My son has a 1976 F100 with what is supposed to be a 390 and an automatic transmission. We don't know for sure what it is. Anyway, A few months ago he was driving home and everything was working fine. He gassed up and shortly after started losing power. There's a hill, long and gradual, that is about 2 miles from home and he lost almost all power going up the hill so he dropped it into first. After that he could barely move the truck to get home. We started checking the engine out and found 4 bent pushrods on the passenger side where the exhaust gasket had been leaking so instead of suspecting a burned valve which is what I thought it was originally I figured it was the pushrods. While we were into the motor that far he pulled the drivers side valve cover where we found more bent push rods, one pushrod broken, haven't found the other part, and the pushrod for the last cylinder down where I can see it but can't get it out of the hole. The questions are can the broken part of the pushrod get into the rest of the motor where it might have messed up something else up and am I looking at pulling the head? Any ideas what caused the problem to begin with? I've worked on engines before but not gone into them this far except motorcycles.

 

Are you willing to at least take off the intake manifold to do a further

inspection?

 

Push rods bend because something is not moving thats sopposed to. Cam pushes the lifter up, push rod pushes on the rocker arm, rocker arm pushes on the valve stem, opening it. If the rocker arm or valve is stuck, the push rod bends under the strain. So something has gone very wrong with your engine to bend and or break that many push rods. You say it started shortly after filling it up, have you checked to see if any water is in the tank. Water could've stuck the intake valves, causing the problem, not sure if on an fe that the pistons hit valves if the timing chain goes out, or jumps a few notches. But yeah, you're gonna have to pull the heads to see the extent of damage.

 

I would agree with khadma, as heavy as it is, I would pull the intake, and probably the heads too, to do a further inspection.
Also, if the engine is original to the truck, check the 4th character of the VIN, if it's "H" or "M" that's a 390, but don't be surprised if it's a "Y", that's a 360, the most common FE. There's no way to tell a 360 from a 390 on the outside and (surprisingly) a lot of 360's become 390's on sale day.
You can see, while unlikely, there are enough holes for a loose pushrod to get in where it doesn't belong.
Just so you know, the intake weighs around 70 lbs.

 

I was looking for the second opinion and you all said what I knew I was needing to do. I'm off to pulling both heads, like it or not. At least it'll be inside and not out in the yard. Any suggestions before I start? Pray? Already doing that!! Any suggestions on checking the timing?

 

Yep , F E 360s are a great and magical engine, turn in to 390s and some times 428s depending on how bad the buyer wants one .
I had a Rocker arm let go, broke, on a 292 Y-block once and really jammed the engine up. The have the same rocker arm shaft design as a FE only with solid lifters. You might want to check that out.

 

It wouldn't be a bad idea before you pull the distributor, get the #1 cylinder TDC on the compression stroke. Mark the position of the rotor on the distributor. Makes it easier to reinstall the distributor when it goes back together.
I don't know how old your son is or his driving habits but over reving can bend pushrods too.

 

You know, here's something else you might try before pulling the heads. On the pushrod that's down too far to get, see if you can fish it out with a small magnet or something. Replace all the pushrods and then run a compression test. If the results are okay, fire it up and see how it runs.

 

First thing to do is take a few good push rods and go put them in a few cylinders at a time unless you have enough to do a complete side and take a feeler gauge and make sure the springs are not at full compression on the lift cycle! If someone swapped the cam and didnt check the clearances it most likely the cause.

Take them all out and crank the motor a few seconds to have oil up throughout the system then do the check.

 

I filled up one time with some old fuel and in a matter of seconds I started bending pushrods. Ended up pulling the heads and getting them rebuilt. Moral of the story is drain your fuel tank and fill it with good fresh fuel before you start it. My $.02. Good luck.

 

j ballon, you just said what my son did to his truck when he first got it. He's short of money so he pulled the gas from the front tank which wasn't working and put it in the back tank to make his gas go farther. The gas smelled really bad and that is when he started having trouble. I guess it another save a penny, spend a dollar time.

 

mikeo0o0o0o, I tried to fish out the pushrod that's down in the back but it won't cooperate. Also I'm still missing part of one pushrod that broke totally. I got about half of it out but can't see the rest to pull it out. Also, on the vin lookup, where on the engine is it located or are you talking about the VIN on the door post?

 

Can the oil pan be pulled without pulling the engine?

 

The vehicle VIN, it'll be on the warranty plate (Ford doesn't call them VIN plates) mounted on the driver's door.
Ford didn't stamp VINs on the engines like GM did.
Sounds like you're going to need to at least pull the intake to get out the pushrods that aren't cooperating.

 

I think your going to find that the timing chain has slipped a few cogs due to the cam gear loosing its teeth