Annual Ramblings

[Dr. O]

Well, tis that time of year again... Besides the usual inspection, I opted to put new cylinders on the left engine - did the right one two annuals ago... The left was field overhauled 1000 hours ago with fresh bearings and reconditioned cylinders... The pressure on the cylinders has been lowering just a bit every year getting down to 61 all around last year...This year we had 3 at 61 and one at 12... That sealed the decision... I've had the new Titan cylinders sitting on the shelf for 2 years, awaiting this moment... We jerked the cylinders and holding my breath I inspected the cam and bottom end... Everything looked like new and we found no evidence of oil leaks at the parting line on the case halves and both AI's agreed there was no need to split the case, so I am $7K to the good on that one...

We pushed the fat boy out onto the ramp today after 3 days of wrenching and started the engine with it's new cylinders... As usual for it, it started immediately... It sounded good with a healthy bark through the augmenter tube... We let it run for two minutes and thirty seconds with a quick mag check and one burst of throttle, then shut it down to avoid glazing the cylinders... No leaks found...

That finished the engine inspections and top overhaul, so we put the airframe up on jacks and started on it... In working through the punch list there is an AD to test the fuel valves for fuel cutoff... Wilbur crawled under the gascolator and began draining whilst I turned various fuel valves off and on... Wouldn't you know it, the fuel would not stop completely with the selector valve off - on both sides (arghhhh)... Now we are busily removing the lower turtle deck cowlings to remove the the entire fuel pump plate and gascolator so we can put in new O rings and adjust the linkage... It's always something...
Plus, Steve found just a trace of slop in the elevator push rod... He said it was within tolerance, but I said for him to crawl his big butt down the fuselage and put in new bushings... He wasn't looking that happy when I left...

More later...
Cheers,

denny-o and Fat Albert the Apache....

 

[SCCutler]

The only thing worse than finding something wrong with your airplane during annual, is not finding it.

You never regret thoroughness.

 

[Ted]

I'm sure you've checked this already, but I'm guessing those Titan cylinders aren't covered under the AD? Migaldi can tell you his feelings on ECi cylinders...

I agree with Spike. Whenever my mechanics have found something that needed fixed, I've been happy - they found it on the ground.

 

[Dr. O]

And the guys who got caught with Lycoming cranks will tell you their feelings, etc... No one company is immune from this, not even Boeing or Airbus... As far as my mechanic can tell my cylinders on both engines are free of any AD notes...

And along those lines of things supposed to be really bad, I was running a pure synthetic oil for many years and when the big publicity campaign against synthetics started... At the request of the FSDO we opened up my engine and pulled a cylinder in front of the Grand Rapids FSDO inspector and at 940 hours on the synthetic oil it was sparkling clean, still had 78 to 79 over 80 pressures on all 6 cylinders and cross hatch marks in the bores... He came right out and said he never saw an engine look like that at 900+ hours... A few bad incidents does not mean there is a widespread problem, that it could simply be isolated failures or ham fisted pilots - but the FAA lawyers never heard of that proposition and rather than restrict synthetic oil in those few turbocharged engines that were evidencing trouble with sludging they leaned on the oil makers who promptly withdrew their products form the market leaving us with engines that wear out long before they should.....
And in years past I put ECI Cermichromes on my Super Viking that 'suddenly' were supposed to be bad, but my cylinders ran like gangbusters during the five years I had that plane after installing the cylinders...
No one person's experience is the answer - not even mine, though I have made out pretty well...

Still waiting on one final bushing for the elevator push rod clevis... At least we were able to find them for a 1957 airframe... Hopefully I get to fly next week...

denny-o

 

[Dr. O]

Well, a lot of air has passed under the wings since last post...

First, the good news... The new cylinders went on, the bushings were installed, and all AD's are covered,, and the annual was signed off...

Then the bad news... Engine with new cylinders idles like crap and the manifold pressure is higher than it is on the right at the same idle RPM... He adjusts the carb - idles 'slightly' better... So I fly it... It makes good power and we get the rings to seat... But it idles like crap still and now it back fires at idle... He checks the timing and the valve lash - all perfect... I fly it... It makes good power but it idles like crap and it back fires at idle...

So, this morning I arrive at the airport before he does and when he wanders in I put my foot down ( or is it my checkbook?) and I inform him that we ARE fixing my airplane today and he is doing nothing else, not finishing the annual on the Skylane sitting in his shop, not napping in his office, we are fixing my AIRPLANE! Capiche?...

I start the engine and he uses infrared thermometer to find the cool cylinder - aha, gotcha Mr. Morning Sickness valve... He regales me with tales of the tight valve guides he has encountered on ECI cylinders over the years... We pull the valve cover on the cold cylinder and drop the valves (one at a time), run the appropriate reamer through the guides to fix the "sticking valve"... Only the guides are the perfect diameter already and you can turn the reamer with your fingers like it is spinning in hot butter and the valves slide in in and out like oil running over honey... OK, put it back together and run it...

It idles like crap and backfires and now we have a cylinder on the other side that is running cold... We look at each other and sigh... Without a word we set about dropping the intake valve springs off the 3 cylinders we have not yet checked - we play dueling prop position whilst doing this... The valves glide effortlessly in oily silence when we check them.. We put the springs back on, verify the push rods are the correct length and go to lunch late... We know one thing now, for sure - the valves are not at fault...

Back at the shop I stare at the engine while he is getting rocker covers on and generally putting the engine into running condition... I go over the primer lines looking for a cracked line.... We pump the primer looking for a drip... We go over the intake runners (which have all new hose and clamp assemblies) looking for a leak, we run the engine and squirt flammable liquid here and there looking for that magic jump in rpm when you hit the leak - nada... I pull the airbox and use a mirror to look up into the carb throat - nada...

He is frustrated and walks away... I am standing and tapping a forefinger on the aluminum tubing that serves the manifold pressure gauge for the engine... The tube is solid, ferrule is tight, no wiggle, no nuttin... On an impulse I cannot explain I unscrew one of the adell clamps that secure the middle of the tubing from vibrating and slide the clamp down... In the middle of darkened area of the tube where the the clamp squeezes, my finger nail detects a slight catch on the surface of the tube... It has an invisible crack that circles about 90% of the tube circumference... As we undo the ferrule on the fitting the tube turns and breaks in half...

Long story short we make a new tube and install it... The engine runs like a million bucks - which is roughly what 7 hours of shop time is going to cost me...

denny-o