Upfront

Finish mounting the starter was no problem: clean up the threads, clean up the studs, torque, done. Then, the alternator.

Belt tensioning... too annoying by hand, but it took me a while to stop trying and become sensible.

Belt Tensioning

You gotta safety two bolts over there, and I decided to make it nice: for the bottom (pivot) bolt, drilled a tiny hole in the bracket lower than where the alternator would be, and for the top bolt attaching the bracket to the motor... hmmm...

Somewhere on VansAirforce someone used a cherry rivet as a "hookup" point for the safety wire. I thought to one-up that, and use a short #8 screw - drilling it's head.

Frankly, I didn't think it'd work out.

Drilled cap head

...but as you can see, it did.

So then, to the hole in the bracket. I needed a #8-32 tap.

Side, fun, story: quite a while ago I ended up bidding in a machine shop liquidation auction. Got quite a few nice things, including a very heavy duty bandsaw - and, accidentally, a massive cabinet full of tooling. Anything you could imagine: inserts, drills, taps, slitting saws, you name it. In all shapes and sizes. When we moved the cabinet, we emptied it into about 10 boxes, so ... I did have a #8-32 tap. In fact, probably about 20 of them. Question was, which one of the boxes were they in.

... apparently, in the one on the top. Hmm. This kind of luck is unusual.

Tap

Look at it carefully. Does it look like a regular tap we are all used to?

Didn't to me either.

So to researching we went.

Aha! "Threadforming" tap. AKA "Cold Rolling". So that's how they're done. Rolled threads are formed into the metal rather than cut; giving them superior strength. Basically, the tap shapes the metal, displacing it in the valleys and raising peaks.

Company that made these taps was advertising them for CNC milling. Well, what's a human if not a bio-CNC machine?!

Okay, problem number 2. I was pretty sure normal tap and drill chart values for hole diameters won't work; making too small a hole. Hmm...

The Bible

Aha! "Ideal Theoretical Hole", and closest drill available charts are just what's needed.

The Word

And with that, the affair was a non-event.

The Hole

Actually safetying was annoying - I had to try twice, because I had to use a hand-twister and you had to get the length just right.

Hand Twister

Safetied!

Airbox

That thing needed to be put back on, and carb final torqued with a new gasket. Cleaned it all up inside as much as I could, and had to cut a couple of special gaskets that I can't for the love of me figure out where to get (carb's base is different size from the top - and this is an "airframe" problem - read, "no standard part from Marvel or Lycoming I could find reasonably"). No problem. Used the same material Lycoming used for their gaskets, ordered from McMaster, and made me a couple.

Cutting gaskets

Where they go

Perceptive will see the "airflow straightener". Glenn had it on when he put on the Rotec TBI, and in the times of my research of TBIs, I have discovered that some folks claimed they helped on carbureted motors as well. Well, it definitely won't hurt - aside from my having to do two gaskets instead of one. No biggie.

Carb

One interesting thing that happened. I had to drain the carb bowl of all the preservative oil, and flush it, so I took off the plug, drained it, and started putting it back in. Plug's an NPT thread with torque listed by Lycoming in SSP-1776 at 144 inch pounds.

Hmmm.. I noticed it was going in way deeper than it was in before, and way "harder" than when I took it out.

Hmmm.. Well, it's Lycoming, they know what the hell they're talking about. So in it went, at 144 inch/lbs.

But this bugged me. I think some other day I pulled out the Marvel's manual. 25-30 inch/lbs?! WHAT?!

Back to Lycoming. 144. Marvel (the makers of the carb)? 25-30. Damn it. Forums? Nothing interesting.

I finally figured it out. In SSP-1776, in the table for special torques, Lycoming lists the plug to have 3/4 pipe threads. Mine were 1/8 NPT. Lycoming's torque for those is 40-44 inch/lbs. Still higher than Marvel, but much closer now.

So, I undid the plug, that cut a bit of the tapered thread "deeper", of course. And put it back in, with the right torque this time.

Other Stuff

And then, minor stuff here and there. Cleaned and prepped spark plugs. Put the exhaust back on. Tightened things that had to be tightened. Charged batteries. Tied up everything hanging loose. Gave the plane a good look all over.

We were ready for the final day. There were a number of things I needed two sets of hands for, and I had just the man lined up.

Day X - or, September 19, to be Precise.

