camarokev400

Hey does anyone on here have any ideas of what might of caused this... The motor is a 406 small block with brand new everything... however i used stock pushrods which i thought were in good shape but i developed a tick which i beleived to be a lifter so i pulled off the valve covers and #1 was ticking so i was like allright get out the socket and adjust it and it stops for a second then starts right back up so i figured broken valve spring and i went to take it apart and found a chewed up pushrod and rocker arm... i am almost positive that it was not too tight if anything maybe it was too loose. I am using cheaper rocker arms also they are the proform roller tip rockers they were only like 80 bucks or something like that... im thinking about pulling them off and putting something better on..

The motor has about 700 miles on it so far, its a 406, 5.7 eagle rods, 64 cc 350 heads, comp cams 268 cam, comp valve springs, stock crank, keith black signature series 30 cc dish pistons, hedman headers, edelbrock perfromer intake, edelbrock 750 carb.... i bought a camshaft kit so all the lifters and valve springs are matched to the cam.. so there shouldnt be a problem there

jimmy_mac

I had a similiar experience recently. On mine however it chewed up the end of the rocker on the valve tip and broke a rocker arm stud. The cause was a broken damper that caused the spring to bind. Do you have dampers in the springs and have you checked to see if maybe the one on that spring is broken? It kind of sounds like that spring may be having a binding problem.

F-BIRD'88

You have some kind of valvetrain interference some where.
Possible areas to look are. Spring coil bind, Damper bind, damper binding on the valve guide boss, retainer to seal interference. Rocker/ stud inferference, rocker/retainer.
the radius of your pushrod tips and rockers may be different.
Improper machining.
Improper rocker geometry.

Over reving the motor.

The push rods could have been worn to start with.
Don't assume that because you bought a "kit" that everythiing
is ok.
At any rate it looks like the rockers and pushrods are trash.

The proform rockers may be made of a cheap inferior material
or not hardened.

The Crane stamped steel roller tip rockers are much better quality
and won't fail like that.

You get what your pay for.

Which "64cc heads do you have" ? Which springs?
Some of the "stock replacement" type spring's damper will bind on some factory heads.

Joshua Leslie

same thing happened to my motor, I snapped the #6 pushrod 3times,always on start up for some reason, until I realized that I was sold the wrong rockers.

RB83L69

Could be several things, starting with simply a combination of worn-out stock parts and cheap rockers...

Other things to specifically check for include having both self-aligning rockers and also either guide slots in the heads or guide plates; and having 1.6 rockers and guide slots, but the slots haven't been elongated toward the stud, so the push rod is being held out of its seat in the rocker by the inner end of the slot.

camarokev400

well i know it wasnt too smart to not put new pushrods in being that new ones only cost around 50 bucks. I am using 1969 GM 64cc 350 heads with 1.94 intake vavles and 1.50 exhaust vavles.. the valves are all brand new and have a 3 angle valve job. Im just looking for some kind of anwsers here, i want to get the other 15 pushrods and rocker arms out of the motor if they are going to do the same thing... i really dont think it is from over-revving because the highest the motor has been is prob 5 thousand and that was maybe one time i have been shifting around 2500-3000 and only opened the four barrels about one time so the motor hasnt been beat on or anything like that. The rocker arms are Proform 1.5 ratio roller tips sold in northern auto parts for $80, and i got the camshaft kit from summit it is comp cams (CCA-K12-242-2) not sure on which valve springs they are i would have to try to find the box..

RB83L69

Check the rockers and make sure they're not "self-aligning"; and look at the guide slots in the heads, and make sure that none of the push rods (especially the wasted one) rub against the end of them toward the rocker stud at any point in their travel.

The damage you have is typical of a push rod that's been forced to push on the rocker somewhere besides its seat. That means you should be looking for a guide problem, and those 2 situations are the most likely, besides just routine parts failure. I'd sure check it over real close before just buying stuff and sticking it on there, and then having womething else tear up - which is highly likely if you don't identify and fix the root cause.

Which head casting # do you have?

AlkyIROC

Not really. It depends on the installation. You didn't say what 268 cam you have but I see all the 268 cams recommend the 981 springs. Those springs can go to maximum of .520" lift if installed at 1.700". Even if you had 1.6 rockers there would still be enough spring with the Xtreme Energy cam.

