Valve Clearances.

[Butch (cb)]

My run out last week to the Distinguished Gentleman's ride finally got me to the 3000 mile service.

I run the clearances on my all iron engine at 010 and 014 thou. One was still at size and the other three were tight, by maybe a couple of thou. I probably looked at these last around 750 miles ago. Is that normal movement or might I be experiencing a little valve seat regression?

I mostly run high octane and always with Castrol valve master lead additive.

[muskrat]

Valves settle in their seats usually within the first couple of heat cycles and no more than a couple of thou.
Would you have nipped up the cylinder base nuts of r/box bolts. That will close'em up.
Cheers

[wilko]

Be thankful. If they had opened up it might have meant your cam is wearing!