So,, During the inspection of my oil pump ( My 351 is out of my car and being rebuilt) I had a crap ton of little plastic valve seal pieces suck in the screen almost to the point of blocking off flow,, and some small strips of what looked like aluminum. Still not sure what its made of. But anyway,, I get to looking in my block and find small ridges of the cam bearing sticking out from between the cam and the block.. and it dawned ,, those little strips were cam bearings!!!!!! Oh, MY ,, So yea,, the block is getting stripped and turned in for a magna flux , cleaning, and measuring so I know what Kind of shape its in and the size of the cylinders. And the machine shop will install new bearings for me. YAY!.

 

I've never seen cam bearings fried like that on a cam-in-block engine. Plenty of rod bearings, but never a cam bearing. Sounds like you lost lubrication and cooked the cam bearings though. And are you sure the plastic was from valve seals and not the timing gear? Some Ford stuff used a fiber/plastic coated gear that usually disintegrated

 

+1 Check your timing gear. I had a mountain of plastic clogging my oil pick-up and only traces had remained on my timing gear.

+1 on the oiling problem frying the cam bearings. Been there. Done that...but ended up blowing the whole motor.

Good call on having the shop install the bearings for you while they do the other work. Sounds like that motor was awfully tired.

 

Its funny that the motor really ran great before I pulled it,, only indication of a problem was the low oil pressure.. Im glad that Im in the motor now and will make a really dependable ride out of my 69..You never know what you have when you buy something.. The guy told me that it was a 302 rebuilt about 5 years ago,, and now I know its a 351w and looks like it was rebuilt a few years back but you never know.

 

When I got my fastback, the PO told me that the motor had been rebuilt at 100K (I bought it at 130K). When I tore it down around 150K, I discovered that it had been gone through...maybe got fresh rings and bearings...but that was it. It was still the original bore, etc. The machine shop guy sounded as surprised as I was when he got it clean up at .020 rather than .030.

...And about 50K later, that was the motor with the oiling problem. I saw the low oil pressure on my gauge, but it had been so gradual, it hadn't really registered until it was too late.

See, the rotating assembly doesn't actually ride on the bearings, it spins in the oil between the bearing and journal. The bearings are mainly there for start-up and low rpms. They do wear, though, thus creating more space that needs to be filled by oil...under pressure. Lose that pressure and you're riding metal on metal, creating heat and breaking down what little oil is there, too, and the problem gets worse and worse until the engine just plain stops. And a break anywhere in the path of the oil causes the pressure to disappear, too.

The cam is near the top and it was having trouble keeping pressure. Imagine what the rest of the valvetrain was like. Luckily it doesn't need the oil quite as much as the rotating assembly.

Good thing you caught the problem when you did!