They said the issues were caused by too high temperatures, probably from over aggressive leaning. There was no evidence of damage caused by detonation (thankfully) . That then discounts the original theory that it was the bad gas from Costco that was the problem. It wasn't.
I never could fully understand the rationale, although at the time, it seemed as good a reason as any. But I was confused with the fact that a) the rpm's increased dramatically when I leaned in flight and b) the plugs were totally sooted up when I pulled them. Both facts point to an overly rich mixture which in fact, cools the cylinder and serves to prevent detonation.
Ok, so that's settled.
I must confess that I am now totally gun shy of screwing up my engine again. My theory that it's impossible to over lean a 150 HP O-320 has been blown to bits.
So what to do?
The answer is to bolt on engine instrumentation and monitor the heck out of it. That means multi-cylinder probes for both CHT and EGT with built in alarming if things go south.
The good news is that there are a number of relatively low cost, digital engine monitoring solutions out there. After some research, I settled on Insight Avionics, a Canadian company based in Fort Erie. They have a nice little system called the G2 that was designed for planes like mine. It also includes a fuel flow monitor/totalizer which will be really useful.
I got a hold of them and was pleasantly surprised that due to the pandemic they were offering some amazing deals, specifically dealer pricing and the Canadian dollar at par (their price list is in US dollars). Yippee! I placed an order right away. Cost will be somewhere around $2K CDN and it will arrive next week. As before, I hope to do the installation myself under Chris' supervision.
So what about the engine and the cylinders? Well, let me fill you in...
Aerotec, the engine shop in Halifax did a great job with the cylinders. They had them cleaned up, valves and seats ground and lapped, painted and shipped in a couple of days. Chris called me to say the cylinders had arrived at his hangar and we could start the installation the next day.
There was only one problem. One was missing.
Whaaaat?
Yup. FedEx had screwed up. They only delivered three and the fourth had been returned to the depot in Barrie. Great. After calling customer support, they assured me it would be on the truck the next day.
Chris had already booked space in his hangar, so we started on the install of the first three. It went quite well. But as I've said before, sometimes it's better not being part of a major overhaul. There are so many moving parts in an engine and you kind of freak out realizing how many things could break.
A top overhaul, or replacing all the cylinders, is like open heart surgery on an engine. Everything in the engine is opened up. It's all there in plain sight--crankshaft, cam shaft, pistons and connecting rods--all open and swinging in the wind.
As I watched Chris work, I realized just how much I depended on him and his skill in putting everything back together. He literally had my life and the life of my passengers in his hands.
The second thing I realized was what an amazing thing an internal combustion engine is. Yet, we so easily take them for granted. Even though this engine had been designed way back in the 1950's, it was an amazing piece of machinery.
As Chris held each cylinder up to the engine block, I pushed the wrist pins through the piston and connecting rod securing them together. Chris then pushed the whole assembly up flush with the case and bolted it down.
What struck me was how beautifully machined each of the components were. The tolerances were perfect and the pins slid smoothly in on a film of oil with absolutely zero play or wiggle.
It reminded me of a quote by Stephen Coonts in his book The Cannibal Queen when he was doing a pre-purchase inspection of the Stearman:
"The engine...ah, that big, round 9 cylinder radial is a work of art...a film of oil on the pushrod bushings and on the bottom of the cowling...I reached in and got some on my fingers and felt that feeling of good, clean oil against precision machined steel."
Exactly.
So what about the missing cylinder? Well, it didn't show up the next day either. We had 3 and 1 installed, but number 4 was next and it was missing. Fortunately, it was also time for the plane's annual inspection so Chris put the install on hold and went to work on that while I went looking for the missing cylinder.
Fedex customer support, probably located in Thailand or something, was only marginally helpful. Yes, the cylinder hadn't been delivered either day. Yes, it should be on the truck the next day. No, they had no way of knowing that for sure. And yes, there was no way of knowing for sure if the cylinder was in Barrie, Tuktoyaktuk or Thailand.
Great.
So with Chris' $90/hour shop rate multiplying in my head, I did the only thing I could do. I got up at the crack of dawn the next day and parked myself at the door of the Fedex Ground Facility in Barrie. Hoping against hope the cylinder was still in there somewhere.
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| To paraphrase the old Birk's advert: "Happiness comes in a Lycoming brown box.' |
It was! So to make a long story short, I drove the missing cylinder to the hangar and Chris had everything back together before the end of the day. After a through going over, we moved the plane outside of the hangar and fired it up.
It started instantly and ran beautifully. Hurray! It was time to start the break-in procedure for the new jugs and that will be the subject of my next post.
Needless to say, it was wonderful to have a healthy running airplane again.
