If it's not one thing...

Ted

Ted

The pilot formerly known as Twin Engine Ted
Joined
Oct 9, 2007
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iFlyNothing
As some of you may remember, last weekend I discovered the starter on the right engine on my Aztec was heading south, and not in the way I'd like to (warm beaches sound very appealing right now). No problem, I got a good deal on a new starter and that's not a big deal to change. I figured that I'd take advantage of the opportunity to do a laundry list of a few things that the Aztec needed to have done on it. Last night, my mechanic and I got started. We had 5 things to accomplish:

1) Change the spark plug in the Janitrol heater. This has been giving me problems since I bought the plane, but since it's only recently gotten cold enough to need the heater again, I had put off getting a new plug. Easy job.

2) Cleaned the injectors on the left engine. I'd done the ones on the right engine a few months ago (they were really bad), and the left ones needed it, too, just not as badly. So I figured this was a good opportunity to get that done.

3) New baffle seals for the left engine. Upon examination, they weren't as bad as I'd thought they were, so I decided to put those off and reevaluate in the spring when it gets warmer out. I had done the ones on the right engine right before Oshkosh, as they were really bad. Changed them and noticed a 5 mph increase in cruise and a 30F drop in oil temp.

4) Cleaned and prepped the de-ice boots. This hadn't been done in at least 3 years, so a lot of scrubbing to get the boots prepped, then washed off, and then applied two coats of sealant. I may go apply a third coat, but the boots are nice and shiny now, looking like they'll do a much better job than they would have previously.

5) Starter. Easy, no brainer.

6) Wait, 6? I had said 5. This can't be good. Found the inner exhaust on the right engine had a nasty crack in it at one of the patches. Taking a closer look, that pipe is all patched up to the point of practically being more patch than pipe. The other parts of the exhaust don't look too bad, but this one definitely needed fixing. We figured I would need to order a new pipe on Monday, but in the mean time I was trying to get flying for an animal rescue today, so we pulled it out and welded it.

Well, the pipe was so screwed up that the weld job only made things worse, not better. About half past midnight last night, we threw in the towel. It's dead, Jim. Time for a new exhaust pipe. Unfortunately, this mean I had to cancel my flight last minute. First time I've done that in the year I've been doing these flights, so I suppose it's not too bad of a record considering the number of flights I've done. Also, in the 200 hours I've put on the Aztec this year, this is the first time I've had to cancel a flight due to mechanical issues (excluding while the thing was in annual). Not bad for a 40 year old plane with 9000 hours on it, especially considering the amount of use that I've been putting on it.

Now the question: Do I just order the pipe to replace it, or order the whole system? There's an STC'd exhaust system that's a better design, and has larger diameter pipes that ought to make a bit of a power boost. I'm going to give the folks a call and see what the cost points are, and go from there. Probably call on Monday. Gotta get this thing back together for next weekend's trip!

Maybe sometime in there I can even get the autopilot fixed. Got the altitude computer back and yellow-tagged, and got the new bridle cable for the roll servo. Now just got to get those installed.

If it's not one thing...
 
Welcome to ownership. You're fortunate that you have the skills and the supervision to do so much of the work yourself.

Sorry about your cancelled flight, though.
 
Ted, I'm glad you weren't sitting behind that engine with the bad exhaust (ASEL scenario). You may have gone asleep (inflight) a long time ago.
 
Ted DuPuis said:
As some of you may remember, last weekend I discovered the starter on the right engine on my Aztec was heading south, and not in the way I'd like to (warm beaches sound very appealing right now). No problem, I got a good deal on a new starter and that's not a big deal to change. I figured that I'd take advantage of the opportunity to do a laundry list of a few things that the Aztec needed to have done on it. Last night, my mechanic and I got started. We had 5 things to accomplish:

1) Change the spark plug in the Janitrol heater. This has been giving me problems since I bought the plane, but since it's only recently gotten cold enough to need the heater again, I had put off getting a new plug. Easy job.

2) Cleaned the injectors on the left engine. I'd done the ones on the right engine a few months ago (they were really bad), and the left ones needed it, too, just not as badly. So I figured this was a good opportunity to get that done.

