Engine
Tear Down
Following a Thursday night meeting tech session with a discussion about
engines and overhauls, the chapter
members gathered in president Jeff Scott's hangar to tear down the
O-290 engine that the chapter inherited
from Arlene Walsh. Under the tutelage of A&P
Jeff Scott and machinist Doug Reid, the engine was torn down
for inspection, then sold to one of the chapter members once some
gauling was discovered on a cam follower.
The victim (O-290) and the executioners.
O-290 on the stand with cylinder wrenches ready to go.
Jeff explains the plan of attack..
Yes, we had some young observers with a critical eye.
The silverware trays laid out to collect and sort the parts.
Jeff demonstrates how to slip the piston pin out.
George takes his turn with the Cylinder base wrench.
This engine appears to have brand new pistons and rings.
Travis gets hands on with the cylinder wrenches.
Doug inspects the rings with lots of observers.
Brian wrenching on one of the front cylinders.
Hmm. Apparently not all of the pistons were new. As
it turns out, this piston wasn't even the same compression
ratio as the other three. This engine would have been a real
shaker had it ever been started.
The left bank apparently had all new pistons.
Thomas gets the feel of the cylinder wrenches.
Thomas seems to really be getting into this engine work..
Jeff working the wrist pin out of a piston.
Finally, an empty hole we can look in!
Jeff starts loosening the rod bolts.
One rod out.
And the rod bearing out of the cap.
The rod bolts had to be gently tapped out with a brass drift.
Inspecting the cam and cam followers.
There it is. A small amount of gauling on the lower cam
follower. The gauling was caused by a mal-adjusted
valve that kept the cam follower pinched against the cam, preventing
the cam follower from rotating. Consequently,
it wore in one spot rather than rotating, which prevents wear.
Doug brought his valve removal tool and demonstrated how to remove
valve keepers and what he looks
for when he inspects valves and guides.
Doug measures the valve stem.
And points out some important facts about this valve.
