Valve adustment - How Necessary? When?

[Vibenator]

I've been wondering if anyone on this site has had a valve adjustment done on their engine. The Vibe engine uses flat tappets with shims to set the valve clearance. I've heard different reports from "get your valves adjusted every 30,000 miles" to "valve adjustment isn't needed on a flat tappet motor." Has anyone here had any experience with having their valves adjusted, or done it themselves? Do the valves go out of adjustment to the point where engine operation is affected? At what point? Are there any symptoms pointing to the need for a valve adjustment? Comments from knowledgeable owners would be appreciated.

[joatmon]

It's easy enough to check the clearances, especially for a GT clutch replacer like you, so go ahead and check them. Haven't heard of anyone actually needing to adjust them yet. I checked mine on my 1ZZ at about 130K miles and they were fine, but that should not be taken as a claim that the clearances don't need to be checked. I don't know what the typical symptoms would be, other than noisy valves. There will be others, perhaps performance/efficiency drop. Supposedly on these little engines clearances can be out spec either side, you can end up with a valve that doesn't open enough, or one that opens too much.Seems like 2ZZ engines are more likely to need lift bolts replaced than valves adjusted.