Just changed the oil in my '66 F100 352 V8 and it started knocking loudly. I had driven the truck prior to the oil change w/o the knocking, but before that, the truck had been sitting up for a while. Are the valve guides bad? Any thoughts?
Thank

 

Sounds like one of your lifters is not filling. What do you know about your motor? Does it have a splash pan section in the oil pan. I had one guy put too much oil in the motor and the rod journals were churning up the oil causing air bubbles in the lifters - thus not letting them pump up. Common with motorcycles with hydraulic valve lifters and too much oil. Valve guides don't go bad just by changing the oil. Do you by chance have an oil pressure gage hooked up or just the idiot light?
You might pull the valve covers and see if any of the push rods are loose. It will at least let you know which one might be causing the problem. That is if indeed a collapsed lifter IS the problem. It could be a broken push rod but also doesn't just happen with a simple oil change.

 

IMHO, Knocking is low, tapping or clicking up top.



John

 

What oil pressure do you have at idle? You Might have debris plugging a gallery, causing a loss of oil to the bearings and heads.. Try Adding half a bottle of Seafoam to the oil and see if the knock goes away, if so let it run for a bit, or drive it for a day or two, and then do a full oil change.... Seafoam will clean things really well but it is hard on rubber seals and gaskets it will also cause a lot of Debris to show up in the filter..... You can get it at Most Autoparts stores..

The oil on a 352 FE leaves teh pump, and then travels up at about a 45 degree angle towards the Oil filter mount just before getting to that mount it makes a real tight 90 degree turn.. the Passageway is just a little over a 1/4 in. MY machine shop guy had me drill mine out to 3/8 in ,and then round the corner out as much as possible just before the oil filter mount.. it made a massive difference in both oil pressure, and volume.. allowing the engine to run much cooler, and quieter.. he also suggested using
5 1/2 quarts of oil... since my rebuild it has run very well, I adjusted the dipstick so it hits full at 5 1/2 Quarts... Oh 6 quarts will have oil lapping on the Crankshaft which causes foaming, and mild power loss.

 

AS said above, all good infromation. One other thing to look into is the fuel pump, you said that the truck was sitting awhile, the spring on the fuel pump arm can get weak and not stay in contact with the cam. That will give a knock.

 

That is a Possibility, although it is not very common, and it is very apparent where the noise is coming from in that case.. Valve Knock, or connecting rod slap are very hard to pin point, as they are internal, not external as the fuel pump is!

It could be very simply a stuck lifter too. which can be diagnosed by pulling the valve covers and looking for a very loose push rod. the fact that it started right after an oil change would tend to lead towards a valve train issue or oiling issue!

 

Noise is on top. I just have the idiot light, so no info on pressure. As I recall, I only had 5 quarts on hand when I changed the oil, so I'm pretty sure it's not overfilled, but I'll double check. Fuel pump is just 6 mos old, so I don't think that's it.

I'll pull the covers and check for loose rods, try the Seafoam and report back.
Thanks for the advice!

 

Yeah check for a slack Rod, or valve lash, also you might have put a rod through a rocker,,, Seen it once quite a few years ago... but mighty unlikely Pull the Dizzy coil wire, and turn it over with the covers off and make sure all of the rods, rockers, and valves are functioning properly.

When I rebuilt my Engine, I had so much varnish built up in the block , that the lifters would only drop out through the bottom after the camshaft was out... Obviously the PO didn't take very good care of it. But the lifters did not want to come to the top of the stroke, and then when they did they would stick ... keeping the valves open.

 

Bad lifter was the problem. Fortunately, it came out the top. Problem solved - thanks!