bent push rods!! AGAIN!!!

So if the motor has not been worked on ok but just so you all know and only because this happens too often and trhe shops always worm their way out of the blame The bronze guide will grab the valve stem long enough to bend the rod or bust the end off the valve. When it cools it will be not stuck although it willoccasionallycause trhe liner to bev come part f the vale stem ad rifde along with it. Obviously that is not what we have here but I mention it becaue it has happened ot a lot of peole know and some I had already frewarned btthe shop they went to talked arounf d it. You might wonderwhy i care. I hate to see a rodder get discouraged when something d goes wrng for no good reason. Often they give up ndin everytwon there are garges with almostfinished projects becaue of things like this. two evewn with in 10 miles of me with bronze liners installed against my advice that never ran again.
Anyway I hope you get it sorted out.
Don

 

See, another new thing learned.

I would have never imagined bad gas to be the culprit of bend push rods...

Thanks for another nugget of priceless info!

Hope you get it all worked out. The HAMB Rocks!

 

so how do you prevent the bad gas / gummed valves from being a problem when firing up an older engine? The car was parked because of a divorce and seized brakes, now dad gave it to me and I want to get it running again. (68 DeVille)

 

okay... i pulled off the valve covers...

before when I first replaced the 8 bent push rods. I replaced them with Sealed Power brand push rods. They are a little bit thicker. And the other 8 I left the ones that were still straight in there. I only replaced the 8 because thats all the auto part store had in stock. (i would have replaced all 16) Well.... I just pulled off the valve covers and took a look. I saw that the Sealed Power brand push rods are still straight and the others (stock ones) are the bent ones... I think what is happening is that some of the valves are getting gummed up. (how you guys were saying) and the stock ones are failing but the thinker Sealed Power brand are just enouph to hold up. So what Im going to do is replace the others with the same Sealed Power brand once, clean out the gas tank, and try to put some lube on the top part of the valve stem and tap the lube in to try to lube the stem up as much as posible. Start the mutha... and let it idle on the drive way as long as posible!! Hoping to brake the guids back in or something... That would be the cheapiest fix and start as I can think of right now. becuase if i go in any deeper by doing a head job. I will just rebuild the whole motor. Im trying to hold off on the whole rebuild of the motor till winter. I just want to enjoy it as much as posible this summer.

 

bad gas my ass,your vavles are hitting the pistons for some reason,and you can take that to the bank.........richie.........

 

hows your push rods now, what have you done to fix them?

 

John f... Clean the gas tank completely ( boil / acid/ vinegar/ something.. ) before you attempt to start the engine. It will be the safest ,smartest thing you do on this car !
Lots of good advice on gas tank cleaning on another thread.
Good luck
Dave

 

Tight guides for whatever reason, gum, too tight a fit at rebuild. If a valve sticks something will give. Also, if your valvetrain is not adjustable you might have too long of a pushrod and the lifter is bottoming out. .075-.125 from bottomed out is about right. If you pull the intake cold and watch the pushrods, find one that is on top. c Have a helper compress that rocker slowly while you watch a dial indicator or even a caliper from top to bottom. They need about roughly .100 clearance really. Racing you can tighten them down more, .030-.050, but you need a slow long warmup and preheated oil or they will bend them too.

 

Marvel mystery oil is good for that. Pull the valve covers and bathe the valves with it. Put them back on. Put some in your oil, a little in your tank and pour some down the carb with it running. It will smoke like a son of a gun, but pour it slow and let it run and smoke awhile then drown it to where it dies. Let it sit awhile, then run it until quits smoking. You will likely need new plugs, and change the oil a little early. The MMO is a good cleaner. Change the fuel filters often for awhile until the varnish clears from the tank.

 

alright!!! im back on the road!!! So what I did was..... I changed all the bent stock pushrods to the Sealed Power brand ones. They looked thicker and stronger then the stock. I then sprayed PB Blast on the top of the valve stems and tapped the valves down to work the lube in.... then I felt a couple of sticky valves. but they got loosed up. Then I put some Marvel oil in the gas tank. Then started it up... I heard a ticking noise. but it sounded different from when I bent the valves. so i just let it sit and idle on the drive way. Then it went away!!!! I let it idle on the drive way for like 45 mins then took it for a drive. turned it off. and started it again an hour later. now it runs sweet. I went to the muffler shop and got a new exhust system. and now the car runs so quite I think it dies at stop lights!!

Thanks again for all the coments and advice...