Valve rocker guide

[Rival5]

Yesterday while driving i had a valve rocker guide come unseated. The rocker arm then was pushed to the side its cam lobe. The side of the lobe was rounded slightly but the machined area where the rocker arm rides on the lobe and the machined area on the rocker arm were undamaged. The valve rocker guide was also undamaged. I looked around and did not see any damage anywhere. I have put everything back together and the car runs fine.

So my question is why did the guide come unseated?

I talked with my friend and my neighbor and we came up with either a poorly adjusted valve clearence or a weak valve spring. Could there be others reasons and should I look for or check for other damage that was not visable with the valve cover off? This is a stock 1980 L6 in a 280ZX.

[spork]

Most likely the adjuster came loose. When was the last time you adjusted your valve lash? Was the adjuster loose at all when you went to put it back together? If you're worried about your springs, have someone at a shop test them for you, its quick and easy to do.

[Rival5]

Its been about a year sence i adjusted my valves. The adjuster was still tight when i cracked open the valve cover.

[datsunlover]

Could be a sticking valve.. not letting the spring come back up enough, therefore allowing too much room between the rocker and guide.. enough vibration/driving, and it would pop off. Worst case it would be a bent valve, and I'm sure you can see why it wouold cause this.. but if you replaced it and the car runs fine, I'm sure evrythings ok.. I'd just check ALL the valves lash cold/hot to be sure.