Bent Pushrod :( HELP

[hemidude426ci]

Hey guys, so I was taking off my old cab and intake setup on my Cuda to install my recently acquired original 1970 Direct Connection 6pack set up and I noticed that one of my pushrods had come off the lifter and was bent.  Now this might seem like a dumb question, but why did that happen? Valve adjustment issue? Rocker arms? The good news is I know exactly when this happened and it was on the way home so the car was only driven about 3 miles with the busted pushrod. Thanks in advance for the info guys.

[Ck[FIN]]

Check your valve springs

[71chally416]

Probably got some dirt in a lifter, the plunger stayed depressed and then the valve closed allowing the pushrod to jump out of position. I'd pull that lifter and take it apart and clean it and put a new pushrod in and not worry about it but it might be time for some new lifters. They don't usually last the life of the cam. When they get cupped and lose their concave or get pitted they should be replaced.

[moper]

As was said, closely inspect the valve and spring of the pushrod that bent. There could be damage there, the valve stuck and/or bent, the spring broken, the valve locks failed, or a weak spring. It could be anything.

[hemidude426ci]

Alright guys, so I pulled the rocker arms off to inspect the valve/springs. I had my dad hit all of the valves and the one with the bent push rod was the same as all the rest.  All of them are pretty stiff, but thats how I imagines it. Should I be able to see a lot of travel??? My other thought was that maybe theres an issue with the cam, and while I see some wear, it doesnt look really bad or anything that would warrant attention, at least thats what I thought.  The motor is pretty fresh so how much wear should there be on the cam? The rocker arms look pretty normal as well.  Thoughts???

[71chally416]

Like I previously said, it could just be a piece of dirt on the lifter plunger when the lifter bled down from sitting prevented the oil from pushing the plunger back up and the pushrod fell out of the rocker hole or lifter and bent when the cam lobe opened with the pushrod out of place. At the very least I would disassemble that lifter and clean it out with carb or brake cleaner. It's rare but I've seen that happen before. Don't get too freaked out by it. Clean the lifter internally and put a new pushrod in and see what happens.

[bb71challenger]

The good thing about a big block is the fact that you can pull the lifters without taking the intake manifold off. I have a lifter puller that grabs the inside lip and you can pull them out. Gotta be careful but with a good puller you can get the one out and fix it or like 416 stated you can change them out.

[hemidude426ci]

Let me start off saying that you guys are wonderful, I seriously dont know what I would do without this Forum.  So let me ask you this now, I noticed that the other pushrod on the same cylinder was a little loose, whereas all the rest were nice and firm. Thoughts? Also a guy who I worked for when I was younger who owns a shop and is like a muscle car Guru in Marin (some of you might know him, Walt Jensen over at Vintage Vehicles) told me that its not good to put new lifters on an old cam.  Keep the advise coming. Thanks a lot guys. 

[71chally416]

Why not? A cam will outlive the lifters because it's harder. Hydraulic lifters also tend to get metal particles and dirt inside them that impedes their function (as you have probably found out) Put a straightedge on the lifter and see if it is crowned or cupped. If it isn't crowned anymore and looks cupped, replace it. Of course if it's REALLY bad and pitted the lobe it goes on is probably hurt to. The only way to check the cam is to pull it out and inspect and mic the lobes. As long as they all measure about the same (if the pattern isn't different on the Int/Exh) I'd use it again. It survived break-in which many of them don't seem to anymore. You can spend a bunch of money to put a new one in that came off a boat from China that could possibly lose it's lobes in 30 minutes and shed all that crap into the motor.

[dodge freak 2]

The good thing about a big block is the fact that you can pull the lifters without taking the intake manifold off. I have a lifter puller that grabs the inside lip and you can pull them out. Gotta be careful but with a good puller you can get the one out and fix it or like 416 stated you can change them out.

I changed my SB cam without pulling the intake off. Used a rod with a magnet to pull the lifters out. Took a few times but got them all out. I even had a lifter valley tray in the way that needed to be lifted out of the way.

If its a fresh motor it could be a valve striking the piston. Was the p/v clearance check. How much lift does the cam have. Are the valve springs binding / could just be one.

Did you do a 7500 rpm-miss shift, lol. Does the motor have a rev limiter? 

[71chally416]

Does the motor have a rev limiter?

If it's a 440 with stock heads it has one built-in 

[426HEMI]

Why not? A cam will outlive the lifters because it's harder. Hydraulic lifters also tend to get metal particles and dirt inside them that impedes their function (as you have probably found out) Put a straightedge on the lifter and see if it is crowned or cupped. If it isn't crowned anymore and looks cupped, replace it. Of course if it's REALLY bad and pitted the lobe it goes on is probably hurt to. The only way to check the cam is to pull it out and inspect and mic the lobes. As long as they all measure about the same (if the pattern isn't different on the Int/Exh) I'd use it again. It survived break-in which many of them don't seem to anymore. You can spend a bunch of money to put a new one in that came off a boat from China that could possibly lose it's lobes in 30 minutes and shed all that crap into the motor.

Better ask GM about the lifter and cam wear thing.  There cams would wear out and flatten out before the lifter.  hehehehe

[71chally416]

True dat.  I've worked on SB Chevies that I had to beat the lifters out of from the bottom they were mushroomed so bad. 

[hemidude426ci]

One last bit of info about when this happened. And no I wasn't doing anything stupid, I was accelerating at a very grandmotherly rate of speed, between 2-3k rpm and I heard metal to metal and thought ohhhh nooo. I obviously haven't driven the car since. 

[moper]

If it was me, I'd pull and look, before I just stuck a new one in. The new lifter  on an old cam? That's exactly how you HAVE to do it. The cam wears to the lifter. Used lifters on a new cam will destroy it. New lifters on a used cam will seat again. But you should go thru the same cam break in even if it's onlt one lifter. So that means making sure it rotates in the bore, adding break in lube, running it at 1800 for 20 minutes, leaving out the inner spring if you have true doubles... I had a 440 that bent two pushrods during spirited driving... but low rpm. I was younger, but I just stuck new pushrods in and it was ok. I was less cynical and a lot younger then...lol