My buddy Mr. N. agreed to help, and be my observer and fireman (just in case). Mr. M. was extremely inquisitive about how we're gonna be putting out a burning airplane, and I had to explain a number of times that the goal of an exercise of starting a motor that's been idle for a year is not to have it go ablaze, and having a fire watch nearby is a part of prudence, not expectations. He seemed to have been disappointed. I would be too, if I was 5.

So, on a nice Saturday, we went to the airport.

First, drained all the pickling oil. Took off the prop (because we'd have to spin the motor to pressurize the oil lines). Put the fuel pump back on. Tightened all new fuel lines, and leak checked them. Mr. M. used my fancy "button with alligator clips" to turn it on. Put new oil in, primed the oil cooler and pump (and this is fun in this airplane, because there's no oil filler neck on the motor). Checked control cable travel, and final cotter pinned them. Checked brakes again (though we bled them when I finished fixing them up).

Then, came the pressurization, and purging of oil lines, time. Mr. M insisted that he wants to "press the button" - which would put +12V onto the starter contactor; bypassing my normal starting circuit (latter would make the left mag hot, and I didn't want that).

I told him to press the button and hold it and not let go till I told him to.

Now, starters with a motor with removed spark plugs are fast, loud, and annoyingly sounding. Mr. M. pressed the button. Jumped a bit. Grimaced a bit. He clearly didn't expect it. I didn't see it, Nick told me afterwards - I was watching the oil line. I yelled "Stop" when I saw the oil come out, and looked at Mr. M - who, at that point, was shaking and at the point of breaking down in tears. But! He didn't let go of the damn button. Man.

Mr. M

And that was that. Plugs went in, and we were ready, but broke for lunch, first. Mr M deserved his hot dog.

... back from lunch. Plane out. Wheels chocked. Brakes tested. Fire watch ready and instructed.

Final prep

... damn, that old Concord battery removed from the Cheetah years ago is weak and barely pulling thru.

... second try: no primer, so I have to pump the throttle a bit.

... she's alive!!!!!

I let the temps go up just a bit, and called N. He confirmed everything seemed to have been fine. We shut down, and went over every fluid fitting. All good.

Started her back up - I wanted to warm the oil to a reasonable temp and let her circulate for a bit, maybe 30 minutes - to get the juice flowing again.

On the second run, I revved her harder, and smelled something. Smelled like... burnt wiring? N. went around the engine, all wires, and everything he could see or think was close to being to a hot surface, or an electrical doodad. No signs of trouble.

We decided to proceed.

She ran just fine. I think we ran for about a total of 30 minutes. Shut her down, dragged her in. Went over the wires again - all of them. Nothing, all clean. There were no bad indications on any of the electrical instrumentation, either. So at that time, we left that as a mystery to be solved.

... and with that, we went home. We were tired.

Research

As much as I am absolutely not afraid of electrical systems, I am very afraid of exhaust systems (and a few other things). I just don't know enough or have enough experience.

What turned up to be even worse was trying to find someone who does know what they're talking about. I poked around, and couldn't find anyone around or in our Chapter that knows this stuff well to be able to tell me "do this, and I got a TIG machine in the corner to weld up whatever you need".

So, I did the second best thing I could.

A couple years back, I met a gentleman at Oshkosh at our Biplane Forum gathering, Mr. T., who wrote a series of articles on motors, including exhaust.

He agreed graciously to listen to me (well, "read", technically) rant, and maybe guide me a bit.

So, to the drawing board!

I had to put the system back on, and hang the cowling back on the airplane as well, so that I could check everything in place.

When I took the exhaust system off, I plugged the stubs coming off of cylinders with duct tape. Big mistake!

Duct tape on the stubs

Cleaning that crap off took GoofOff and about an hour.

Old tailpipe

That's the head on picture of the old stub.

The first and the easiest possibility was, what would happen if I just extended it straight out?

Straight extension - head on

Straight extension - side view

I used a piece of paper to mock that up. Mind you, that'd be about a 10" extension! Lots of pipe, considering that the original tailpipe was maybe 16 inches long total.

It was obvious that doing this would move the exhaust outboard way more than moving it down. Why is this bad? Well, the bulk of it was hitting the aluminum side of the fuse and the plastic (okay, okay, fiberglass :) ) root fairing. Moved out this way, it would be hitting the fabric-covered leading edge. Somehow, that didn't sit well with me, and Mr. T. concurred.

So, I went on a scavenging run, and borrowed a nice piece of exhaust grade 3" SCAT from Mr. Dick G., my friendly neighbor, and attempted to mock something up with that.

