Broken Rocker
11-01-2017, 03:52 PM
#1
Instructor
Thread Starter
Broken Rocker
Advice appreciated. I was in first slowly going down my street when instantly the engine began popping and running rough. I idled into my garage and today pulled the covers to find this. Any obvious reason for the carnage?
11-01-2017, 03:58 PM
#2
Le Mans Master
Lack of lube. I've seen that happen many times. Check the pushrod to make sure it's not plugged. Past that, it's one of those things that happens. If it's an exhaust, they seem to be more prone to that failure- move one from an intake to that position and then put the new one on the intake. GM says the intakes run a bit cooler.
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Akroland (11-01-2017)
11-01-2017, 04:00 PM
#3
Team Owner
45 year old parts or as Tim stated lack of oil.
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Akroland (11-01-2017)
11-01-2017, 04:18 PM
#4
Nam Labrat
Member Since: Sep 2013
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Did it have a steel pivot ball between the rocker arm and the retaining nut......(stuff gets forgotten sometimes 
)
)
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Akroland (11-02-2017)
11-01-2017, 04:18 PM
#5
Race Director
Make sure valve isn't hanging up.
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Akroland (11-02-2017)
11-02-2017, 11:16 PM
#6
Drifting
As was previously mentioned, 45 year old parts, but still check for proper oiling and make sure the push rod is not bent and the valve is not hung up so it will not open. There appears to be significant wear on the end of the rocker. Might be a good time to upgrade to roller rockers, which are a better design and will also give you 20-30 extra horsepower.
11-02-2017, 11:22 PM
#7
Team Owner
No lack of lube and nix to the 45 year-old part. The problem here is re-using stock rockers with significantly stronger springs than came on the stock engine. (At least, that's my 'guess'.)
The rocker broke because it was overstressed. The fracturing is in tensile failure and there is no discoloration on the wear areas of the part.
How'd I do, OP?
The rocker broke because it was overstressed. The fracturing is in tensile failure and there is no discoloration on the wear areas of the part.
How'd I do, OP?
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Akroland (11-05-2017)
11-03-2017, 12:35 AM
#8
Race Director
I had 2 on a recent rebuild. poor quality parts. Lasted less than 100 miles.
Went to roller rockers... now have 3k miles on the motor.
Have a high volume oil pump, no discoloration, just stress cracks on new rockers.
Went to roller rockers... now have 3k miles on the motor.
Have a high volume oil pump, no discoloration, just stress cracks on new rockers.
Last edited by BLUE1972; 11-03-2017 at 12:37 AM.
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Akroland (11-05-2017)
11-05-2017, 05:42 AM
#9
Instructor
Thread Starter
It’s back on the road. After checking the head, springs and pushrod I installed another Rocker. When tightening the Rocker bolt down I noticed it didn’t get tight in it proper position. The nuts are bent a little oval to ensure they don’t come loose. Everyone probably knows this but for me....I’m learning. I changed the nut and checked all the others and it’s back on the road! ........ and quitting on me. Next problem. Fuel pump. ☹️
11-05-2017, 10:13 AM
#10
Team Owner
What nuts are you "tightening" for the rockers? Those are adjustment nuts to set the valve lash...they don't get "tightened".
11-07-2017, 08:55 AM
#11
Safety Car
after 2-3 different problems (over many years) from stock rockers.
I won't build a performance motor, without min. roller tipped, or full Roller rockers.
especially with higher lift cams and springs.
I won't build a performance motor, without min. roller tipped, or full Roller rockers.
especially with higher lift cams and springs.
11-07-2017, 10:51 AM
#12
Melting Slicks
I had a rocker fail in the same manner as the OP, and with stock valve springs.
11-08-2017, 10:44 AM
#13
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11-08-2017, 10:45 AM
#14
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