Check everything already mentioned. How did you set your valve lash?

If you had to tighten it to get it to stop ticking then there's something wrong since hydraulic lifters don't need to be readjusted. Is the pushrod bent? You have have a collapsed lifter or a cam lobe is wiped out.

camarokev400

allright.... I have the comp cams 268 series with .477/.480 lift and the rocker arms are 1.5 ratio so the cam didnt have too much lift for the vavle springs. As for adjusting my valves i went by the book and set the motor on top dead center and adjusted the ones the book said then rotated the motor and did all the other ones, the book said to take them a full turn more when the rocker arm stops wiggling up and down, however my dad told me to take them all half a turn. When the engine was first started it was good no ticks then on cold start up i would get a little tick that would go away... i believe that was the start of the #1 lifter ticking and i let it go for a week and put about 700 miles on the car and then last sunday morning i was out driving and i developed a constant tick so i pulled it apart and that is what i found on the #1 exhaust valve. I really dont think the cam is hurt becasue there is no miss to the engine and all the rocker arms were moving the same amount.

AlkyIROC

After tightening the rocker until the pushrod doesn't move (zero lash) a half turn is all that's required. That puts a .030" preload on the lifter.

Just to double check everything, pull your other pushrods out and have a look at them. If the rest look ok the replace the one pushrod and rocker and try again.

camarokev400

well this weekend i am going to pull it back apart again and check my other 15 pushrods and rocker arms.. i have been driving it all week after replacing the #1 pushrod and rocker arm and the motor is as quiet as can be and is running pretty good, still have a little hesitation i think that is in the carb though.. hopefully the rest of the pushrods are ok

camarokev400

well i kept driving the car with no probs, then 2 nights ago i was driving around and that damn tick came back again this time it was on the passenger side so i took both sides apart and found about 7 pushrods all messed up on the rocker arm side... well i was reading one my chevy books and it said in there that one end on some pushrods is hardened and the other isnt well turns ou that i had the hardened end down on the lifter instead of on the rocker arm so im hoping this is what my problem is.... i put 16 new pushrods in with the hardened end touching the rocker arm so we'll see how it works. thanks for the helps guys... i also checked for coil bind when i had it apart and i have plenty of room

GilmourD

Why didn't you just get a set of Comp or Crane pushrods that are hardened tip to tip?

camarokev400

because all of the chevy books that i have read so far have said to use the stock ones.... i dont know i might end up getting a set of nice hardened ones.... we'll see

GilmourD

Which Chevy books are these? If you read Chevy magazines, their advice is usually "Hey, while you're in there, why the hell not". That's what I did. I pulled my motor. So, new motor mounts. You know what? New tranny mount, too. I'm right there, anyhow, why not?

camarokev400

IT HAPENED AGAIN......... This motor is really confusing the hell outta me. My dad has been building engines since he was about 15 and is ASE certified and all that crap and he says he has never seen anything like it. We put those 16 pushrods in it out of a virgin 283 and made sure all the hardened ends were up towards the rocker arm and everything was good for about a month then saturday morning the tick came back every so slightly so i took it apart and sure enough another broken pushrod.... this was the worst one so far it actually took the whole end off it and ruined the rocker arm. We do not know what to do next...... i really dont think i have that much lift (.477/.480) i mean its decent but nothing that should be causing this. I am really starting to lean towards these pro form rocker arms..... i mean i dont know what else to suspect now. This motor is only turned 5000 rpms usually at the max i think it has hit 6000 or 6200 like twice by accident doing a burnout. What are your guy's thoughts i could really use your info right now, im thinking about pulling the motor back out this winter and ripping it back down to get to the bottom of this.




Oh yeah by the way it was out of those HOW TO REBUILD A SMALL BLOCK CHEVY BOOK'S, just the books that talk about stock parts and how to build HP and stuff like that pretty much just have them to look up torque specs. but i happened to see some of that stuff i stated in earlier posts in that book.

