Need help.Sound from the engine

[smilasm]

Hello,
writing from EU LT. From last year on my 1956 DeVille I have a sound from the engine and want to fix it. Looks like it's from right side by the firewall and sounds like valve.On a free idle it's hard to hear,when accelerating it's stronger,but not to bad,but if I starting to drive the car it's loud,especially up the hill.When I am driving,the more I press the pedal the sound is louder.Today I removed a right side valve cover,looks like all the rocker arms getting oil.Then I removed all the rocker arms,they also looks good.Push rods also looks good.I am thinking of buying a set of new hydraulic valve lifters,but decided to ask you guys before that.Few years ago I had valve sound,from both engine sides,it was to little oil,maybe middle level,but since that I am holding oil on max level,sometimes a little bit more as max and was ok for few years.
Maybe someone had similar problem?

[fishnjim]

EU - one for Roger.

Really need to articulate what type of sound it is; ticking, tapping, knocking, clanging, whirring, etc.   
Since you got it apart, might as well examine/inspect all the way down to the cam.   Could be the cam lob is worn, lifter dishing, etc.   
A lot depends on the mileage(kms) and condition which we can't know from the internet.   Seems it's had a history of lubes issues.
I'd change the oil and inspect the filter, if equipped(cut open, clean reservoir) and look for metal(magnet). 
Things like cracks start and change tolerances/tightness, etc in these cars, so it's not a one size fits all.   Common failures in '56?   

[The Tassie Devil(le)]

Could it be a case of really bad pre-ignition, or Pinking?

Yes, I know I am clutching at straws, but these days with poor quality fuel, as well as lower octane fuel, anything is possible.

Descriptions over any media is very difficult to diagnose, but any mechanic worth his salt could rule that out.

Bruce.

[TJ Hopland]

Pinging / detonation usually happens worst at a steady state which is often cruise.   When its happens easing off the gas or adding some will usually change or eliminate it.    Mechanical issues won't usually respond like that.

[carguyblack]

Sometimes weird engine noises end up being a leaky exhaust manifold noise instead.
Chuck

[TJ Hopland]

Does a 56 have a 'heat riser'?    I had 80's cars were that would rattle.

[carguyblack]

Yes they do and a leak there or elsewhere along the manifold sometimes sounds like a harsh lifter smack when it's really an exhaust pop.
It has on one of my 1956 Cads.
Chuck

[35-709]

My vote is that it is an exhaust leak.  Might be a cracked manifold, bad manifold gasket, bad heat riser.  Exhaust leaks sometimes sound just like a lifter tick. 

[smilasm]

I don't think it's exhaust,the sound is loud when driving only.Accelerating in the garage looks normal.
And bad ignition,also I think no,as the sound comes from right rear cylinder looks like.

[Cadman-iac]

 A piston wrist pin will make a noise under a load but is barely audible at idle. Does it make a noise at a higher rpm, say around 1500 to 2000, while the car is in park or neutral?
A piston with a cracked or broken skirt will also make a noise under load but not at an idle.
As others have said though,  it can also just be an exhaust leak. Your exhaust back pressure will increase the more you load the engine, even at a lower rpm, like when you are going uphill.
Good luck on finding the cause,

Rick

[bullet bob]

Any way you can capture it on Youtube video & include that link here?

[Michael Petti]

I know a person with a 56 who had the same issue. It was a leaky exhaust manifold doughnut gasket. A new gasket solved the problem. I am a fan of checking out the simple cheap stuff first before tearing into an engine.

[cadman56]

Please describe the sound as earlier mentioned.  If the sound is more like a bark/sharp retort is is probably exhaust leaks.  If it is a knock the problem is probably more serious like piston or even rod bearings.
The procedure to isolate the sound is simple enough and a helper makes it much easier.
Good luck.

[smilasm]

Thank you all.I have ordered an engine gasket set from Rock Auto and 16 hydraulic valve lifters from Caddy Daddy.When I will get the parts,I will start with exhaust manifold,if will not help,valve lifters and later piston and connecting rod.Thanks one more time.I will let you know 

["Cadillac Kid" Greg Surfas 15364]

Marius,
Before you start throwing parts at it I would strongly suggest finding out exactly what is wrong.  You can track down an exhaust leak using a piece of say 1/2 inch rubber hose, placing one end near your ear and searching the exhaust system with the other end.  An accurate diagnosis is worth a whole lot of money spent on unnecessary parts.
Greg Surfas

[smilasm]

It's hard to hear when engine running in park or n.The sound is loud when I am driving and accelerating

[Jon S]

Sometimes weird engine noises end up being a leaky exhaust manifold noise instead.
Chuck

My thought also. Heat riser or gasket.

[smilasm]

Is there a smart way to unscrew exhaust manifold screws without breaking any studs? Or just a nut release spray?

[dadscad]

From the description, it would probably be a classic exhaust leak.

[fishnjim]

Smart way is do it by "hand" - no power (impact, etc) tools.
Start off with normal length wrenches, and take all the loose ones, then soak the frozen ones.  Increase lever arm as needed but pull smoothly, don't snap or pound.   If it doesn't come out, soak again.  Getting in a hurry will lengthen the process, if you snap one off.   
I'd do it with them at least "warm" cooling down, where you can touch them with gloves on.   Worse case is to snap them off flush with the block.   You're better off if one is stuck to cut off the head, leaving the shaft, so you can work it with a pipe wrench or channellocks, later.   Soak, and rock it back and forth til it breaks free.   Plus, you can heat with torch or weld on a nut, if needed.   Better to take the head off if need to drill broken ones out.   But you're exposed to more old bolts, so best to avoid breaking off - not always possible.   The heat cycle tends to "rust weld" them after a time.   
Put some HT never seize on them going back.  Chase the threads first to remove scale for proper torque.
I'd also inspect for cracks.   Someone else had a manifold issue and it turned out to be broken casting.