2 bent pushrods

so saturday me and my kid were racing around and i must have seriously overeved my motor,had a bad miss and loud noise from drivers side valve cover,took cover off noticed back rocker laying in head and rocker shaft bent and one bent pushrod.last night was gonna fix it and then next push rod was bent real bad,got that out and i looked down the holes and the back lifter seems to have popped out of the hole.i guess i have to pull intake now would it be wise to get a new lifter,i hope nothing else is wrong.

 

Pull the intake and check the lifter that jumped outta its hole.
Good thing it’s just the drivers side that lifter popped out of, if it were the pass. side (right) you probably would have bad bearing damage.
What kind of valve springs you running?
Stock original?
I bent a few pushrods way back when, I still had the original stock (wimpy) valve springs, high speed running the valve spring looses control of the valve, things start bouncing and slapping, the pushrod is usually the first to get damaged.

 

A couple of things gotta happen here now.

First is to confirm that in the top of lifter that got kicked out that the clip that holds the plunger in is still there, if not then you need to go looking for it, and if so hopefully it did not make its way into the Crank case!

The next thing is put a new lifter back in ( I would not reuse that kicked out one ) that Bore along the a new push rod and what else may be needed, make your adjustments and then pull all the plugs out so you can spin the motor over on the starter at a good rate and look to see if the push rod spins like all the others do.

If it does not spin like the others then it's new Cam time.

Lastly it may also be time for new valve springs if that lifter got kicked out before 5800 rpm.

 

Curious, assuming it's not otherwise damaged, why you recommend a new lifter & not reusing the one that is already seemingly matched to & was working with that cam lobe? I'd be inclined to re-use it and crank it over by hand w/o a pushrod to see if it spins but I'm no expert.

If I were OP, I think I'd be more worried about bent valves than anything.

 

If you do not use a new lifter to check the and see if the push rod spins then if it does not spin you still then don’t know if the cam lobe is bad or if it’s the lifter.

it does not have to be a brand new lifter, you can use one of the other ones from the motor that are known good and just swap them for a test out.

also think about this, how would the valves bend if the cam was still in time, I mean what’s going to hold them open , bent push rods?

The push rods bent from getting hammered by the valves floating, not from contacting the pistons.

 

If the valves float, what happens to piston-to-valve clearance during overlap?

 

Yes there is a possibility that the valve may touch the piston , but think about it , the valve is not being driven into the piston as it would if the can jumped timing or was way off.

PS, thinking about this again maybe the push rods folded up in response to the valves kissing the pistons and not just being slapped around at a high rate.
if so I still don’t think it would be enough to bend a valve.

I guess the motor will tell it’s story the next time it’s started up unless a compression test is done first.

 

intake is coming off tonight,can you tell if you have a bent valve without doing a compression test.

 

I'm by no means an expert, so someone correct me if I'm wrong, but here are my thoughts ... You can set the piston to TDC on the compression stroke (so in theory both valves will be closed), pressurize the cylinder with air, and listen for any air leaking through the intake or exhaust. If you hear air in the intake, then your intake valve is bent. If you hear air in the exhaust, then your exhaust value is bad. If you're considering a compression test, I'd lean more towards a leak down test. I believe a leak down test is more appropriate for determining if a valve is bent. Again, I'm no expert.

 

I would pull the plugs, remove valve covers, replace the affected push rods and lifters. Then manually bar the engine over with a helper to inspect the top end valve train for proper travel. A compression test on the cylinders with bent push rods would be my next step.

 

Compression test, Leakdown test, or X-ray Vision.

Leakdown test will be best by far.

 

Nothing to see here other than the lifter popping out of it bore. When the shaft broke(assuming at the bolt) the rocker came off the pushrod obviously and stopped lifting the valve. When the exhaust stops opening all of a sudden there is no pressure release from that particular cylinder. At pretty much any kind of throttle opening the intake valve has a huge amount of cylinder pressure under it when there is no exhaust relief. A couple of revolutions later boing(!), either the intake pushrod bends or that rocker breaks. Replacing them and you should be ok. Ben there and done that just lately. I just did it at the traps. Sounds like a diesel jake brake for a second until the pushrod bends, blapp!

If you are worried about valve bent, which it shouldn't be, do a quick compression check even with the intake off after replacing parts. All you are looking for is a very noticable difference between cylinder. A straight edge across the valves may be able to tell if a particular valve tip is low. The tip Jim above gave about filling cylinder with air a quick way to find a leaking valve. If the valve is bent it will be blowing air like all heck into the intake or exhaust.

Get yourself some heavy duty rocker shafts or add the shaft clamps that were used on the '69 and earlier rockers. I'm in a situation where I have too much cam and rpm too often for the stock rockers which break. If you have a pretty sizable cam consider roller rockers. That is next on my list.

 

This is exactly what I was thinking in my initial comment about a bent valve being of concern. I had it happen on a missed shift & bent only the valve but I could envision it bending a pushrod & breaking the rocker shaft.

I'd be suprised if the cam lobe was damaged & I'd think it's possible because of wear patterns, inconsistent lifter/cam grinding/etc. that the orig. lifter might spin but a different one may not although I agree w/you that checking it w/a different one isn't a bad idea.

Fortunately only one lifter popped out so at least the OP doesn't have to worry about which one went where.

 

lifter looked okay was just laying in there,took passenger cover off nothing bad there,ill work on cleaning up things tonight and tommorrow,one question what length bolts are for the intake its a performer,i have a mixture of crap for bolts,is there a certain grade of bolt and washer also.thanks for all the help.

 

You don't need anything more then a common grade 5. ( 3 lines on bolt head ) bolt to hold down the Intake.

 

put everything together sat nite,let it sit till sunday,started right up with alittle lifter noise then went away.seems to run the way it use to,happy about that,never checked for a bent valve,i also always had a leak below the thermostat housing,used 3 different housings and sealed it 5 different times still leaked this time used that indian head sealer with a gasket will see if that works.thanks for all the suggestions.

 

I ended up using the Cometic cork on a roll and making my own thermostat gasket, to get it to seal. Harder then it should be.

 

I fought that damn thermostat housing leak on my car for a while too. Ended up using the Fel-Pro gasket without the adhesive backing, and used High Tack on both sided of it, and torqued it to the factory spec. Finally sealed after my 4th attempt.