Blew it up... GRRRRR!!!!!

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FASTBACK340

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Well, maybe not totally blown up, but I shoved 2 pushrods through the rocker arms this afternoon. Cylinder #1.... I'll probably pull the intake to make sure there's no further damage to the lifters. I punctured #1 cylinder exhaust rocker when I first got her running. I wonder why cylinder # 1 again... I installed used rockers and am planning to buy a set of new ones, but why? I hope there's nothing wrong with the lifters or the bore in the block.....

And here's the kick in the ***. About 15 minutes before this happened a young lady in, of all things... a Prius snarls at me while at a red light. I politely thanked her for saving some gas for me and lit `em up on the green. A few miles later I'm running on 7 cylinders.....
 
Have you checked for valve spring coil bind and retainer to valve stem seal clearance and how much clearance is there? How much preload are you running? What lifters are you running? At what rpm did you puncture a rocker?

Now go into the garage and hit yourself in the head with a brick three times. :-D

Edit: Oh yeah, one more thing. Does it look as though it's slowly worn through or pushed through in one big whack?
 
It started running crappy for about 10 minutes. I was headed home when all of a sudden, while cruising at maybe 2,500 RPM, it went went *Clank-Clank-Clank* and ran like a sack of ****. I managed to get off the main road and onto a side street where the noise went away, but it had no power. I had oil pressure and it was running, so I limped home the 1/2 mile or so.....

I pulled the valve covers and found oil in the top end, but both rockers on #1 are punched through clean. Push rods appear to be straight as if there wasn't a sudden stab. They were used rockers and push rods when installed, that I was going to replace "in the near future". The heads are stock Edelbrocks and the cam, pushrods, & lifters are new Comp. Cams pieces. Lift is advertised at .488/.491 so it's not a huge lift. I'm shopping for push rods and lifters as we speak, and I just comitted to purchase a set of grills.


Expensive day... :blackeye:
 
I have the same heads and cam. I used the MP HD rockers and have run them for about 12k miles. I am stunned that you blew these so fast.
 
AdamR said:
Couldnt you have waited till the 19th ?
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I think I was better off having it go *BOOM* a half a mile from my house as opposed to in the middle of a bridge going to Ct. I'm OK.... Just sedating myself as we speak.
 
redfastback said:
I have the same heads and cam. I used the MP HD rockers and have run them for about 12k miles. I am stunned that you blew these so fast.
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They were used pieces..... and I was, ummmm.... "flexing" some muscle the past 2 days. I guess I earned it. I just hope there isn't any more damage.
 
FASTBACK340 said:
It started running crappy for about 10 minutes. I was headed home when all of a sudden, while cruising at maybe 2,500 RPM, it went went *Clank-Clank-Clank* and ran like a sack of ****. I managed to get off the main road and onto a side street where the noise went away, but it had no power. I had oil pressure and it was running, so I limped home the 1/2 mile or so.....

I pulled the valve covers and found oil in the top end, but both rockers on #1 are punched through clean. Push rods appear to be straight as if there wasn't a sudden stab. They were used rockers and push rods when installed, that I was going to replace "in the near future". The heads are stock Edelbrocks and the cam, pushrods, & lifters are new Comp. Cams pieces. Lift is advertised at .488/.491 so it's not a huge lift. I'm shopping for push rods and lifters as we speak, and I just comitted to purchase a set of grills.


Expensive day... :blackeye:
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Yes, that was expensive. Was moly lube applied to the pushrod tips when you installed them? Is there metal filings on the head?
 
FASTBACK340 said:
I think I was better off having it go *BOOM* a half a mile from my house as opposed to in the middle of a bridge going to Ct. I'm OK.... Just sedating myself as we speak.
Click to expand...

Im sedating myself as well, LOL
 
redfastback said:
I have the same heads and cam. I used the MP HD rockers and have run them for about 12k miles. I am stunned that you blew these so fast.
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If I am not mistaken the MP stamped steel rockers have more meat in the pushrod cup to aid in the bigger cams and higher rpm's. Might try you a set of those to see if that cures the problem. Just my 2 cents.
Matt
 
i was having this problem over and over and over untill i finnaly switched to some comp roller rockers i love them havnt had this problem again
 
I had a '76 Volare Roadrunner years and years ago. It had a 340 from a previous owner. One day while cruising home it started popping through the carb. Pulled over and it died. Got it started and would die again. Wouldn't stay running long enough for me to get under the hood. Limped it home. Next day pull the valve covers. One pushrod through an exhaust rocker. Rolled the pushrod on the bench. Looked straight. Ordered one new rocker. Never had another problem regarding the rockers after that.