Now that went way better!

Approx 45 degrees

That moved the exhaust point downward, and I realized that I could play with it even more by bringing it closer to the airbox via cutting progressively more off of the old tailpipe (at this point with SCAT I haven't yet cut anything, because I was just playing and wasn't committed).

That seemed like a way to go. So, next step was to mock this up with a real 45 degree bend.

I got the cheapest slip-on 45 degree mandrel bend from Summit.

At this point, I had to commit, because using this slip-on would require some cutting.

Some cutting

I was committed!

And some more cutting

And then, the fit with the bottom cowl on.

Front view

Side view

That looked just perfect! A total of about 8 inches of tube added overall, and the exhaust actually moved inboard, and way down into the slip stream.

All that was left to do was to buy the actual 45 degree bend I'd be using, and find a welder.

Unobtanium

I was looking around for welder who'd be willing and able while playing with the geometry. Asking around the airport didn't yield much.

Backup plan was Seth from Marioshop - the guy I take my cars to (his boss is a dragster, and Seth welded a lot of tube and exhaust - although, automotive, much thicker kind, with MIG).

I contacted folks from another EAA Chapter, the Waco 59, a great and dynamic EAA Chapter which I am also a member of, and scored - their very experienced Tech Counselor and metalworker Mike M. agreed to help me with the project. He welded himself, and also knew a gentleman that was "very artistic with his welds", as he put it.

I just had to get the material, jig it up to position it, and come over to weld everything up.

My tailpipe was 3 inches in diameter (jumping a bit ahead of myself, unusual for a motor of my size - too big). I measured .049 with my dial calipers, which translated into 18GA, and ordered the nicest shiny new bend from Summit. When it came, I realized...

It was the wrong thing.

Way thicker than what I had.

I think I mis-measured. Maybe I was asleep when I did it, maybe there was a lot of crud on the old pipe and I didn't pay attention, maybe .. but I needed 0.035 material. 20 gauge.

Quick Internet search - nothing.

More Internet searching - nothing.

I could buy all kinds of bends in smaller diameter tubing with 0.035 wall thickness. I could buy 3" tubing with 0.049 wall. I could not find 3" 45 degree bend in 0.035.

One company offered to sell me a straight piece. That was a good backup - we could've mitered and welded up the 45 degree bend in sections, but I wanted to see if I could find a bend. That same company offered to make me one - at a low price of about 600 bucks. Yikes!

Attempting to Hail Mary again, I posted on the Biplane Forum. Guys came back with a bunch of phone ##s of their contacts, and I started calling around!

Nope, nope, nope. I don't remember who it was, but one of the guys I called suggested contacting Custom Aircraft Parts.

A nice lady answered. "You gotta talk to Clint", she said, and transferred me.

Clint

Clint picked up. I asked if they could sell me the bend. Clint asked, "What are you trying to do"?

I explained.

He asked for pictures. A bit weirded out, I sent them over.

"I have two things I wanna tell you", said Clint.

"Buy yourself a bottle of soap and a nice rag".

"Be careful what you wish for".

Clit knew this 4-into-1 setup with a muffler in between very well. He told me that even with me trying to keep the extension as short as possible, I was running a risk of it cracking off at the muffler. Would it for sure? He didn't know. But the risk was increasing a lot.

I called my old friend and a Grumman aficionado Ben the same night. Grummans have this style mufflers (mine didn't by the way because it was sporting Powerflow - a very different system).

"Hey, do you recall welding cracked off tailpipes?"

"For sure".

Damn! Damn damn damn.

More mulling over ensued. I did not want to risk a tail pipe cracked off at the muffler. No way. That puts hot exhaust into a very tight cowling. On a biplane. With my having elevated fear of any in flight fire. Remember, I embarked on the electrical rebuild because I judged this airplane to be a flying fire hazard.

I talked with Ben more. I talked with Mike from Waco 59 more.

The attempted fix solidified.

Exhaust hanger

I would put a ball joint somewhere close to the muffler, with one end on the old pipe, and one end on the new extension that includes the bend. That ball would isolate the extension from the existing system, and allow them to move relative to one another.

I would then hang the new extension to the oil sump on some kind of hanger with a clamp - likely, a kind of tube with ends flattened and bent as required.

I sent this schematic to Clint. Well, no, not this one. This is a nice one I did when writing this post, over a picture I took when mocking up this solution. The one I sent to Clint was this. But, same idea.

