wrote:
Well the decision is made. I am replacing my engine (O360) with a
Lycoming factory reman. I have a few questions for the group. What is
the feeling about the new roller cam? They offer roller or regular for
the same $$. Any comments pro or con? The engine comes stock with
Slick mags with the option (more $$$) for Bendix mags. Is there a
preference? I have heard/read that the Slicks are difficult/expensive
to overhaul. Are there any ADs on the Slicks? Right now I have Bendix
mags installed.

Regards,
Jerry

I look after six airplanes, all having Lycoming factory remans.
(4 O-320s, 1 O-235, 1 O-540). Three of those O-320s we replaced just
this spring. The Lyc prices were lower than having the old ones redone
closer to home, and we were able to keep the turnaround time to much
less.
One of them has the roller cam. I notice no difference in noise
or performance. I think the cam will last longer; I just hope Lyc has
tested the setup well enough. The roller will have less contact area
than the old lifter face, placing more pressure on the cam lobe, though
not rubbing it so much. The camshaft itself is ground differently to
accommodate the roller, with a more square profile to get the same
travel characteristics as the old lifter, and maybe the camshaft metal
is tougher. One of Lycoming's weak areas was the camshaft, with more
wear than Continental. We use only Aeroshell 15W50 because it has the
additive recommended by Lycoming to protect that shaft. The crankcase
is modified to fit the new lifters, which have an indexing feature to
keep the rollers lined up with the cam. You can spot the roller-cam
engines by the much larger green pushrod tube seals at the case.
Five of out six engines have Slick mags, which all work well.
They are no problem at all to service. We stick to the 500-hour
ionspection intervals, removing the mags and opening them up to check
the points and distributor. Those parts usually need replacing around
the 1500-hour mark. There are very few ADs on modern Slicks. The O-540
has the dual Bendix mag which is a certified first-class pain to
maintain by comparison.
Only beef: One of the carbs on the recent engines ran rich
enough at full throttle to be rough in the climb. Turned out that the
accelerator pump check ball spring was missing and extra fuel was being
drawn past the valve.

Dan