Got a 76 440 in a 70 Charger Runs fine but...

No idea of internals other than has mild cam(buddy I purchased from doesn't remember what he installed "but it was purple") could be 3 - 5 mins after running and a loud Screeching appears coming from front or upper pass side of engine. Car sat long through winter not running. Fresh oil 5/30 change last spring(2012) when bought and Went for body n paint. Oil PSI is consistantly strong 75-80 cold, 45-50 hot idle. I changed the Mechanical fuel pump last week as that side of motor noise is coming from, same screech occasionally reappears. Removed all drive belts to eliminate pulleys or alternator. Changed water pump recently also. Noise tone changes or lessens when I remove valve cover breather.

Valve cover to come off next. Thinking blocked oil passage or scored/scorched rocker shaft or rocker arm? Again, some days the noise is there, others not a peep. Am considering Seafoam or Marvel mystery before fresh oil change. Currently has conventional oil and Wix oil filter.

Haven't done anything to trannny except add 1 quart when first took delivery of car. Mentioning because I know noises can travel and mislead.

Been awhile since I have posted here - Many thanks for your time and thoughts.

my guess would be rocker/valve train issue. Have you done the screw drive to the ear method yet? if not start it up (and hope it makes the noise) then take a long screw driver to your ear and see where the noise is...then you can pop the valve cover and inspect.

Yes I'd pull the valve cover on that side & good visual. I'd more suspect the oil slinger/tchain, something in that area. The pump vanes were far enough from the housing (& they usually are way too far)?. Could pull the pump/pushrod & feed the carb from a can suspended like a bag of plasma in a hospital but I'd think more likely the first two. Holler how it goes

So I removed the ps valve cover, rockers n shaft - noted forward most shaft bolt was missing spacer tab and instead had few washers...

I replaced with proper tab, cleaned and inspected entire assembly, no oil flow issues, shaft oiling holes installed properly downward towards springs. Reassembled n installed.

Fired it up - no schreech noise for first minute then started again.

Here's where it gets weird: When I remove the pcv valve breather she quiets down!

Ran it a few mins, noise comes n goes.

For poops n giggles I swapped in another distributor. Zero Noise!! - for only two mins cuz while patting myself on the back I reconnected the pcv valve n the screech came back louder about 10 seconds later so abruptly I jumped.

Any Thoughts? Not in a huge hurry to remove water pump n timing cover but I think that's next.

Point to note, has old crappy Moroso chrome valve covers(free) and a cheapo set of chrome breather n pcv combo - the pcv rattles back n forth noticably when installed; Power Brake vacuum line runs to rear of intake, TorkerII and pcv runs from front of carb, Carter 625cfm.

If you have a clutch fan, check it. When they are about to seize up, they start screeching intermittently.

You say the sound changes or stops when you pull the PCV or the breather. My guess is something with the PCV(plugged breather?) is causing a vacuum on the engine which is leaking through a small opening in a gasket surface(Valve covers?)Laugh if you want but I had a S-Blazer with a screeching rear main seal caused by a PCV system issue. Drove me crazy at first.

I would check out those breathers as well, as long as they are cheapies. Some of them have a very slight crack in the steel flap that may cause a problem like that, and may just need to be opened up a bit with a screwdriver etc.

I sencond the breather PCV double check. If you want to make sure it's not the clutch fan, diso the belt and see if you can wiggle the assembly, then fire it up. If it doesn't squeeeeal it's the clutch.

Yes, clutch fan is old/wiggles but I mentioned all belts were removed and issue still there.

For the heck of it I went out this afternoon, poured in a small bottle of Marvel Mys oil and fired it up, Minus the Breather cap(ds) or the PCV hose/cap. Ran perfectly for ten mins. As soon as i reconnected PCV she began screeching again. Disconnected it and screeching almost went away, revved motor few blips and came back.

Been playing with these 25 years. This is a first for me.

The only time I had a screech I could not find it was a spun bearing, obviously I eventually found it, oil pressure was adequate on the factory oil pressure gauge considering the age/miles on the engine.

^^^^^ What he said!

Your screech is vacuum through somewhere cause your pcv/crankcase venting is plugged... STOP and fix it.. I have seen this before, It is your ONLY problem....

mine was a crack in the cylinder wall,after trying everything,even running it with the timing cover off.it didn't sound like it was that deep in the motor but it was.this was on a 440 I bought that had never been started after it was assembled,machine shop missed something.

Record it and slow it down... I bet it is your car screaming GET...ME...A...HEMI...!

In an absolute bind one time with my Charger, i was forced to buy the only big block i could find locally... a "good" 440 still in its attractive (though completely trashed) 67 Imperial carrying case. The wiring in the Imp had been so mangled that there would be no starting it up before buying it, and the owner could not tell me exactly why it was parked (was selling it for some long lost relative). So i bought it, dumped it in the Charger, crossed my fingers and started it up.

Well... didn't take a second to learn why it had been parked... and i mean aside from the plumes ov blue smoke out the sidepipes. The engine had this absolutely brutal sounding screech. It literally sounded like the crank was trying to scrape its way through the oil pan... sounding exactly like a very slow grinding wheel on sheet metal. We couldn't diagnose it. No dented sheetmetal, nothing loose, no metal in the oil, no hot spots, nothing. I just ended up driving the damn thing, and after a couple weeks the noise had pretty much gone (steadily) away. Man it sure got some looks in the first week though... that noise was LOUD.

That engine burned just too much oil to last more than a few months in the car, but it had served its purpose. I was actually extremely excited to finally get to pull it apart... I'd been anticipating this since the initial start-up. We couldn't find ANY evidence ov grinding/scraping/anything that would cause this noise. The mystery remains... a mystery.

You do have a breather in the other valve cover correct ? If not its sucking air into the engine from else where maybe causing your noise.

The large port at the lower front of the Carb was loaded w/black crap, I shot in bunch of carb cleaner spray n scraped out the build up crud.

Zero noise last couple of days.

Make any sense? Gotta grab my rebuild kits n booklets I loaned to a buddy, i'll remove carb n thoroughly clean it.

Any further thoughts? other than it allegedly screaming "I Want a Hemi". That one was especially helpful.