Rocker nut and swivel foot came loose!

[PropellerHead]

I noted a strange exhaust note during a recent track session in my stock '71 911T. I perceived a loss of power too but with a stock 2.2T, there isn't much to begin with. There was an obvious engine vibration at lower revs. I brought it in straight away (still under power) and noted significant valvetrain clatter from the right side of the car as I took off my helmet and got out. Thought I could isolate the noise to the intake side and shut the car down. I expected based on the noise to find a broken rocker but instead found a missing nut and swivel foot on the #6 intake side:



I last adjusted the valves about 18 months ago and have driven the car several thousand miles and several track sessions. No obscure valve noise, car was running great, etc. Looks like the valve stem is unharmed from what I can see thus far and the adjuster screw ball end also doesn't have witness marks.

Ideas to cause and/or where the nut and swivel foot might be found? Sustained high RPM running, somewhat elevated temperatures (this was a cool track weeeknd and temps stayed very reasonable)? I'm crossing fingers that both missing pieces might be resting directly below on the exhaust side under the rocker cover but I haven't opened that up yet. Wish me luck on that!

Sad part is that I'm building a 'hotrod' engine on the side so that I don't subject the #'s matching original engine to as much risk on the track......but it isn't completed yet and wasn't planning on going into the car probably until next winter. I also debated about adjusting/checking valves before this driving season begain in earnest but I decided to wait. Silly me!

Cheers,
Chet

[porschenut]

I've heard of that happening before. Take off the lower valve cover and the parts will fall out.

[PropellerHead]

Dave,
Thanks. I hope I am so fortunate.
When you've heard of this previously, any idea to the cause or situation surrounding? Were they also high RPM related?
Chet

[john walker's workshop]

check your other nuts for enough torque. that's the likely cause.

[porschenut]

Originally Posted by PropellerHead

Dave,
Thanks. I hope I am so fortunate.
When you've heard of this previously, any idea to the cause or situation surrounding? Were they also high RPM related?
Chet

It was some time ago and I don't completely recall the circumstances, but I'm pretty sure it was not long after a valve adjustment had been done, and it was most likely a result of what JW suggested - an improperly torqued nut. Yours seems to have remained there for a while before letting go.

[CorsePerVita]

Originally Posted by john walker's workshop

check your other nuts for enough torque. that's the likely cause.

Something I've never been able to find is a torque number for those nuts. Does anyone know what the actual amount of torque is recommended for those things? I have heard everything from "I just torque them to what feels good" to "snug" to "tight"... I do not like playing guessing games with valves.

[PropellerHead]

Problem is you have to hold the screw while torquing the nut. To do so precludes the use of standard torque wrenches. So you have to calibrate your hand in all sorts of contorted positions.
Clearly I didn't get it tight but as many miles as I had on it I find it odd that it chose to come loose when it did.

Obviously I will re-set/check them all again. Heck, I have to remove at least the exhaust side to try and find the missing pieces!

[Eagledriver]

The elephant foot will just "pop" back on (if it's not damaged). Might have to remove the rocker arm to work on popping it back on.

[PropellerHead]

Found the missing pieces just as Dave predicted! I don't plan to reuse the screw, nut or foot for good measure. The foot has a little damage on the socket edge but nothing major.
Thanks for the help!
Chet

[vuepfg]

I do not like playing guessing games with valves.

[PropellerHead]

Not willing to take chances with potentially compromised parts, I removed the rocker arm and replaced the foot/adjuster/nut and reinstalled. Was able to do that in the car with some creative use of tools and patience. I drilled a small hole in the shroud portion of the engine oil cooler to allow a drift to pass through so I could tap the rocker shaft back into position without removal of the carbs, engine shroud, oil cooler, etc. My '71 has the one piece engine shroud which makes oil cooler removal a much more involved process so I attempted to make the repair without. All told it was a ~4 hr repair from start to finish inclusive of a valve lash check. Much better than I had assumed when I first pulled off the track.
Car is back up and running beautifully and without any (new) oil leaks with minimal down time! Good thing as it was a long winter here and hopefully the spring/summer driving season will be able to be enjoyed.
Thanks all for the help.
Chet

[Porboynz]

Nice follow up, great job.

[savoyjfas]

I have to remove at least the exhaust side to try and find the missing pieces!