F2 Engine Knock

[TAS1974FJ40]

I have a 1974 FJ40 with a 1978 F2 engine. I have had the vehicle for about a year and don't know anything about it's history. The engine recently started making a knocking (loud tapping?) noise from what seems like the top front of the engine. The noise is not present at idle speed. Have done the following diagnostics:

-Oil pressure is 60psi at start-up and drops to about 50-55 after 10 mins of warm-up. I installed a mechanical gauge because the stock sensor/gauge is not working.
-Pulled ignition wires one-by-one with no discernible difference in the knocking.
-Knocking seems to be in sync with engine RPM
-Removed valve cover and did not see any sticking or damaged push rods.

Any suggestions on what else to do to diagnose the problem? Thanks in advance for input.

Here is a video of the noise:

 

[Pighead]

When did you last adjust the valves?

 

[Steamer]

Knocking seems to be in sync with engine RPM

If it truly is in sync with engine RPM than you can rule out the valve train.
Keep in mind the cam & valve train operate at half the speed of the crankshaft and pistons. So therefore say, a rod knock frequency would be twice the speed of a valve or lifter tapping. Knowing the engine RPM and counting the knocks, you can figure out which assembly the knock is associated with.

I have no luck getting your video.

 

[TAS1974FJ40]

When did you last adjust the valves?

Never. Guess I need to put that on my to do list.

 

[zerotreedelta]

Need to open the permission on the vid'...

Top front, any play/slop in the water pump?

 

[TAS1974FJ40]

If it truly is in sync with engine RPM than you can rule out the valve train.
Keep in mind the cam & valve train operate at half the speed of the crankshaft and pistons. So therefore say, a rod knock frequency would be twice the speed of a valve or lifter tapping. Knowing the engine RPM and counting the knocks, you can figure out which assembly the knock is associated with.

I have no luck getting your video.

Hey Steamer,

I listened to the video again and I'm pretty certain the knock and engine RPM are in sync. I assume then that it is more likely a rod knock or piston slap issue rather than something in the cam & valve train. I had trouble getting the video attached to the post. When I click on "Attach files' I am not able to select videos.

Thanks for your input.

 

[TAS1974FJ40]

Need to open the permission on the vid'...

Top front, any play/slop in the water pump?

Need to open the permission on the vid'...

Top front, any play/slop in the water pump?

I haven't checked that, but will.

I cant' figure out how to open permissions.

 

[65swb45]

???

If you pulled plug wires without a noticeable difference, I’d lean more towards valve adjustmen, cam/lifter wear.

 

[whitey45]

No knock at idle speed, so plug wire trick might not work. Simply a rod bearing failing and will only get worse is my guess. Pull the pan and check your rod bearings, crank could still be savable at this point.

 

[TAS1974FJ40]

No knock at idle speed, so plug wire trick might not work. Simply a rod bearing failing and will only get worse is my guess. Pull the pan and check your rod bearings, crank could still be savable at this point.

Thanks for input whitey45. I plan on pulling the pan this weekend.