Valve adjustment

[PeteInLongBeach]

Originally Posted by Fredvon4

Pete nothing is missing
The procedure is well documented for the 4B series motor that this 3B variant is related to.

Well, without factory documentation available to us, it's hard to know these things.

I disagree with your first bullet conclusion... this is a high rev motor and 4 valve head with low density parts availability and ZERO aftermarket motor parts
As the gap increases the results are not "relatively benign tapping noise and less valve actuation " as you suggest. The more the gap the faster the gap widens.... or more wear per unit of time/RPM... Who knows how much wear becomes too much, and catastrophic damage occurs because the micro millimeter cam lobe hardened surface is compromised

The smart/mitsubishi motor is no more mechanically exotic or higher revving than most other 3-cylinder automotive engine out there (Honda, Suzuki, Subaru, Daihatsu, etc.). I've been driving and repairing smaller high-rpm motors all my life. Small amounts of extra valve gap are not significantly destructive, mostly just a bit noisier. And notice I intentionally used the term "relatively" benign tappet noise, which I meant in comparison to the much more damaging effects of insufficient valve gap.

It's disappointing to know that the valve gap is not easier to maintain, considering most other similar motors utilize shims or rocker adjustments that do not require the dealer dropping the motor and removal of the camshafts.

[PeteInLongBeach]

Originally Posted by fortow

Nontheless, the wear on this type of valve train is mainly in the valve head seating. The tolerances tend to tighten, not loosen as a result. So, if people are expecting to hear tapping sound to alert them to do an adjustment, they may never hear that. The clearances should be checked periodically, at least at 60,000 miles to make certain that there is still some clearance left. Otherwise burned valves may have to be replaced.

This is exactly my concern, and such maintenance on the smart is not user (owner) friendly - to say the least.