3) New baffle seals for the left engine. Upon examination, they weren't as bad as I'd thought they were, so I decided to put those off and reevaluate in the spring when it gets warmer out. I had done the ones on the right engine right before Oshkosh, as they were really bad. Changed them and noticed a 5 mph increase in cruise and a 30F drop in oil temp.

4) Cleaned and prepped the de-ice boots. This hadn't been done in at least 3 years, so a lot of scrubbing to get the boots prepped, then washed off, and then applied two coats of sealant. I may go apply a third coat, but the boots are nice and shiny now, looking like they'll do a much better job than they would have previously.

5) Starter. Easy, no brainer.

6) Wait, 6? I had said 5. This can't be good. Found the inner exhaust on the right engine had a nasty crack in it at one of the patches. Taking a closer look, that pipe is all patched up to the point of practically being more patch than pipe. The other parts of the exhaust don't look too bad, but this one definitely needed fixing. We figured I would need to order a new pipe on Monday, but in the mean time I was trying to get flying for an animal rescue today, so we pulled it out and welded it.

Well, the pipe was so screwed up that the weld job only made things worse, not better. About half past midnight last night, we threw in the towel. It's dead, Jim. Time for a new exhaust pipe. Unfortunately, this mean I had to cancel my flight last minute. First time I've done that in the year I've been doing these flights, so I suppose it's not too bad of a record considering the number of flights I've done. Also, in the 200 hours I've put on the Aztec this year, this is the first time I've had to cancel a flight due to mechanical issues (excluding while the thing was in annual). Not bad for a 40 year old plane with 9000 hours on it, especially considering the amount of use that I've been putting on it.

Now the question: Do I just order the pipe to replace it, or order the whole system? There's an STC'd exhaust system that's a better design, and has larger diameter pipes that ought to make a bit of a power boost. I'm going to give the folks a call and see what the cost points are, and go from there. Probably call on Monday. Gotta get this thing back together for next weekend's trip!

Maybe sometime in there I can even get the autopilot fixed. Got the altitude computer back and yellow-tagged, and got the new bridle cable for the roll servo. Now just got to get those installed.

If it's not one thing...
Click to expand...
With 160 hours to go on the Rt. Engine, I just put in for the LTSIO360EB1B reman......it'll probably occur in the pit of winter, when I wont' miss it for a week or two....It's pricey but has has a lot of those "somethings" new.
 
Yeah, the fact that I can do most of the work myself is a huge help.

And definitely glad this wasn't on a single. I had exhaust leaks happen to me in the Mooney I used to fly. CO exposure is not fun. This crack was way worse than the crack on the Mooney. From my experience there, it doesn't take much of a crack to get a substantial amount of CO in the cabin.
 
There's a nationally recognized shop near me that specializes in aircraft exhaust repairs called Aerospace Welding. Their prices are reasonable and they do outstanding work. I'd call for a quote and send my exhaust to them. They'll probably only use the flanges in their "repair" but what you get back will be better than factory new! AFaIK they also have PMA approval to build several exhausts from scratch and that might be another option for you. They've worked on the exhausts for my B55 and completely rebuilt the stacks on my Porterfield which involved some weird triangular heat muffs and all turned out very good.

http://www.awi-ami.com/
 
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bbchien said:
With 160 hours to go on the Rt. Engine, I just put in for the LTSIO360EB1B reman......it'll probably occur in the pit of winter, when I wont' miss it for a week or two....It's pricey but has has a lot of those "somethings" new.
Click to expand...

Sounds like a good plan. Plus it's always nicer when you can get this stuff just done and out of the way during a time when you aren't using the plane so that you (theoretically) don't have to worry about it. In another 500 hours or so my right engine will be due for an overhaul.

I'm going to be out of the country for a week and a half later this month, and feel like I should get something done on the Aztec while I'm gone. I'm just not sure what. Thinking of trying to get the door to seal properly, but as we discussed at WV62, that is probably an exercise in futility.
 
Thanks for the tip, Lance. I'll see what they can offer. Aircraftexhaust.com has an STC'd replacement that offers some significant improvements over the factory exhaust. I'm tempted to go with that, but I'm going to call them up on Monday (closed today) to see what they can offer me price wise. Will definitely also check with Aerospace Welding.

