180HP Rocker cover/cowling interference

[Lopez]

I have a 54 B model with a Lycoming O-360A1A. The right cowl door latch is hitting the top of the rocker cover. When I overhauled the engine, I replaced one of the rocker covers because it was dented on the top, now I think I know why. Am I missing something in the Avcon instructions? I don't remember any instruction to beat in the top of a rocker box cover to create clearance in the Avcon info. I also had to grind the back side of the front latch on the left hand side to create clearance between the latch and rocker cover. I'm not opposed to "making" clearance, I just want to make sure there isn't something else thoroughly screwed up in my mount or cowling somewhere. Everything else fits great.

I've attached a pic of the RH side where it is hitting the rocker cover.

[bagarre]

All of the Lycoming 360 conversions I've ever seen have blisters added to the cowl in order to get the needed clearance.

[Lopez]

The blisters are for clearance between the FRONT cylinders and the cowl. This interference is at the rear cylinder.

[bagarre]

Oops

[DaveF]

My '54 with Avcon has no such problem, but I know the clearance is small. My airplane has been down for many weeks for a major overhaul, and I hope this problem doesn't appear with the new engine mounts.

[c170b53]

Mine although not an Avcon conversion and a 0-320 rather than its bigger brother, does the same thing. With mine if I'm careful and latch the fwd end first, I can avoid hitting the cover if I slowly begin latching as I close the door

[Roesbery]

On my '55' I made new cowl doors because the original ones were a bit worn. I very carefully located the two new Hartwell latches where the old ones were located and had the same problem of scratching the rocker cover as you have. I ground off the corner of the latch tip for clearence. I also installed a third latch between that one and the top lip of the cowl door to eliminate the need for screws to hold the door closed. That one had to be located so as to not contact the engine baffeling. Hind sight being what it is, if I do it again I will move the latch up a eighth or quarter inch on that side.

[johneeb]

Aryana is the increased dorsal fin because 3497C sometimes operates on floats?