The Stovebolt Site Forums The Shop Area Engine Shop Smacking sound on pushrod cover?

OK, I finally got a few hours to investigate the 216 that backfired hard. The vacuum advance had jammed on full retard (dist rotation stuck), I cleaned it up and got it rotating freely and it runs better - no vacuum leaks. Carb is way to rich now, something must have let loose inside as even when I screw the idle mixture screw all the way in it runs too rich at idle, I can disconnect the vacuum line going to the wipers and it runs a lot better. I also noticed a metalic smacking sound coming from the pushrod cover between cylinders 1 & 2. I can feel something with my hand actually hitting on the inside at anything above about 1500 rpm - not regular, but about every 3rd or 4th firing cycle on the #1 or #2 cylinder. No change in intermittant sound when I disconnect the plug wires one at a time. Time to rebuild the carb and take that side cover off and see what is going on . . . any ideas?

Gosh Ken I think you answered your own question
"Time to rebuild the carb and take that side cover off and see what is going on". But sounds like a broken push rod.
I hope still your Amigo, Kip

It's good to hear an update Ken .
That sure sounds like a bent pushrod under the side plate . Easy to replace .
The big backfire might have upset a check valve in the accelerator pump circuit , causing the excessive rich condition .
Happy hunting .

Ken I think this is actually a plot to give a reason to go out and buy another Truck! Now for a small amount of hush money I won't tell Lisa! Just call me when you have your check book and pen in hand.

Hey I gotta do something I didn't win the lottery yesterday!

Well, the #1 Cylinder intake valve pushrod was bent. I pulled the valve cover and spun the pushrods by hand and it was obviously way out of whack. I loosened the adjuster and slid the rocker toward the back of the motor and pulled the rod right out. Took it into the shop and bent and rolled and bent and rolled and bent and rolled until it was pretty straight. Put it back in and will adjust cold and try it tommorow. Meanwhile, the carb is all torn apart and soaking in solvent overnight. We will see about that on Saturday.

How would the pushrod have gotten bent? All of the others appeared straight and true. That would mean the intake wasn't opening all the way. Probably wouldn't cause a miss or anything. Hmmmmm :confused:

Several possibilties that come to mind. 1) Stuck valve, real easy to rule out. 2) Valve spring that is way to stiff. 3) Weakened pushrod due to fatigue. 4) Valve lash set way to tight. 5) Detonation with the valve partially open combined with a weak pushrod. Most likely. Don't know what your plans are for the engine, but unless it's future includes hard use, I would get a pushrod out of another 216 to replace it.

I just got a full set of push rods from Patricks for like $35.-
Every single one of mine was bent.

I had a sound coming from the same general area. I took off the pushrod cover only to discover that the bolt that holds the coil to head was too long. The bolt was hitting the push rod, sounded really bad. Easy fix replaced the pushrod, added a shorter bolt, and problem soloved.

Ken, your engine has alzheimers,,,,The valve forgot to close before the piston came up and reminded it!!!

I wondered why this thread surfaced again. That engine has been running like a champ the last few weeks. I did everything you aren't supposed to do. I straightened the bent pushrods. One pushrod had a boogered up end and I swapped it out for one from another 216 in a 49 I have sitting out back. Put it all back together, warmed up and adjusted the valves . . . now it runs pretty good and quiet as can be. Only problem is that the carb is still too lean, I just pull out the choke a little when I want some power. I hauled some good 4 yard loads of dirt up my driveway today. First gear, low range and just growled up at about 1 mph. Ran outta gas on the last trip while dumping and there she sits with the box still half full. I'll pick up some gas on my way home from work tommorow. I have hauled and dumped more than 100 yards of dirt since I fixed that pushrod! I love that old truck!

Ken, I am of the school of thought that the dump truck is perhaps second only to the thermos in the world of great inventions. Much more practical than a pickup, and it's manly to drive.