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Hi guys, wasn't too long ago,that i was so happy i had gotten my 67 coupe. Today something terrible happen and i am so sad.
While driving down the road looking cool (well driving a cool car), my engine started to make some strange noises. After stopping and checking everything out, it is a pop/bang coming from the carb. I get the car towed home.
My brother comes and looks, checks the timing and other things, he says he suspects the cam went bad (ugh). We remove the valve covers and find this.
http://www.garza.ws/brokenrocker.jpg
What should i look at? i don't know how this can break and not cause other problems. He checked the push rod and anything else that may look out of place. I have a 289 stock PO said that it had been rebuilt, in 1984 or 1700 miles since he took possession. I have put about 2000 on it since i got it.

Thanks
 

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check the push rods: lay them over a flat surface (a pane of glass works well) to see if they're all straight and not bent.

Generally, if there has been valve to piston contact, the push rods bend first, the valve next, followed by a rocker arm failure. If all your pushrods are straight, it may be just a fluke arm failure, although I've never heard of "just" that happening. If they are all straight, I'd replace the rocker arm, pump up the oil pressure, and rotate the engine by hand with the plugs out to feel or hear anything strange. If that goes well, I'd throw the plugs in a start the puppy. If a valve has tapped a piston, it doesn't neccesasarily mean it bends. If one did, you'll have some odd backfire or intake reversion-- perhaps unnoticable at idle, although you'll notice the unsteadiness as the rpm increases.

Good luck.
 

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Sometimes the rockers just break. Do a compression test in that cyl, this will detect a bent valve if you have one. If the push rods look good, and the compression is good, I'd replace the rocker and fire it up. See what happens. If it runs fine, I wouldn't worry about it.
 
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Had this happen to my buddies '68 coupe 289. Pushrods looked ok and compression was decent. A couple of bucks at the parts store and he was back in business. It has been about six months and no further problems.
 

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in the 110k+ miles on my motor, I have had two rocker arms break. Both TRW brand. They too have resorted to the 'Made in China' syndrome. Absolute C-R-A-P.

Next time, I will purchase only made in U.S.A. components...

I would recommend you purchase a replacement rocker arm, re-assemble everyhting and rive it like you stole it!/forums/images/icons/shocked.gif
 

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AS the odd voice here, I would go along with the other posts, but also suggest that you check the lifter. If he hydrolic lifter failed, it is possible to damage the valve train. To check this, I would pull the plugs so as to reduce compression and make the engine easy to turn over by hand, then rotate the engine by hand with the valve cover off and all the components reassembled, watch the replaced rocker and see if the lift is the same as other rockers. In other words, does the rocker at rest have the same angle as the other rockers at rest and when it is at the high side of the cam lobe, does the rocker angle up the same amount as the other rockers that are at the high spot of the cam lobe.

I had something kind of like this on a 352 I rebuilt. Got 12 miles on it and a massive failure when the valve train over one cylinder failed, the cam broke in thirds and two lobes of cam dropped down into the cylinder and impact with the piston, cracked the block. /Turned out it was bad cam bearing installation by the machine shop.
 

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Probably just metal fatigue. If the rod is bent then replace it. Otherwise, just replace the rocker and drive on, cool. . .
 

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This happen to me and it was a fresh rebuild.
 

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when the previous owner rebuilt the engine, he must have reused the original cast rockers (of which can stress, crack and break over long periods of use or high mileage use)

The remedy is to get some comp cams or crane cams top of the ine forged roller rockers......I got the comp cams chromemoly rockers to avoid this specifically.

The parts are worth the money.....you get what you pay for.

I would do a partial if not complete teardown and double check rotating assembly etc....then reinstall everything with the new parts so you can have piece of mind.

It is worth the trouble to double check things thoroughly.

regards
 
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