What went wrong?

[Lifted2x]

Well I am working on my 85 2.8, it wouldnt start one morning after running fine the night before. So i started checking a few things and found the connection of the tfi module was really messed up so i went ahead and durasparked it. I t tried to get it to start but it still sounded like the timing was way off, so i figured the cam gear may have failed. Pulled the motor and the gears are fine but found a bent push rod on the front four cylinders, they where just sitting next to the rocker arms, what would have caused this to happen?

 

[bagdranger]

weird.

 

[dangerranger83]

The only thing I can think of is when a valve was opening/closing the combustion cycle occured to soon and pushed the valve up hard enough to bend the rod. Thats all that I can think of. Ive never heard of such a thing happening.

 

[schmoo]

does the dist turn? you would think
it would have to be a broken cam
or drive gear or key.

 

[Lifted2x]

The dist was turning and it was where it should be at tdc, I have not had time to check the cam timing besides making sure the cam marks lined up. The engine looks good inside (only 120k) no metal or obviously broken parts other than the push rods. I did look and they are all push rods on intake valves on the front 4 cylinders. I did just switch it to the second gas tank that I have never used before. someone told me that bad gas could cause this but it doesn't make sense to me or anyone else.

 

[85_Ranger4x4]

How are the rocker arms? I have heard of them getting dry enough (poor oiling) to start seizing where they pivot and the pushrods break/bend trying to move them.

I could see them getting pummeled and maybe bending/breaking if they were set really loose too.

 

[Lifted2x]

Checked over everything and everything is ok and in good shape. Rocker arms are all free no sticking valves I dont get it. I already have started putting it back together. I even pulled the heads to make sure there was nothing damaged inside and everything was ok. At least I got around to fixing all the oil leaks and painting everything.

 

[hickboy86]

I could see how bad gas could possibly cause this from hydrolock but you're more likely to bend a connecting rod. If the cylinders get bad gas in them then they don't fire properly and start collecting the moisture. If they collect enough moisture they increase compression in the engine and at some point you run out of room and try to compress the fluid instead of the air. I'm sure we all remember from school that you can compress air but not a liquid. When the cylinder comes up and tries to compress the liquid it has nowhere to go and starts FUBARin' things.

To me it sounds like you may have floated the valves??? This happens when the engine is over rev'ed and the valves leave the rocker arms.When they slam shut, if the pushrods are on the lift portion of the cam lobes, they can stop the rockers dead and bend the pushrods. Is it possible u turned her over a lil' to fast or even hit the wrong gear in a downshift? Or did you loan the truck to someone not used to driving it? Many things can bend a pushrod but thats kinda' a worst case senerio.

 

[Lifted2x]

It wouldn't be from over revving, it ran fine when it was parked and did not start the next morning. I am the only one thats been driving it and it never went near redline. i dont know what happened but i just got it all back together.