Hello everyone,

I have an 87 Econoline 3/4 ton with 4.9L (300 CID) EFI that I use rarely for hauling things. It always worked great; it's practically new (35K original miles). Then I worked overseas for 2 years but kept my van in storage. When I returned, I tried to start it but it wouldn't fire up. After some analysis, I discovered a few bent push rods and replaced them. Again, the motor returned to its original clock-running norm. It ran absolutely perfectly! This was last fall and I had not used the van since. I tried to start it now (one year later) and the same problem has repeated itself. Do any of you experts know what would cause this? I suspect the long and somewhat weak original push rods are to blame. Are there any super heavy duty aftermarket rods that would guarantee not to bend? This is a fairly big job (harder in a van with EFI) and I don't want to repeat the work. I read that others had issues with bent rods in the I-6. How have you racers and high performance guys modified the valve train to remedy this flaw? I would appreciate any other suggestions or modifications that would prevent this in the future? I love my Ford and want to keep it forever!

 

I have no expertise with the 300 CID, but I have seen bent pushrods in other engines that was traced to sticking valves or rocker arms. Maybe some kind of top end treatment might help before you store it each time.

 

#1 suspect with an EFI 300 would be binding/ sticking rocker arms. The EFI heads use non-adjustable pedistal mount rockers which are more prone to binding. Root cause is simple lack of use. After sitting for so long all the oil has drained down and there's nothing left to lube the valvetrain. Any engine that sits for a year+ without being started should be treated much like a new engine before startup. Prime the oiling system with a drill, pull the plugs and squirt some oil into each cylinder, then turn it over a few times by hand to make sure everything is nice and smooth.
If something does stick your arm power isn't going to bend anything, whereas the starter and all its gear driven torque certainly can. After you're certain everything spins smoothly re-install the plugs and start it up.

Best prevention is to simply start it up and run it for a few minutes at least once every month or two. Switching to a full synthetic oil should help too. They have a much greater film strength, and the film which remains won't gum up like conventional oils. As far as replacing the pushrods, stock should be fine, just be careful and don't over torque the rocker arm bolts. Crane does make chromemoly pushrods for the 300, but they're not cheap [about $90/set] and honestly overkill unless you're building a race motor with super stiff valve springs. I just used standard Melling pushrods in my rebuild, a whopping $18/set.