I just bought a '72 3/4 ton camper special from an old man. This is a truck buyers dream, Almost mint, perfect bed, solid truck! The motor was said to have been rebuilt at 50k miles and it currently has 72k total miles, leaving it at estimated 12k on the rebuilt. It sat for about 4 years. When first tried to start it (390 2 barrel) it bent the push rods (intake rods only). I replaced the rods, timing chain, lifters, fuel pump, water pump, plugs, wires, cap, changed all fluids and rebuilt carb. After refreshing the motor it ran absolutly perfect but the next day when starting it bent 7 pushrods (all intake) and the only one that didn't bend was the one closest to the driver? There is no marks on the pistons, the cylindar walls don't even have any signs of wear and it is extremely clean inside the motor and I can't figure out why it keeps bending intake pushrods only?

If you want you can Email me at layz@pcwan.net
Thanks for any suggestions,
Kenny

 

I don't know if this will help you, but this tech article can be found here on this site. FE's That Bend Push-rods, A Dirty little Secret
By Bill Ballinger
Just click over on the right where it says tech articles, and then scroll until you find it.

 

maybe a stupid question but have you turning this 390 over by hand with the valve covers off and made sure the valves and rocker arms are working properly and moving full distance?

it sounds like you've done the stuff on the other end

 

Kenny, how long was the truck sitting before you bought it. I bought a 73 F-350 that had been sitting for a year and a half. The guy said he had started it every week but it was the same gas from a year and a half ago.He never let it get good and hot when he ran it. When I drove it home after the purchase(50 miles on freeway)I turned it off . The next morning I started it up and bent almost all of the pushrods. The old gas was so varnished that it accumulated on the valve stems and froze them in the guides when the motor cooled down from a hot run.After pulling the valvetrain I found most of the valves were froze in the guides, I mean you couldnt move them with a hammer.I hooked up air pressure to the cylinder to keep the valve up and removed the valve spring. Then I used Gunk cleaner and carb cleaner and slowly was able to free all the valves in this manner.I removed both gas tanks and cleaned them completely, also blew out the fuel lines and drain the carb.I changed the oil for fear there was some of the varnished up gas in there too.Well after putting it all back together with new gas and all I took it for an hour drive on the freeway to blow the whole thing out and make sure I had good gas in the system.I returned home and parked it overnite then started it in the morning and bent 5 more pushrods. As it turned out I didnt get all the varnish or shellack or whatever you want to call it off 5 of the valvestems so another days work and it finally quit bending the pushrods and I have not had the problem since then(9 years ago). That's my 10 cents worth, hope it helps.
"bowties in the rearview mirror"