Rebuilt 340 knocking sound

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MoparLeo said:
2 things you can do without tearing it down. Pull the valve covers, disconnect the coil wire. Use a remote switch on the solenoid wire to rotate the engine and watch the rockers. They should all rise and fall the same amount. Bent push rod, flat cam lobe will show minimal movement. If that checks out ok put it back together.
Get a good set of insulated plug boot pliers and/or good rubber gloves. and start the engine. Pull the plug wires one at a time until you hear the knock go away. That is your bad bearing.
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With that much metal flake in the oil, there will be crud all over in the engine. All the bearings will be embedded. The only proper solution is to air out the engine and inspect every part. That way all oil passages can be cleaned with a rifle brush. Personally, at this time I would consider a swap to a roller cam. Takes oil selection out of the equasion.
With that metal in the oil, low oil pressure and knocking, running it more only damages more stuff, with the resulting cost of replacement.
 
16richard said:
You may be signing up for heart surgery when all you have is a bad connection .
I have seen bad electrical systems cause misfiring, low rpms, crazy oil pressure readings and knocks . The orginal regulators 6 volt for dash gauges are a joke. Plugged oil pickups are possible but the builder would have to be responsible (stupid) if they didn't inspect it.

A hammer wants to hammer a nail .
Good luck
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Knock, knock usually preceeds let me out. Failure to pay attention just gets more expensive. Unfortunately this is already going to be expensive enough.
 
Due process trouble shooting
I would
look closer at the oil.
Double check your electrical.
Any other mods , external clearances?

New bearings wear in , would that not explain some discolored oil as well the builder(s) may have used paints/ antiseise compounds etc.. . Were the oil pans spotless when he drained the oil . What is at the bottom of the pans or inside the oil filter?
Not enough info in my opinion for a heart operation .
 
16richard said:
Due process trouble shooting
I would
look closer at the oil.
Double check your electrical.
Any other mods , external clearances?

New bearings wear in , would that not explain some discolored oil as well the builder(s) may have used paints/ antiseise compounds etc.. . Were the oil pans spotless when he drained the oil . What is at the bottom of the pans or inside the oil filter?
Not enough info in my opinion for a heart operation .
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Knock, knock saying let me out. Not just dirty drain pan or antiseize on bolts. I could maybe see dropping the oil pan to have a look and check for bearing damage. That oil is pretty contaminated.
 
replicaracer43 said:
Hilarious guys dont bother to read the whole thread before putting there 2c in....
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I am curious if this ends up being a camshaft failure..... I have a Solid flat tappet I hope to fire off by the end of the year (Nitrated) and it's a baby stick in regards to spring pressure but when I see threads like this that's the first thing to pop in my head is a Camshaft gone south.....

JW
 
My thought is we will find what letting a fresh rebuild sitting on a stand for 1 1/2 years to dry up and rust can do.
 
replicaracer43 said:
Hilarious guys dont bother to read the whole thread before putting there 2c in....
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Yes, a lot of that goes on. Good of you to step up with a documented yeardown and rebuild. Myself I would be curious to have a looksee. Like you without hearing but reading the OP and your observation and the description, I believe it is terminal in the current situation and needs to be aired out. No sense prolonging the inevitable.
 
chryslerfat said:
My thought is we will find what letting a fresh rebuild sitting on a stand for 1 1/2 years to dry up and rust can do.
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The OP did say he primed it before starting. I find if it is on an engine stand, turn it 45° to get one bank level. Put a couple of squirts from an oil can in those 4 cylinders. Turn it over to distribuye oil on the cylinders and rings. Put the plugs back in and let it sit a day. Rotate the engine 90° and do the dame to the other 4 cylinders. Rotate back to level after another day. Easy access to prime the engine on the stand by spinning the oil pump with a drill. Remove Rocker covers first to verify oil up top.
Sitting in a heated shop should not be a problem. In a cold in winter environment maybe condensation could build up.
 
chryslerfat said:
You would be amazed what a hot tanked and never started rebuild will look like inside after sitting for 1 1/2 years.
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Especially when compared to something that was pulled out of an engine in use from say 50 or 60 years ago and left to sit in the corner like a slant crankshaft I have...and it doesn't have a speck of rust on it.
 
chryslerfat said:
That sludge protects them when sitting.
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Not quite, but I get what you're trying to say.
Heat cycled with oil.
They don't have to be sludgy and grimy and caked to be protected they could look just fine just not have that iron gray look to it journals can be shiny and all and they won't rust unless they're in some really salty right on the beach type of **** scenario
 
I have a PMD stamped 360 crank from a E58 sitting on the garage floor on its flex plate flange. It looks like someone air brushed rust on the lower part and faded to iron up top.
 
Dave_J said:
I have a PMD stamped 360 crank from a E58 sitting on the garage floor on its flex plate flange. It looks like someone air brushed rust on the lower part and faded to iron up top.
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Maybe that's the trick mine's got a damn bro that's frozen on the front of it I never got off so it sits on it's dampener with the timing cover and all on LOL
 
I pulled the 340 from my 71 Demon in 1993. Had it on a stand in my garage until 2021. Pulled it apart figuring I would find it all rusty. Nope, looked like it had run yesterday inside, including the bores. I was quite (pleasantly) surprised!!
 
I just swapped the 302 in my Bronco for one that's been sitting under my bench for 4 years or more, pulled the oil pan, to put a new pump in and check the bearings, and replaced all the gaskets and seals. It looked like it ran last week.
 
The cylinders with open valves suffer from hot/cold humidity weather "breathing".
Moored marine engines particularly prone to that kind of corrosion .
 
inertia said:
The cylinders with open valves suffer from hot/cold humidity weather "breathing".
Moored marine engines particularly prone to that kind of corrosion .
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Need to be "pickled", spray storage oil in the cylinders while running and shut off. Tough on a diesel as they run on about any oil or hydrocarbon. Best to start and run until warm every 2 to 4 weeks.
 
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