By the way, I got the Altimatic IIIB looked at. The altitude computer was shot (now repaired and yellow tagged) and the bridle cable for the roll servo broke (this was post our testing at Gaston's). They also cleaned the contacts on the roll switch. So now I need to get all that installed and should be good to go. Maybe that's what I'll have done while I'm in Europe.
 
Ted DuPuis said:
I'm going to be out of the country for a week and a half later this month, and feel like I should get something done on the Aztec while I'm gone. I'm just not sure what. Thinking of trying to get the door to seal properly, but as we discussed at WV62, that is probably an exercise in futility.
Click to expand...

Getting your door to seal properly and close properly can be done, it just takes some work and some shimming of the hinges. I had to do the same thing to my PA23-150 years ago and the doors are very similar.

What ruins these doors (and doors on other airplanes) is when people feel they have to slam the door to shut it. Over time it warps slightly.
 
Sounds like your plane wants something in return for all those hrs of flying, lol. Welcome to ownership, it never ends.
 
Rotor&Wing said:
Getting your door to seal properly and close properly can be done, it just takes some work and some shimming of the hinges. I had to do the same thing to my PA23-150 years ago and the doors are very similar.

What ruins these doors (and doors on other airplanes) is when people feel they have to slam the door to shut it. Over time it warps slightly.
Click to expand...

Don't know about Aztec doors, but Baron/Bonanza doors suffer from three ailments. One is getting warped from people using the door for a handrail when getting into and out of the airplane (I often stand between the open door and the plane when pax unfamiliar with the door's fragility are coming or going). Another is the hinges themselves which tend to get real sloppy over time and aren't easy to replace. There is a procedure where the hinge pins are removed and the hinges are bushed that can repair this and I'm due. Finally there's the seals themselves which get pretty shoddy after 20 years of operation. I replaced mine with a product from Aircraft Door Seals which uses memory foam and works much better than the original did when new. You can also get inflatable seals but they don't always last long and shouldn't be needed if the door fits properly and the hinges are in good shape.
 
Well, after 40 years and 9000 hours the door has definitely been slammed a number of times. The door itself does appear to be warped slightly. Even when it's closed and locked there's a bit of air you can see. If I could find a specialit in this not too far away, I'd take it there to get it worked on. The door seals (for the main door and the two baggage doors) are completely shot, so those need replaced.

Lance, that memory foam thing sounds like a great idea. Annoyingly, it looks like they don't have anything for the PA23. I wonder if they could work something out for me.
 
If you don't replace the engine, I'd go for a full exhast replacement. There are a couple of shops that will "remanufacture" your old system (in reality you get new).... I used one a few years back after developing a leak near the turbo and it worked out great.
 
Yeah, twins are better. Now you know what to expect with the one on the other side.:wink2:
Ted DuPuis said:
Yeah, the fact that I can do most of the work myself is a huge help.

And definitely glad this wasn't on a single. I had exhaust leaks happen to me in the Mooney I used to fly. CO exposure is not fun. This crack was way worse than the crack on the Mooney. From my experience there, it doesn't take much of a crack to get a substantial amount of CO in the cabin.
Click to expand...
 
We had a REALLY good experience with Dawley Aviation in Burlington, WI when we needed a complete exhaust system replacement for our 200 HP Mooney M20.

http://www.dawley.net

Give 'em a call, they've gained their good reputation for a reason.
 
Well, I looked into my options this morning and decided to go with the STC upgraded exhaust from AircraftExhaust.com, see here:

http://aircraftexhaust.com/nav.cfm?...b=0&as_id=5&mg_id=50&sys_id=33&display=system

The design looks to be a significant improvement vs. the factory one in terms of longevity, plus it's a larger diameter which I would expect to improve performance a smidge (the factory exhaust on the Aztec is pathetic at best). The old pipe was just not worth salvaging, and that whole exhaust system looked to be very old. Plus I've had enough problems with the exhaust on that engine that it made sense to just pull the whole thing off and redo it right. And this way I feel good about spending money since I'm theoretically upgrading something. :)

It's supposed to arrive Wednesday, so we're going to plan on starting the install Wednesday night, hopefully finish it up. If not then, we'll finish it on Thursday.
 
Given what I heard you had paid for the Aztruck, I am not surprised. You pay sooner or later...
 
steingar said:
Given what I heard you had paid for the Aztruck, I am not surprised. You pay sooner or later...
Click to expand...

