so....push rods.

[Filippo]

I checked compression in all 4 cylinders and 3 were right around 180 psi but #1 was way down...i got a reading of 60 and double checked it. it was higher (around 120) when the engine was cold. I tried to run compressed air into cylinder #1 to see where my leak was but nothing was leaking. i had it a TDC, pretty sure anyway (used the prop in the spark plug hole technique) . cranked the psi up to 60 and had no leak down. I went ahead and took the valve cover off and inspected the cam and rods and springs and what did I find?.... this:


a push rod had apparently broken off. I am in the process of learning as I repair this van. so why would this happen to only one valve and the others seem fine. How much work is it to replace? and does it have anything to do with the fact that there was a puddle of gas in the intake manifold at injector #1. I'm supposing its the intake valve and its not letting the gas from inj #1 into the engine so it is building up in the manifold. If a push rod broke, what could it mean for other parts of the engine?

[Megadysart]

I had my number 2 cylinder throw an exhaust pushrod. Had to drive it home on 3 cylinders. I just bought one off RRockauto.com. it was a Sealed Power unit, part #SRE RP-3268. With shipping it was about 20 dollars. I ended up being able to pull the valve cover, loosen the rocker shaft bolts little by little, and pry up on the rocker arm carefully (using a pry bar against the head and rubber to protect from scratching or gouging the head) enough to squeeze the new push rod into place. If you can't do that you'll have to pull the whole shaft and it can honestly be a pain in the butt to install all of the pushrods again, they have to be held in place (cardboard with holes can make this easier). 2000 miles later I'm not having any trouble and it seems to be holding up....we'll see. Make sure you get any broken pushrod material out and it would be a good idea to do an oil change and get a new filter just in case.


As for the pushrod breaking.....there are a number of possibilities. A backfire from a preignition event (misfire from a hotspot, carbon on a piston/valve etc), bad gas, skipped timing, or simply old age and wear could have broken the pushrod. Was the van driving well before? How was the engine performance and gas mileage? Maybe you have a leaking injector that caused a premature ignition scenario and the engine backfired and broke the weakest link being the pushrod. There are a lotv if variables to factor in. I still haven't figured out what caused mine to fail. Good luck.