Valve springs seating?
 

Hello, is it common to have a 'ptoing'-like sound coming from the valve train when you put some initial load on the valves after installation of the rocker? It occured a few times during rotation and then did not return after numerous turns.

The heads have been rebuild.

Otherwise, could it come from the just installed, new chain tensioners?

The sound occured approx 1x during a crank revolution, but not predictable. It did happen at the some point in the rotation I think

To provide some context: I'm tackling subproject 8 in Wayne's book: piston/valve clearance (seems to be okay for #1 inlet). The sound happened before I started adjusting the valve adjustment screw, so I do not suspect any valve/piston interferance

?

TIA

Dennis

Things have to get happy with each other and a slow rotation may not do it. When I rebuild heads I always give the valves a good hit with a plastic hammer to seat the springs, retainers etc, sometimes they can hang up on the retaining cups.

Are you running a high lift cam? stock or aftermarket springs?

hi, thanks for your reply, it might mean that there's nothing serious going on. This is an S cam using stock springs (as in: the springs that belong in this S engine)

what exactly do you mean by ' hanging up' on the retaining cups? Is it a condition I could check for visually?

The only other thing that could make a strange sound when turning it over by hand would be if you put both cam gears on the same way, one side the gear dish faces out and the other side it faces in. This would cause misalignment and binding in the chain and make a nasty sound.

Hi Craig,

thx for the suggestion. These have been fitted correctly though (and aligned within spec). I'm guessing it's the valve springs. I will check the cam timing today, as my line of thought is that if something was not seated properly on inlet #1 or #4, possibly the timing measurements are off...