Had a rocker arm failure last weekend, center three rockers on right side. Looks like they started to seize to the shaft and heated up and stretched and broke. All other rockers on that side and other side are ok. Checked cam lobes (solid cam), valves, coil bind and retainer clearance. Engine has good oil pressure and has oil to rockers on both sides when turning oil pump with drill. These are the older hughes/dove rockers. This engine has been together and running great for a few years. Not sure what caused the failure. Any ideas?

2

3

If they were oiling right then it was just their time to go IMO. Low quality parts don't last. The newer Hughes rockers seem to be much better quality. Damn that sucks, hope those were the only casualties.

By the looks of the shaft things got pretty hot to turn it blue. Were those roller rockers? wheres the needles?

Did you have adequate side clearance? Oil pressure and flow is needed, oil needs come & go.

were the shafts on correctly?

Quote:

---

were the shafts on correctly?

---

x2; curious if oiling holes were installed upright thus preventing oil from lubricating the rockers.

Have also read that pretty much any set under $500 is prone to failure (cheap imports, cheap materials)

Sorry to see the carnage.

how many passes on them? assuming they where correct
they have a life span..
they stretch on the shaft..loose oil then
fail

What brand are they...............

Are they 1.6 or higher ratio? Was there notch where the push rod cut into the rocker body for clearance? With stout springs sometimes that's all it takes, We fried a few from notching for spring clearance that failed the same way from the other side.

These are the 1.6 ratio Dove/Hughes rockers. The shafts were installed correctly, that was the first thing I checked. This is mainly a street car that has only been down the track a few times.

Those rockers didn't fail because they were cheap or inferior, and the scoring on the shafts indicates the shaft was installed correctly. Look for a loss of oiling such as low oil level, turned camshaft bearing or clogged oiling holes. Also look for a reason for abnormally high spring loads or rocker loads that would clear the oil film.

Here's a long shot: How a bout a misfire resulting in late combustion and the exhaust valve trying to open against abnormally high combustion pressures.

Here's what I see, first if the rockers were on the shafts exactly the way they are layed out in that picture then the shaft is backwards. next by looking at the banana grooves and the mrks on the shaft it looks as though the grooves are a little too long and there was a loss of oil pressure because it was squirting out past the rocker.

Next, unbushed alum body rockers on steel shafts , those 2 things do not play well , sooner or later this will happen.

I would be looking for all the aluminum,and where it went....pull the pan,if not engine to inspect,imho.

you say this car has been running great for a few years but how many miles?did it sit for extended periods of time between drives?

My opinion... if you notice they all started to blue(heat)
on the adjuster side(load side) and in the
one pic you can see smeared alum in the groove...
myself I think the grooves cut and smeared the alum
into the grooves and blocked off the oil... I have a
set of similar type rockers but with no oil groove..
the groove takes away load area ... and if there is
ANY edge on the shaft its gonna cut the rocker... JMO

That is what I was thinking, the bannana groove cut into the rocker and started the damage. The car sits all winter and usually for a week or two between driving in the summer.