So check it out. Might not be as expensive a problem as you think.




Wylde.
 
Make sure you're getting oil to the rockers on that cylinder.

With used parts it's POSSIBLE you got that one in 10 million chance of 2 going bad at once, but next to each other is astronomical, or by some faulty design.

I'm not convinced you have a fitment problem, coil bind or such other problem, but it could be a lube issue.
With the pushrod seats destroyed, you can't even tell if the lube holes were plugged, now.

Mark.
 
The reason I asked about what type rockers you were using is because Edelbrock says that adjustable rockers must be used.
 
I had the same problem with stock rocker arms. I believe they are good for low lift but anything over .450 they don't hold up very well (just guessing).

But for facts I had a .420 cam in my engine and ran it hard with no problems. Then I installed a .474 cam and one intake and one exhaust punched through on each head. I didn't have coil bind or anything like that because I checked before starting the engine and with my engine builder friend. I went with a cheap brand of roller rockers for a while then switched to Comp rollers.
 
So you are using stock stamped rockers?

Get some good ones, I used to see stockers in mundane grocery getters with the pushrods pushed through.
 
John,
My experience with an old 73 Power Wagon I owned in the 80's showed me to NEVER mix old rockers/pushrods on a Mopar. That truck with the factory 318 did the same as your car; push the pushrods through the rocker arms. My problem was I took the top end apart to replace a head gasket, and didn't keep the parts marked for reassembly.
Once you replace the pushrods/rocker arms, you'll be good to go. Just make sure that thing is running on all 8 before the 17th! I wanna see it! :D

George
 
hi, how much valve spring pressure is on the heads ? open and closed!! the reason I ask, is , stock stamped rockers don't like a lot of spring pressure.
how much preload on the lifters?
 
perfacar said:
hi, how much valve spring pressure is on the heads ? open and closed!! the reason I ask, is , stock stamped rockers don't like a lot of spring pressure.
how much preload on the lifters?
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with stock rockers there is really no way of telling what kind of preload there is on any of the lifters being non ajdustable you just torque the shafts and the preload is what ever was designed into them which i think is little to none when the lifter is on the bottom of the cam lobe with stock rockers you can wiggle the rocker back and forth a bit
 
edelbrock heads are around 125 lbs on the seat....

get rid of the stock rockers...

I have used the MP heavy duty rockers on eddy heads, so the claim by edelbrock that adjustable rockers are needed is not totally true...
 
1qwikScamp said:
with stock rockers there is really no way of telling what kind of preload there is on any of the lifters being non ajdustable you just torque the shafts and the preload is what ever was designed into them which i think is little to none when the lifter is on the bottom of the cam lobe with stock rockers you can wiggle the rocker back and forth a bit
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sure there is, thats why they make adjustable length pushrod checkers. all you do is put the checker in, tighten the shaft down, set the length so you have zero lash then remove it. once you have it out measure it and add the amount of preload you want. then all you have to do is order up the length you want.
 
Sorry to hear of your misfortune, John. But I love the exchange with the self-righteous Prius owner!
 
camd64 said:
sure there is, thats why they make adjustable length pushrod checkers. all you do is put the checker in, tighten the shaft down, set the length so you have zero lash then remove it. once you have it out measure it and add the amount of preload you want. then all you have to do is order up the length you want.
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Exactly, you can even make your own. This is for an adjustable valvetrain but the same can be done for a non-adjustable. I made this on a cheap drill press with a drill press vise, a grade 8 bolt and two nuts.

IMG_0427.jpg
 
ramcharger said:
Exactly, you can even make your own. This is for an adjustable valvetrain but the same can be done for a non-adjustable.
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I cheated and bought one from comp. the new ones are sweet they are marked so you don't even have to use calipers. by the way I know you dig the home made tools, check out the spring compressor i came up with in the home made tools forum. its cool the stuff you come up with when your broke! :cheers:
 
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