Actually, the plane is in remarkably good shape given the price I paid. In 200 hours of flight time so far the only things I've had to do on it were the alternator and now the starter and exhaust, plus the Janitrol spark plug. Given the age of the plane and number of hours, nothing's been out of line with normal wear and tear.
 
The lines on the chart (fuel & MX vs. purchase price) will soon cross and diverge forever.

steingar said:
Given what I heard you had paid for the Aztruck, I am not surprised. You pay sooner or later...
Click to expand...
 
What do you mean "soon"? This "soon" date already happened some time ago.
 
Ted DuPuis said:
Actually, the plane is in remarkably good shape given the price I paid. In 200 hours of flight time so far the only things I've had to do on it were the alternator and now the starter and exhaust, plus the Janitrol spark plug. Given the age of the plane and number of hours, nothing's been out of line with normal wear and tear.
Click to expand...

I know someone who just acquired a 1969 Aztec that he wants to sell for something like $45k. The engines are near TBO but running fine and he said the airframe hours were in the 2500 range which is pretty low. I'm going to make a post about it in the POA Classifieds forum. I have no idea what it's really worth, but I know he just would like to trade it for some needed cash. I think he got it as part a larger group of airplanes.
 
And now I'm trying to go somewhere, and the starter on the left engine has decided that it doesn't want to work (spins but bendix won't pop out). Better here than once I get to my destination, I suppose. Better still would've been a few days ago when we were working on it already.
 
Ted DuPuis said:
And now I'm trying to go somewhere, and the starter on the left engine has decided that it doesn't want to work (spins but bendix won't pop out). Better here than once I get to my destination, I suppose. Better still would've been a few days ago when we were working on it already.
Click to expand...

Remeber that little part you dropped? I know where it went :mad2: :D
 
Ted,
One thing we did on our Aztec is to drill a small 3/16" hole in the left nosebowl of each engine cowl, on the bottom of the air intake hole, so we can insert the spray tube on an aerosol can of silicone spray and lube the starter's bendix shaft without removing the nose bowls. Simply remove the side cowl, insert the spray tube and aim it into the bendix opening while watching from the side. The bendix houseing has a drain hole in the bottom, near the rear, and any excess will drain out the bottom. Haven't had any starter problems since we begin doing this once per month or so.

Caught this thread after you bought your new exhaust. Ours were re-man'ed by Dawley about 8 years ago and they shortened the drop tubes to raise the entire exhaust so the front cross tube and other low points provide better clearance with the bottom of the nose bowls and the lower cowl.

Jim
 
I had somewhat the opposite problem on the IAR. The starter spur gear would not disengage the ring gear after starting. I talked to Kelly Aerospace about it and they said they'd never heard of that where it didn't destroy the starter drive, but mine would still be engaged after a flight. It was pointed out to me by a lineman. I started paying attention to the ring gear much more closely on pre-flight after that and noticed it was a some time thing which I couldn't detect until after a flight. I ended up buying a new starter and, guess what, the new starter did the same thing right out of the box! Guess what the fix was... cleaning the starter ring gear teeth with a degreaser and a tooth brush. The engine leaked enough oil in the past that the oil had formed a semi-hard sludge on the ring gear teeth that prevented the retraction of the spur gear. So that is something to check.

KA recommended keeping the starter mechanism lubed up with (and only with) silicone spray and that because of the drain hole you couldn't over do it. What happens on my plane with the big spinner is a low pressure area exists just behind spinner bulkhead and it actually pulls the excess silicone forward and then slings it out to the blade and eventually creating a film on the windshield, which can be disconcerting. The first time it happened I thought the prop hub was leaking because of the staining on the black backside of the propeller blades, not realizing at the time that it would have grease, not oil, if that had been the case. And this was right after getting the propeller back from a complete overhaul. I finally realized that the blade staining originated about a half inch from the blade clamp just about in line with the circumference of the spinner bulk head. So be prepared for some benign, but unintended consequences if you keep the starter lubed per the mfgr's recommendations.

Fun stuff.

Ted DuPuis said:
And now I'm trying to go somewhere, and the starter on the left engine has decided that it doesn't want to work (spins but bendix won't pop out). Better here than once I get to my destination, I suppose. Better still would've been a few days ago when we were working on it already.
Click to expand...
 
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