Schematic I sent to Clint

Clint's response? Verbatim:

Adding a ball joint and brace solves all of my concerns, you are free to do anything you want to the tailpipe. If you weld the bend on as your latest drawing shows, looks more reasonable. When adding a support brace it is imperative that it stabilizes the tailpipe to the engine, they must move together.

WOOT! Did I find a way to do what I wanted?

One thing to absolutely ensure was that the ball joint would fit.

We went back and forth a bit, me asking about dimensions. Then, I threw together a quick drawing of the widest part of the ball joint - the clamp holding it together - and tried it next time I was in the hangar.

No way. No way it hell it would fit. Airbox would get in the way.

Here's probably the best picture I have of why.

Clearances

That little triangle of "air" in between the cowling (bottom), exhaust pipe, and airbox is probably 1 inch on sides. No way a ball would fit in there. No freaking way.

So, what am I left with?

Putting it Back Together, the Way It Was

I gave up.

Called Clint on the way back from the airport, and asked him to sell me a straight length of pipe with a slip fit on one end.

Got it a week later.

Called Mike, got a contact for his welder, and went there.

The gentleman didn't like the fit - too loose - and wanted to make sure I pinned it exactly where I wanted (and actually, I should've done that in the first place, because the opening in the cowling is very tight, and just a degree of being off would make it interfere with the cowling). He also wanted me to clean all the gunk off.

So, back to the hangar, and fun fun fun with a die grinder, deburring wheel, wire brush... This 40 year old exhaust is gunky!!!

Back on for tailpipe fit

Put new section of pipe on, clocked it just right, drilled a couple of holes thru, and put in a couple screws.

Putting a nut on the inside of a 3" pipe about 10 inches "in" is .. exciting!

Nuts on the inside of the pipe

Then, pulled it off and put in more screws, to be absolutely sure that if it had to come apart, it would come back together in the exact clocking I needed.

Mike's welder fell thru, and that cost me a couple weeks at least. I focused on some other work - panels, compass, etc.

One of those days, I was on the phone with D. when a gentleman I didn't recognise walked over from the hangar next door housing a PT-19, and asked to borrow a hex key. When I hung up, I walked over to introduce myself.

"Hi, I'm M."

M.?! The M.?

Yep.

He's somewhat of a local celebrity, having built a ton of airplanes, and having worked on more. I met him on a couple occasions in passing, but not really, and I didn't remember his face when he walked over. He's a sheet metal and generally a metal guy. He was working on the PT-19's electrical (ha, fun coincidence, eh?)

A lot of hangar flying ensued.

He looked over the biplane. He told me of his building a replica Hughes H-1. Of his own design basically.

When parting ways, I asked, "Hey, do you have a welder by any chance?" Asking doesn't hurt right? "Yep, I got a TIG machine".

Ha! Of course :) I meant to ask if he knew a welder. But he was one. I should've thought of that myself.

He agreed to help me weld the damn thing back on, of course. He asked for me to clean the insides. It kinda made sense, too - you want full penetration when welding, and you don't want all that crud on the inside of the tube to "float up".

So, lots more of a die grinder time, with flapwheels, with a compressor barely large enough to run the damn thing for a minute straight.

Then, drove to M's shop, drooled over the H-1 and the MP-14 that he had on it.

And then, the final fit of the tailpipe to put it where it was when I cut it off.

We put the exhaust back on the plane,..

Back on the plane

...put the cowling back on, and I started fiddling around with things to try to figure out how to mark an even line to cut it off on.

Rubber band maybe?

Rubber bands actually worked quite well. The kind I had was too tight, and I was playing with it trying to make it work and considering running to a nearby Office Depot, when I was offered a schematic to help guide me.

Exhaust cutoff schematic

But prior to emptying local stationery stores' rubber band supplies, I tried something else - pieces I cut off from the old pipe. Had to trim them a bit more to fit them over the new pipe, but that worked quite well in the end.

Using chunks of old pipe

Starting the hacksaw at this shallow an angle is... annoying? Is that the right description?

Starting a cut

I suck at hacksawing.

Ugly cut

Ugly edge

My punishment? 30 minutes of grinding.

Finished edge.

And so, I am back to where I have started with this little project. My supply of rags is large, and my soap came in a 5 gallon pail (okay, okay, I do have some old stock is all :) ).

But, on the other hand, I think this is the Hump. It's when in a project, there are no more unknowns. You now just have to finish doing everything you've started.