Rocker failure...

[acarlson]

I just thought I'd post this. I had my Turbo Corsa out the other day and just before I got home I heard a weird noise and lost some power. I only had a mile to go to get home but it seemed like it was running on only 5 cylinders. I pulld the plugs and did a compression test on all the cylinders. All except #3 were between 120 and 130 PSI. #3 was 0. I retested 6 or 7 times. #3 was either 0 PSI or 60 PSI. I pulled the valve cover off. #3 intake rocker was not seated on the valve stem. I removed the rocker and discovered this:
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IMG_0371s.jpg (161.51 KiB) Viewed 1092 times

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IMG_0372s.jpg (180.33 KiB) Viewed 1092 times

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I've never had a rocker fail like this before. I do have heavy duty valve springs installed for my OTTO-20 cam. Maybe they plus 50 years of wear and tear finally got the best of that poor rocker arm.

Alec

[66vairguy]

That rocker failure happens. Lots of speculation from folks, but probably just an old age failure. If the replacement rocker works then just figure it was old age.

Yes high tension valve springs are tougher on a valve train. Going with a more aggressive cam and high tension valve springs increases the high RPM output, but there is a price. I've been down that road when younger. Now I just use mild cams and the stock low tension valve springs and keep the RPM's under 5,000. Just me.

[miniman82]

Time for rollers! hehe

[davemotohead]

Check the clearance between the Rocker and stud, sometimes with a big cam the rocker will contact the stud and cause the rocker or stud to break, also the Clarks Repop Rockers seem to break in short order, Replace it with a good used GM Rocker arm.

[acarlson]

...also the Clarks Repop Rockers seem to break in short order, Replace it with a good used GM Rocker arm.

Ahh, Dave - I wish you had posted that yesterday I already ordered a couple of Clark’s rocker sets

I’ll give’em a try and let everyone know how they perform

[davemotohead]

Carry a complete set of Original ones with you for road side repairs!

[illinicorsa]

I had one fail just like that on my 1966 Monza -- in 1970, with ~40,000 miles.

Steve
'66 Corsa

[Bill MC]

I have had three original rockers fail so far, identical to the failure pictured.
Picture doesn't look like an original rocker...IMHO, did OEM pivot balls have slots for lube?
I have an Isky 260 cam, not sure if that is the smoking gun here
I reloaded with new set from Clarks so will see what happens i guess. Carry a few old ones in the tool box just in case.

[bbodie52]

Make certain that all push rods are inserted with the side oil hole at the rocker arm end.



Rocker arms have a hole in them to permit oil from the push rod to squirt through and lubricate the rocker arm ball area.




The grooved rocker arm balls are an aftermarket modification to improve lubrication...