I have a 99 F-150, 5.4 triton. The motor broke while my wife was driving it. The dealer said that a piston was siezed up do to sludge. This in turn broke the end of the cam where it connects to the timing chain.

The motor will still start and run on 4 cylinders. How is this possible, wouldn't the rod have to be broken.
I have alrady ordered a new motor.

Just curious as to what went wrong. If the piston did lock up, how would that have broken the cam?

Thanks for any ideas.

 

No ideas?????

 

This is kinda away from the original idea, but I read in my 97 owners manual of the engine having a preventitive measure for overheating.

Baiscally the idea is that when the engine overheats, the computer only fires on 4 cylinders at a time. It then alternates to the other 4 cylinders. This allows each cylinder a "break" from the intense heat of combustion.

I dont know alot about this, but it may be a computer issue if you truck did overheat while the wife was driving it.

Hopefully this helps.

 

Thanks, but no overheating.

And the cam broke on the end.

 

I'm guessing that there would have to be a whole lot of sludge for this to happen?

There are people on these boards with over 200,000 miles on the same engines. Was the oil changed at regular intervals??

 

Ok if the piston siezed up it will either bend or brake the con rod. If the con rod brakes it could push the piston up into the valves. If the valves jam thay can stop the follower from moving which will stop the cam from turning. if the cam stops turning it will stop the timing chain from turning. If the chain stops turning it makes the crankshaft stop turning. The crank shaft doesn't want to stop becasue there are 7 pistons trying to turn it. Something has to break. The chain the gear or the cam.
Your dealer says the cam broke. Soooo you now have a 2.7L 4 cylinder engine. In simple trems each bank is a seperate 4 cylinder engine that share the same crank shaft. Becasue the cylinders on the broken cam side have no valve action they do not provide power to push the pistons on that side down.


Depending on how bad the damage is and who is rebuilding the engine you might be getting a reman or a bone yard special.

Regards

Jean Marc Chartier

 

Hey Pumpkinhead, about how much are u looking at to replace engine? Im in sort of the same boat!