Thread: damaged push rods

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Looking for some help and advice. I've got a 1970 402, I'm running Edelbrock performer 2 Intake and their #60479 aluminum heads. Engine ran great, but the other day the carb started leaking and i had a lifter tapping, so i decided that while i was at that i'd go ahead and install a new CAM and lifters. As i was tearing the engine down I found several exhaust push rods with damage on the rocker arm side. The push rods were stock in length. I just confirmed with Edelbrock as that being correct for that package. Now my questions...
1. Any idea as to what might of caused this damage?
2. When i put it back together do you guys think roller rocker arms are worth the money?

oh, my new CAM is going to be an Edelbrock #2162, can give the size if needed. thanks in advance for any help, David

First off, welcome to CHR David. Hope you find us helpful and that you stay a long time!

Bent pushrods are never good – they are always bad. Was there a significant event just prior to the noise starting (like a missed shift and a real high rev – if even for a few seconds?) There are a couple easy answers and a couple not-so-easy ones. One of the most common reasons is a lifter failure or wiped lobe on the cam which allows too much clearance and allows the pushrod to get off center and pinch causing a bend. What does the existing cam look like? Are any lobes flat or even the slightest tinge of blue? What are your existing rocker arms? Is it possible that your rocker arm studs have backed out (come loose)?

You said the carburetor was leaking. Was it at the base? It’s also possible that you have some sticky valves that are holding thing up (which would cause pushrods to bend) as well as blow pressure back toward the carburetor and cause leaking. Did you do a compression test before disassembly to check for leak-down on the cylinders in question?

What we don’t know is what your pistons and head gaskets are (so we can’t tell what clearances may be there) and there’s also a possibility that some damage has been done internally as well. As a minimum, I’d pull the heads and check for damage – both in the cylinder and on the combustion chambers. I have seen real damage done when something very tiny (like a small screw) gets trapped between the valve and the seat and wreaks havoc on the valves, the head and in some cases the piston. You really need to remove the heads and check everything real carefully and find out where the bind is or you’ll trash your cam and continue to bend pushrods – possible doing considerable damage.

As to your new cam – profile is fine but you may want to consider a roller as the additives in modern oils (or lack thereof) have provided real challenges for proper break in. Pat McCarthy will hopefully chime in with more information and he’s really the wizard as far as engine building with special emphasis on big blocks. If you do go with the flat tappet follow the installation instructions to the absolute letter and use their (Edelbrock’s) break in lube.

Again, welcome and let us know what you’re finding,
Glenn

Glen, thank for your response and your welcoming.
First, the rods were not bent. They, approx. 1/3, had wear on their tops. Cam looked fine as did the lifters. One was much worse than the others and was probably the one I could hear ticking. The carb was leaking from the acc pumps and just needed a rebuild. I've read about using the oil additives and heard some horror stories about not using it. So have already bought some.
My pistons are stock, the head gaskets were from edelbrock. Heads are only a year or two old with maybe 2,000 miles on them. I don't think the studs have backed out but will check that. Rockers were the original ones that came on the engine.
Just trying to figure out what happened and prevent it from happening again. Also wondering if roller rockers are worth the money?

roller tip rocker arm are a fine way to wast good money

Originally Posted by pat mccarthy

roller tip rocker arm are a fine way to wast good money

Really? That's good to know. I definitely don't want to spend the money if its not going to improve anything. Would you recommend stock rockers or any particular brands? Do you have any thoughts on the wear on the push rods?
Thank you, David

Ahh - much better. I absolutely concur w/Pat - roller tip rockers are not a good investment for your build. Roller cam - yes.

Is this the original cam and lifters? If so, you could have a couple lifters going soft as the springs in your new heads are much stiffer than the stock springs. So you may do just fine with a new cam and lifters..

Could you post a few pictures?

