Attributed to astronaut Alan B. Shepard, the first American in space. It is usually quoted as “Dear Lord, please don’t let me f**k up” – which is exactly how I felt as I started towards the engine with tools and intent. Time to investigate the oil leak.
Pretty sure it was coming from the oil sump gasket, I realised that to change the gasket would involve taking at least the four inlet tubes off, and if the sump didn’t drop far enough, the exhausts too.
The tubes came off quite easily:
But is was still a little crowded under there:
And the exhausts would have to come off. Great.
Once the exhausts were off it made it a lot easier to get at the sump bolts:
But eagle-eyed readers with a bit of Lycoming O-320 knowledge will notice that the starter motor is removed too. That sucker was preventing me getting at just one of the sump bolts. One bolt. And that starter motor is heavy. So to get at one bolt I had to undo another five bolts, four spacers and two plates. Even minor tinkering grows arms and legs.
Once I could get at the bolts it was relatively straightforward to drop the sump and remove the old gasket. You can see the new one ready to go in the photo above.
Before putting it all back together I had to order new exhaust gaskets, inlet gaskets, new hose for the warm air ducts, new exhaust bolts and washers. Once they arrived it was relatively straightforward to get it all back together. With no parts left over. Always a bonus.
Time for a ground run to check for leaks. Filled with oil and a sploosh of “Camguard” – it guards the cams, what else can I say? I started up, checked oil pressure and temperature rising, let it run for about a minute and shut down. I jumped out and had a good look around the engine. No leaks.
Then it hit me – the engine started! I didn’t f**k up putting the starter motor back on. Ole Shepard produced an effective prayer, I’ll be using it regularly.
Another run, this time for about five minutes and up to 1700rpm for an ignition check. All looked good so we shut down and put the aircraft back in the hangar.
I was tidying up the tools when I noticed this under the left side of the engine:
And it was getting bigger! Bugger. I followed the drops back up to the source and found leaks at the base of both left side cylinder head covers. Removing both revealed splits in the silcone rubber gaskets:
Definitely a route for oil to leak out. They’ll need to be replaced. Here we go off to the Light Aero Spares website again…they must love me.
New ones are on order (£7.77 each)…but I’m back at work so tinkering will have to wait for a few days.
At least the oil sump has a new gasket, whether it needed one or not…