1950 Plymouth

[LauraL]

Hi! I’m submitting on behalf of my grandfather. He goes to his shop daily although he’s no longer is open to the public. A friend asked him to look into a 1950 Plymouth. Attaching a video so you can hear the knocking once it’s cranked. 

Any tips would be appreciated! 

Thanks,

Laura

77C0F2C3-16C2-4005-9254-BC8E935DA890.MOVFetching info... Edited August 31, 2019 by LauraL
Typo

[bobus8]

Sounds to me like a Broken piston.  Could be a rod knock.  Listening to the drivers side of the block with a stethoscope may help identify a particular cylinder if it is a broken piston.  My recommendation is to pull the oil pan and look for pieces of "stuff".  I wouldn't think that something is bouncing between the piston and the head but the oil pan gasket is the cheapest way to go to check internals as far as I know.  If nothing is found in oil pan, you might consider pulling the head off.  

[LauraL]

Thanks! Oil pan was pulled and a bunch of junk was in there. 

[Go Fleiter]

..that noise would definitely have stopped me from letting the engine work any more, before having found the source of it!

Sadly, I can´t give You a diagnosis based on the noise in the video.

I suppose, You have excluded exterior damage: belt, fan, water pump, starter and Bendix drive, generator...

If You don´t find the cause, take next step. This would be my step for step approach,

if I hadn´t the whish to take the engine out for rebuilding :

1.) check the oilpan for bigger parts and try to identify them

2.) at the crank shaft: check, shake, knock bearings of shaft and rods for improper noise or clearance

3.) check timing chain

4.) take cylinder head off for inspection of cylinders, pistons, chunks of the rings, valves

5.) take the valve covers off for inspection of cam shaft

6.) no result? consider total rebuilding!

 

Good Luck!

Greetings from Düsseldorf!

Go

 

Edited September 1, 2019 by Go Fleiter

[dpollo]

only one solution.  do not run it anymore.  remove all six pistons and the cause of the knock will be revealed.

In 60 years , I have rarely heard such a terrifying knock and when I did it was quickly followed by catastrophic failure.

you never forget.

Edited September 2, 2019 by dpollo
correct spelling error