I'll try and get some pics up tomorrow . The cam was installed maybe 10 yrs ago when I rebuilt the engine. It wasn't stock, but less than what I just bought. I've already purchased a new cam and lifter, but..... Any thoughts as to what I'd gain with a roller cam? David

i am waiting for photos of what you have going on . on roller rockers not to long ago i had a job that bit me in the ass why? trying to save a buck .i knew better as this was borded in my head many years ago by my old boss at the boat yard i worked at. all i could tell the customer is that it was the part. as it was not what it should of been. i would make it right .as i failed him as well .Welcome to the big money and fun world of building engines for a livening.buy a name brand of roller rocker stay with comps line up or crower or harland sharp .or crane . stay way from the cheap Ebay stuff i do not care how cool they look .stay way from used stuff less you can looked them over very well and can tell how old they are by the update on the rocker body much like the cranes from the 70s till now. i can but i live for this stuff. if you can not buy roller rockers.then a new set of steel stamp rockers will work. old rockers or cheap ones pin bearing can fall ou in time like cheap rockers or worn out used ones can .the trick on the steel stamp rockers . some may not go along with this but at the time i had a 600 lift soild cam on the street for many years and i used steel stamp rockers .but i liked the gm low hp rocker balls good used set as they would not cut in the rocker like the Hi hp grooved balls every one sold you and told you they were the best when the carry load surface is cut for oil grooves. i would buy new rockers L slot rockers and find a good set of used rocker balls that were not grooved for oil. then buff them with some wet dry 400 paper wash them very good put them in with a very good coat of moly lube . i had very good luck doing them this way . you may want to look at the gulde plates used GM or manley .dart.or comp .nothing else there alot of cheap suff out there that is not even right for the BBC and it is a big deal

I'm thinking he is talking about push rod/guide plate wear?????????

Originally Posted by jerry clayton

I'm thinking he is talking about push rod/guide plate wear?????????

Nope, the the tops of the push rods, where they seat into the rockers was worn down, exhaust only. Some worse than others. It was enough to make it sound like a bad lifter or one that needed adjusting. I know I need to now replace push rods and rockers. Just still confused/undecided as to what to go with. I can get COMP steel roller tip arms for $150.00 or i could get Edelbrock Aluminum pretty red ones (that only i will know are there) for $440.00. Or could probably get some factory style replacements for even less.

Originally Posted by 402 gator

Nope, the the tops of the push rods, where they seat into the rockers was worn down, exhaust only. Some worse than others. It was enough to make it sound like a bad lifter or one that needed adjusting. I know I need to now replace push rods and rockers. Just still confused/undecided as to what to go with. I can get COMP steel roller tip arms for $150.00 or i could get Edelbrock Aluminum pretty red ones (that only i will know are there) for $440.00. Or could probably get some factory style replacements for even less.

do not buy a roller tip only rocker arm .. but it your money not mine. the tip is not that big of a deal that needs a roller it is the trunion/fulcrum that see the load this is not adressed on a roller tip rocker as it has the same rocker ball as stock rockers .i can get good roller rocker arms for under 400. there not that much . if the rocker tip were beat up and blue that is lack of oil .another thing may be heads were not set up right push rods are not right length or in bind at max lift that could be springs stacking . retainer hitting guides . valves hanging up from put together to tight thats why it is only the ex side valves get hot they grow then hang up or put drag by added load on the ex side killing valve train .some of the intake bolt go rigth threw the push rod holes on bbc head. all intake bolts should only be as long as they need to work and should have sealer on threads of intake bolts

Ok, I guess I also need some help on figuring out how to attach pics using an iPad. Pat, I definitely appreciate your advice. I'll look for some stock rockers and use them. Didn't see any on summits website but will look again. Do you feel a roller cam is worth it? My new one is still in box so I'm pretty they'd take it back if I went for a roller one and lifters. or would i just be spending a lot of cash for only a few horses? The truck is a 1970 c-10 the engine is original to the truck. It did in 330-340 on a dyno a while back so I don't know how much more hp is out there for this engine. I was hoping the new cam would give me a little more. I'm not very familiar with a roller cam setup so I'm not sure what improvement it will offer. I'm going to keep trying yo upload the pics of the push rods. Thank you again. David

Think I may have gotten one to upload....

One more pic. Keep in mind that these are my original push rods. However when I installed the heads they had none of this damage. I did not replace lifter or cam when I installed the heads. I did mark all rods and rockers and put everything back where it came from. I can't imagine I've put more than 500 miles of this set up. However the miles on it have been pretty hard.

Oh, according to edelbrock the my stock push rods are correct for this setup. Or least were supposed to be correct....
Thanks again for all the help.