Valve Guide Deterioration. Total Mileage on Reconditioned Head = 300.
The valve guides, springs, seats and valves were all replaced during Reconditioning.
Pool of Bronze powder in Port Side Exhaust cover chamber. See quantity that rests on edge of cover.
Bronze debris in Adjacent Cover. All 3 chambers had this amount.
Evidently it became oil borne and moved through the whole system.
"Wipe Pattern" of the rocker on the Exhaust Stem.
The "thin color" area is the contact patch.
"Wipe Pattern" on the tip of the Exhaust Rocker.
The "thin color" area is the contact patch.
"Wipe Pattern" of the rocker on the Intake Stem. (For Comparison)
The "thin color" area is the contact patch.
"Wipe Pattern" on the tip of the Intake Rocker. (For Comparison)
The "thin color" area is the contact patch.
Bronze Debris on Exhaust Valve stem after removing springs.
Note "spatter" as exhaust pressure drove debris into surrounding chamber.
Worn Exhaust Guide. The major wear is inside the exhaust port end of the guide.
The bore is about .020" out of round (0.5mm)
The wear is all toward the center of the cylinder
The Exhaust Valve from this head (300 Miles total running)
Close Up of stem showing contamination.
This would not wash off with Carburetor Cleaner.