance Exhaust Header Gasket Sets | Summit Racing

 

[DeltaV]

Look around the exhaust manifold at night with all sources of light off. You might be able to see a dull orange glow each time you hear the click. Do it at idle and around 1,500(?) rpm... something above idle speed.

I hope you don't have a cracked exhaust manifold.

 

[Don Frelier]

I don't think anyone mentioned the heat riser valve. They can clang when the spring is weak or broken.