Archive for the ‘Engine’ Category

Installed new cylinders

Sunday, February 10th, 2013

After an unexpectedly long delay – due to schedule issues and also because ECI didn't send me all the expected parts on the first try – I finally managed to get my four new engine cylinders installed.

The cylinders are mounted and torqued, the pushrods and rocker arms are in, the oil drain tubes are back on, and the fuel injection lines are reinstalled and clamped. The intake and exhaust pipes are still off, since I want to get the EGT and CHT probes installed before I put them back on for good. And the rocker covers are not on yet because I ran out of steam and got tired of standing in the cold garage.

Grey cylinders with red pushrod tubes and crankcase is kind of a cool color scheme. Can't order 'em that way.

While I was complying with SB08-1, I also took care of SB12-1 by installing new stainless parts for the pushrod shroud tube retainer spring and lock tab.

Guiding me through this whole adventure was local engine guru Jerry Gippner, who taught me a lot about engine maintenance in the process. I think I could probably do it again on my own next time, so thanks Jerry for the education!

Next: Reinstalling baffles and other engine parts, hopefully for the last time (for the foreseeable future anyway).

Removed engine cylinders

Saturday, January 5th, 2013

One of the things I've been putting off for as long as possible is dealing with SB08-1, the dreaded ECI service bulletin. The gist of it is that if you are unlucky enough to have a cylinder that came from a bad batch, it must be replaced with a new one, lest it develop a crack in-flight with spectacular and exciting results. Imagine how lucky you have to be for all four of your cylinders to be bad, like mine are! Fortunately I was able to work out a warranty deal with the company, but it's still going to be an expensive fix. At least I'll come out ahead of where I'd be if I had to buy four new cylinders at full retail price.

I waited until I couldn't make any further progress on the engine without starting to attach things semi-permanently, then finally gritted my teeth and started unbolting things. I took off the baffles, dropped the exhaust (and sent it back to the manufacturer to fix a different potential cracking issue), pulled the spark plugs, and so forth.

One of the many piles of stuff that came off the engine:

I've owned and maintained Lycoming engines before, but I've never done any serious maintenance like removing a cylinder. I decided to hire out the job to a local A&P, from whom I learned a lot about how it's done. Definitely worth the cost of hiring a pro to show you the ropes the first time when you're working on an engine that costs as much as a nice new car. But now look how sad it looks with the jugs removed:

Four bad cylinder assemblies, ready to be shipped back to where they came from. If you've never seen an air-cooled aircraft engine cylinder up close, these are about the size of a gallon of milk (I guess that's why they call them jugs?) and weigh maybe twenty pounds apiece. I saved the valve covers, pushrods, rocker arms, injector nozzles, and wrist pins – everything else including the pistons and rings goes back and gets replaced with new parts.

Amazing how many little things have to be removed before you can take the cylinders off:

On the bright side, pulling the cylinders gives me a chance to look inside the engine for corrosion. I was slightly worried that some internal rust might have started during the (sadly) extended period the engine has been sitting in my non climate controlled garage, but happily everything I can see inside the engine looks shiny and new.

The ever-critical camshaft looks great as well. Once the cam starts to go, you're looking at a five-figure engine teardown. Luckily that date appears to still be a long ways off.

I boxed up the old cylinders and sent them on their way. Meanwhile I threw a tarp over the engine to keep stuff from falling into the open cylinder holes while I'm waiting for new jugs to arrive.

Although it is without a doubt an unfortunate backwards step, this chore is actually also a bit exciting, since it means that once the new cylinders are installed, I'll be able to start attaching things to the engine for the last time. Think positive

Desiccant plugs

Saturday, May 9th, 2009

I put in a new set of desiccant plugs in the engine this weekend… after two years of service, the old ones were starting to lose their magic ability to dry out when I put them in the oven every few months.


Sniffle valve

Sunday, June 29th, 2008

Fuel-injected Lycoming engines can sometimes experience a phenomenon wherein excess fuel drips down the induction tubes and pools in the intake manifold after shutdown. This can be a problem, since it could cause a troublesome fire during the next start. To alleviate this, you install a simple little one-way check valve in the bottom of the intake, which lets the fuel drip out of the engine onto the ground. For whatever reason, this item is colloquially referred to as a sniffle valve.

Here's a bad picture of the one I bought from Airflow Performance for a few bucks – it's basically just a normal AN fitting that's been drilled out and had a ball bearing and retainer clip inserted. Reduced pressure inside the manifold causes the ball to be sucked up to close the valve when the engine is running, but it drops down and lets the fuel drip out when the engine is shut down.

I knew from previous reading that the sniffle valve is too close to the exhaust pipes on an IO-360 with horizontal induction, so I installed it in a 45-degree brass street elbow to clear the pipes. The exact orientation of the valve is said not to matter much, as long as the ball is free to drop when the airplane is at rest. I also attached a 1/4" hose barb to 1/4" AN flare adapter, similar to the one I used for the fuel pump drain line.

I ran another 1/4" aluminum line from the firewall up to the sniffle valve, using a length of 1/4" rubber fuel hose as a flexible coupling. The forward (engine) end of the aluminum tube is ever so slightly flared to give the clamps something to work with – using a real beading tool would have been best, but I can't afford one and this is not a critical application. The aft end of the drain tube is attached to the firewall flange with an adel clamp, just like its twin the fuel drain line.

One more of the million firewall forward tasks is complete… and with that, I'm off to try and make a dent in the beer and ice cream still left over from Saturday's party.