GilmourD

That's why we said to go for the hardened aftermarket pushrods. You're obviously having a problem with the stock type. When I ordered my cam kit (same one you got) for rebuilding my engine, the FIRST thing my father said to replace was the pushrods. I got the Comp ones.

camarokev400

yeah..... i understand what you are saying but something has to be causing this. And just think if i had a hardened pushrod it would not break or give like the stock ones, i would be breaking valve springs and rocker arms and pulling studs outta my heads or whatever........ thats the way i see it maybe im wrong but i know there are motors out there that have a hell of a lot more lift than i do with stock pushrods..... but i will consider hardened rods if it comes down to that thanks for your thoughts

GilmourD

Where did you get hte rocker arms you're using?

camarokev400

I got them from Norhtern Auto Parts for $80 they were new.... but very cheap. I have heard a few ohter guys on here talking about having problems with them but i really dont know what to think.

GilmourD

What kind are they? For not much more, you could've gotten the roller tip Comp Cam ones.

Mark A Shields

You don't have to get hardened pushrods for that setup. So, like your saying there is another problem, sorry I don't know though.

camarokev400

they are proform roller tip rockers

GilmourD

Eeek... I think that I'm probably not the only one redflagged by that... I've heard problems with the Proforms. Like I said before, for not that much more, you can get a rockin' set of Comp's Magnum roller tips.

91L98Z28

maybe the valvetrain geometry is wrong. if the pushrod is pushing into the rocker at too severe of an angle, maybe it's getting bound up and busting the tip off the pushrod.

check the pushrod geometry both visually (rotate motor by hand and observe range of motion) and also check wear the rocker tip is contacting the valve stem (should be in center 1/3 of valve stem).

while you're at it, bring a rocker to max lift and observe the valve spring and see if anything looks out of place (like it's bound up).

maybe if the lash is wrong, and the lifter has cold (thick) oil in it, the valve is contacting the piston ever so slightly and it's hammering the valvetrain and thus busting the pushrods. i think that one is a stretch but hey who knows.

camarokev400

Yeah i have considered most of your thoughts and checked some of the stuff already....... this is what i know so far....

The valve springs are not binding up

The pushrods are in correctly with the hardened end towards the rocker arm

The valves are adjusted correctly

Timing is right

Camshaft is not worn



Stuff i am not sure about yet:

Valvetrain Geometry

Correct valve springs.... they came in the camshaft kit but as you guys said they may not be compatiable with my heads... need to pull a valve cover (for the 100th time) and get a casting number.


Do you guys have any other thoughts i can use all the info you can supply me with as this motor will be coming out shortly if i cant fix it before winter.

91L98Z28

If the rockers are self aligning, you can NOT run guideplates.

If the rockers are NOT self aligning, you MUST run guideplates.

don't re-use a rocker that has been on a chewed up pushrod, i assume the rocker would have damage and then chew up the new pushrod.

check all the valve train with the engine running and make sure all 16 pushrods are oiling properly.

with a rocker and pushrod in your hand, make sure the pushrod mades smoothly and freely with a good range of motion to the rocker arm

make sure the pushrod is not contacting the head through it's range of motion, and then misaligning the pushrod on the rocker arm

make sure the rockers are not somehow wearing through or developing a wear pocket that is catching the pushrod and snapping it

make sure the rockers are not binding up around full lift (limited range of travel). you'll probably have to develop some tool that you can use to compress the valvespring via the rocker with the cam already at max lift. this goes hand in hand with my next suggestion:

make sure the retainers/locks are not contacting the valve guide (ala vortecs, with their 0.480" lift maximum).

check the rocker contact with the valve stem and make sure it contacts in the middle 1/3 as it's supposed to. if not it could be related to a pushrod length problem.

check to make sure the rocker is not contacting the retainer or any other part of the valvespring assembly.

i think if you do all this stuff eventually you are going to find something inherently flawed with your valvetrain setup or oil to the valvetrain. If you find it difficult to check geometry and range of motion, you may want to load one cylinder of the head with some weak "test only" valvesprings that you can manipualte by hand to at least see if the valve has for some reason reached max lift, or the rocker won't rock any further.

post some pictures of the valvetrain if you can get some clear ones, preferrablyh from the rockers side at no lift and max lift