Good Day All,

I have a 1976 Ford F-150 4x4 with the 360 FE. The engine has 90,000 original miles on it, however it sat untouched for a solid 10-15 years until the first of this year when I started bringing it back. The motor has run great for the last several months, since I got it back going again after some basic tune-up things. Since the truck sat I have changed the oil three times and replaced with 15W-40 Diesel Oil on recommendation from this forum and others, plus adding some Marvel Mystery Oil. I had a pretty good oil leak from the rear of the intake manifold so I opted to just replace it with an aluminum Edelbrok variety and a Holley 4-Barrell Carburetor, with all new gaskets. When I put everything back together and fired it up for the first time with the new parts the engine had a terrible knock in the passenger side valve train. I took the valve cover back off and double checked everything to be sure I didn't miss something, including making sure the correct bolt for the oiling port on the rocker shaft didn't get accidentally swapped. I put the push-rods back in the same order they were removed when the old intake came off. I re-torqued to the correct specs and tried again. The second time the knock is barely noticeable at idle but if you bring the RPMs up at all it gets worse. With my hand resting on the passenger side valve cover I can distinctly feel the knocking. This is my first FE motor and I know the valve train is different from other Ford engines of the same era I have fooled with. Everything I can see is checking out; good oil pressure, valve lash is within spec, and push rods spin freely. I know anything is possible, but I can't believe this thing would have just all of a sudden dropped a valve or something along those lines. I've tried letting the engine idle for a period of time 15-20 minutes to see if maybe it was that oil just needed to get back to the top end effectively but no change. I am very hesitant to try and drive or rev this thing currently as I don't want to damage anything more than necessary. I know there is a-lot on FE lifter and valve train noises however, I am hoping maybe someone experienced something similar and found a solution.

 

Is it a "tapping" sound or a "knocking" sound. A video with good sound quality would help. I'm worried it might be a rod knock.

 

You may want to check pushrod clearance on the manifold. Did you replace the valve covers with aftermarket ones? Just asking.

 

Are you sure the rocker shaft marks are turned down ?

Manifold clearance is a good thought.

 

It is a knocking sound, it sounds like it resonates inside the valve cover. I do have a short video but it is too big of a file to upload.

 

It does have aftermarket covers but they were on there before with no issues.

 

As far as I know this stuff checks out, but I will double check.

 

I was able to upload a short clip to Youtube. Here is the link.
https://www.youtube.com/shorts/_1S3af5a2os

 

Pretty hard to hear it well enough to tell. but I had fresh 383 making a similar sound and it turned out to be a plugged oil passage and the rocker shaft was getting ground up . maybe I'm hearing it wrong but I'd check it.

Valve cover gaskets can be different thicknesses too. if you were almost hitting before a thinner gasket might do it.

 

Thank you, its an odd sound for sure. When I take the valve cover back off I plan to disassemble the rocker arm and punch the plugs out of each end and clean everything really good. I have replacement plugs Dorman #555-007 so I'm hoping to find a bunch of sludge inside the rocker shaft that is just obstructing oil flow. I think I can idle the engine with the cover off just to rule out that nothing is hitting the cover.

 

That sounds like a valve train problem to me. Not hollow or metallic enough to be a rod knock. Run it without the valve cover just to eliminate the clearance issue there. Check for incidence marks. Might be pretty obvious once you get the cover pulled. If you're really worried about oil spillover, cut out some cardboard and put it on top of the exhaust manifold.

 

Unlikely it's plugged with gunk, but if you're not positive you have the bosses turned down it would starve the pressure sides of the rockers and cause havoc. it's easy to forget , I always triple check mine.

 

I will check this. Please excuse my ignorance as I've never really messed with these FE motors before, but what are you referring to specifically by the bosses being turned down? How would they have moved so I know to check in the future? When I removed the rocker shaft, I just slowly loosened the four bolts 1/2 turn at a time until I could thread them out by hand. I left the bolts in the rocker shaft and lifted the whole thing off and sat it on a towel. When I reinstalled, I picked up the assembly and sat it back on the head and hand tightened the bolts before following with the torque sequence.

 

That's what I plan to do and I will report back. I am hoping for some reason there is just a clearance issue. It sounds an awful lot like something is making contact with the valve cover.

 

Problem solved! I took the valve cover off and idled the engine, no noise. I raised the RPMs slightly to confirm and still no noise. I replaced the valve cover with no bolts and ran the engine again with no noise, however if I used my hand and applied slight pressure to the top of the cover the noise started. I thought the cover had just been overtightened so I bolted it back down gently, but the noise was still there. This confirmed the suggestions that the cover had a clearance issue. I was able to get it to stop by pulling the valve cover towards the front of the engine like 1/16'' and tightening the bolts but if the clearance is that close with the cover I do not want to leave it like that. My plan for now is to double up the gaskets to ensure there is extra clearance if anything and then try and source some better covers or OEM ones. Thank you to everyone for the help, I learned a-lot more about this FE platform through the process.