Bent pushrod dillema!!!

[ClydesdaleKevin]

Okay folks. I'm at my wits end! I bought a 1984 Van Wagon LE with only 129k from the original owner that stored it inside when it broke down 10 years ago. Keyway was sheared off the crankshaft by a hack mechanic that tried to replace the harmonic balancer pulley with a hammer and then tried to WELD it back on. I bought the van at the end of November 2024.

I had the engine completely rebuilt with a brand new crankshaft. Replaced every hose and the fuel pump, cleaned out the gas tank, etc. Then I made the mistake of using aftermarket Standard Ignition injectors. They are slightly shorter than Densos so we had to take the the intake manifold off a few times, put on thicker o rings, and finally got them to stop leaking. Started it up and it ran perfect for ONE DAY before two of the injectors, 1 and 4, failed in the open position, hydrolocked the engine, and bent two of the pushrods. That was the FIRST time it bent pushrods, but not the last!

So off the intake comes again and we installed refurbished Densos. Started right up and ran like brand new...again for just ONE DAY! I go out the next morning and it won't start...then finally starts but was skipping badly. Pulled the cover and 2 more pushrods were bent, along with a couple of valves!

Pulled the head, replaced the bent valves and lapped them in, reinstalled the head with a new gasket, replaced ALL the pushrods with genuine Toyota pushrods, got everything put back together and it fired right up and ran like new again! Let it cool down...and it started right back up. I did that several times that day and it started up and ran perfectly every time. Then I drove it on a 90 mile round trip and it drove and ran perfectly! Got home, let it cool down...and it started and ran perfectly! Until the next morning!

I go out to start it, and had to use ether to get it to crank. Skipping and running rough...so I pulled the valve cover again and ANOTHER BENT PUSHROD!!! FML!!!

What is causing this? Timing is spot on. Valve guides seem fine, and the hydrolic lifters seem fine.

5 speed manual transmission.

Will only run with the fuel pump jumper in place...is it bad to leave it jumped?

I'm running 20w-50 as the break in oil. Too thick? Could that cause sticky lifters and bent pushrods?

I installed one of the old pushrods and put the valve cover back on this morning...and it started right up and runs like new again. But I don't have much confidence that it will start and run tomorrow!!!

Any idea what is going on folks? I'm almost 6k into this van now and I'm at my wits end!

[Jan-Willem]

Oh that is very frustrating. I hope someone here knows what the issue is.

But if I look at this from a purely logical perspective.
You think the injectors caused hydrolock, which bent the pushrods.
Then you fixed the injector thing, and again bent the pushrods.
It seems unlikely that you have two distinct things cause such a rare failure.

So either it wasn't the injector thing that bent the pushrods, or it is still hydrolocking.
My guess would be the first.
The valvetrain sort of consist of valves, rockers, lifters, pushrods and camshaft.
The camshaft has been changed, now the pushrods bend.

Also, the symptoms really sound like what happens if you put in a performance cut cam, and the stock springs cannot keep up, and you get valve float at high rpm. Which would if you do this for long enough will surely damage valves or rods.
Now I am not saying you have a performance cut cam, because chances are astronomical that you accidentally found some brospeed performance cam. But my guess would be that the new cam is not compatible with the rest of the valvetrain.

Also, if you hydrolock the engine, would the pushrods really be the first thing to go? And are they going on one specific cylinder, or randomly? If it is randomly, it would be weird if this is caused by something cylinder-specific like hydrolock.

[ClydesdaleKevin]

SWEET!!! After much trials and tribulations my 84 Toyota Van Wagon LE 5 speed is running perfectly! 133 miles so far since the rebuild. Leaving the fuel pump jumper wire in place was the solution...and letting it prime for 3 seconds before starting. Now I've just got to figure out how to tighten up the steering gear box since there is a LOT of play in the steering wheel. 😁😁😁😁😁

[Jan-Willem]

Since it is an 84, have you checked your idler arm/center arm for play on the bushings/ball joint?