Hey guys. I opened up the valve/rocker cover & took off the rocker arm assembly & found 1 bent & 2 broken (at top & bottom) pushrods. I know where to get new ones, but I'm wondering if I should just place the new ones in & see what happens or should I've looking for something else? The car hadn't run for 35 years & then I got it started before giving it a tune up but it wouldn't idle. I really have no idea if the pushrods were damaged before or after I started the car. Should I pull the lifters & look at them or am I waisting my time being that maybe the lifters were frozen but now there free after starting the car. Any suggestions would help. Thanks. Posted using the Full Custom H.A.M.B. App!
Yep stuck valves. Squirt some penetrating oil around the valve stems and tap the end of the rocker lightly with a hammer. Good valves will bounce the hammer like a rubber ball, stuck ones will be like driving a nail. Usually the spring pulls the valve up but might need light assistance from a pry or screwdriver. Get it moving up and down a few times and they are usually OK. If it is really stuck, you will have to take the head off. But if they come loose just put in new (or used) pushrods and adjust to spec, then recheck adjustment after a couple hundred miles. Incidentally I have only run into this problem a couple of times on motors that have been out of commission for years, and both times the engine came back and ran great after a little running. I suspect the valves only stick if the engine is in decent shape and not worn out. Badly worn valve stems have lots of clearance and won't stick. That's my theory anyway. So, there is a good chance your motor will turn out to be good.
this definately , the cam will nock the lifters loose of bust , the valves if thye stick you will be buying loads of pushrods and maybe a rocker arm or too . on motors that sat a long time we used to pull the rockers and used a rubber mallet on the valve stem and hit it lightly a few times to see if they are loose or to jar them loose and see if they stick .
I fired up a 50 GMC that sat for 20 years and it broke a couple rocker arms,it did not do it instantly but a couple days after I had it running. I did not think about checking the valves even though I had to get the motor unstuck.
A good friend of mine, Bob, whose business is repairing and maintaining old cars had a customer with a '52 Buick that came in with bent pushrods.....yep, stuck valves. Bob pulled the head, cleaned the valves and guides and reassembled the engine, sent it on it's way. A year or so later the Buick was back with bent push rods. Now, Bob is no amateur....he is thorough...he pulled the head again and the intake valves all had a build up of black 'crap' on them. Bob cleaned it all up and reassembled and again sent it on it's way, A year or so later this happened AGAIN! Ultimately his conclusion was that the fuel, which was gasohol, plus infrequent use, was causing this problem. Thoroughly cleaned the fuel system, tank and all as I recall, switched the Buick to straight gasoline and the problem did not reappear.
Thanks for all the info guys. I'm a little confused on where the valves are. This is the first time I've taken a motor apart this far. The rocker arms were all definitely stuck. I had to soak them oil & work them around on the the shaft to free them up. Could this have caused the broken push rods? Are the valves located under the springs? Do I just tap on the springs with a malet? I'm confused. Thanks guys. Posted using the Full Custom H.A.M.B. App!
That little round flat spot in the center of the valve spring is the end of the valve. The rocker arm contacts/pushes on it. By looking through the spring from the side you can see a small "shaft" coming up out of the head, that is another view of the valve stem. Yes the frozen rocker arms could very well be causing your problems, but I would check for sticky valves also, as others have mentioned.
Ok. Perfect. I'll do as the others have recommended. Would it be wise to poor some marvel mystery oil down into the valves? What's the best way to do this. Is poring marvel oil into the pushrod holes going to loosen the valves or just the lifters? Will pouring oil onto the spring allow & allow in the run down allow it to get deep enough into TE valves or should I use something to get it directly on the valves. Sorry for the dumb questions, but I was always told if you don't know it's better to ask than cause more problems. Posted using the Full Custom H.A.M.B. App!
Thanks again for everyone's help. I'll try doing the suggestions posted & let everyone know how it all work out. Posted using the Full Custom H.A.M.B. App!
One other thing. Is it a problem if the old pushrods that aren't bent have a little bit of rust on the shafts or is it ok? Thanks a bunch fellas. In Need Of: 1950 Buick Front & Rear Bumper Guards. 1955 Buick Headlight Bezels w/out lower marker lights. Posted using the Full Custom H.A.M.B. App!
I had a valve sticking and it bent the push rod a couple of times and I straightened it/ I put air in the cyl. and compressed the spring and removed the valve spring keepers. I then attached a drill to the valve stem and run the valve up and down and put it back together. no other problems.
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